From patchwork Tue Feb 4 06:00:35 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958622 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0126213AA38; Tue, 4 Feb 2025 06:03:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649002; cv=none; b=P0dmINhXmU5Bry3P9ffh1buwYlHbj40xQUVQmB2E4f+TIm1fFMZo/QzI/Fl62MoEcna4L4TLyZ96L5LKIMXIjG8lyguasPLYBzsLJLUOrgzWgB/1XUnd+MwZbxa6kZxEemZicBFzdxYVJOR7zgYAnJiNqdiPYwglhelZ0YKC56c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649002; c=relaxed/simple; bh=W8STe/9/37E571aJXYqJ1vZp8uSORVtWj9PdSXQl0eI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SDX/jN7RfmjshG9WQRKqaTfVG24YVcfJ8DPpNiXhf5K7e8Z9UEGgSY2JX7fZGbLIaIe7HF0l19/eDbQNQtsO9LEDcRo+dVht1kFGaDW3s6e+ZUN8ZwetIBk52ruaOlmbjLinDoPWVQA1oXyGaPwN0lgUeACURoeyqC0OFE8mCEY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Au3ITdAs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Au3ITdAs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B677C4CEE3; Tue, 4 Feb 2025 06:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649001; bh=W8STe/9/37E571aJXYqJ1vZp8uSORVtWj9PdSXQl0eI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Au3ITdAsDDoCClwWgL75NnmdIJ5SzfMlq6YfI2rolP+t/dEp/KcqlKR2XfnxeOQGO t70lg0xI6VJgFAbFfzOqrPxooWoVyoBGnnsDyCPp1iUtNE9Oq0mfbIKfGfWe6YC4Fi /8mjRBQGtKGQ5pEKqjOrRmjt5USO+ugfDCEgiE6nj8cNuS8Aq+MZxYQn5o6eFRCOj9 +Ub349wWqiuYoDxJiO6j0vz9vJd25/SNxJcDon9o7iXqb1aT2blI/YdRh2BsXT+sZW SFlRKzu4pWJ5SI1JWjgec7n8/wcFpc+nF0hj2Kv+5+hNevrAAkd1eWyeBbbvhC0iuq lm6i2ei//PCWQ== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 1/7] blk-crypto: add basic hardware-wrapped key support Date: Mon, 3 Feb 2025 22:00:35 -0800 Message-ID: <20250204060041.409950-2-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers To prevent keys from being compromised if an attacker acquires read access to kernel memory, some inline encryption hardware can accept keys which are wrapped by a per-boot hardware-internal key. This avoids needing to keep the raw keys in kernel memory, without limiting the number of keys that can be used. Such hardware also supports deriving a "software secret" for cryptographic tasks that can't be handled by inline encryption; this is needed for fscrypt to work properly. To support this hardware, allow struct blk_crypto_key to represent a hardware-wrapped key as an alternative to a raw key, and make drivers set flags in struct blk_crypto_profile to indicate which types of keys they support. Also add the ->derive_sw_secret() low-level operation, which drivers supporting wrapped keys must implement. For more information, see the detailed documentation which this patch adds to Documentation/block/inline-encryption.rst. Signed-off-by: Eric Biggers --- Documentation/block/inline-encryption.rst | 219 +++++++++++++++++++++- block/blk-crypto-fallback.c | 7 +- block/blk-crypto-internal.h | 1 + block/blk-crypto-profile.c | 46 +++++ block/blk-crypto.c | 61 ++++-- drivers/md/dm-table.c | 1 + drivers/mmc/host/cqhci-crypto.c | 8 +- drivers/mmc/host/sdhci-msm.c | 3 +- drivers/ufs/core/ufshcd-crypto.c | 7 +- drivers/ufs/host/ufs-exynos.c | 3 +- drivers/ufs/host/ufs-qcom.c | 3 +- fs/crypto/inline_crypt.c | 4 +- include/linux/blk-crypto-profile.h | 20 ++ include/linux/blk-crypto.h | 72 ++++++- 14 files changed, 417 insertions(+), 38 deletions(-) diff --git a/Documentation/block/inline-encryption.rst b/Documentation/block/inline-encryption.rst index 90b733422ed46..f03bd5b090d89 100644 --- a/Documentation/block/inline-encryption.rst +++ b/Documentation/block/inline-encryption.rst @@ -75,14 +75,14 @@ Constraints and notes Basic design ============ We introduce ``struct blk_crypto_key`` to represent an inline encryption key and -how it will be used. This includes the actual bytes of the key; the size of the -key; the algorithm and data unit size the key will be used with; and the number -of bytes needed to represent the maximum data unit number the key will be used -with. +how it will be used. This includes the type of the key (raw or +hardware-wrapped); the actual bytes of the key; the size of the key; the +algorithm and data unit size the key will be used with; and the number of bytes +needed to represent the maximum data unit number the key will be used with. We introduce ``struct bio_crypt_ctx`` to represent an encryption context. It contains a data unit number and a pointer to a blk_crypto_key. We add pointers to a bio_crypt_ctx to ``struct bio`` and ``struct request``; this allows users of the block layer (e.g. filesystems) to provide an encryption context when @@ -299,5 +299,216 @@ and disallow the combination for now. Whenever a device supports integrity, the kernel will pretend that the device does not support hardware inline encryption (by setting the blk_crypto_profile in the request_queue of the device to NULL). When the crypto API fallback is enabled, this means that all bios with and encryption context will use the fallback, and IO will complete as usual. When the fallback is disabled, a bio with an encryption context will be failed. + +.. _hardware_wrapped_keys: + +Hardware-wrapped keys +===================== + +Motivation and threat model +--------------------------- + +Linux storage encryption (dm-crypt, fscrypt, eCryptfs, etc.) traditionally +relies on the raw encryption key(s) being present in kernel memory so that the +encryption can be performed. This traditionally isn't seen as a problem because +the key(s) won't be present during an offline attack, which is the main type of +attack that storage encryption is intended to protect from. + +However, there is an increasing desire to also protect users' data from other +types of attacks (to the extent possible), including: + +- Cold boot attacks, where an attacker with physical access to a system suddenly + powers it off, then immediately dumps the system memory to extract recently + in-use encryption keys, then uses these keys to decrypt user data on-disk. + +- Online attacks where the attacker is able to read kernel memory without fully + compromising the system, followed by an offline attack where any extracted + keys can be used to decrypt user data on-disk. An example of such an online + attack would be if the attacker is able to run some code on the system that + exploits a Meltdown-like vulnerability but is unable to escalate privileges. + +- Online attacks where the attacker fully compromises the system, but their data + exfiltration is significantly time-limited and/or bandwidth-limited, so in + order to completely exfiltrate the data they need to extract the encryption + keys to use in a later offline attack. + +Hardware-wrapped keys are a feature of inline encryption hardware that is +designed to protect users' data from the above attacks (to the extent possible), +without introducing limitations such as a maximum number of keys. + +Note that it is impossible to **fully** protect users' data from these attacks. +Even in the attacks where the attacker "just" gets read access to kernel memory, +they can still extract any user data that is present in memory, including +plaintext pagecache pages of encrypted files. The focus here is just on +protecting the encryption keys, as those instantly give access to **all** user +data in any following offline attack, rather than just some of it (where which +data is included in that "some" might not be controlled by the attacker). + +Solution overview +----------------- + +Inline encryption hardware typically has "keyslots" into which software can +program keys for the hardware to use; the contents of keyslots typically can't +be read back by software. As such, the above security goals could be achieved +if the kernel simply erased its copy of the key(s) after programming them into +keyslot(s) and thereafter only referred to them via keyslot number. + +However, that naive approach runs into a couple problems: + +- It limits the number of unlocked keys to the number of keyslots, which + typically is a small number. In cases where there is only one encryption key + system-wide (e.g., a full-disk encryption key), that can be tolerable. + However, in general there can be many logged-in users with many different + keys, and/or many running applications with application-specific encrypted + storage areas. This is especially true if file-based encryption (e.g. + fscrypt) is being used. + +- Inline crypto engines typically lose the contents of their keyslots if the + storage controller (usually UFS or eMMC) is reset. Resetting the storage + controller is a standard error recovery procedure that is executed if certain + types of storage errors occur, and such errors can occur at any time. + Therefore, when inline crypto is being used, the operating system must always + be ready to reprogram the keyslots without user intervention. + +Thus, it is important for the kernel to still have a way to "remind" the +hardware about a key, without actually having the raw key itself. + +Somewhat less importantly, it is also desirable that the raw keys are never +visible to software at all, even while being initially unlocked. This would +ensure that a read-only compromise of system memory will never allow a key to be +extracted to be used off-system, even if it occurs when a key is being unlocked. + +To solve all these problems, some vendors of inline encryption hardware have +made their hardware support *hardware-wrapped keys*. Hardware-wrapped keys +are encrypted keys that can only be unwrapped (decrypted) and used by hardware +-- either by the inline encryption hardware itself, or by a dedicated hardware +block that can directly provision keys to the inline encryption hardware. + +(We refer to them as "hardware-wrapped keys" rather than simply "wrapped keys" +to add some clarity in cases where there could be other types of wrapped keys, +such as in file-based encryption. Key wrapping is a commonly used technique.) + +The key which wraps (encrypts) hardware-wrapped keys is a hardware-internal key +that is never exposed to software; it is either a persistent key (a "long-term +wrapping key") or a per-boot key (an "ephemeral wrapping key"). The long-term +wrapped form of the key is what is initially unlocked, but it is erased from +memory as soon as it is converted into an ephemerally-wrapped key. In-use +hardware-wrapped keys are always ephemerally-wrapped, not long-term wrapped. + +As inline encryption hardware can only be used to encrypt/decrypt data on-disk, +the hardware also includes a level of indirection; it doesn't use the unwrapped +key directly for inline encryption, but rather derives both an inline encryption +key and a "software secret" from it. Software can use the "software secret" for +tasks that can't use the inline encryption hardware, such as filenames +encryption. The software secret is not protected from memory compromise. + +Key hierarchy +------------- + +Here is the key hierarchy for a hardware-wrapped key:: + + Hardware-wrapped key + | + | + + | + ----------------------------- + | | + Inline encryption key Software secret + +The components are: + +- *Hardware-wrapped key*: a key for the hardware's KDF (Key Derivation + Function), in ephemerally-wrapped form. The key wrapping algorithm is a + hardware implementation detail that doesn't impact kernel operation, but a + strong authenticated encryption algorithm such as AES-256-GCM is recommended. + +- *Hardware KDF*: a KDF (Key Derivation Function) which the hardware uses to + derive subkeys after unwrapping the wrapped key. The hardware's choice of KDF + doesn't impact kernel operation, but it does need to be known for testing + purposes, and it's also assumed to have at least a 256-bit security strength. + All known hardware uses the SP800-108 KDF in Counter Mode with AES-256-CMAC, + with a particular choice of labels and contexts; new hardware should use this + already-vetted KDF. + +- *Inline encryption key*: a derived key which the hardware directly provisions + to a keyslot of the inline encryption hardware, without exposing it to + software. In all known hardware, this will always be an AES-256-XTS key. + However, in principle other encryption algorithms could be supported too. + Hardware must derive distinct subkeys for each supported encryption algorithm. + +- *Software secret*: a derived key which the hardware returns to software so + that software can use it for cryptographic tasks that can't use inline + encryption. This value is cryptographically isolated from the inline + encryption key, i.e. knowing one doesn't reveal the other. (The KDF ensures + this.) Currently, the software secret is always 32 bytes and thus is suitable + for cryptographic applications that require up to a 256-bit security strength. + Some use cases (e.g. full-disk encryption) won't require the software secret. + +Example: in the case of fscrypt, the fscrypt master key (the key that protects a +particular set of encrypted directories) is made hardware-wrapped. The inline +encryption key is used as the file contents encryption key, while the software +secret (rather than the master key directly) is used to key fscrypt's KDF +(HKDF-SHA512) to derive other subkeys such as filenames encryption keys. + +Note that currently this design assumes a single inline encryption key per +hardware-wrapped key, without any further key derivation. Thus, in the case of +fscrypt, currently hardware-wrapped keys are only compatible with the "inline +encryption optimized" settings, which use one file contents encryption key per +encryption policy rather than one per file. This design could be extended to +make the hardware derive per-file keys using per-file nonces passed down the +storage stack, and in fact some hardware already supports this; future work is +planned to remove this limitation by adding the corresponding kernel support. + +Kernel support +-------------- + +The inline encryption support of the kernel's block layer ("blk-crypto") has +been extended to support hardware-wrapped keys as an alternative to raw keys, +when hardware support is available. This works in the following way: + +- A ``key_types_supported`` field is added to the crypto capabilities in + ``struct blk_crypto_profile``. This allows device drivers to declare that + they support raw keys, hardware-wrapped keys, or both. + +- ``struct blk_crypto_key`` can now contain a hardware-wrapped key as an + alternative to a raw key; a ``key_type`` field is added to + ``struct blk_crypto_config`` to distinguish between the different key types. + This allows users of blk-crypto to en/decrypt data using a hardware-wrapped + key in a way very similar to using a raw key. + +- A new method ``blk_crypto_ll_ops::derive_sw_secret`` is added. Device drivers + that support hardware-wrapped keys must implement this method. Users of + blk-crypto can call ``blk_crypto_derive_sw_secret()`` to access this method. + +- The programming and eviction of hardware-wrapped keys happens via + ``blk_crypto_ll_ops::keyslot_program`` and + ``blk_crypto_ll_ops::keyslot_evict``, just like it does for raw keys. If a + driver supports hardware-wrapped keys, then it must handle hardware-wrapped + keys being passed to these methods. + +blk-crypto-fallback doesn't support hardware-wrapped keys. Therefore, +hardware-wrapped keys can only be used with actual inline encryption hardware. + +Testability +----------- + +Both the hardware KDF and the inline encryption itself are well-defined +algorithms that don't depend on any secrets other than the unwrapped key. +Therefore, if the unwrapped key is known to software, these algorithms can be +reproduced in software in order to verify the ciphertext that is written to disk +by the inline encryption hardware. + +However, the unwrapped key will only be known to software for testing if the +"import" functionality is used. Proper testing is not possible in the +"generate" case where the hardware generates the key itself. The correct +operation of the "generate" mode thus relies on the security and correctness of +the hardware RNG and its use to generate the key, as well as the testing of the +"import" mode as that should cover all parts other than the key generation. + +For an example of a test that verifies the ciphertext written to disk in the +"import" mode, see the fscrypt hardware-wrapped key tests in xfstests, or +`Android's vts_kernel_encryption_test +`_. diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c index 29a205482617c..f154be0b575ad 100644 --- a/block/blk-crypto-fallback.c +++ b/block/blk-crypto-fallback.c @@ -85,11 +85,11 @@ static struct bio_set crypto_bio_split; /* * This is the key we set when evicting a keyslot. This *should* be the all 0's * key, but AES-XTS rejects that key, so we use some random bytes instead. */ -static u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE]; +static u8 blank_key[BLK_CRYPTO_MAX_RAW_KEY_SIZE]; static void blk_crypto_fallback_evict_keyslot(unsigned int slot) { struct blk_crypto_fallback_keyslot *slotp = &blk_crypto_keyslots[slot]; enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode; @@ -117,11 +117,11 @@ blk_crypto_fallback_keyslot_program(struct blk_crypto_profile *profile, if (crypto_mode != slotp->crypto_mode && slotp->crypto_mode != BLK_ENCRYPTION_MODE_INVALID) blk_crypto_fallback_evict_keyslot(slot); slotp->crypto_mode = crypto_mode; - err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key->raw, + err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key->bytes, key->size); if (err) { blk_crypto_fallback_evict_keyslot(slot); return err; } @@ -537,11 +537,11 @@ static int blk_crypto_fallback_init(void) int err; if (blk_crypto_fallback_inited) return 0; - get_random_bytes(blank_key, BLK_CRYPTO_MAX_KEY_SIZE); + get_random_bytes(blank_key, sizeof(blank_key)); err = bioset_init(&crypto_bio_split, 64, 0, 0); if (err) goto out; @@ -559,10 +559,11 @@ static int blk_crypto_fallback_init(void) goto fail_free_profile; err = -ENOMEM; blk_crypto_fallback_profile->ll_ops = blk_crypto_fallback_ll_ops; blk_crypto_fallback_profile->max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE; + blk_crypto_fallback_profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; /* All blk-crypto modes have a crypto API fallback. */ for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) blk_crypto_fallback_profile->modes_supported[i] = 0xFFFFFFFF; blk_crypto_fallback_profile->modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0; diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h index 93a141979694b..1893df9a8f06c 100644 --- a/block/blk-crypto-internal.h +++ b/block/blk-crypto-internal.h @@ -12,10 +12,11 @@ /* Represents a crypto mode supported by blk-crypto */ struct blk_crypto_mode { const char *name; /* name of this mode, shown in sysfs */ const char *cipher_str; /* crypto API name (for fallback case) */ unsigned int keysize; /* key size in bytes */ + unsigned int security_strength; /* security strength in bytes */ unsigned int ivsize; /* iv size in bytes */ }; extern const struct blk_crypto_mode blk_crypto_modes[]; diff --git a/block/blk-crypto-profile.c b/block/blk-crypto-profile.c index 7fabc883e39f1..a990d9026c837 100644 --- a/block/blk-crypto-profile.c +++ b/block/blk-crypto-profile.c @@ -350,10 +350,12 @@ bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile, return false; if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size)) return false; if (profile->max_dun_bytes_supported < cfg->dun_bytes) return false; + if (!(profile->key_types_supported & cfg->key_type)) + return false; return true; } /* * This is an internal function that evicts a key from an inline encryption @@ -460,10 +462,48 @@ bool blk_crypto_register(struct blk_crypto_profile *profile, q->crypto_profile = profile; return true; } EXPORT_SYMBOL_GPL(blk_crypto_register); +/** + * blk_crypto_derive_sw_secret() - Derive software secret from wrapped key + * @bdev: a block device that supports hardware-wrapped keys + * @eph_key: a hardware-wrapped key in ephemerally-wrapped form + * @eph_key_size: size of @eph_key in bytes + * @sw_secret: (output) the software secret + * + * Given a hardware-wrapped key in ephemerally-wrapped form (the same form that + * it is used for I/O), ask the hardware to derive the secret which software can + * use for cryptographic tasks other than inline encryption. This secret is + * guaranteed to be cryptographically isolated from the inline encryption key, + * i.e. derived with a different KDF context. + * + * Return: 0 on success, -EOPNOTSUPP if the block device doesn't support + * hardware-wrapped keys, -EBADMSG if the key isn't a valid + * ephemerally-wrapped key, or another -errno code. + */ +int blk_crypto_derive_sw_secret(struct block_device *bdev, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + struct blk_crypto_profile *profile = + bdev_get_queue(bdev)->crypto_profile; + int err; + + if (!profile) + return -EOPNOTSUPP; + if (!(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) + return -EOPNOTSUPP; + if (!profile->ll_ops.derive_sw_secret) + return -EOPNOTSUPP; + blk_crypto_hw_enter(profile); + err = profile->ll_ops.derive_sw_secret(profile, eph_key, eph_key_size, + sw_secret); + blk_crypto_hw_exit(profile); + return err; +} + /** * blk_crypto_intersect_capabilities() - restrict supported crypto capabilities * by child device * @parent: the crypto profile for the parent device * @child: the crypto profile for the child device, or NULL @@ -483,14 +523,16 @@ void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent, parent->max_dun_bytes_supported = min(parent->max_dun_bytes_supported, child->max_dun_bytes_supported); for (i = 0; i < ARRAY_SIZE(child->modes_supported); i++) parent->modes_supported[i] &= child->modes_supported[i]; + parent->key_types_supported &= child->key_types_supported; } else { parent->max_dun_bytes_supported = 0; memset(parent->modes_supported, 0, sizeof(parent->modes_supported)); + parent->key_types_supported = 0; } } EXPORT_SYMBOL_GPL(blk_crypto_intersect_capabilities); /** @@ -519,10 +561,13 @@ bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target, if (reference->max_dun_bytes_supported > target->max_dun_bytes_supported) return false; + if (reference->key_types_supported & ~target->key_types_supported) + return false; + return true; } EXPORT_SYMBOL_GPL(blk_crypto_has_capabilities); /** @@ -553,7 +598,8 @@ void blk_crypto_update_capabilities(struct blk_crypto_profile *dst, { memcpy(dst->modes_supported, src->modes_supported, sizeof(dst->modes_supported)); dst->max_dun_bytes_supported = src->max_dun_bytes_supported; + dst->key_types_supported = src->key_types_supported; } EXPORT_SYMBOL_GPL(blk_crypto_update_capabilities); diff --git a/block/blk-crypto.c b/block/blk-crypto.c index 4d760b092deb9..72975a980fbca 100644 --- a/block/blk-crypto.c +++ b/block/blk-crypto.c @@ -21,28 +21,32 @@ const struct blk_crypto_mode blk_crypto_modes[] = { [BLK_ENCRYPTION_MODE_AES_256_XTS] = { .name = "AES-256-XTS", .cipher_str = "xts(aes)", .keysize = 64, + .security_strength = 32, .ivsize = 16, }, [BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV] = { .name = "AES-128-CBC-ESSIV", .cipher_str = "essiv(cbc(aes),sha256)", .keysize = 16, + .security_strength = 16, .ivsize = 16, }, [BLK_ENCRYPTION_MODE_ADIANTUM] = { .name = "Adiantum", .cipher_str = "adiantum(xchacha12,aes)", .keysize = 32, + .security_strength = 32, .ivsize = 32, }, [BLK_ENCRYPTION_MODE_SM4_XTS] = { .name = "SM4-XTS", .cipher_str = "xts(sm4)", .keysize = 32, + .security_strength = 16, .ivsize = 16, }, }; /* @@ -74,13 +78,19 @@ static int __init bio_crypt_ctx_init(void) goto out_no_mem; /* This is assumed in various places. */ BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0); - /* Sanity check that no algorithm exceeds the defined limits. */ + /* + * Validate the crypto mode properties. This ideally would be done with + * static assertions, but boot-time checks are the next best thing. + */ for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) { - BUG_ON(blk_crypto_modes[i].keysize > BLK_CRYPTO_MAX_KEY_SIZE); + BUG_ON(blk_crypto_modes[i].keysize > + BLK_CRYPTO_MAX_RAW_KEY_SIZE); + BUG_ON(blk_crypto_modes[i].security_strength > + blk_crypto_modes[i].keysize); BUG_ON(blk_crypto_modes[i].ivsize > BLK_CRYPTO_MAX_IV_SIZE); } return 0; out_no_mem: @@ -313,21 +323,24 @@ int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio, } /** * blk_crypto_init_key() - Prepare a key for use with blk-crypto * @blk_key: Pointer to the blk_crypto_key to initialize. - * @raw_key: Pointer to the raw key. Must be the correct length for the chosen - * @crypto_mode; see blk_crypto_modes[]. + * @key_bytes: the bytes of the key + * @key_size: size of the key in bytes + * @key_type: type of the key -- either raw or hardware-wrapped * @crypto_mode: identifier for the encryption algorithm to use * @dun_bytes: number of bytes that will be used to specify the DUN when this * key is used * @data_unit_size: the data unit size to use for en/decryption * * Return: 0 on success, -errno on failure. The caller is responsible for - * zeroizing both blk_key and raw_key when done with them. + * zeroizing both blk_key and key_bytes when done with them. */ -int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key, +int blk_crypto_init_key(struct blk_crypto_key *blk_key, + const u8 *key_bytes, size_t key_size, + enum blk_crypto_key_type key_type, enum blk_crypto_mode_num crypto_mode, unsigned int dun_bytes, unsigned int data_unit_size) { const struct blk_crypto_mode *mode; @@ -336,25 +349,37 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key, if (crypto_mode >= ARRAY_SIZE(blk_crypto_modes)) return -EINVAL; mode = &blk_crypto_modes[crypto_mode]; - if (mode->keysize == 0) + switch (key_type) { + case BLK_CRYPTO_KEY_TYPE_RAW: + if (key_size != mode->keysize) + return -EINVAL; + break; + case BLK_CRYPTO_KEY_TYPE_HW_WRAPPED: + if (key_size < mode->security_strength || + key_size > BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE) + return -EINVAL; + break; + default: return -EINVAL; + } if (dun_bytes == 0 || dun_bytes > mode->ivsize) return -EINVAL; if (!is_power_of_2(data_unit_size)) return -EINVAL; blk_key->crypto_cfg.crypto_mode = crypto_mode; blk_key->crypto_cfg.dun_bytes = dun_bytes; blk_key->crypto_cfg.data_unit_size = data_unit_size; + blk_key->crypto_cfg.key_type = key_type; blk_key->data_unit_size_bits = ilog2(data_unit_size); - blk_key->size = mode->keysize; - memcpy(blk_key->raw, raw_key, mode->keysize); + blk_key->size = key_size; + memcpy(blk_key->bytes, key_bytes, key_size); return 0; } bool blk_crypto_config_supported_natively(struct block_device *bdev, @@ -370,12 +395,14 @@ bool blk_crypto_config_supported_natively(struct block_device *bdev, * blk-crypto-fallback is enabled and supports the cfg). */ bool blk_crypto_config_supported(struct block_device *bdev, const struct blk_crypto_config *cfg) { - return IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) || - blk_crypto_config_supported_natively(bdev, cfg); + if (IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) && + cfg->key_type == BLK_CRYPTO_KEY_TYPE_RAW) + return true; + return blk_crypto_config_supported_natively(bdev, cfg); } /** * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device * @bdev: block device to operate on @@ -385,19 +412,25 @@ bool blk_crypto_config_supported(struct block_device *bdev, * supports the key's crypto settings, or the crypto API fallback has transforms * for the needed mode allocated and ready to go. This function may allocate * an skcipher, and *should not* be called from the data path, since that might * cause a deadlock * - * Return: 0 on success; -ENOPKG if the hardware doesn't support the key and - * blk-crypto-fallback is either disabled or the needed algorithm - * is disabled in the crypto API; or another -errno code. + * Return: 0 on success; -EOPNOTSUPP if the key is wrapped but the hardware does + * not support wrapped keys; -ENOPKG if the key is a raw key but the + * hardware does not support raw keys and blk-crypto-fallback is either + * disabled or the needed algorithm is disabled in the crypto API; or + * another -errno code if something else went wrong. */ int blk_crypto_start_using_key(struct block_device *bdev, const struct blk_crypto_key *key) { if (blk_crypto_config_supported_natively(bdev, &key->crypto_cfg)) return 0; + if (key->crypto_cfg.key_type != BLK_CRYPTO_KEY_TYPE_RAW) { + pr_warn_ratelimited("%pg: no support for wrapped keys\n", bdev); + return -EOPNOTSUPP; + } return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode); } /** * blk_crypto_evict_key() - Evict a blk_crypto_key from a block_device diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 0ef5203387b26..bf9a61191e9a2 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1248,10 +1248,11 @@ static int dm_table_construct_crypto_profile(struct dm_table *t) blk_crypto_profile_init(profile, 0); profile->ll_ops.keyslot_evict = dm_keyslot_evict; profile->max_dun_bytes_supported = UINT_MAX; memset(profile->modes_supported, 0xFF, sizeof(profile->modes_supported)); + profile->key_types_supported = ~0; for (i = 0; i < t->num_targets; i++) { struct dm_target *ti = dm_table_get_target(t, i); if (!dm_target_passes_crypto(ti->type)) { diff --git a/drivers/mmc/host/cqhci-crypto.c b/drivers/mmc/host/cqhci-crypto.c index cb80440934022..5a467098a0d6c 100644 --- a/drivers/mmc/host/cqhci-crypto.c +++ b/drivers/mmc/host/cqhci-crypto.c @@ -82,15 +82,15 @@ static int cqhci_crypto_keyslot_program(struct blk_crypto_profile *profile, cfg.crypto_cap_idx = cap_idx; cfg.config_enable = CQHCI_CRYPTO_CONFIGURATION_ENABLE; if (ccap_array[cap_idx].algorithm_id == CQHCI_CRYPTO_ALG_AES_XTS) { /* In XTS mode, the blk_crypto_key's size is already doubled */ - memcpy(cfg.crypto_key, key->raw, key->size/2); + memcpy(cfg.crypto_key, key->bytes, key->size/2); memcpy(cfg.crypto_key + CQHCI_CRYPTO_KEY_MAX_SIZE/2, - key->raw + key->size/2, key->size/2); + key->bytes + key->size/2, key->size/2); } else { - memcpy(cfg.crypto_key, key->raw, key->size); + memcpy(cfg.crypto_key, key->bytes, key->size); } cqhci_crypto_program_key(cq_host, &cfg, slot); memzero_explicit(&cfg, sizeof(cfg)); @@ -202,10 +202,12 @@ int cqhci_crypto_init(struct cqhci_host *cq_host) profile->dev = dev; /* Unfortunately, CQHCI crypto only supports 32 DUN bits. */ profile->max_dun_bytes_supported = 4; + profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; + /* * Cache all the crypto capabilities and advertise the supported crypto * modes and data unit sizes to the block layer. */ for (cap_idx = 0; cap_idx < cq_host->crypto_capabilities.num_crypto_cap; diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index e3d39311fdc75..3c383bce4928f 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -1893,10 +1893,11 @@ static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host, if (err) return err; profile->ll_ops = sdhci_msm_crypto_ops; profile->max_dun_bytes_supported = 4; + profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; profile->dev = dev; /* * Currently this driver only supports AES-256-XTS. All known versions * of ICE support it, but to be safe make sure it is really declared in @@ -1966,11 +1967,11 @@ static int sdhci_msm_ice_keyslot_program(struct blk_crypto_profile *profile, return -EOPNOTSUPP; return qcom_ice_program_key(msm_host->ice, QCOM_ICE_CRYPTO_ALG_AES_XTS, QCOM_ICE_CRYPTO_KEY_SIZE_256, - key->raw, + key->bytes, key->crypto_cfg.data_unit_size / 512, slot); } static int sdhci_msm_ice_keyslot_evict(struct blk_crypto_profile *profile, diff --git a/drivers/ufs/core/ufshcd-crypto.c b/drivers/ufs/core/ufshcd-crypto.c index 694ff7578fc19..9e63a9d3cb7e2 100644 --- a/drivers/ufs/core/ufshcd-crypto.c +++ b/drivers/ufs/core/ufshcd-crypto.c @@ -70,15 +70,15 @@ static int ufshcd_crypto_keyslot_program(struct blk_crypto_profile *profile, cfg.crypto_cap_idx = cap_idx; cfg.config_enable = UFS_CRYPTO_CONFIGURATION_ENABLE; if (ccap_array[cap_idx].algorithm_id == UFS_CRYPTO_ALG_AES_XTS) { /* In XTS mode, the blk_crypto_key's size is already doubled */ - memcpy(cfg.crypto_key, key->raw, key->size/2); + memcpy(cfg.crypto_key, key->bytes, key->size/2); memcpy(cfg.crypto_key + UFS_CRYPTO_KEY_MAX_SIZE/2, - key->raw + key->size/2, key->size/2); + key->bytes + key->size/2, key->size/2); } else { - memcpy(cfg.crypto_key, key->raw, key->size); + memcpy(cfg.crypto_key, key->bytes, key->size); } ufshcd_program_key(hba, &cfg, slot); memzero_explicit(&cfg, sizeof(cfg)); @@ -183,10 +183,11 @@ int ufshcd_hba_init_crypto_capabilities(struct ufs_hba *hba) goto out; hba->crypto_profile.ll_ops = ufshcd_crypto_ops; /* UFS only supports 8 bytes for any DUN */ hba->crypto_profile.max_dun_bytes_supported = 8; + hba->crypto_profile.key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; hba->crypto_profile.dev = hba->dev; /* * Cache all the UFS crypto capabilities and advertise the supported * crypto modes and data unit sizes to the block layer. diff --git a/drivers/ufs/host/ufs-exynos.c b/drivers/ufs/host/ufs-exynos.c index 13dd5dfc03eb3..6a415d9bdc85a 100644 --- a/drivers/ufs/host/ufs-exynos.c +++ b/drivers/ufs/host/ufs-exynos.c @@ -1318,10 +1318,11 @@ static void exynos_ufs_fmp_init(struct ufs_hba *hba, struct exynos_ufs *ufs) dev_err(hba->dev, "Failed to initialize crypto profile: %d\n", err); return; } profile->max_dun_bytes_supported = AES_BLOCK_SIZE; + profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; profile->dev = hba->dev; profile->modes_supported[BLK_ENCRYPTION_MODE_AES_256_XTS] = DATA_UNIT_SIZE; /* Advertise crypto support to ufshcd-core. */ @@ -1364,11 +1365,11 @@ static inline __be64 fmp_key_word(const u8 *key, int j) static int exynos_ufs_fmp_fill_prdt(struct ufs_hba *hba, const struct bio_crypt_ctx *crypt_ctx, void *prdt, unsigned int num_segments) { struct fmp_sg_entry *fmp_prdt = prdt; - const u8 *enckey = crypt_ctx->bc_key->raw; + const u8 *enckey = crypt_ctx->bc_key->bytes; const u8 *twkey = enckey + AES_KEYSIZE_256; u64 dun_lo = crypt_ctx->bc_dun[0]; u64 dun_hi = crypt_ctx->bc_dun[1]; unsigned int i; diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c index 23b9f6efa0475..c3f0aa81ff983 100644 --- a/drivers/ufs/host/ufs-qcom.c +++ b/drivers/ufs/host/ufs-qcom.c @@ -145,10 +145,11 @@ static int ufs_qcom_ice_init(struct ufs_qcom_host *host) if (err) return err; profile->ll_ops = ufs_qcom_crypto_ops; profile->max_dun_bytes_supported = 8; + profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; profile->dev = dev; /* * Currently this driver only supports AES-256-XTS. All known versions * of ICE support it, but to be safe make sure it is really declared in @@ -200,11 +201,11 @@ static int ufs_qcom_ice_keyslot_program(struct blk_crypto_profile *profile, ufshcd_hold(hba); err = qcom_ice_program_key(host->ice, QCOM_ICE_CRYPTO_ALG_AES_XTS, QCOM_ICE_CRYPTO_KEY_SIZE_256, - key->raw, + key->bytes, key->crypto_cfg.data_unit_size / 512, slot); ufshcd_release(hba); return err; } diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 40de69860dcf9..7fa53d30aec30 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -128,10 +128,11 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) * crypto configuration that the file would use. */ crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode; crypto_cfg.data_unit_size = 1U << ci->ci_data_unit_bits; crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); + crypto_cfg.key_type = BLK_CRYPTO_KEY_TYPE_RAW; devs = fscrypt_get_devices(sb, &num_devs); if (IS_ERR(devs)) return PTR_ERR(devs); @@ -164,11 +165,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, blk_key = kmalloc(sizeof(*blk_key), GFP_KERNEL); if (!blk_key) return -ENOMEM; - err = blk_crypto_init_key(blk_key, raw_key, crypto_mode, + err = blk_crypto_init_key(blk_key, raw_key, ci->ci_mode->keysize, + BLK_CRYPTO_KEY_TYPE_RAW, crypto_mode, fscrypt_get_dun_bytes(ci), 1U << ci->ci_data_unit_bits); if (err) { fscrypt_err(inode, "error %d initializing blk-crypto key", err); goto fail; diff --git a/include/linux/blk-crypto-profile.h b/include/linux/blk-crypto-profile.h index 90ab33cb5d0ef..7764b4f7b45b9 100644 --- a/include/linux/blk-crypto-profile.h +++ b/include/linux/blk-crypto-profile.h @@ -55,10 +55,24 @@ struct blk_crypto_ll_ops { * Must return 0 on success, or -errno on failure. */ int (*keyslot_evict)(struct blk_crypto_profile *profile, const struct blk_crypto_key *key, unsigned int slot); + + /** + * @derive_sw_secret: Derive the software secret from a hardware-wrapped + * key in ephemerally-wrapped form. + * + * This only needs to be implemented if BLK_CRYPTO_KEY_TYPE_HW_WRAPPED + * is supported. + * + * Must return 0 on success, -EBADMSG if the key is invalid, or another + * -errno code on other errors. + */ + int (*derive_sw_secret)(struct blk_crypto_profile *profile, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); }; /** * struct blk_crypto_profile - inline encryption profile for a device * @@ -82,10 +96,16 @@ struct blk_crypto_profile { * specifying the data unit number (DUN). Specifically, the range of * supported DUNs is 0 through (1 << (8 * max_dun_bytes_supported)) - 1. */ unsigned int max_dun_bytes_supported; + /** + * @key_types_supported: A bitmask of the supported key types: + * BLK_CRYPTO_KEY_TYPE_RAW and/or BLK_CRYPTO_KEY_TYPE_HW_WRAPPED. + */ + unsigned int key_types_supported; + /** * @modes_supported: Array of bitmasks that specifies whether each * combination of crypto mode and data unit size is supported. * Specifically, the i'th bit of modes_supported[crypto_mode] is set if * crypto_mode can be used with a data unit size of (1 << i). Note that diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h index 5e5822c18ee41..81f932b3ea376 100644 --- a/include/linux/blk-crypto.h +++ b/include/linux/blk-crypto.h @@ -4,10 +4,11 @@ */ #ifndef __LINUX_BLK_CRYPTO_H #define __LINUX_BLK_CRYPTO_H +#include #include enum blk_crypto_mode_num { BLK_ENCRYPTION_MODE_INVALID, BLK_ENCRYPTION_MODE_AES_256_XTS, @@ -15,43 +16,94 @@ enum blk_crypto_mode_num { BLK_ENCRYPTION_MODE_ADIANTUM, BLK_ENCRYPTION_MODE_SM4_XTS, BLK_ENCRYPTION_MODE_MAX, }; -#define BLK_CRYPTO_MAX_KEY_SIZE 64 +/* + * Supported types of keys. Must be bitflags due to their use in + * blk_crypto_profile::key_types_supported. + */ +enum blk_crypto_key_type { + /* + * Raw keys (i.e. "software keys"). These keys are simply kept in raw, + * plaintext form in kernel memory. + */ + BLK_CRYPTO_KEY_TYPE_RAW = 0x1, + + /* + * Hardware-wrapped keys. These keys are only present in kernel memory + * in ephemerally-wrapped form, and they can only be unwrapped by + * dedicated hardware. For details, see the "Hardware-wrapped keys" + * section of Documentation/block/inline-encryption.rst. + */ + BLK_CRYPTO_KEY_TYPE_HW_WRAPPED = 0x2, +}; + +/* + * Currently the maximum raw key size is 64 bytes, as that is the key size of + * BLK_ENCRYPTION_MODE_AES_256_XTS which takes the longest key. + * + * The maximum hardware-wrapped key size depends on the hardware's key wrapping + * algorithm, which is a hardware implementation detail, so it isn't precisely + * specified. But currently 128 bytes is plenty in practice. Implementations + * are recommended to wrap a 32-byte key for the hardware KDF with AES-256-GCM, + * which should result in a size closer to 64 bytes than 128. + * + * Both of these values can trivially be increased if ever needed. + */ +#define BLK_CRYPTO_MAX_RAW_KEY_SIZE 64 +#define BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE 128 + +#define BLK_CRYPTO_MAX_ANY_KEY_SIZE \ + MAX(BLK_CRYPTO_MAX_RAW_KEY_SIZE, BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE) + +/* + * Size of the "software secret" which can be derived from a hardware-wrapped + * key. This is currently always 32 bytes. Note, the choice of 32 bytes + * assumes that the software secret is only used directly for algorithms that + * don't require more than a 256-bit key to get the desired security strength. + * If it were to be used e.g. directly as an AES-256-XTS key, then this would + * need to be increased (which is possible if hardware supports it, but care + * would need to be taken to avoid breaking users who need exactly 32 bytes). + */ +#define BLK_CRYPTO_SW_SECRET_SIZE 32 + /** * struct blk_crypto_config - an inline encryption key's crypto configuration * @crypto_mode: encryption algorithm this key is for * @data_unit_size: the data unit size for all encryption/decryptions with this * key. This is the size in bytes of each individual plaintext and * ciphertext. This is always a power of 2. It might be e.g. the * filesystem block size or the disk sector size. * @dun_bytes: the maximum number of bytes of DUN used when using this key + * @key_type: the type of this key -- either raw or hardware-wrapped */ struct blk_crypto_config { enum blk_crypto_mode_num crypto_mode; unsigned int data_unit_size; unsigned int dun_bytes; + enum blk_crypto_key_type key_type; }; /** * struct blk_crypto_key - an inline encryption key - * @crypto_cfg: the crypto configuration (like crypto_mode, key size) for this - * key + * @crypto_cfg: the crypto mode, data unit size, key type, and other + * characteristics of this key and how it will be used * @data_unit_size_bits: log2 of data_unit_size - * @size: size of this key in bytes (determined by @crypto_cfg.crypto_mode) - * @raw: the raw bytes of this key. Only the first @size bytes are used. + * @size: size of this key in bytes. The size of a raw key is fixed for a given + * crypto mode, but the size of a hardware-wrapped key can vary. + * @bytes: the bytes of this key. Only the first @size bytes are significant. * * A blk_crypto_key is immutable once created, and many bios can reference it at * the same time. It must not be freed until all bios using it have completed * and it has been evicted from all devices on which it may have been used. */ struct blk_crypto_key { struct blk_crypto_config crypto_cfg; unsigned int data_unit_size_bits; unsigned int size; - u8 raw[BLK_CRYPTO_MAX_KEY_SIZE]; + u8 bytes[BLK_CRYPTO_MAX_ANY_KEY_SIZE]; }; #define BLK_CRYPTO_MAX_IV_SIZE 32 #define BLK_CRYPTO_DUN_ARRAY_SIZE (BLK_CRYPTO_MAX_IV_SIZE / sizeof(u64)) @@ -85,11 +137,13 @@ void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key, bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc, unsigned int bytes, const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE]); -int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key, +int blk_crypto_init_key(struct blk_crypto_key *blk_key, + const u8 *key_bytes, size_t key_size, + enum blk_crypto_key_type key_type, enum blk_crypto_mode_num crypto_mode, unsigned int dun_bytes, unsigned int data_unit_size); int blk_crypto_start_using_key(struct block_device *bdev, @@ -101,10 +155,14 @@ void blk_crypto_evict_key(struct block_device *bdev, bool blk_crypto_config_supported_natively(struct block_device *bdev, const struct blk_crypto_config *cfg); bool blk_crypto_config_supported(struct block_device *bdev, const struct blk_crypto_config *cfg); +int blk_crypto_derive_sw_secret(struct block_device *bdev, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); + #else /* CONFIG_BLK_INLINE_ENCRYPTION */ static inline bool bio_has_crypt_ctx(struct bio *bio) { return false; From patchwork Tue Feb 4 06:00:36 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958623 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F967202C4D; Tue, 4 Feb 2025 06:03:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649002; cv=none; b=I6d2mBn18Teth+2TjAclw5h54bhcCdDnwKjvnchOZUY9UDavshSgrVr1U3zFXoUit1L55n6co8vHFBmyanBVQSAaEhcyMuAU9B4H2vC+ftTcD2ORUzp7f+y7NL/n/bleDFS72LuMF+M7v020U7SJZR11GpvOEU6a36HJfY7PWB8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649002; c=relaxed/simple; bh=2Tte54TUDVLcPYS9n+Sc9AyUCpGqQ1pGHhPEHfjRkOI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DsGRKShdAtt7iAdQqWntX7RJFy045bF0frShKotlODoE39ALZirLEqqOzEbfYIcuLS0H34hu+WXHTyRg1YAI7RgdR67vxnRaT13ObIfPEGeBhpSPl94G7O+kbIRwFjvFOqTI6FX5hbeRGzVTupBA9pGfSeQpKfbWsgt0EVTdnKY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jp8fqQ8F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jp8fqQ8F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A0C7C4CEE8; Tue, 4 Feb 2025 06:03:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649002; bh=2Tte54TUDVLcPYS9n+Sc9AyUCpGqQ1pGHhPEHfjRkOI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jp8fqQ8FsHEfV6Ao6eylUk2w3fi7DikzzRRBr1p7uoTR6T3YXnK2RW6/UH4h4Rq8q qz4Ph2hQ+E6mU5uyclE24g1+G2KuppgcOMcuDGtETNidTBs314jSaFf7rpxCcHhhHw XWI9OfgUbTjkefgM0ItBs+ueivJEM5x2lJHcTFtxgrrrvNWxUx9RramIWZqIOLZ2Q8 nkh2dyJPoZRiGpIwERnHbmbMBHdcmO7bc2UP+njuXdYHeCxfXK/ixYtElTMO8jqKtH 2f6wKwslDRkcr3jP6QkvUER1tBL78l5e7JtXs481a9KUFIpDza+GPn1kDq4gCpglUR jHKyg8Y2QdMQA== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 2/7] blk-crypto: show supported key types in sysfs Date: Mon, 3 Feb 2025 22:00:36 -0800 Message-ID: <20250204060041.409950-3-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers Add sysfs files that indicate which type(s) of keys are supported by the inline encryption hardware associated with a particular request queue: /sys/block/$disk/queue/crypto/hw_wrapped_keys /sys/block/$disk/queue/crypto/raw_keys Userspace can use the presence or absence of these files to decide what encyption settings to use. Don't use a single key_type file, as devices might support both key types at the same time. Signed-off-by: Eric Biggers --- Documentation/ABI/stable/sysfs-block | 20 ++++++++++++++++ block/blk-crypto-sysfs.c | 35 ++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block index 0cceb2badc836..890cde28bf90d 100644 --- a/Documentation/ABI/stable/sysfs-block +++ b/Documentation/ABI/stable/sysfs-block @@ -227,10 +227,21 @@ Description: subdirectory contains files which describe the inline encryption capabilities of the device. For more information about inline encryption, refer to Documentation/block/inline-encryption.rst. +What: /sys/block//queue/crypto/hw_wrapped_keys +Date: February 2025 +Contact: linux-block@vger.kernel.org +Description: + [RO] The presence of this file indicates that the device + supports hardware-wrapped inline encryption keys, i.e. key blobs + that can only be unwrapped and used by dedicated hardware. For + more information about hardware-wrapped inline encryption keys, + see Documentation/block/inline-encryption.rst. + + What: /sys/block//queue/crypto/max_dun_bits Date: February 2022 Contact: linux-block@vger.kernel.org Description: [RO] This file shows the maximum length, in bits, of data unit @@ -265,10 +276,19 @@ Contact: linux-block@vger.kernel.org Description: [RO] This file shows the number of keyslots the device has for use with inline encryption. +What: /sys/block//queue/crypto/raw_keys +Date: February 2025 +Contact: linux-block@vger.kernel.org +Description: + [RO] The presence of this file indicates that the device + supports raw inline encryption keys, i.e. keys that are managed + in raw, plaintext form in software. + + What: /sys/block//queue/dax Date: June 2016 Contact: linux-block@vger.kernel.org Description: [RO] This file indicates whether the device supports Direct diff --git a/block/blk-crypto-sysfs.c b/block/blk-crypto-sysfs.c index a304434489bac..e832f403f2002 100644 --- a/block/blk-crypto-sysfs.c +++ b/block/blk-crypto-sysfs.c @@ -29,10 +29,17 @@ static struct blk_crypto_profile *kobj_to_crypto_profile(struct kobject *kobj) static struct blk_crypto_attr *attr_to_crypto_attr(struct attribute *attr) { return container_of(attr, struct blk_crypto_attr, attr); } +static ssize_t hw_wrapped_keys_show(struct blk_crypto_profile *profile, + struct blk_crypto_attr *attr, char *page) +{ + /* Always show supported, since the file doesn't exist otherwise. */ + return sysfs_emit(page, "supported\n"); +} + static ssize_t max_dun_bits_show(struct blk_crypto_profile *profile, struct blk_crypto_attr *attr, char *page) { return sysfs_emit(page, "%u\n", 8 * profile->max_dun_bytes_supported); } @@ -41,24 +48,52 @@ static ssize_t num_keyslots_show(struct blk_crypto_profile *profile, struct blk_crypto_attr *attr, char *page) { return sysfs_emit(page, "%u\n", profile->num_slots); } +static ssize_t raw_keys_show(struct blk_crypto_profile *profile, + struct blk_crypto_attr *attr, char *page) +{ + /* Always show supported, since the file doesn't exist otherwise. */ + return sysfs_emit(page, "supported\n"); +} + #define BLK_CRYPTO_RO_ATTR(_name) \ static struct blk_crypto_attr _name##_attr = __ATTR_RO(_name) +BLK_CRYPTO_RO_ATTR(hw_wrapped_keys); BLK_CRYPTO_RO_ATTR(max_dun_bits); BLK_CRYPTO_RO_ATTR(num_keyslots); +BLK_CRYPTO_RO_ATTR(raw_keys); + +static umode_t blk_crypto_is_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + struct blk_crypto_profile *profile = kobj_to_crypto_profile(kobj); + struct blk_crypto_attr *a = attr_to_crypto_attr(attr); + + if (a == &hw_wrapped_keys_attr && + !(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) + return 0; + if (a == &raw_keys_attr && + !(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_RAW)) + return 0; + + return 0444; +} static struct attribute *blk_crypto_attrs[] = { + &hw_wrapped_keys_attr.attr, &max_dun_bits_attr.attr, &num_keyslots_attr.attr, + &raw_keys_attr.attr, NULL, }; static const struct attribute_group blk_crypto_attr_group = { .attrs = blk_crypto_attrs, + .is_visible = blk_crypto_is_visible, }; /* * The encryption mode attributes. To avoid hard-coding the list of encryption * modes, these are initialized at boot time by blk_crypto_sysfs_init(). From patchwork Tue Feb 4 06:00:37 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958624 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19A592045A8; Tue, 4 Feb 2025 06:03:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649003; cv=none; b=RjxBOQ7y0btq2cvCnPhE257gFjKE3DITqPQFOt1sOuLU/Jm0inXDJYiYlDeyEyKgXk7zVe90eqROXBA/BHw7QFbvntX49XXJqprvkBpcChBBwi+NnFPoOUHghpb7LsOmsIJdrpbtA+wG0jxNJ7wPOtDzSdtK6kCaJoQ/oujSa2o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649003; c=relaxed/simple; bh=Xuv/0u7szKfAAbXGFj6qZLAPpxoWh217briSJhoKzjs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sSGmDP3k170CbxawZj4QBBssOLfCVVHx+7/R9QNNfsOdPltwzfYAWned4DuK+gLZI0cpTewX4H374DHeetw2fNwFozir28BZ6MHdzubK8Dhzo7nSwe+m1XendrJlLABKfcXoNEbDQEkeVBtz/oe26SdnRiZdotlzDx8UuNIuZjs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CTDmU6Hd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CTDmU6Hd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BEA6C4CEE5; Tue, 4 Feb 2025 06:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649002; bh=Xuv/0u7szKfAAbXGFj6qZLAPpxoWh217briSJhoKzjs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CTDmU6HdMBeeOYeZseIrd2OMZjf9OkSaJeXXel8Lo0loCCDfi8q4hTGDSTH7fo1un 2FUnZ3Y/7hcaQcHmB5zznR7VTF4Nkx3qsWmbAqcuN69ynl4T3MoIjzEIlIEaYwPWgT FVWVoJxih57aw3a4kdPQjf3oI5208xNf9JbaxvJ49yiJ+/Qz8q4Ej3LJudgPQ3CvUY 97YK7ef27SdBJjzciTJJ4I7zA7Emt3d/WRrK3+FTfNe3VaKyyVoa16WYS2cUUqEUgP zkqEregjQd3g5hb/wfQtjKbN/x01VQmn0OVGdU7EjdEfOvMDFq6CkEfc9+itCO0sg/ S5jqx6rooeAbw== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 3/7] blk-crypto: add ioctls to create and prepare hardware-wrapped keys Date: Mon, 3 Feb 2025 22:00:37 -0800 Message-ID: <20250204060041.409950-4-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers Until this point, the kernel can use hardware-wrapped keys to do encryption if userspace provides one -- specifically a key in ephemerally-wrapped form. However, no generic way has been provided for userspace to get such a key in the first place. Getting such a key is a two-step process. First, the key needs to be imported from a raw key or generated by the hardware, producing a key in long-term wrapped form. This happens once in the whole lifetime of the key. Second, the long-term wrapped key needs to be converted into ephemerally-wrapped form. This happens each time the key is "unlocked". In Android, these operations are supported in a generic way through KeyMint, a userspace abstraction layer. However, that method is Android-specific and can't be used on other Linux systems, may rely on proprietary libraries, and also misleads people into supporting KeyMint features like rollback resistance that make sense for other KeyMint keys but don't make sense for hardware-wrapped inline encryption keys. Therefore, this patch provides a generic kernel interface for these operations by introducing new block device ioctls: - BLKCRYPTOIMPORTKEY: convert a raw key to long-term wrapped form. - BLKCRYPTOGENERATEKEY: have the hardware generate a new key, then return it in long-term wrapped form. - BLKCRYPTOPREPAREKEY: convert a key from long-term wrapped form to ephemerally-wrapped form. These ioctls are implemented using new operations in blk_crypto_ll_ops. Signed-off-by: Eric Biggers --- Documentation/block/inline-encryption.rst | 36 +++++ .../userspace-api/ioctl/ioctl-number.rst | 2 + block/blk-crypto-internal.h | 9 ++ block/blk-crypto-profile.c | 55 +++++++ block/blk-crypto.c | 143 ++++++++++++++++++ block/ioctl.c | 5 + include/linux/blk-crypto-profile.h | 53 +++++++ include/linux/blk-crypto.h | 1 + include/uapi/linux/blk-crypto.h | 44 ++++++ include/uapi/linux/fs.h | 6 +- 10 files changed, 350 insertions(+), 4 deletions(-) create mode 100644 include/uapi/linux/blk-crypto.h diff --git a/Documentation/block/inline-encryption.rst b/Documentation/block/inline-encryption.rst index f03bd5b090d89..6380e6ab492b0 100644 --- a/Documentation/block/inline-encryption.rst +++ b/Documentation/block/inline-encryption.rst @@ -490,10 +490,46 @@ when hardware support is available. This works in the following way: keys being passed to these methods. blk-crypto-fallback doesn't support hardware-wrapped keys. Therefore, hardware-wrapped keys can only be used with actual inline encryption hardware. +All the above deals with hardware-wrapped keys in ephemerally-wrapped form only. +To get such keys in the first place, new block device ioctls have been added to +provide a generic interface to creating and preparing such keys: + +- ``BLKCRYPTOIMPORTKEY`` converts a raw key to long-term wrapped form. It takes + in a pointer to a ``struct blk_crypto_import_key_arg``. The caller must set + ``raw_key_ptr`` and ``raw_key_size`` to the pointer and size (in bytes) of the + raw key to import. On success, ``BLKCRYPTOIMPORTKEY`` returns 0 and writes + the resulting long-term wrapped key blob to the buffer pointed to by + ``lt_key_ptr``, which is of maximum size ``lt_key_size``. It also updates + ``lt_key_size`` to be the actual size of the key. On failure, it returns -1 + and sets errno. An errno of ``EOPNOTSUPP`` indicates that the block device + does not support hardware-wrapped keys. An errno of ``EOVERFLOW`` indicates + that the output buffer did not have enough space for the key blob. + +- ``BLKCRYPTOGENERATEKEY`` is like ``BLKCRYPTOIMPORTKEY``, but it has the + hardware generate the key instead of importing one. It takes in a pointer to + a ``struct blk_crypto_generate_key_arg``. + +- ``BLKCRYPTOPREPAREKEY`` converts a key from long-term wrapped form to + ephemerally-wrapped form. It takes in a pointer to a ``struct + blk_crypto_prepare_key_arg``. The caller must set ``lt_key_ptr`` and + ``lt_key_size`` to the pointer and size (in bytes) of the long-term wrapped + key blob to convert. On success, ``BLKCRYPTOPREPAREKEY`` returns 0 and writes + the resulting ephemerally-wrapped key blob to the buffer pointed to by + ``eph_key_ptr``, which is of maximum size ``eph_key_size``. It also updates + ``eph_key_size`` to be the actual size of the key. On failure, it returns -1 + and sets errno. Errno values of ``EOPNOTSUPP`` and ``EOVERFLOW`` mean the + same as they do for ``BLKCRYPTOIMPORTKEY``. An errno of ``EBADMSG`` indicates + that the long-term wrapped key is invalid. + +Userspace needs to use either ``BLKCRYPTOIMPORTKEY`` or ``BLKCRYPTOGENERATEKEY`` +once to create a key, and then ``BLKCRYPTOPREPAREKEY`` each time the key is +unlocked and added to the kernel. Note that these ioctls have no relevance for +raw keys; they are only for hardware-wrapped keys. + Testability ----------- Both the hardware KDF and the inline encryption itself are well-defined algorithms that don't depend on any secrets other than the unwrapped key. diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst index 6d1465315df32..d448c010d307a 100644 --- a/Documentation/userspace-api/ioctl/ioctl-number.rst +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst @@ -83,10 +83,12 @@ Code Seq# Include File Comments 0x10 00-0F drivers/char/s390/vmcp.h 0x10 10-1F arch/s390/include/uapi/sclp_ctl.h 0x10 20-2F arch/s390/include/uapi/asm/hypfs.h 0x12 all linux/fs.h BLK* ioctls linux/blkpg.h + linux/blkzoned.h + linux/blk-crypto.h 0x15 all linux/fs.h FS_IOC_* ioctls 0x1b all InfiniBand Subsystem 0x20 all drivers/cdrom/cm206.h 0x22 all scsi/sg.h diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h index 1893df9a8f06c..ccf6dff6ff6be 100644 --- a/block/blk-crypto-internal.h +++ b/block/blk-crypto-internal.h @@ -81,10 +81,13 @@ int __blk_crypto_evict_key(struct blk_crypto_profile *profile, const struct blk_crypto_key *key); bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile, const struct blk_crypto_config *cfg); +int blk_crypto_ioctl(struct block_device *bdev, unsigned int cmd, + void __user *argp); + #else /* CONFIG_BLK_INLINE_ENCRYPTION */ static inline int blk_crypto_sysfs_register(struct gendisk *disk) { return 0; @@ -128,10 +131,16 @@ static inline bool blk_crypto_rq_is_encrypted(struct request *rq) static inline bool blk_crypto_rq_has_keyslot(struct request *rq) { return false; } +static inline int blk_crypto_ioctl(struct block_device *bdev, unsigned int cmd, + void __user *argp) +{ + return -ENOTTY; +} + #endif /* CONFIG_BLK_INLINE_ENCRYPTION */ void __bio_crypt_advance(struct bio *bio, unsigned int bytes); static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes) { diff --git a/block/blk-crypto-profile.c b/block/blk-crypto-profile.c index a990d9026c837..94a155912bf1c 100644 --- a/block/blk-crypto-profile.c +++ b/block/blk-crypto-profile.c @@ -500,10 +500,65 @@ int blk_crypto_derive_sw_secret(struct block_device *bdev, sw_secret); blk_crypto_hw_exit(profile); return err; } +int blk_crypto_import_key(struct blk_crypto_profile *profile, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int ret; + + if (!profile) + return -EOPNOTSUPP; + if (!(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) + return -EOPNOTSUPP; + if (!profile->ll_ops.import_key) + return -EOPNOTSUPP; + blk_crypto_hw_enter(profile); + ret = profile->ll_ops.import_key(profile, raw_key, raw_key_size, + lt_key); + blk_crypto_hw_exit(profile); + return ret; +} + +int blk_crypto_generate_key(struct blk_crypto_profile *profile, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int ret; + + if (!profile) + return -EOPNOTSUPP; + if (!(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) + return -EOPNOTSUPP; + if (!profile->ll_ops.generate_key) + return -EOPNOTSUPP; + blk_crypto_hw_enter(profile); + ret = profile->ll_ops.generate_key(profile, lt_key); + blk_crypto_hw_exit(profile); + return ret; +} + +int blk_crypto_prepare_key(struct blk_crypto_profile *profile, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int ret; + + if (!profile) + return -EOPNOTSUPP; + if (!(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) + return -EOPNOTSUPP; + if (!profile->ll_ops.prepare_key) + return -EOPNOTSUPP; + blk_crypto_hw_enter(profile); + ret = profile->ll_ops.prepare_key(profile, lt_key, lt_key_size, + eph_key); + blk_crypto_hw_exit(profile); + return ret; +} + /** * blk_crypto_intersect_capabilities() - restrict supported crypto capabilities * by child device * @parent: the crypto profile for the parent device * @child: the crypto profile for the child device, or NULL diff --git a/block/blk-crypto.c b/block/blk-crypto.c index 72975a980fbca..4b1ad84d1b5ab 100644 --- a/block/blk-crypto.c +++ b/block/blk-crypto.c @@ -467,5 +467,148 @@ void blk_crypto_evict_key(struct block_device *bdev, */ if (err) pr_warn_ratelimited("%pg: error %d evicting key\n", bdev, err); } EXPORT_SYMBOL_GPL(blk_crypto_evict_key); + +static int blk_crypto_ioctl_import_key(struct blk_crypto_profile *profile, + void __user *argp) +{ + struct blk_crypto_import_key_arg arg; + u8 raw_key[BLK_CRYPTO_MAX_RAW_KEY_SIZE]; + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]; + int ret; + + if (copy_from_user(&arg, argp, sizeof(arg))) + return -EFAULT; + + if (memchr_inv(arg.reserved, 0, sizeof(arg.reserved))) + return -EINVAL; + + if (arg.raw_key_size < 16 || arg.raw_key_size > sizeof(raw_key)) + return -EINVAL; + + if (copy_from_user(raw_key, u64_to_user_ptr(arg.raw_key_ptr), + arg.raw_key_size)) { + ret = -EFAULT; + goto out; + } + ret = blk_crypto_import_key(profile, raw_key, arg.raw_key_size, lt_key); + if (ret < 0) + goto out; + if (ret > arg.lt_key_size) { + ret = -EOVERFLOW; + goto out; + } + arg.lt_key_size = ret; + if (copy_to_user(u64_to_user_ptr(arg.lt_key_ptr), lt_key, + arg.lt_key_size) || + copy_to_user(argp, &arg, sizeof(arg))) { + ret = -EFAULT; + goto out; + } + ret = 0; + +out: + memzero_explicit(raw_key, sizeof(raw_key)); + memzero_explicit(lt_key, sizeof(lt_key)); + return ret; +} + +static int blk_crypto_ioctl_generate_key(struct blk_crypto_profile *profile, + void __user *argp) +{ + struct blk_crypto_generate_key_arg arg; + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]; + int ret; + + if (copy_from_user(&arg, argp, sizeof(arg))) + return -EFAULT; + + if (memchr_inv(arg.reserved, 0, sizeof(arg.reserved))) + return -EINVAL; + + ret = blk_crypto_generate_key(profile, lt_key); + if (ret < 0) + goto out; + if (ret > arg.lt_key_size) { + ret = -EOVERFLOW; + goto out; + } + arg.lt_key_size = ret; + if (copy_to_user(u64_to_user_ptr(arg.lt_key_ptr), lt_key, + arg.lt_key_size) || + copy_to_user(argp, &arg, sizeof(arg))) { + ret = -EFAULT; + goto out; + } + ret = 0; + +out: + memzero_explicit(lt_key, sizeof(lt_key)); + return ret; +} + +static int blk_crypto_ioctl_prepare_key(struct blk_crypto_profile *profile, + void __user *argp) +{ + struct blk_crypto_prepare_key_arg arg; + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]; + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]; + int ret; + + if (copy_from_user(&arg, argp, sizeof(arg))) + return -EFAULT; + + if (memchr_inv(arg.reserved, 0, sizeof(arg.reserved))) + return -EINVAL; + + if (arg.lt_key_size > sizeof(lt_key)) + return -EINVAL; + + if (copy_from_user(lt_key, u64_to_user_ptr(arg.lt_key_ptr), + arg.lt_key_size)) { + ret = -EFAULT; + goto out; + } + ret = blk_crypto_prepare_key(profile, lt_key, arg.lt_key_size, eph_key); + if (ret < 0) + goto out; + if (ret > arg.eph_key_size) { + ret = -EOVERFLOW; + goto out; + } + arg.eph_key_size = ret; + if (copy_to_user(u64_to_user_ptr(arg.eph_key_ptr), eph_key, + arg.eph_key_size) || + copy_to_user(argp, &arg, sizeof(arg))) { + ret = -EFAULT; + goto out; + } + ret = 0; + +out: + memzero_explicit(lt_key, sizeof(lt_key)); + memzero_explicit(eph_key, sizeof(eph_key)); + return ret; +} + +int blk_crypto_ioctl(struct block_device *bdev, unsigned int cmd, + void __user *argp) +{ + struct blk_crypto_profile *profile = + bdev_get_queue(bdev)->crypto_profile; + + if (!profile) + return -EOPNOTSUPP; + + switch (cmd) { + case BLKCRYPTOIMPORTKEY: + return blk_crypto_ioctl_import_key(profile, argp); + case BLKCRYPTOGENERATEKEY: + return blk_crypto_ioctl_generate_key(profile, argp); + case BLKCRYPTOPREPAREKEY: + return blk_crypto_ioctl_prepare_key(profile, argp); + default: + return -ENOTTY; + } +} diff --git a/block/ioctl.c b/block/ioctl.c index 6554b728bae6a..faa40f383e273 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -13,10 +13,11 @@ #include #include #include #include #include "blk.h" +#include "blk-crypto-internal.h" static int blkpg_do_ioctl(struct block_device *bdev, struct blkpg_partition __user *upart, int op) { struct gendisk *disk = bdev->bd_disk; @@ -618,10 +619,14 @@ static int blkdev_common_ioctl(struct block_device *bdev, blk_mode_t mode, mode | BLK_OPEN_STRICT_SCAN); case BLKTRACESTART: case BLKTRACESTOP: case BLKTRACETEARDOWN: return blk_trace_ioctl(bdev, cmd, argp); + case BLKCRYPTOIMPORTKEY: + case BLKCRYPTOGENERATEKEY: + case BLKCRYPTOPREPAREKEY: + return blk_crypto_ioctl(bdev, cmd, argp); case IOC_PR_REGISTER: return blkdev_pr_register(bdev, mode, argp); case IOC_PR_RESERVE: return blkdev_pr_reserve(bdev, mode, argp); case IOC_PR_RELEASE: diff --git a/include/linux/blk-crypto-profile.h b/include/linux/blk-crypto-profile.h index 7764b4f7b45b9..4f39e9cd75766 100644 --- a/include/linux/blk-crypto-profile.h +++ b/include/linux/blk-crypto-profile.h @@ -69,10 +69,52 @@ struct blk_crypto_ll_ops { * -errno code on other errors. */ int (*derive_sw_secret)(struct blk_crypto_profile *profile, const u8 *eph_key, size_t eph_key_size, u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); + + /** + * @import_key: Create a hardware-wrapped key by importing a raw key. + * + * This only needs to be implemented if BLK_CRYPTO_KEY_TYPE_HW_WRAPPED + * is supported. + * + * On success, must write the new key in long-term wrapped form to + * @lt_key and return its size in bytes. On failure, must return a + * -errno value. + */ + int (*import_key)(struct blk_crypto_profile *profile, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); + + /** + * @generate_key: Generate a hardware-wrapped key. + * + * This only needs to be implemented if BLK_CRYPTO_KEY_TYPE_HW_WRAPPED + * is supported. + * + * On success, must write the new key in long-term wrapped form to + * @lt_key and return its size in bytes. On failure, must return a + * -errno value. + */ + int (*generate_key)(struct blk_crypto_profile *profile, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); + + /** + * @prepare_key: Prepare a hardware-wrapped key to be used. + * + * Prepare a hardware-wrapped key to be used by converting it from + * long-term wrapped form to ephemerally-wrapped form. This only needs + * to be implemented if BLK_CRYPTO_KEY_TYPE_HW_WRAPPED is supported. + * + * On success, must write the key in ephemerally-wrapped form to + * @eph_key and return its size in bytes. On failure, must return + * -EBADMSG if the key is invalid, or another -errno on other error. + */ + int (*prepare_key)(struct blk_crypto_profile *profile, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); }; /** * struct blk_crypto_profile - inline encryption profile for a device * @@ -161,10 +203,21 @@ unsigned int blk_crypto_keyslot_index(struct blk_crypto_keyslot *slot); void blk_crypto_reprogram_all_keys(struct blk_crypto_profile *profile); void blk_crypto_profile_destroy(struct blk_crypto_profile *profile); +int blk_crypto_import_key(struct blk_crypto_profile *profile, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); + +int blk_crypto_generate_key(struct blk_crypto_profile *profile, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); + +int blk_crypto_prepare_key(struct blk_crypto_profile *profile, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); + void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent, const struct blk_crypto_profile *child); bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target, const struct blk_crypto_profile *reference); diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h index 81f932b3ea376..58b0c5254a678 100644 --- a/include/linux/blk-crypto.h +++ b/include/linux/blk-crypto.h @@ -6,10 +6,11 @@ #ifndef __LINUX_BLK_CRYPTO_H #define __LINUX_BLK_CRYPTO_H #include #include +#include enum blk_crypto_mode_num { BLK_ENCRYPTION_MODE_INVALID, BLK_ENCRYPTION_MODE_AES_256_XTS, BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV, diff --git a/include/uapi/linux/blk-crypto.h b/include/uapi/linux/blk-crypto.h new file mode 100644 index 0000000000000..97302c6eb6afe --- /dev/null +++ b/include/uapi/linux/blk-crypto.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_LINUX_BLK_CRYPTO_H +#define _UAPI_LINUX_BLK_CRYPTO_H + +#include +#include + +struct blk_crypto_import_key_arg { + /* Raw key (input) */ + __u64 raw_key_ptr; + __u64 raw_key_size; + /* Long-term wrapped key blob (output) */ + __u64 lt_key_ptr; + __u64 lt_key_size; + __u64 reserved[4]; +}; + +struct blk_crypto_generate_key_arg { + /* Long-term wrapped key blob (output) */ + __u64 lt_key_ptr; + __u64 lt_key_size; + __u64 reserved[4]; +}; + +struct blk_crypto_prepare_key_arg { + /* Long-term wrapped key blob (input) */ + __u64 lt_key_ptr; + __u64 lt_key_size; + /* Ephemerally-wrapped key blob (output) */ + __u64 eph_key_ptr; + __u64 eph_key_size; + __u64 reserved[4]; +}; + +/* + * These ioctls share the block device ioctl space; see uapi/linux/fs.h. + * 140-141 are reserved for future blk-crypto ioctls; any more than that would + * require an additional allocation from the block device ioctl space. + */ +#define BLKCRYPTOIMPORTKEY _IOWR(0x12, 137, struct blk_crypto_import_key_arg) +#define BLKCRYPTOGENERATEKEY _IOWR(0x12, 138, struct blk_crypto_generate_key_arg) +#define BLKCRYPTOPREPAREKEY _IOWR(0x12, 139, struct blk_crypto_prepare_key_arg) + +#endif /* _UAPI_LINUX_BLK_CRYPTO_H */ diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 2bbe00cf12482..e762e1af650c4 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -210,14 +210,12 @@ struct fsxattr { #define BLKDISCARDZEROES _IO(0x12,124) #define BLKSECDISCARD _IO(0x12,125) #define BLKROTATIONAL _IO(0x12,126) #define BLKZEROOUT _IO(0x12,127) #define BLKGETDISKSEQ _IOR(0x12,128,__u64) -/* - * A jump here: 130-136 are reserved for zoned block devices - * (see uapi/linux/blkzoned.h) - */ +/* 130-136 are used by zoned block device ioctls (uapi/linux/blkzoned.h) */ +/* 137-141 are used by blk-crypto ioctls (uapi/linux/blk-crypto.h) */ #define BMAP_IOCTL 1 /* obsolete - kept for compatibility */ #define FIBMAP _IO(0x00,1) /* bmap access */ #define FIGETBSZ _IO(0x00,2) /* get the block size used for bmap */ #define FIFREEZE _IOWR('X', 119, int) /* Freeze */ From patchwork Tue Feb 4 06:00:38 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958625 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F32A204680; Tue, 4 Feb 2025 06:03:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649003; cv=none; b=OvpT95/wf1Ppl3znk59KvENailt31Yq9TB//OnH3KCg1/OtDlJVK4YF3yJEuEG/9KgWYuW7GPZM2inlO/NcVLi9uS2+nTvkGmf1kixX76+fzArzo2plx+xIZXPK8D07ELhERb7E30lyC67Qn49HIIAjklqKdwktKaEx3RtdpX70= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649003; c=relaxed/simple; bh=xhkna5FRtkwZktkg9SlhYA5EGF5UCj9juWxWAgULbic=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XYPvfNqs/iEVcaSJbdOHVx506ZkY+mYPdSdrWfHFnwIfkbrfSjAeydsdkPgqLcGtNMXUCvBKk6ToMtZK7VCBDg/QE9O3MIKZ43etCOM50CveVK8bkxKJ6D43KaCECEfVjag5JGbONOdmvv0REup5QmScQYbkhOinz3UTBDPDkWc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hlmeVxa3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hlmeVxa3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B433CC4CEF5; Tue, 4 Feb 2025 06:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649003; bh=xhkna5FRtkwZktkg9SlhYA5EGF5UCj9juWxWAgULbic=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hlmeVxa3c8fr/XD+HbH5aNpM1P7GYY7VLzzKInEPZlnd6/XX0MIPoDG0/cgLCvl1u 07gW21msrged9L7C8K9uYauLXA0V4UUylzCwbfAECm0m1gvgnKph50FqthMiW7Uiq7 x0OZsOcYUD6mJ4XY0j1Obw2ffBNM/KO4bzhRjC0kST8eNVJGysjk8iDHfoeyr8THPw F86aqSrvqpDVTE7VCq0D+AIyPIf+rPUUjwUXRHLfOeRuEFescQ+WkG8RdHki150qWz jOg0GcyNF/JD8YfrUJTye0QQKXMH1lwBKEPOnLbnXQgqew3ByGqHAyNZ1+BdeD0tbl xLylHU9UVf21g== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 4/7] fscrypt: add support for hardware-wrapped keys Date: Mon, 3 Feb 2025 22:00:38 -0800 Message-ID: <20250204060041.409950-5-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers Add support for hardware-wrapped keys to fscrypt. Such keys are protected from certain attacks, such as cold boot attacks. For more information, see the "Hardware-wrapped keys" section of Documentation/block/inline-encryption.rst. To support hardware-wrapped keys in fscrypt, we allow the fscrypt master keys to be hardware-wrapped. File contents encryption is done by passing the wrapped key to the inline encryption hardware via blk-crypto. Other fscrypt operations such as filenames encryption continue to be done by the kernel, using the "software secret" which the hardware derives. For more information, see the documentation which this patch adds to Documentation/filesystems/fscrypt.rst. Note that this feature doesn't require any filesystem-specific changes. However it does depend on inline encryption support, and thus currently it is only applicable to ext4 and f2fs. The version of this feature introduced by this patch is mostly equivalent to the version that has existed downstream in the Android kernels since 2020. However, a couple fixes are included. First, the flags field in struct fscrypt_add_key_arg is now placed in the proper location. Second, an option is now provided to derive key identifiers for HW-wrapped keys using a distinct HKDF context byte; this fixes a bug where a raw key could have the same identifier as a HW-wrapped key. This patch has been heavily rewritten from the original version by Gaurav Kashyap and Barani Muthukumaran . Signed-off-by: Eric Biggers --- Documentation/filesystems/fscrypt.rst | 200 ++++++++++++++++++++------ fs/crypto/fscrypt_private.h | 75 ++++++++-- fs/crypto/hkdf.c | 4 +- fs/crypto/inline_crypt.c | 44 +++++- fs/crypto/keyring.c | 157 ++++++++++++++------ fs/crypto/keysetup.c | 63 ++++++-- fs/crypto/keysetup_v1.c | 4 +- include/uapi/linux/fscrypt.h | 7 +- 8 files changed, 443 insertions(+), 111 deletions(-) diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst index 04eaab01314bc..4b855d45f5541 100644 --- a/Documentation/filesystems/fscrypt.rst +++ b/Documentation/filesystems/fscrypt.rst @@ -68,11 +68,11 @@ an authorized user later accessing the filesystem. Online attacks -------------- fscrypt (and storage encryption in general) can only provide limited -protection, if any at all, against online attacks. In detail: +protection against online attacks. In detail: Side-channel attacks ~~~~~~~~~~~~~~~~~~~~ fscrypt is only resistant to side-channel attacks, such as timing or @@ -97,20 +97,27 @@ system itself, is *not* protected by the mathematical properties of encryption but rather only by the correctness of the kernel. Therefore, any encryption-specific access control checks would merely be enforced by kernel *code* and therefore would be largely redundant with the wide variety of access control mechanisms already available.) -Kernel memory compromise -~~~~~~~~~~~~~~~~~~~~~~~~ +Read-only kernel memory compromise +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Unless `hardware-wrapped keys`_ are used, an attacker who gains the +ability to read from arbitrary kernel memory, e.g. by mounting a +physical attack or by exploiting a kernel security vulnerability, can +compromise all fscrypt keys that are currently in-use. This also +extends to cold boot attacks; if the system is suddenly powered off, +keys the system was using may remain in memory for a short time. -An attacker who compromises the system enough to read from arbitrary -memory, e.g. by mounting a physical attack or by exploiting a kernel -security vulnerability, can compromise all encryption keys that are -currently in use. +However, if hardware-wrapped keys are used, then the fscrypt master +keys and file contents encryption keys (but not other types of fscrypt +subkeys such as filenames encryption keys) are protected from +compromises of arbitrary kernel memory. -However, fscrypt allows encryption keys to be removed from the kernel, -which may protect them from later compromise. +In addition, fscrypt allows encryption keys to be removed from the +kernel, which may protect them from later compromise. In more detail, the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (or the FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl) can wipe a master encryption key from kernel memory. If it does so, it will also try to evict all cached inodes which had been "unlocked" using the key, @@ -143,10 +150,28 @@ However, these ioctls have some limitations: - Secret keys might still exist in CPU registers, in crypto accelerator hardware (if used by the crypto API to implement any of the algorithms), or in other places not explicitly considered here. +Full system compromise +~~~~~~~~~~~~~~~~~~~~~~ + +An attacker who gains "root" access and/or the ability to execute +arbitrary kernel code can freely exfiltrate data that is protected by +any in-use fscrypt keys. Thus, usually fscrypt provides no meaningful +protection in this scenario. (Data that is protected by a key that is +absent throughout the entire attack remains protected, modulo the +limitations of key removal mentioned above in the case where the key +was removed prior to the attack.) + +However, if `hardware-wrapped keys`_ are used, such attackers will be +unable to exfiltrate the master keys or file contents keys in a form +that will be usable after the system is powered off. This may be +useful if the attacker is significantly time-limited and/or +bandwidth-limited, so they can only exfiltrate some data and need to +rely on a later offline attack to exfiltrate the rest of it. + Limitations of v1 policies ~~~~~~~~~~~~~~~~~~~~~~~~~~ v1 encryption policies have some weaknesses with respect to online attacks: @@ -169,10 +194,14 @@ this reason among others, it is recommended to use v2 encryption policies on all new encrypted directories. Key hierarchy ============= +Note: this section assumes the use of raw keys rather than +hardware-wrapped keys. The use of hardware-wrapped keys modifies the +key hierarchy slightly. For details, see `Hardware-wrapped keys`_. + Master Keys ----------- Each encrypted directory tree is protected by a *master key*. Master keys can be up to 64 bytes long, and must be at least as long as the @@ -834,11 +863,14 @@ a pointer to struct fscrypt_add_key_arg, defined as follows:: struct fscrypt_add_key_arg { struct fscrypt_key_specifier key_spec; __u32 raw_size; __u32 key_id; - __u32 __reserved[8]; + #define FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 0x00000001 + #define FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1 0x00000002 + __u32 flags; + __u32 __reserved[7]; __u8 raw[]; }; #define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR 1 #define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER 2 @@ -853,11 +885,11 @@ a pointer to struct fscrypt_add_key_arg, defined as follows:: } u; }; struct fscrypt_provisioning_key_payload { __u32 type; - __u32 __reserved; + __u32 flags; __u8 raw[]; }; struct fscrypt_add_key_arg must be zeroed, then initialized as follows: @@ -881,28 +913,41 @@ as follows: - ``raw_size`` must be the size of the ``raw`` key provided, in bytes. Alternatively, if ``key_id`` is nonzero, this field must be 0, since in that case the size is implied by the specified Linux keyring key. -- ``key_id`` is 0 if the raw key is given directly in the ``raw`` - field. Otherwise ``key_id`` is the ID of a Linux keyring key of - type "fscrypt-provisioning" whose payload is - struct fscrypt_provisioning_key_payload whose ``raw`` field contains - the raw key and whose ``type`` field matches ``key_spec.type``. - Since ``raw`` is variable-length, the total size of this key's - payload must be ``sizeof(struct fscrypt_provisioning_key_payload)`` - plus the raw key size. The process must have Search permission on - this key. - - Most users should leave this 0 and specify the raw key directly. - The support for specifying a Linux keyring key is intended mainly to +- ``key_id`` is 0 if the key is given directly in the ``raw`` field. + Otherwise ``key_id`` is the ID of a Linux keyring key of type + "fscrypt-provisioning" whose payload is struct + fscrypt_provisioning_key_payload whose ``raw`` field contains the + key, whose ``type`` field matches ``key_spec.type``, and whose + ``flags`` field matches ``flags``. Since ``raw`` is + variable-length, the total size of this key's payload must be + ``sizeof(struct fscrypt_provisioning_key_payload)`` plus the number + of key bytes. The process must have Search permission on this key. + + Most users should leave this 0 and specify the key directly. The + support for specifying a Linux keyring key is intended mainly to allow re-adding keys after a filesystem is unmounted and re-mounted, - without having to store the raw keys in userspace memory. + without having to store the keys in userspace memory. + +- ``flags`` contains optional flags from ````: + + - FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0: Similar to + FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1 but selects an old on-disk + format. Prefer to use V1 on new directories. This flag can only be + used by privileged users. (V1 does not have that restriction.) + + - FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1: This denotes that the key is a + hardware-wrapped key. See `Hardware-wrapped keys`_. This flag + can't be used if FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR is used. - ``raw`` is a variable-length field which must contain the actual key, ``raw_size`` bytes long. Alternatively, if ``key_id`` is - nonzero, then this field is unused. + nonzero, then this field is unused. Note that despite being named + ``raw``, if one of the FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_* flags is + specified then it will contain a wrapped key, not a raw key. For v2 policy keys, the kernel keeps track of which user (identified by effective user ID) added the key, and only allows the key to be removed by that user --- or by "root", if they use `FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS`_. @@ -910,34 +955,38 @@ removed by that user --- or by "root", if they use However, if another user has added the key, it may be desirable to prevent that other user from unexpectedly removing it. Therefore, FS_IOC_ADD_ENCRYPTION_KEY may also be used to add a v2 policy key *again*, even if it's already added by other user(s). In this case, FS_IOC_ADD_ENCRYPTION_KEY will just install a claim to the key for the -current user, rather than actually add the key again (but the raw key -must still be provided, as a proof of knowledge). +current user, rather than actually add the key again (but the key must +still be provided, as a proof of knowledge). FS_IOC_ADD_ENCRYPTION_KEY returns 0 if either the key or a claim to the key was either added or already exists. FS_IOC_ADD_ENCRYPTION_KEY can fail with the following errors: -- ``EACCES``: FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR was specified, but the - caller does not have the CAP_SYS_ADMIN capability in the initial - user namespace; or the raw key was specified by Linux key ID but the - process lacks Search permission on the key. +- ``EACCES``: FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR or + FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 was specified, but the caller + does not have the CAP_SYS_ADMIN capability in the initial user + namespace; or the key was specified by Linux key ID but the process + lacks Search permission on the key. +- ``EBADMSG``: invalid hardware-wrapped key - ``EDQUOT``: the key quota for this user would be exceeded by adding the key - ``EINVAL``: invalid key size or key specifier type, or reserved bits were set -- ``EKEYREJECTED``: the raw key was specified by Linux key ID, but the - key has the wrong type -- ``ENOKEY``: the raw key was specified by Linux key ID, but no key - exists with that ID +- ``EKEYREJECTED``: the key was specified by Linux key ID, but the key + has the wrong type +- ``ENOKEY``: the key was specified by Linux key ID, but no key exists + with that ID - ``ENOTTY``: this type of filesystem does not implement encryption - ``EOPNOTSUPP``: the kernel was not configured with encryption support for this filesystem, or the filesystem superblock has not - had encryption enabled on it + had encryption enabled on it; or a hardware wrapped key was specified + but the filesystem does not support inline encryption or the hardware + does not support hardware-wrapped keys Legacy method ~~~~~~~~~~~~~ For v1 encryption policies, a master encryption key can also be @@ -996,13 +1045,12 @@ These two ioctls differ only in cases where v2 policy keys are added or removed by non-root users. These ioctls don't work on keys that were added via the legacy process-subscribed keyrings mechanism. -Before using these ioctls, read the `Kernel memory compromise`_ -section for a discussion of the security goals and limitations of -these ioctls. +Before using these ioctls, read the `Online attacks`_ section for a +discussion of the security goals and limitations of these ioctls. FS_IOC_REMOVE_ENCRYPTION_KEY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The FS_IOC_REMOVE_ENCRYPTION_KEY ioctl removes a claim to a master @@ -1318,19 +1366,89 @@ encryption when possible; it doesn't force its use. fscrypt will still fall back to using the kernel crypto API on files where the inline encryption hardware doesn't have the needed crypto capabilities (e.g. support for the needed encryption algorithm and data unit size) and where blk-crypto-fallback is unusable. (For blk-crypto-fallback to be usable, it must be enabled in the kernel configuration with -CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK=y.) +CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK=y, and the file must be +protected by a raw key rather than a hardware-wrapped key.) Currently fscrypt always uses the filesystem block size (which is usually 4096 bytes) as the data unit size. Therefore, it can only use inline encryption hardware that supports that data unit size. Inline encryption doesn't affect the ciphertext or other aspects of the on-disk format, so users may freely switch back and forth between -using "inlinecrypt" and not using "inlinecrypt". +using "inlinecrypt" and not using "inlinecrypt". An exception is that +files that are protected by a hardware-wrapped key can only be +encrypted/decrypted by the inline encryption hardware and therefore +can only be accessed when the "inlinecrypt" mount option is used. For +more information about hardware-wrapped keys, see below. + +Hardware-wrapped keys +--------------------- + +fscrypt supports using *hardware-wrapped keys* when the inline +encryption hardware supports it. Such keys are only present in kernel +memory in wrapped (encrypted) form; they can only be unwrapped +(decrypted) by the inline encryption hardware and are temporally bound +to the current boot. This prevents the keys from being compromised if +kernel memory is leaked. This is done without limiting the number of +keys that can be used and while still allowing the execution of +cryptographic tasks that are tied to the same key but can't use inline +encryption hardware, e.g. filenames encryption. + +Note that hardware-wrapped keys aren't specific to fscrypt; they are a +block layer feature (part of *blk-crypto*). For more details about +hardware-wrapped keys, see the block layer documentation at +:ref:`Documentation/block/inline-encryption.rst +`. The rest of this section just focuses on +the details of how fscrypt can use hardware-wrapped keys. + +fscrypt supports hardware-wrapped keys by allowing the fscrypt master +keys to be hardware-wrapped keys as an alternative to raw keys. To +add a hardware-wrapped key with `FS_IOC_ADD_ENCRYPTION_KEY`_, +userspace must specify one of the FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_* +flags in the ``flags`` field of struct fscrypt_add_key_arg and also in +the ``flags`` field of struct fscrypt_provisioning_key_payload when +applicable. The key must be in ephemerally-wrapped form, not +long-term wrapped form. + +Some limitations apply. First, files protected by a hardware-wrapped +key are tied to the system's inline encryption hardware. Therefore +they can only be accessed when the "inlinecrypt" mount option is used, +and they can't be included in portable filesystem images. Second, +currently the hardware-wrapped key support is only compatible with +`IV_INO_LBLK_64 policies`_ and `IV_INO_LBLK_32 policies`_, as it +assumes that there is just one file contents encryption key per +fscrypt master key rather than one per file. Future work may address +this limitation by passing per-file nonces down the storage stack to +allow the hardware to derive per-file keys. + +Implementation-wise, to encrypt/decrypt the contents of files that are +protected by a hardware-wrapped key, fscrypt uses blk-crypto, +attaching the hardware-wrapped key to the bio crypt contexts. As is +the case with raw keys, the block layer will program the key into a +keyslot when it isn't already in one. However, when programming a +hardware-wrapped key, the hardware doesn't program the given key +directly into a keyslot but rather unwraps it (using the hardware's +ephemeral wrapping key) and derives the inline encryption key from it. +The inline encryption key is the key that actually gets programmed +into a keyslot, and it is never exposed to software. + +However, fscrypt doesn't just do file contents encryption; it also +uses its master keys to derive filenames encryption keys, key +identifiers, and sometimes some more obscure types of subkeys such as +dirhash keys. So even with file contents encryption out of the +picture, fscrypt still needs a raw key to work with. To get such a +key from a hardware-wrapped key, fscrypt asks the inline encryption +hardware to derive a cryptographically isolated "software secret" from +the hardware-wrapped key. fscrypt uses this "software secret" to key +its KDF to derive all subkeys other than file contents keys. + +Note that this implies that the hardware-wrapped key feature only +protects the file contents encryption keys. It doesn't protect other +fscrypt subkeys such as filenames encryption keys. Direct I/O support ================== For direct I/O on an encrypted file to work, the following conditions diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 8371e4e1f596a..c1d92074b65c5 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -10,10 +10,11 @@ #ifndef _FSCRYPT_PRIVATE_H #define _FSCRYPT_PRIVATE_H #include +#include #include #include #include #define CONST_STRLEN(str) (sizeof(str) - 1) @@ -25,10 +26,27 @@ * if ciphers with a 256-bit security strength are used. This is just the * absolute minimum, which applies when only 128-bit encryption is used. */ #define FSCRYPT_MIN_KEY_SIZE 16 +/* Maximum size of a raw fscrypt master key */ +#define FSCRYPT_MAX_RAW_KEY_SIZE 64 + +/* Maximum size of a hardware-wrapped fscrypt master key */ +#define FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE + +/* Maximum size of an fscrypt master key across both key types */ +#define FSCRYPT_MAX_ANY_KEY_SIZE \ + MAX(FSCRYPT_MAX_RAW_KEY_SIZE, FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE) + +/* + * FSCRYPT_MAX_KEY_SIZE is defined in the UAPI header, but the addition of + * hardware-wrapped keys has made it misleading as it's only for raw keys. + * Don't use it in kernel code; use one of the above constants instead. + */ +#undef FSCRYPT_MAX_KEY_SIZE + #define FSCRYPT_CONTEXT_V1 1 #define FSCRYPT_CONTEXT_V2 2 /* Keep this in sync with include/uapi/linux/fscrypt.h */ #define FSCRYPT_MODE_MAX FSCRYPT_MODE_AES_256_HCTR2 @@ -358,41 +376,49 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, * the first byte of the HKDF application-specific info string to guarantee that * info strings are never repeated between contexts. This ensures that all HKDF * outputs are unique and cryptographically isolated, i.e. knowledge of one * output doesn't reveal another. */ -#define HKDF_CONTEXT_KEY_IDENTIFIER 1 /* info= */ +#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY 1 /* info= */ #define HKDF_CONTEXT_PER_FILE_ENC_KEY 2 /* info=file_nonce */ #define HKDF_CONTEXT_DIRECT_KEY 3 /* info=mode_num */ #define HKDF_CONTEXT_IV_INO_LBLK_64_KEY 4 /* info=mode_num||fs_uuid */ #define HKDF_CONTEXT_DIRHASH_KEY 5 /* info=file_nonce */ #define HKDF_CONTEXT_IV_INO_LBLK_32_KEY 6 /* info=mode_num||fs_uuid */ #define HKDF_CONTEXT_INODE_HASH_KEY 7 /* info= */ +#define HKDF_CONTEXT_KEY_IDENTIFIER_FOR_HW_WRAPPED_KEY \ + 8 /* info= */ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context, const u8 *info, unsigned int infolen, u8 *okm, unsigned int okmlen); void fscrypt_destroy_hkdf(struct fscrypt_hkdf *hkdf); /* inline_crypt.c */ #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT -int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci); +int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci, + bool is_hw_wrapped_key); static inline bool fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) { return ci->ci_inlinecrypt; } int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, - const u8 *raw_key, + const u8 *key_bytes, size_t key_size, + bool is_hw_wrapped, const struct fscrypt_inode_info *ci); void fscrypt_destroy_inline_crypt_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key); +int fscrypt_derive_sw_secret(struct super_block *sb, + const u8 *wrapped_key, size_t wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); + /* * Check whether the crypto transform or blk-crypto key has been allocated in * @prep_key, depending on which encryption implementation the file will use. */ static inline bool @@ -412,11 +438,12 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, return smp_load_acquire(&prep_key->tfm) != NULL; } #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ -static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) +static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci, + bool is_hw_wrapped_key) { return 0; } static inline bool @@ -425,11 +452,12 @@ fscrypt_using_inline_encryption(const struct fscrypt_inode_info *ci) return false; } static inline int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, - const u8 *raw_key, + const u8 *key_bytes, size_t key_size, + bool is_hw_wrapped, const struct fscrypt_inode_info *ci) { WARN_ON_ONCE(1); return -EOPNOTSUPP; } @@ -438,10 +466,19 @@ static inline void fscrypt_destroy_inline_crypt_key(struct super_block *sb, struct fscrypt_prepared_key *prep_key) { } +static inline int +fscrypt_derive_sw_secret(struct super_block *sb, + const u8 *wrapped_key, size_t wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + fscrypt_warn(NULL, "kernel doesn't support hardware-wrapped keys"); + return -EOPNOTSUPP; +} + static inline bool fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, const struct fscrypt_inode_info *ci) { return smp_load_acquire(&prep_key->tfm) != NULL; @@ -454,24 +491,42 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key, * fscrypt_master_key_secret - secret key material of an in-use master key */ struct fscrypt_master_key_secret { /* - * For v2 policy keys: HKDF context keyed by this master key. - * For v1 policy keys: not set (hkdf.hmac_tfm == NULL). + * The KDF with which subkeys of this key can be derived. + * + * For v1 policy keys, this isn't applicable and won't be set. + * Otherwise, this KDF will be keyed by this master key if + * ->is_hw_wrapped=false, or by the "software secret" that hardware + * derived from this master key if ->is_hw_wrapped=true. */ struct fscrypt_hkdf hkdf; /* - * Size of the raw key in bytes. This remains set even if ->raw was + * True if this key is a hardware-wrapped key; false if this key is a + * raw key (i.e. a "software key"). For v1 policy keys this will always + * be false, as v1 policy support is a legacy feature which doesn't + * support newer functionality such as hardware-wrapped keys. + */ + bool is_hw_wrapped; + + /* + * Size of the key in bytes. This remains set even if ->bytes was * zeroized due to no longer being needed. I.e. we still remember the * size of the key even if we don't need to remember the key itself. */ u32 size; - /* For v1 policy keys: the raw key. Wiped for v2 policy keys. */ - u8 raw[FSCRYPT_MAX_KEY_SIZE]; + /* + * The bytes of the key, when still needed. This can be either a raw + * key or a hardware-wrapped key, as indicated by ->is_hw_wrapped. In + * the case of a raw, v2 policy key, there is no need to remember the + * actual key separately from ->hkdf so this field will be zeroized as + * soon as ->hkdf is initialized. + */ + u8 bytes[FSCRYPT_MAX_ANY_KEY_SIZE]; } __randomize_layout; /* * fscrypt_master_key - an in-use master key diff --git a/fs/crypto/hkdf.c b/fs/crypto/hkdf.c index 5a384dad2c72f..7e007810e4346 100644 --- a/fs/crypto/hkdf.c +++ b/fs/crypto/hkdf.c @@ -2,11 +2,13 @@ /* * Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation * Function"), aka RFC 5869. See also the original paper (Krawczyk 2010): * "Cryptographic Extraction and Key Derivation: The HKDF Scheme". * - * This is used to derive keys from the fscrypt master keys. + * This is used to derive keys from the fscrypt master keys (or from the + * "software secrets" which hardware derives from the fscrypt master keys, in + * the case that the fscrypt master keys are hardware-wrapped keys). * * Copyright 2019 Google LLC */ #include diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 7fa53d30aec30..1d008c440cb69 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -87,11 +87,12 @@ static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode, } } } /* Enable inline encryption for this file if supported. */ -int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) +int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci, + bool is_hw_wrapped_key) { const struct inode *inode = ci->ci_inode; struct super_block *sb = inode->i_sb; struct blk_crypto_config crypto_cfg; struct block_device **devs; @@ -128,11 +129,12 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) * crypto configuration that the file would use. */ crypto_cfg.crypto_mode = ci->ci_mode->blk_crypto_mode; crypto_cfg.data_unit_size = 1U << ci->ci_data_unit_bits; crypto_cfg.dun_bytes = fscrypt_get_dun_bytes(ci); - crypto_cfg.key_type = BLK_CRYPTO_KEY_TYPE_RAW; + crypto_cfg.key_type = is_hw_wrapped_key ? + BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW; devs = fscrypt_get_devices(sb, &num_devs); if (IS_ERR(devs)) return PTR_ERR(devs); @@ -149,29 +151,31 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci) return 0; } int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key, - const u8 *raw_key, + const u8 *key_bytes, size_t key_size, + bool is_hw_wrapped, const struct fscrypt_inode_info *ci) { const struct inode *inode = ci->ci_inode; struct super_block *sb = inode->i_sb; enum blk_crypto_mode_num crypto_mode = ci->ci_mode->blk_crypto_mode; + enum blk_crypto_key_type key_type = is_hw_wrapped ? + BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW; struct blk_crypto_key *blk_key; struct block_device **devs; unsigned int num_devs; unsigned int i; int err; blk_key = kmalloc(sizeof(*blk_key), GFP_KERNEL); if (!blk_key) return -ENOMEM; - err = blk_crypto_init_key(blk_key, raw_key, ci->ci_mode->keysize, - BLK_CRYPTO_KEY_TYPE_RAW, crypto_mode, - fscrypt_get_dun_bytes(ci), + err = blk_crypto_init_key(blk_key, key_bytes, key_size, key_type, + crypto_mode, fscrypt_get_dun_bytes(ci), 1U << ci->ci_data_unit_bits); if (err) { fscrypt_err(inode, "error %d initializing blk-crypto key", err); goto fail; } @@ -226,10 +230,38 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb, kfree(devs); } kfree_sensitive(blk_key); } +/* + * Ask the inline encryption hardware to derive the software secret from a + * hardware-wrapped key. Returns -EOPNOTSUPP if hardware-wrapped keys aren't + * supported on this filesystem or hardware. + */ +int fscrypt_derive_sw_secret(struct super_block *sb, + const u8 *wrapped_key, size_t wrapped_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + int err; + + /* The filesystem must be mounted with -o inlinecrypt. */ + if (!(sb->s_flags & SB_INLINECRYPT)) { + fscrypt_warn(NULL, + "%s: filesystem not mounted with inlinecrypt\n", + sb->s_id); + return -EOPNOTSUPP; + } + + err = blk_crypto_derive_sw_secret(sb->s_bdev, wrapped_key, + wrapped_key_size, sw_secret); + if (err == -EOPNOTSUPP) + fscrypt_warn(NULL, + "%s: block device doesn't support hardware-wrapped keys\n", + sb->s_id); + return err; +} + bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) { return inode->i_crypt_info->ci_inlinecrypt; } EXPORT_SYMBOL_GPL(__fscrypt_inode_uses_inline_crypto); diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index 787e9c8938ba3..9c2f51b62ff2c 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -147,15 +147,15 @@ static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec) static int fscrypt_user_key_instantiate(struct key *key, struct key_preparsed_payload *prep) { /* - * We just charge FSCRYPT_MAX_KEY_SIZE bytes to the user's key quota for - * each key, regardless of the exact key size. The amount of memory + * We just charge FSCRYPT_MAX_RAW_KEY_SIZE bytes to the user's key quota + * for each key, regardless of the exact key size. The amount of memory * actually used is greater than the size of the raw key anyway. */ - return key_payload_reserve(key, FSCRYPT_MAX_KEY_SIZE); + return key_payload_reserve(key, FSCRYPT_MAX_RAW_KEY_SIZE); } static void fscrypt_user_key_describe(const struct key *key, struct seq_file *m) { seq_puts(m, key->description); @@ -551,50 +551,95 @@ static int do_add_master_key(struct super_block *sb, return err; } static int add_master_key(struct super_block *sb, struct fscrypt_master_key_secret *secret, - struct fscrypt_key_specifier *key_spec) + struct fscrypt_key_specifier *key_spec, u32 flags) { int err; if (key_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) { - err = fscrypt_init_hkdf(&secret->hkdf, secret->raw, - secret->size); - if (err) - return err; + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]; + u8 *kdf_key = secret->bytes; + unsigned int kdf_key_size = secret->size; + u8 keyid_kdf_ctx = HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY; /* - * Now that the HKDF context is initialized, the raw key is no - * longer needed. + * For raw keys, the fscrypt master key is used directly as the + * fscrypt KDF key. For hardware-wrapped keys, we have to pass + * the master key to the hardware to derive the KDF key, which + * is then only used to derive non-file-contents subkeys. + */ + if (secret->is_hw_wrapped) { + err = fscrypt_derive_sw_secret(sb, secret->bytes, + secret->size, sw_secret); + if (err) + return err; + kdf_key = sw_secret; + kdf_key_size = sizeof(sw_secret); + /* + * To avoid weird behavior if someone manages to + * determine sw_secret and add it as a raw key, ensure + * that hardware-wrapped keys and raw keys will have + * different key identifiers by deriving their key + * identifiers using different KDF contexts. + */ + if (!(flags & FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0)) + keyid_kdf_ctx = + HKDF_CONTEXT_KEY_IDENTIFIER_FOR_HW_WRAPPED_KEY; + } + err = fscrypt_init_hkdf(&secret->hkdf, kdf_key, kdf_key_size); + /* + * Now that the KDF context is initialized, the raw KDF key is + * no longer needed. */ - memzero_explicit(secret->raw, secret->size); + memzero_explicit(kdf_key, kdf_key_size); + if (err) + return err; /* Calculate the key identifier */ - err = fscrypt_hkdf_expand(&secret->hkdf, - HKDF_CONTEXT_KEY_IDENTIFIER, NULL, 0, + err = fscrypt_hkdf_expand(&secret->hkdf, keyid_kdf_ctx, NULL, 0, key_spec->u.identifier, FSCRYPT_KEY_IDENTIFIER_SIZE); if (err) return err; } return do_add_master_key(sb, secret, key_spec); } +/* + * Validate the size of an fscrypt master key being added. Note that this is + * just an initial check, as we don't know which ciphers will be used yet. + * There is a stricter size check later when the key is actually used by a file. + */ +static inline bool fscrypt_valid_key_size(size_t size, u32 add_key_flags) +{ + u32 max_size = (add_key_flags & (FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 | + FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1)) ? + FSCRYPT_MAX_HW_WRAPPED_KEY_SIZE : + FSCRYPT_MAX_RAW_KEY_SIZE; + + return size >= FSCRYPT_MIN_KEY_SIZE && size <= max_size; +} + static int fscrypt_provisioning_key_preparse(struct key_preparsed_payload *prep) { const struct fscrypt_provisioning_key_payload *payload = prep->data; - if (prep->datalen < sizeof(*payload) + FSCRYPT_MIN_KEY_SIZE || - prep->datalen > sizeof(*payload) + FSCRYPT_MAX_KEY_SIZE) + if (prep->datalen < sizeof(*payload)) + return -EINVAL; + + if (!fscrypt_valid_key_size(prep->datalen - sizeof(*payload), + payload->flags)) return -EINVAL; if (payload->type != FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR && payload->type != FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) return -EINVAL; - if (payload->__reserved) + if (payload->flags & ~(FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 | + FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1)) return -EINVAL; prep->payload.data[0] = kmemdup(payload, prep->datalen, GFP_KERNEL); if (!prep->payload.data[0]) return -ENOMEM; @@ -634,25 +679,25 @@ static struct key_type key_type_fscrypt_provisioning = { .describe = fscrypt_provisioning_key_describe, .destroy = fscrypt_provisioning_key_destroy, }; /* - * Retrieve the raw key from the Linux keyring key specified by 'key_id', and - * store it into 'secret'. + * Retrieve the key from the Linux keyring key specified by 'key_id', and store + * it into 'secret'. * - * The key must be of type "fscrypt-provisioning" and must have the field - * fscrypt_provisioning_key_payload::type set to 'type', indicating that it's - * only usable with fscrypt with the particular KDF version identified by - * 'type'. We don't use the "logon" key type because there's no way to - * completely restrict the use of such keys; they can be used by any kernel API - * that accepts "logon" keys and doesn't require a specific service prefix. + * The key must be of type "fscrypt-provisioning" and must have the 'type' and + * 'flags' field of the payload set to the given values, indicating that the key + * is intended for use for the specified purpose. We don't use the "logon" key + * type because there's no way to completely restrict the use of such keys; they + * can be used by any kernel API that accepts "logon" keys and doesn't require a + * specific service prefix. * * The ability to specify the key via Linux keyring key is intended for cases * where userspace needs to re-add keys after the filesystem is unmounted and - * re-mounted. Most users should just provide the raw key directly instead. + * re-mounted. Most users should just provide the key directly instead. */ -static int get_keyring_key(u32 key_id, u32 type, +static int get_keyring_key(u32 key_id, u32 type, u32 flags, struct fscrypt_master_key_secret *secret) { key_ref_t ref; struct key *key; const struct fscrypt_provisioning_key_payload *payload; @@ -665,16 +710,20 @@ static int get_keyring_key(u32 key_id, u32 type, if (key->type != &key_type_fscrypt_provisioning) goto bad_key; payload = key->payload.data[0]; - /* Don't allow fscrypt v1 keys to be used as v2 keys and vice versa. */ - if (payload->type != type) + /* + * Don't allow fscrypt v1 keys to be used as v2 keys and vice versa. + * Similarly, don't allow hardware-wrapped keys to be used as + * non-hardware-wrapped keys and vice versa. + */ + if (payload->type != type || payload->flags != flags) goto bad_key; secret->size = key->datalen - sizeof(*payload); - memcpy(secret->raw, payload->raw, secret->size); + memcpy(secret->bytes, payload->raw, secret->size); err = 0; goto out_put; bad_key: err = -EKEYREJECTED; @@ -732,27 +781,52 @@ int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg) if (arg.key_spec.type == FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR && !capable(CAP_SYS_ADMIN)) return -EACCES; memset(&secret, 0, sizeof(secret)); + + if (arg.flags) { + if (arg.flags & ~(FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 | + FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1)) + return -EINVAL; + if (arg.flags & FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0) { + if (arg.flags & FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1) + return -EINVAL; /* Ambiguous flags */ + /* + * HW_WRAPPED_V0 keys reuse the same HKDF context byte + * as raw keys when deriving the key identifier. This + * creates an ambiguity where a file encrypted by a + * HW-wrapped key can be unlocked with the wrong key by + * using a raw key. Strictly speaking this breaks the + * security model of the fscrypt keyring where different + * keys should have different identifiers. Thus + * technically HW_WRAPPED_V0 is only safe when keys are + * system-managed, so we require CAP_SYS_ADMIN for it. + */ + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + } + secret.is_hw_wrapped = true; + } + if (arg.key_id) { if (arg.raw_size != 0) return -EINVAL; - err = get_keyring_key(arg.key_id, arg.key_spec.type, &secret); + err = get_keyring_key(arg.key_id, arg.key_spec.type, arg.flags, + &secret); if (err) goto out_wipe_secret; } else { - if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE || - arg.raw_size > FSCRYPT_MAX_KEY_SIZE) + if (!fscrypt_valid_key_size(arg.raw_size, arg.flags)) return -EINVAL; secret.size = arg.raw_size; err = -EFAULT; - if (copy_from_user(secret.raw, uarg->raw, secret.size)) + if (copy_from_user(secret.bytes, uarg->raw, secret.size)) goto out_wipe_secret; } - err = add_master_key(sb, &secret, &arg.key_spec); + err = add_master_key(sb, &secret, &arg.key_spec, arg.flags); if (err) goto out_wipe_secret; /* Return the key identifier to userspace, if applicable */ err = -EFAULT; @@ -768,31 +842,32 @@ int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg) EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key); static void fscrypt_get_test_dummy_secret(struct fscrypt_master_key_secret *secret) { - static u8 test_key[FSCRYPT_MAX_KEY_SIZE]; + static u8 test_key[FSCRYPT_MAX_RAW_KEY_SIZE]; - get_random_once(test_key, FSCRYPT_MAX_KEY_SIZE); + get_random_once(test_key, sizeof(test_key)); memset(secret, 0, sizeof(*secret)); - secret->size = FSCRYPT_MAX_KEY_SIZE; - memcpy(secret->raw, test_key, FSCRYPT_MAX_KEY_SIZE); + secret->size = sizeof(test_key); + memcpy(secret->bytes, test_key, sizeof(test_key)); } int fscrypt_get_test_dummy_key_identifier( u8 key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE]) { struct fscrypt_master_key_secret secret; int err; fscrypt_get_test_dummy_secret(&secret); - err = fscrypt_init_hkdf(&secret.hkdf, secret.raw, secret.size); + err = fscrypt_init_hkdf(&secret.hkdf, secret.bytes, secret.size); if (err) goto out; - err = fscrypt_hkdf_expand(&secret.hkdf, HKDF_CONTEXT_KEY_IDENTIFIER, + err = fscrypt_hkdf_expand(&secret.hkdf, + HKDF_CONTEXT_KEY_IDENTIFIER_FOR_RAW_KEY, NULL, 0, key_identifier, FSCRYPT_KEY_IDENTIFIER_SIZE); out: wipe_master_key_secret(&secret); return err; @@ -815,11 +890,11 @@ int fscrypt_add_test_dummy_key(struct super_block *sb, { struct fscrypt_master_key_secret secret; int err; fscrypt_get_test_dummy_secret(&secret); - err = add_master_key(sb, &secret, key_spec); + err = add_master_key(sb, &secret, key_spec, 0); wipe_master_key_secret(&secret); return err; } /* diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index b4fe01ea4bd4c..0d71843af9469 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -151,11 +151,13 @@ int fscrypt_prepare_key(struct fscrypt_prepared_key *prep_key, const u8 *raw_key, const struct fscrypt_inode_info *ci) { struct crypto_skcipher *tfm; if (fscrypt_using_inline_encryption(ci)) - return fscrypt_prepare_inline_crypt_key(prep_key, raw_key, ci); + return fscrypt_prepare_inline_crypt_key(prep_key, raw_key, + ci->ci_mode->keysize, + false, ci); tfm = fscrypt_allocate_skcipher(ci->ci_mode, raw_key, ci->ci_inode); if (IS_ERR(tfm)) return PTR_ERR(tfm); /* @@ -193,18 +195,33 @@ static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci, const struct inode *inode = ci->ci_inode; const struct super_block *sb = inode->i_sb; struct fscrypt_mode *mode = ci->ci_mode; const u8 mode_num = mode - fscrypt_modes; struct fscrypt_prepared_key *prep_key; - u8 mode_key[FSCRYPT_MAX_KEY_SIZE]; + u8 mode_key[FSCRYPT_MAX_RAW_KEY_SIZE]; u8 hkdf_info[sizeof(mode_num) + sizeof(sb->s_uuid)]; unsigned int hkdf_infolen = 0; + bool use_hw_wrapped_key = false; int err; if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX)) return -EINVAL; + if (mk->mk_secret.is_hw_wrapped && S_ISREG(inode->i_mode)) { + /* Using a hardware-wrapped key for file contents encryption */ + if (!fscrypt_using_inline_encryption(ci)) { + if (sb->s_flags & SB_INLINECRYPT) + fscrypt_warn(ci->ci_inode, + "Hardware-wrapped key required, but no suitable inline encryption capabilities are available"); + else + fscrypt_warn(ci->ci_inode, + "Hardware-wrapped keys require inline encryption (-o inlinecrypt)"); + return -EINVAL; + } + use_hw_wrapped_key = true; + } + prep_key = &keys[mode_num]; if (fscrypt_is_key_prepared(prep_key, ci)) { ci->ci_enc_key = *prep_key; return 0; } @@ -212,10 +229,20 @@ static int setup_per_mode_enc_key(struct fscrypt_inode_info *ci, mutex_lock(&fscrypt_mode_key_setup_mutex); if (fscrypt_is_key_prepared(prep_key, ci)) goto done_unlock; + if (use_hw_wrapped_key) { + err = fscrypt_prepare_inline_crypt_key(prep_key, + mk->mk_secret.bytes, + mk->mk_secret.size, true, + ci); + if (err) + goto out_unlock; + goto done_unlock; + } + BUILD_BUG_ON(sizeof(mode_num) != 1); BUILD_BUG_ON(sizeof(sb->s_uuid) != 16); BUILD_BUG_ON(sizeof(hkdf_info) != 17); hkdf_info[hkdf_infolen++] = mode_num; if (include_fs_uuid) { @@ -334,10 +361,18 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci, struct fscrypt_master_key *mk, bool need_dirhash_key) { int err; + if (mk->mk_secret.is_hw_wrapped && + !(ci->ci_policy.v2.flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 | + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32))) { + fscrypt_warn(ci->ci_inode, + "Hardware-wrapped keys are only supported with IV_INO_LBLK policies"); + return -EINVAL; + } + if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) { /* * DIRECT_KEY: instead of deriving per-file encryption keys, the * per-file nonce will be included in all the IVs. But unlike * v1 policies, for v2 policies in this case we don't encrypt @@ -360,11 +395,11 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_inode_info *ci, true); } else if (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) { err = fscrypt_setup_iv_ino_lblk_32_key(ci, mk); } else { - u8 derived_key[FSCRYPT_MAX_KEY_SIZE]; + u8 derived_key[FSCRYPT_MAX_RAW_KEY_SIZE]; err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, HKDF_CONTEXT_PER_FILE_ENC_KEY, ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE, derived_key, ci->ci_mode->keysize); @@ -443,14 +478,10 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci, struct super_block *sb = ci->ci_inode->i_sb; struct fscrypt_key_specifier mk_spec; struct fscrypt_master_key *mk; int err; - err = fscrypt_select_encryption_impl(ci); - if (err) - return err; - err = fscrypt_policy_to_key_spec(&ci->ci_policy, &mk_spec); if (err) return err; mk = fscrypt_find_master_key(sb, &mk_spec); @@ -474,10 +505,14 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci, } if (unlikely(!mk)) { if (ci->ci_policy.version != FSCRYPT_POLICY_V1) return -ENOKEY; + err = fscrypt_select_encryption_impl(ci, false); + if (err) + return err; + /* * As a legacy fallback for v1 policies, search for the key in * the current task's subscribed keyrings too. Don't move this * to before the search of ->s_master_keys, since users * shouldn't be able to override filesystem-level keys. @@ -495,13 +530,25 @@ static int setup_file_encryption_key(struct fscrypt_inode_info *ci, if (!fscrypt_valid_master_key_size(mk, ci)) { err = -ENOKEY; goto out_release_key; } + err = fscrypt_select_encryption_impl(ci, mk->mk_secret.is_hw_wrapped); + if (err) + goto out_release_key; + switch (ci->ci_policy.version) { case FSCRYPT_POLICY_V1: - err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); + if (WARN_ON_ONCE(mk->mk_secret.is_hw_wrapped)) { + /* + * This should never happen, as adding a v1 policy key + * that is hardware-wrapped isn't allowed. + */ + err = -EINVAL; + goto out_release_key; + } + err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.bytes); break; case FSCRYPT_POLICY_V2: err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key); break; default: diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c index cf3b58ec32cce..b70521c55132b 100644 --- a/fs/crypto/keysetup_v1.c +++ b/fs/crypto/keysetup_v1.c @@ -116,11 +116,11 @@ find_and_lock_process_key(const char *prefix, goto invalid; payload = (const struct fscrypt_key *)ukp->data; if (ukp->datalen != sizeof(struct fscrypt_key) || - payload->size < 1 || payload->size > FSCRYPT_MAX_KEY_SIZE) { + payload->size < 1 || payload->size > sizeof(payload->raw)) { fscrypt_warn(NULL, "key with description '%s' has invalid payload", key->description); goto invalid; } @@ -147,11 +147,11 @@ struct fscrypt_direct_key { struct hlist_node dk_node; refcount_t dk_refcount; const struct fscrypt_mode *dk_mode; struct fscrypt_prepared_key dk_key; u8 dk_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; - u8 dk_raw[FSCRYPT_MAX_KEY_SIZE]; + u8 dk_raw[FSCRYPT_MAX_RAW_KEY_SIZE]; }; static void free_direct_key(struct fscrypt_direct_key *dk) { if (dk) { diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index 7a8f4c2901873..6246a190934a7 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -117,20 +117,23 @@ struct fscrypt_key_specifier { * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw. */ struct fscrypt_provisioning_key_payload { __u32 type; - __u32 __reserved; + __u32 flags; __u8 raw[]; }; /* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */ struct fscrypt_add_key_arg { struct fscrypt_key_specifier key_spec; __u32 raw_size; __u32 key_id; - __u32 __reserved[8]; +#define FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V0 0x00000001 +#define FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED_V1 0x00000002 + __u32 flags; + __u32 __reserved[7]; __u8 raw[]; }; /* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */ struct fscrypt_remove_key_arg { From patchwork Tue Feb 4 06:00:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958626 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 44856204F9F; Tue, 4 Feb 2025 06:03:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Tue, 4 Feb 2025 06:03:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649003; bh=NXVPjLWo3dqxqPJkwh7ZiCOKZ/h9ZiAuohKDgcahAlM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nhxtkFtxsr2pmCxjZ0anm+dc1LKqxK7aNvAgESlovjAWGob+WsmMupYQFvSE8EQyr kwy7Rj8IhqqiYPf48MtZWqrV63ibIdZXP2a7kNHLRVeXV7vV3MH5P7yy20sXCjFceA GofNCrn5druWRtwpf/qHT9BEFRLyVhgCQ85t0ujSfRJOTpGtb4NF7BOyl2pv4rpCTw id28XJEqIDJuekqlwS2wRNHv/h6rjJT0L5Ch7GuTwAg0SQLFP5QoTidVAFCVlyXV2U D9CGbBHwedv32+0xX/0qE5L8W7S88ojdbvV7aTPGIFNa6KZlUpi03eevc7QjPRQ8ww ufItTMN/Jj9nA== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 5/7] soc: qcom: ice: make qcom_ice_program_key() take struct blk_crypto_key Date: Mon, 3 Feb 2025 22:00:39 -0800 Message-ID: <20250204060041.409950-6-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers qcom_ice_program_key() currently accepts the key as an array of bytes, algorithm ID, key size enum, and data unit size. However both callers have a struct blk_crypto_key which contains all that information. Thus they both have similar code that converts the blk_crypto_key into the form that qcom_ice_program_key() wants. Once wrapped key support is added, the key type would need to be added to the arguments too. Therefore, this patch changes qcom_ice_program_key() to take in all this information as a struct blk_crypto_key directly. The calling code is updated accordingly. This ends up being much simpler, and it makes the key type be passed down automatically once wrapped key support is added. Based on a patch by Gaurav Kashyap that replaced the byte array argument only. This patch makes the blk_crypto_key replace other arguments like the algorithm ID too, ensuring that there remains only one source of truth. Signed-off-by: Eric Biggers --- drivers/mmc/host/sdhci-msm.c | 11 +---------- drivers/soc/qcom/ice.c | 23 ++++++++++++----------- drivers/ufs/host/ufs-qcom.c | 11 +---------- include/soc/qcom/ice.h | 22 +++------------------- 4 files changed, 17 insertions(+), 50 deletions(-) diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index 3c383bce4928f..2c926f566d053 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -1960,20 +1960,11 @@ static int sdhci_msm_ice_keyslot_program(struct blk_crypto_profile *profile, unsigned int slot) { struct sdhci_msm_host *msm_host = sdhci_msm_host_from_crypto_profile(profile); - /* Only AES-256-XTS has been tested so far. */ - if (key->crypto_cfg.crypto_mode != BLK_ENCRYPTION_MODE_AES_256_XTS) - return -EOPNOTSUPP; - - return qcom_ice_program_key(msm_host->ice, - QCOM_ICE_CRYPTO_ALG_AES_XTS, - QCOM_ICE_CRYPTO_KEY_SIZE_256, - key->bytes, - key->crypto_cfg.data_unit_size / 512, - slot); + return qcom_ice_program_key(msm_host->ice, slot, key); } static int sdhci_msm_ice_keyslot_evict(struct blk_crypto_profile *profile, const struct blk_crypto_key *key, unsigned int slot) diff --git a/drivers/soc/qcom/ice.c b/drivers/soc/qcom/ice.c index 393d2d1d275f1..78780fd508f0b 100644 --- a/drivers/soc/qcom/ice.c +++ b/drivers/soc/qcom/ice.c @@ -159,41 +159,42 @@ int qcom_ice_suspend(struct qcom_ice *ice) return 0; } EXPORT_SYMBOL_GPL(qcom_ice_suspend); -int qcom_ice_program_key(struct qcom_ice *ice, - u8 algorithm_id, u8 key_size, - const u8 crypto_key[], u8 data_unit_size, - int slot) +int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, + const struct blk_crypto_key *blk_key) { struct device *dev = ice->dev; union { u8 bytes[AES_256_XTS_KEY_SIZE]; u32 words[AES_256_XTS_KEY_SIZE / sizeof(u32)]; } key; int i; int err; /* Only AES-256-XTS has been tested so far. */ - if (algorithm_id != QCOM_ICE_CRYPTO_ALG_AES_XTS || - key_size != QCOM_ICE_CRYPTO_KEY_SIZE_256) { - dev_err_ratelimited(dev, - "Unhandled crypto capability; algorithm_id=%d, key_size=%d\n", - algorithm_id, key_size); + if (blk_key->crypto_cfg.crypto_mode != + BLK_ENCRYPTION_MODE_AES_256_XTS) { + dev_err_ratelimited(dev, "Unsupported crypto mode: %d\n", + blk_key->crypto_cfg.crypto_mode); return -EINVAL; } - memcpy(key.bytes, crypto_key, AES_256_XTS_KEY_SIZE); + if (blk_key->size != AES_256_XTS_KEY_SIZE) { + dev_err_ratelimited(dev, "Incorrect key size\n"); + return -EINVAL; + } + memcpy(key.bytes, blk_key->bytes, AES_256_XTS_KEY_SIZE); /* The SCM call requires that the key words are encoded in big endian */ for (i = 0; i < ARRAY_SIZE(key.words); i++) __cpu_to_be32s(&key.words[i]); err = qcom_scm_ice_set_key(slot, key.bytes, AES_256_XTS_KEY_SIZE, QCOM_SCM_ICE_CIPHER_AES_256_XTS, - data_unit_size); + blk_key->crypto_cfg.data_unit_size / 512); memzero_explicit(&key, sizeof(key)); return err; } diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c index c3f0aa81ff983..9330022e98eec 100644 --- a/drivers/ufs/host/ufs-qcom.c +++ b/drivers/ufs/host/ufs-qcom.c @@ -193,21 +193,12 @@ static int ufs_qcom_ice_keyslot_program(struct blk_crypto_profile *profile, { struct ufs_hba *hba = ufs_hba_from_crypto_profile(profile); struct ufs_qcom_host *host = ufshcd_get_variant(hba); int err; - /* Only AES-256-XTS has been tested so far. */ - if (key->crypto_cfg.crypto_mode != BLK_ENCRYPTION_MODE_AES_256_XTS) - return -EOPNOTSUPP; - ufshcd_hold(hba); - err = qcom_ice_program_key(host->ice, - QCOM_ICE_CRYPTO_ALG_AES_XTS, - QCOM_ICE_CRYPTO_KEY_SIZE_256, - key->bytes, - key->crypto_cfg.data_unit_size / 512, - slot); + err = qcom_ice_program_key(host->ice, slot, key); ufshcd_release(hba); return err; } static int ufs_qcom_ice_keyslot_evict(struct blk_crypto_profile *profile, diff --git a/include/soc/qcom/ice.h b/include/soc/qcom/ice.h index 5870a94599a25..4cecc7f088b4b 100644 --- a/include/soc/qcom/ice.h +++ b/include/soc/qcom/ice.h @@ -4,34 +4,18 @@ */ #ifndef __QCOM_ICE_H__ #define __QCOM_ICE_H__ +#include #include struct qcom_ice; -enum qcom_ice_crypto_key_size { - QCOM_ICE_CRYPTO_KEY_SIZE_INVALID = 0x0, - QCOM_ICE_CRYPTO_KEY_SIZE_128 = 0x1, - QCOM_ICE_CRYPTO_KEY_SIZE_192 = 0x2, - QCOM_ICE_CRYPTO_KEY_SIZE_256 = 0x3, - QCOM_ICE_CRYPTO_KEY_SIZE_512 = 0x4, -}; - -enum qcom_ice_crypto_alg { - QCOM_ICE_CRYPTO_ALG_AES_XTS = 0x0, - QCOM_ICE_CRYPTO_ALG_BITLOCKER_AES_CBC = 0x1, - QCOM_ICE_CRYPTO_ALG_AES_ECB = 0x2, - QCOM_ICE_CRYPTO_ALG_ESSIV_AES_CBC = 0x3, -}; - int qcom_ice_enable(struct qcom_ice *ice); int qcom_ice_resume(struct qcom_ice *ice); int qcom_ice_suspend(struct qcom_ice *ice); -int qcom_ice_program_key(struct qcom_ice *ice, - u8 algorithm_id, u8 key_size, - const u8 crypto_key[], u8 data_unit_size, - int slot); +int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, + const struct blk_crypto_key *blk_key); int qcom_ice_evict_key(struct qcom_ice *ice, int slot); struct qcom_ice *of_qcom_ice_get(struct device *dev); #endif /* __QCOM_ICE_H__ */ From patchwork Tue Feb 4 06:00:40 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958627 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8F68205E0B; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jx3LMcqn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4998C4CEE3; Tue, 4 Feb 2025 06:03:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649004; bh=S9oV8VPjoc9zz9574R5uYjcrBYnqmmVeoE+IqO+4MHE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Jx3LMcqnjRJqziYG/K4MvpLOLuuWlcXYpLckaE3WpEzYtzs/u4qVwUSZkYGLSNKUY XFhay7V+/IOnBDLi9858mEd06fEf/tZEzZzL5zGgGbFcAobW3dA6A2mOUGZ8FtxXLF ZzlveSalUWyzTWyWooc6i1Oc7ZdXXdvyaox8FfilyQuq0kh544M397d9L+fNOikRo7 p7aCaJy0IANfVN2j2n71K4sCHWMj8Yjd6VTgHHoxCJ0+foL8p7zUhksGIRGRc86ssi Fmybf/3qTjfUmwFKyuwL1h7vjBczaaJjDVTYYB6kYbkLfu3vwOeh9f5amGjysBSqzJ qCKVkHtaH/aNA== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov , Bartosz Golaszewski Subject: [PATCH v11 6/7] soc: qcom: ice: add HWKM support to the ICE driver Date: Mon, 3 Feb 2025 22:00:40 -0800 Message-ID: <20250204060041.409950-7-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Gaurav Kashyap Qualcomm's Inline Crypto Engine (ICE) version 3.2 and later includes a key management hardware block called the Hardware Key Manager (HWKM). Add support for HWKM to the ICE driver. HWKM provides hardware-wrapped key support where the ICE (storage) keys are not exposed to software and instead are protected in hardware. Later patches will wire up this feature to ufs-qcom and sdhci-msm using the support added in this patch. HWKM and legacy mode are currently mutually exclusive. The selection of which mode to use has to be made before the storage driver(s) registers any inline encryption capable disk(s) with the block layer (i.e., generally at boot time) so that the appropriate crypto capabilities can be advertised to upper layers. Therefore, make the ICE driver select HWKM mode when the all of the following are true: - The new module parameter qcom_ice.use_wrapped_keys=1 is specified. - HWKM is present and is at least v2, i.e. ICE is v3.2.1 or later. - The SCM calls needed to fully use HWKM are supported by TrustZone. Signed-off-by: Gaurav Kashyap Signed-off-by: Bartosz Golaszewski [EB: merged related patches; fixed the module parameter to work correctly; dropped unnecessary support for HWKM v1; fixed error handling; improved log messages, comments, and commit message; fixed naming; merged enable and init functions; and other cleanups] Co-developed-by: Eric Biggers Signed-off-by: Eric Biggers --- drivers/mmc/host/sdhci-msm.c | 5 + drivers/soc/qcom/ice.c | 326 +++++++++++++++++++++++++++++++++-- drivers/ufs/host/ufs-qcom.c | 5 + include/soc/qcom/ice.h | 12 ++ 4 files changed, 338 insertions(+), 10 deletions(-) diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index 2c926f566d053..2772e34490cc5 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -1880,10 +1880,15 @@ static int sdhci_msm_ice_init(struct sdhci_msm_host *msm_host, } if (IS_ERR_OR_NULL(ice)) return PTR_ERR_OR_ZERO(ice); + if (qcom_ice_get_supported_key_type(ice) != BLK_CRYPTO_KEY_TYPE_RAW) { + dev_warn(dev, "Wrapped keys not supported. Disabling inline encryption support.\n"); + return 0; + } + msm_host->ice = ice; /* Initialize the blk_crypto_profile */ caps.reg_val = cpu_to_le32(cqhci_readl(cq_host, CQHCI_CCAP)); diff --git a/drivers/soc/qcom/ice.c b/drivers/soc/qcom/ice.c index 78780fd508f0b..ba94a32554c70 100644 --- a/drivers/soc/qcom/ice.c +++ b/drivers/soc/qcom/ice.c @@ -18,36 +18,86 @@ #include #include -#define AES_256_XTS_KEY_SIZE 64 +#define AES_256_XTS_KEY_SIZE 64 /* for raw keys only */ +#define QCOM_ICE_HWKM_WRAPPED_KEY_SIZE 100 /* assuming HWKM v2 */ /* QCOM ICE registers */ + +#define QCOM_ICE_REG_CONTROL 0x0000 +#define QCOM_ICE_LEGACY_MODE_ENABLED BIT(0) + #define QCOM_ICE_REG_VERSION 0x0008 + #define QCOM_ICE_REG_FUSE_SETTING 0x0010 +#define QCOM_ICE_FUSE_SETTING_MASK BIT(0) +#define QCOM_ICE_FORCE_HW_KEY0_SETTING_MASK BIT(1) +#define QCOM_ICE_FORCE_HW_KEY1_SETTING_MASK BIT(2) + #define QCOM_ICE_REG_BIST_STATUS 0x0070 +#define QCOM_ICE_BIST_STATUS_MASK GENMASK(31, 28) + #define QCOM_ICE_REG_ADVANCED_CONTROL 0x1000 -/* BIST ("built-in self-test") status flags */ -#define QCOM_ICE_BIST_STATUS_MASK GENMASK(31, 28) +#define QCOM_ICE_REG_CRYPTOCFG_BASE 0x4040 +#define QCOM_ICE_REG_CRYPTOCFG_SIZE 0x80 +#define QCOM_ICE_REG_CRYPTOCFG(slot) (QCOM_ICE_REG_CRYPTOCFG_BASE + \ + QCOM_ICE_REG_CRYPTOCFG_SIZE * (slot)) +union crypto_cfg { + __le32 regval; + struct { + u8 dusize; + u8 capidx; + u8 reserved; +#define QCOM_ICE_HWKM_CFG_ENABLE_VAL BIT(7) + u8 cfge; + }; +}; + +/* QCOM ICE HWKM (Hardware Key Manager) registers */ + +#define HWKM_OFFSET 0x8000 + +#define QCOM_ICE_REG_HWKM_TZ_KM_CTL (HWKM_OFFSET + 0x1000) +#define QCOM_ICE_HWKM_DISABLE_CRC_CHECKS_VAL (BIT(1) | BIT(2)) -#define QCOM_ICE_FUSE_SETTING_MASK 0x1 -#define QCOM_ICE_FORCE_HW_KEY0_SETTING_MASK 0x2 -#define QCOM_ICE_FORCE_HW_KEY1_SETTING_MASK 0x4 +#define QCOM_ICE_REG_HWKM_TZ_KM_STATUS (HWKM_OFFSET + 0x1004) +#define QCOM_ICE_HWKM_KT_CLEAR_DONE BIT(0) +#define QCOM_ICE_HWKM_BOOT_CMD_LIST0_DONE BIT(1) +#define QCOM_ICE_HWKM_BOOT_CMD_LIST1_DONE BIT(2) +#define QCOM_ICE_HWKM_CRYPTO_BIST_DONE_V2 BIT(7) +#define QCOM_ICE_HWKM_BIST_DONE_V2 BIT(9) + +#define QCOM_ICE_REG_HWKM_BANK0_BANKN_IRQ_STATUS (HWKM_OFFSET + 0x2008) +#define QCOM_ICE_HWKM_RSP_FIFO_CLEAR_VAL BIT(3) + +#define QCOM_ICE_REG_HWKM_BANK0_BBAC_0 (HWKM_OFFSET + 0x5000) +#define QCOM_ICE_REG_HWKM_BANK0_BBAC_1 (HWKM_OFFSET + 0x5004) +#define QCOM_ICE_REG_HWKM_BANK0_BBAC_2 (HWKM_OFFSET + 0x5008) +#define QCOM_ICE_REG_HWKM_BANK0_BBAC_3 (HWKM_OFFSET + 0x500C) +#define QCOM_ICE_REG_HWKM_BANK0_BBAC_4 (HWKM_OFFSET + 0x5010) #define qcom_ice_writel(engine, val, reg) \ writel((val), (engine)->base + (reg)) #define qcom_ice_readl(engine, reg) \ readl((engine)->base + (reg)) +static bool qcom_ice_use_wrapped_keys; +module_param_named(use_wrapped_keys, qcom_ice_use_wrapped_keys, bool, 0660); +MODULE_PARM_DESC(use_wrapped_keys, + "Support wrapped keys instead of raw keys, if available on the platform"); + struct qcom_ice { struct device *dev; void __iomem *base; struct clk *core_clk; + bool use_hwkm; + bool hwkm_init_complete; }; static bool qcom_ice_check_supported(struct qcom_ice *ice) { u32 regval = qcom_ice_readl(ice, QCOM_ICE_REG_VERSION); @@ -73,10 +123,39 @@ static bool qcom_ice_check_supported(struct qcom_ice *ice) QCOM_ICE_FORCE_HW_KEY1_SETTING_MASK)) { dev_warn(dev, "Fuses are blown; ICE is unusable!\n"); return false; } + /* + * Check for HWKM support and decide whether to use it or not. ICE + * v3.2.1 and later have HWKM v2. ICE v3.2.0 has HWKM v1. Earlier ICE + * versions don't have HWKM at all. However, for HWKM to be fully + * usable by Linux, the TrustZone software also needs to support certain + * SCM calls including the ones to generate and prepare keys. That + * effectively makes the earliest supported SoC be SM8650, which has + * HWKM v2. Therefore, this driver doesn't include support for HWKM v1, + * and it checks for the SCM call support before it decides to use HWKM. + * + * Also, since HWKM and legacy mode are mutually exclusive, and + * ICE-capable storage driver(s) need to know early on whether to + * advertise support for raw keys or wrapped keys, HWKM cannot be used + * unconditionally. A module parameter is used to opt into using it. + */ + if ((major >= 4 || + (major == 3 && (minor >= 3 || (minor == 2 && step >= 1)))) && + qcom_scm_has_wrapped_key_support()) { + if (qcom_ice_use_wrapped_keys) { + dev_info(dev, "Using HWKM. Supporting wrapped keys only.\n"); + ice->use_hwkm = true; + } else { + dev_info(dev, "Not using HWKM. Supporting raw keys only.\n"); + } + } else if (qcom_ice_use_wrapped_keys) { + dev_warn(dev, "A supported HWKM is not present. Ignoring qcom_ice.use_wrapped_keys=1.\n"); + } else { + dev_info(dev, "A supported HWKM is not present. Supporting raw keys only.\n"); + } return true; } static void qcom_ice_low_power_mode_enable(struct qcom_ice *ice) { @@ -120,21 +199,75 @@ static int qcom_ice_wait_bist_status(struct qcom_ice *ice) int err; err = readl_poll_timeout(ice->base + QCOM_ICE_REG_BIST_STATUS, regval, !(regval & QCOM_ICE_BIST_STATUS_MASK), 50, 5000); - if (err) + if (err) { dev_err(ice->dev, "Timed out waiting for ICE self-test to complete\n"); + return err; + } - return err; + if (ice->use_hwkm && + qcom_ice_readl(ice, QCOM_ICE_REG_HWKM_TZ_KM_STATUS) != + (QCOM_ICE_HWKM_KT_CLEAR_DONE | + QCOM_ICE_HWKM_BOOT_CMD_LIST0_DONE | + QCOM_ICE_HWKM_BOOT_CMD_LIST1_DONE | + QCOM_ICE_HWKM_CRYPTO_BIST_DONE_V2 | + QCOM_ICE_HWKM_BIST_DONE_V2)) { + dev_err(ice->dev, "HWKM self-test error!\n"); + /* + * Too late to revoke use_hwkm here, as it was already + * propagated up the stack into the crypto capabilities. + */ + } + return 0; +} + +static void qcom_ice_hwkm_init(struct qcom_ice *ice) +{ + u32 regval; + + if (!ice->use_hwkm) + return; + + BUILD_BUG_ON(QCOM_ICE_HWKM_WRAPPED_KEY_SIZE > + BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE); + /* + * When ICE is in HWKM mode, it only supports wrapped keys. + * When ICE is in legacy mode, it only supports raw keys. + * + * Put ICE in HWKM mode. ICE defaults to legacy mode. + */ + regval = qcom_ice_readl(ice, QCOM_ICE_REG_CONTROL); + regval &= ~QCOM_ICE_LEGACY_MODE_ENABLED; + qcom_ice_writel(ice, regval, QCOM_ICE_REG_CONTROL); + + /* Disable CRC checks. This HWKM feature is not used. */ + qcom_ice_writel(ice, QCOM_ICE_HWKM_DISABLE_CRC_CHECKS_VAL, + QCOM_ICE_REG_HWKM_TZ_KM_CTL); + + /* + * Allow the HWKM slave to read and write the keyslots in the ICE HWKM + * slave. Without this, TrustZone cannot program keys into ICE. + */ + qcom_ice_writel(ice, GENMASK(31, 0), QCOM_ICE_REG_HWKM_BANK0_BBAC_0); + qcom_ice_writel(ice, GENMASK(31, 0), QCOM_ICE_REG_HWKM_BANK0_BBAC_1); + qcom_ice_writel(ice, GENMASK(31, 0), QCOM_ICE_REG_HWKM_BANK0_BBAC_2); + qcom_ice_writel(ice, GENMASK(31, 0), QCOM_ICE_REG_HWKM_BANK0_BBAC_3); + qcom_ice_writel(ice, GENMASK(31, 0), QCOM_ICE_REG_HWKM_BANK0_BBAC_4); + + /* Clear the HWKM response FIFO. */ + qcom_ice_writel(ice, QCOM_ICE_HWKM_RSP_FIFO_CLEAR_VAL, + QCOM_ICE_REG_HWKM_BANK0_BANKN_IRQ_STATUS); + ice->hwkm_init_complete = true; } int qcom_ice_enable(struct qcom_ice *ice) { qcom_ice_low_power_mode_enable(ice); qcom_ice_optimization_enable(ice); - + qcom_ice_hwkm_init(ice); return qcom_ice_wait_bist_status(ice); } EXPORT_SYMBOL_GPL(qcom_ice_enable); int qcom_ice_resume(struct qcom_ice *ice) @@ -146,23 +279,67 @@ int qcom_ice_resume(struct qcom_ice *ice) if (err) { dev_err(dev, "failed to enable core clock (%d)\n", err); return err; } - + qcom_ice_hwkm_init(ice); return qcom_ice_wait_bist_status(ice); } EXPORT_SYMBOL_GPL(qcom_ice_resume); int qcom_ice_suspend(struct qcom_ice *ice) { clk_disable_unprepare(ice->core_clk); + ice->hwkm_init_complete = false; return 0; } EXPORT_SYMBOL_GPL(qcom_ice_suspend); +static unsigned int translate_hwkm_slot(struct qcom_ice *ice, unsigned int slot) +{ + return slot * 2; +} + +static int qcom_ice_program_wrapped_key(struct qcom_ice *ice, unsigned int slot, + const struct blk_crypto_key *bkey) +{ + struct device *dev = ice->dev; + union crypto_cfg cfg = { + .dusize = bkey->crypto_cfg.data_unit_size / 512, + .capidx = QCOM_SCM_ICE_CIPHER_AES_256_XTS, + .cfge = QCOM_ICE_HWKM_CFG_ENABLE_VAL, + }; + int err; + + if (!ice->use_hwkm) { + dev_err_ratelimited(dev, "Got wrapped key when not using HWKM\n"); + return -EINVAL; + } + if (!ice->hwkm_init_complete) { + dev_err_ratelimited(dev, "HWKM not yet initialized\n"); + return -EINVAL; + } + + /* Clear CFGE before programming the key. */ + qcom_ice_writel(ice, 0x0, QCOM_ICE_REG_CRYPTOCFG(slot)); + + /* Call into TrustZone to program the wrapped key using HWKM. */ + err = qcom_scm_ice_set_key(translate_hwkm_slot(ice, slot), bkey->bytes, + bkey->size, cfg.capidx, cfg.dusize); + if (err) { + dev_err_ratelimited(dev, + "qcom_scm_ice_set_key failed; err=%d, slot=%u\n", + err, slot); + return err; + } + + /* Set CFGE after programming the key. */ + qcom_ice_writel(ice, cfg.regval, QCOM_ICE_REG_CRYPTOCFG(slot)); + return 0; +} + int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, const struct blk_crypto_key *blk_key) { struct device *dev = ice->dev; union { @@ -178,10 +355,18 @@ int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, dev_err_ratelimited(dev, "Unsupported crypto mode: %d\n", blk_key->crypto_cfg.crypto_mode); return -EINVAL; } + if (blk_key->crypto_cfg.key_type == BLK_CRYPTO_KEY_TYPE_HW_WRAPPED) + return qcom_ice_program_wrapped_key(ice, slot, blk_key); + + if (ice->use_hwkm) { + dev_err_ratelimited(dev, "Got raw key when using HWKM\n"); + return -EINVAL; + } + if (blk_key->size != AES_256_XTS_KEY_SIZE) { dev_err_ratelimited(dev, "Incorrect key size\n"); return -EINVAL; } memcpy(key.bytes, blk_key->bytes, AES_256_XTS_KEY_SIZE); @@ -200,14 +385,135 @@ int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, } EXPORT_SYMBOL_GPL(qcom_ice_program_key); int qcom_ice_evict_key(struct qcom_ice *ice, int slot) { + if (ice->hwkm_init_complete) + slot = translate_hwkm_slot(ice, slot); return qcom_scm_ice_invalidate_key(slot); } EXPORT_SYMBOL_GPL(qcom_ice_evict_key); +/** + * qcom_ice_get_supported_key_type() - Get the supported key type + * @ice: ICE driver data + * + * Return: the blk-crypto key type that the ICE driver is configured to use. + * This is the key type that ICE-capable storage drivers should advertise as + * supported in the crypto capabilities of any disks they register. + */ +enum blk_crypto_key_type qcom_ice_get_supported_key_type(struct qcom_ice *ice) +{ + if (ice->use_hwkm) + return BLK_CRYPTO_KEY_TYPE_HW_WRAPPED; + return BLK_CRYPTO_KEY_TYPE_RAW; +} +EXPORT_SYMBOL_GPL(qcom_ice_get_supported_key_type); + +/** + * qcom_ice_derive_sw_secret() - Derive software secret from wrapped key + * @ice: ICE driver data + * @eph_key: an ephemerally-wrapped key + * @eph_key_size: size of @eph_key in bytes + * @sw_secret: output buffer for the software secret + * + * Use HWKM to derive the "software secret" from a hardware-wrapped key that is + * given in ephemerally-wrapped form. + * + * Return: 0 on success; -EBADMSG if the given ephemerally-wrapped key is + * invalid; or another -errno value. + */ +int qcom_ice_derive_sw_secret(struct qcom_ice *ice, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + int err = qcom_scm_derive_sw_secret(eph_key, eph_key_size, + sw_secret, + BLK_CRYPTO_SW_SECRET_SIZE); + if (err == -EIO || err == -EINVAL) + err = -EBADMSG; /* probably invalid key */ + return err; +} +EXPORT_SYMBOL_GPL(qcom_ice_derive_sw_secret); + +/** + * qcom_ice_generate_key() - Generate a wrapped key for inline encryption + * @ice: ICE driver data + * @lt_key: output buffer for the long-term wrapped key + * + * Use HWKM to generate a new key and return it as a long-term wrapped key. + * + * Return: the size of the resulting wrapped key on success; -errno on failure. + */ +int qcom_ice_generate_key(struct qcom_ice *ice, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int err; + + err = qcom_scm_generate_ice_key(lt_key, QCOM_ICE_HWKM_WRAPPED_KEY_SIZE); + if (err) + return err; + + return QCOM_ICE_HWKM_WRAPPED_KEY_SIZE; +} +EXPORT_SYMBOL_GPL(qcom_ice_generate_key); + +/** + * qcom_ice_prepare_key() - Prepare a wrapped key for inline encryption + * @ice: ICE driver data + * @lt_key: a long-term wrapped key + * @lt_key_size: size of @lt_key in bytes + * @eph_key: output buffer for the ephemerally-wrapped key + * + * Use HWKM to re-wrap a long-term wrapped key with the per-boot ephemeral key. + * + * Return: the size of the resulting wrapped key on success; -EBADMSG if the + * given long-term wrapped key is invalid; or another -errno value. + */ +int qcom_ice_prepare_key(struct qcom_ice *ice, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int err; + + err = qcom_scm_prepare_ice_key(lt_key, lt_key_size, + eph_key, QCOM_ICE_HWKM_WRAPPED_KEY_SIZE); + if (err == -EIO || err == -EINVAL) + err = -EBADMSG; /* probably invalid key */ + if (err) + return err; + + return QCOM_ICE_HWKM_WRAPPED_KEY_SIZE; +} +EXPORT_SYMBOL_GPL(qcom_ice_prepare_key); + +/** + * qcom_ice_import_key() - Import a raw key for inline encryption + * @ice: ICE driver data + * @raw_key: the raw key to import + * @raw_key_size: size of @raw_key in bytes + * @lt_key: output buffer for the long-term wrapped key + * + * Use HWKM to import a raw key and return it as a long-term wrapped key. + * + * Return: the size of the resulting wrapped key on success; -errno on failure. + */ +int qcom_ice_import_key(struct qcom_ice *ice, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + int err; + + err = qcom_scm_import_ice_key(raw_key, raw_key_size, + lt_key, QCOM_ICE_HWKM_WRAPPED_KEY_SIZE); + if (err) + return err; + + return QCOM_ICE_HWKM_WRAPPED_KEY_SIZE; +} +EXPORT_SYMBOL_GPL(qcom_ice_import_key); + static struct qcom_ice *qcom_ice_create(struct device *dev, void __iomem *base) { struct qcom_ice *engine; diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c index 9330022e98eec..f34527fb02fb2 100644 --- a/drivers/ufs/host/ufs-qcom.c +++ b/drivers/ufs/host/ufs-qcom.c @@ -132,10 +132,15 @@ static int ufs_qcom_ice_init(struct ufs_qcom_host *host) } if (IS_ERR_OR_NULL(ice)) return PTR_ERR_OR_ZERO(ice); + if (qcom_ice_get_supported_key_type(ice) != BLK_CRYPTO_KEY_TYPE_RAW) { + dev_warn(dev, "Wrapped keys not supported. Disabling inline encryption support.\n"); + return 0; + } + host->ice = ice; /* Initialize the blk_crypto_profile */ caps.reg_val = cpu_to_le32(ufshcd_readl(hba, REG_UFS_CCAP)); diff --git a/include/soc/qcom/ice.h b/include/soc/qcom/ice.h index 4cecc7f088b4b..c0e32afd7fb81 100644 --- a/include/soc/qcom/ice.h +++ b/include/soc/qcom/ice.h @@ -15,7 +15,19 @@ int qcom_ice_enable(struct qcom_ice *ice); int qcom_ice_resume(struct qcom_ice *ice); int qcom_ice_suspend(struct qcom_ice *ice); int qcom_ice_program_key(struct qcom_ice *ice, unsigned int slot, const struct blk_crypto_key *blk_key); int qcom_ice_evict_key(struct qcom_ice *ice, int slot); +enum blk_crypto_key_type qcom_ice_get_supported_key_type(struct qcom_ice *ice); +int qcom_ice_derive_sw_secret(struct qcom_ice *ice, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]); +int qcom_ice_generate_key(struct qcom_ice *ice, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); +int qcom_ice_prepare_key(struct qcom_ice *ice, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); +int qcom_ice_import_key(struct qcom_ice *ice, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]); struct qcom_ice *of_qcom_ice_get(struct device *dev); #endif /* __QCOM_ICE_H__ */ From patchwork Tue Feb 4 06:00:41 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 13958628 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1572205E3B; Tue, 4 Feb 2025 06:03:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649005; cv=none; b=WUVk7pdBDqk3CkEH3PaoXwXmCEZn8bagzU5jzHyfllTJOzC200nxUiz5aDWpq43x1fP47Ji57Wp4VayYeQ1uDMGp7mcajO/JqSPIMWfKXHvjKxyrY5rFYCdU0rn8I4zxf9+flyy3DJi8TGSU2gBu4KaUcPTOVrG14pNHo72He8A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738649005; c=relaxed/simple; bh=YXruEiMk7Z0SmUMhsRZ5knXXsH2CoZdEoFSRKJf1RGc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jRfMUxg6OALoTmrKwcS0Mro2JK4wWTfrQ0Ojuew1Sp2UZ1mb1rtEEp8WybXlVMUv+Yw2YLuBrirRNdOi2flA51p3Lkc6XXf08sLbAQZGFx9QHtga8Yvz88al1lAiTUdq6MQbJ101xuCrbMUDpD/8DSbFNGEQThJzYHWO5iKS5is= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=garOtrXB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="garOtrXB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EE01C4CEEC; Tue, 4 Feb 2025 06:03:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738649004; bh=YXruEiMk7Z0SmUMhsRZ5knXXsH2CoZdEoFSRKJf1RGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=garOtrXBfk87XX+HKV3vl1JuwQYttO4QQ1AKchE5eO/0jiReyy1XvWDD2yZGLa9FC AeKmy+jUsslnY2mPcu5mEUS2c2H2bCHjQWof2mTJgn93SLPnVMi5LEeBC6WJcpadnk u2DOpDfoE7IluiD1NS0ecBDa051JLaGewLijvwGI2eN6QM4y5FmrBT8Krub6mQAAY1 Zt/MpKhOFfwK5m6oLaqZs2K6rlQzhNYy6gzAJPG/FvI3ILHbh0NflYxDC7Xmq2OP0c 49B9SNkzewZfyYQob96/Zyxm1qXzL4tfODbRqxSLgBPgjVdd4wwy4Gq447+twUUlW8 wy9WykkXhfD1w== From: Eric Biggers To: linux-block@vger.kernel.org, Jens Axboe , Bartosz Golaszewski , Gaurav Kashyap Cc: linux-fscrypt@vger.kernel.org, linux-mmc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Dmitry Baryshkov Subject: [PATCH v11 7/7] ufs: qcom: add support for wrapped keys Date: Mon, 3 Feb 2025 22:00:41 -0800 Message-ID: <20250204060041.409950-8-ebiggers@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250204060041.409950-1-ebiggers@kernel.org> References: <20250204060041.409950-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers Wire up the wrapped key support for ufs-qcom by implementing the needed methods in struct blk_crypto_ll_ops and setting the appropriate flag in blk_crypto_profile::key_types_supported. For more information about this feature and how to use it, refer to the sections about hardware-wrapped keys in Documentation/block/inline-encryption.rst and Documentation/filesystems/fscrypt.rst. Based on patches by Gaurav Kashyap . Reworked to use the custom crypto profile support. Signed-off-by: Eric Biggers --- drivers/ufs/host/ufs-qcom.c | 51 ++++++++++++++++++++++++++++++++----- 1 file changed, 45 insertions(+), 6 deletions(-) diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c index f34527fb02fb2..dc3eb6f29f5b2 100644 --- a/drivers/ufs/host/ufs-qcom.c +++ b/drivers/ufs/host/ufs-qcom.c @@ -132,15 +132,10 @@ static int ufs_qcom_ice_init(struct ufs_qcom_host *host) } if (IS_ERR_OR_NULL(ice)) return PTR_ERR_OR_ZERO(ice); - if (qcom_ice_get_supported_key_type(ice) != BLK_CRYPTO_KEY_TYPE_RAW) { - dev_warn(dev, "Wrapped keys not supported. Disabling inline encryption support.\n"); - return 0; - } - host->ice = ice; /* Initialize the blk_crypto_profile */ caps.reg_val = cpu_to_le32(ufshcd_readl(hba, REG_UFS_CCAP)); @@ -150,11 +145,11 @@ static int ufs_qcom_ice_init(struct ufs_qcom_host *host) if (err) return err; profile->ll_ops = ufs_qcom_crypto_ops; profile->max_dun_bytes_supported = 8; - profile->key_types_supported = BLK_CRYPTO_KEY_TYPE_RAW; + profile->key_types_supported = qcom_ice_get_supported_key_type(ice); profile->dev = dev; /* * Currently this driver only supports AES-256-XTS. All known versions * of ICE support it, but to be safe make sure it is really declared in @@ -218,13 +213,57 @@ static int ufs_qcom_ice_keyslot_evict(struct blk_crypto_profile *profile, err = qcom_ice_evict_key(host->ice, slot); ufshcd_release(hba); return err; } +static int ufs_qcom_ice_derive_sw_secret(struct blk_crypto_profile *profile, + const u8 *eph_key, size_t eph_key_size, + u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) +{ + struct ufs_hba *hba = ufs_hba_from_crypto_profile(profile); + struct ufs_qcom_host *host = ufshcd_get_variant(hba); + + return qcom_ice_derive_sw_secret(host->ice, eph_key, eph_key_size, + sw_secret); +} + +static int ufs_qcom_ice_import_key(struct blk_crypto_profile *profile, + const u8 *raw_key, size_t raw_key_size, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + struct ufs_hba *hba = ufs_hba_from_crypto_profile(profile); + struct ufs_qcom_host *host = ufshcd_get_variant(hba); + + return qcom_ice_import_key(host->ice, raw_key, raw_key_size, lt_key); +} + +static int ufs_qcom_ice_generate_key(struct blk_crypto_profile *profile, + u8 lt_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + struct ufs_hba *hba = ufs_hba_from_crypto_profile(profile); + struct ufs_qcom_host *host = ufshcd_get_variant(hba); + + return qcom_ice_generate_key(host->ice, lt_key); +} + +static int ufs_qcom_ice_prepare_key(struct blk_crypto_profile *profile, + const u8 *lt_key, size_t lt_key_size, + u8 eph_key[BLK_CRYPTO_MAX_HW_WRAPPED_KEY_SIZE]) +{ + struct ufs_hba *hba = ufs_hba_from_crypto_profile(profile); + struct ufs_qcom_host *host = ufshcd_get_variant(hba); + + return qcom_ice_prepare_key(host->ice, lt_key, lt_key_size, eph_key); +} + static const struct blk_crypto_ll_ops ufs_qcom_crypto_ops = { .keyslot_program = ufs_qcom_ice_keyslot_program, .keyslot_evict = ufs_qcom_ice_keyslot_evict, + .derive_sw_secret = ufs_qcom_ice_derive_sw_secret, + .import_key = ufs_qcom_ice_import_key, + .generate_key = ufs_qcom_ice_generate_key, + .prepare_key = ufs_qcom_ice_prepare_key, }; #else static inline void ufs_qcom_ice_enable(struct ufs_qcom_host *host)