From patchwork Tue May 28 21:08:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 13677460 X-Patchwork-Delegate: herbert@gondor.apana.org.au 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 B028117F391; Tue, 28 May 2024 21:08:52 +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=1716930532; cv=none; b=euaRFZAOY8zJ8ve83YVGXsSwDWx5M6tildPV2Bh1kCHdOzk4fLOWTbF2F+d4NZDR5apNyOKexmrWHxgef2T1J+Te5pgEMtoXbIG/+omqwOWDXqVfK+gdibLylVAYE7MgWG6uHfvTssVUgAyp7kuK2yBwyhWx7ziN0i7kqrnu/cA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716930532; c=relaxed/simple; bh=EWHB6qTYSbsxlpqEBR475FoQwTMhLEpw2cwYyM3OlHA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nv1V7Ffk6MeGEmA/je8DnUYUg6DWOffPG1HwBAILwP0/KydM0QOeeq5WJxULdt3SxjTvzdS7xKAuoLi/6w/WuWcRkdBsE/vK3WHYct15+2Q22QKw+bhNJu3upVDDK7NgSq/HrHiPSQPm/OotA+fu+D8ckCu+S0nvPvpIoIhAwHs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OWh/c2GB; 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="OWh/c2GB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35ADFC3277B; Tue, 28 May 2024 21:08:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716930532; bh=EWHB6qTYSbsxlpqEBR475FoQwTMhLEpw2cwYyM3OlHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OWh/c2GB5JK0y0fHHWP/fgvLY0LmqfUJK6qkWwcLgvTIwVgbgk1A/hA66wxUMPqUx fSgGsTiaa99NGF65O0j25xIAN2xof///+VEmPSMJVfblJ3nar8EvWVPl7VNvKveHc+ V2yt6fAW8rZqbah+pxKL2kdZjAFc0DifwR999xefPMguER3fsoPuTMcQk9qqp0bJls 3LDhNn9oZo9H9lg6IOJ0IgU2WAuneySrl7MyCQsG6naR/dQDORhQeje32vZVY6s7gj CSPdlG+LpumyQFTwcUNrpY9EF1aykdZpeYsdeOzcA1v8cJs6I0dIjtY0K1LxAxtIAI N5Z/0/Zo13aRQ== From: Jarkko Sakkinen To: Herbert Xu Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, Andreas.Fuchs@infineon.com, James Prestwood , David Woodhouse , Eric Biggers , James Bottomley , linux-crypto@vger.kernel.org, Stefan Berger , Lennart Poettering , Jarkko Sakkinen , "David S. Miller" , linux-kernel@vger.kernel.org (open list), David Howells , James Bottomley , Ard Biesheuvel , Mario Limonciello Subject: [PATCH v7 4/5] keys: asymmetric: Add tpm2_key_rsa Date: Wed, 29 May 2024 00:08:09 +0300 Message-ID: <20240528210823.28798-5-jarkko@kernel.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240528210823.28798-1-jarkko@kernel.org> References: <20240528210823.28798-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 * Asymmetric TPM2 RSA key with signing and verification. * Encryption and decryption when pcks1 encoding is used. * Enabled with CONFIG_ASYMMETRIC_TPM2_KEY_ECDSA_SUBTYPE. Signed-off-by: James Prestwood Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- v6: * Validate RSA parameters, and also that the blob has space for them. * Fix tpm2_key_rsa_destroy() memory corruption: cast to tpm2_key_rsa * Allocate temporary buffers from heap. * Rename tpm2_key_rsa_extract_pub to tpm2_key_rsa_probe. * While pre-parsing, return -EBADMSG when the probing fails. This translates to "not detected" for the framework, i.e. should not be considered as an error but instead "move on". E.g. TPM_ALG_RSA is checked and if it is instead TPM_ALG_ECDSA, then it is passed to that module. v5: * akcipher has two *undocumented* parameters. Document this clearly. * Remove unused variable. v4: * Just put the values to the buffer instead of encoding them. * Adjust buffer sizes. * Make tpm2_rsa_key_encode() not to allocate from heap and simplify the serialization. v3: * Drop the special case for null handle i.e. do not define policy. * Remove extra empty line. v2: * Remove two spurios pr_info() messsages that I forgot to remove. * Clean up padding functions and add additional checks for length also in tpm2_unpad_pcks1(). * Add the missing success check kzalloc() in tpm2_key_rsa_decrypt(). * Check that params->out_len for capacity before copying the result. --- crypto/asymmetric_keys/Kconfig | 15 + crypto/asymmetric_keys/Makefile | 1 + crypto/asymmetric_keys/tpm2_key_rsa.c | 678 ++++++++++++++++++++++++++ include/linux/tpm.h | 2 + 4 files changed, 696 insertions(+) create mode 100644 crypto/asymmetric_keys/tpm2_key_rsa.c diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig index e1345b8f39f1..9d88c1190621 100644 --- a/crypto/asymmetric_keys/Kconfig +++ b/crypto/asymmetric_keys/Kconfig @@ -15,6 +15,7 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE select MPILIB select CRYPTO_HASH_INFO select CRYPTO_AKCIPHER + select CRYPTO_RSA select CRYPTO_SIG select CRYPTO_HASH help @@ -23,6 +24,20 @@ config ASYMMETRIC_PUBLIC_KEY_SUBTYPE appropriate hash algorithms (such as SHA-1) must be available. ENOPKG will be reported if the requisite algorithm is unavailable. +config ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE + tristate "Asymmetric TPM2 RSA crypto algorithm subtype" + depends on TCG_TPM + select CRYPTO_RSA + select CRYPTO_SHA256 + select CRYPTO_HASH_INFO + select CRYPTO_TPM2_KEY + select ASN1 + help + This option provides support for asymmetric TPM2 key type handling. + If signature generation and/or verification are to be used, + appropriate hash algorithms (such as SHA-256) must be available. + ENOPKG will be reported if the requisite algorithm is unavailable. + config X509_CERTIFICATE_PARSER tristate "X.509 certificate parser" depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile index bc65d3b98dcb..c6da84607824 100644 --- a/crypto/asymmetric_keys/Makefile +++ b/crypto/asymmetric_keys/Makefile @@ -11,6 +11,7 @@ asymmetric_keys-y := \ signature.o obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o +obj-$(CONFIG_ASYMMETRIC_TPM2_KEY_RSA_SUBTYPE) += tpm2_key_rsa.o # # X.509 Certificate handling diff --git a/crypto/asymmetric_keys/tpm2_key_rsa.c b/crypto/asymmetric_keys/tpm2_key_rsa.c new file mode 100644 index 000000000000..4bc322580037 --- /dev/null +++ b/crypto/asymmetric_keys/tpm2_key_rsa.c @@ -0,0 +1,678 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* TPM2 asymmetric public-key crypto subtype + * + * Asymmetric TPM2 RSA key: + * - Decrypts RSA with TPM2_RSA_Decrypt. + * - Signs with PKCS#1 1.5 padding. Signing is implemented with + * TPM2_RSA_Decrypt operation. + * - Encrypts with the akcipher rsa-pcks1pad. + * + * See Documentation/crypto/asymmetric-keys.rst + * + * Copyright (c) 2020 Intel Corporation + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#undef pr_fmt +#define pr_fmt(fmt) "tpm2_key_rsa: "fmt + +#define PKCS1_PAD_MIN_SIZE 11 + +/* TPM2 Structures 12.2.3.5: TPMS_RSA_PARMS */ +struct tpm2_rsa_parms { + __be16 symmetric; + __be16 scheme; + __be16 key_bits; + __be32 exponent; + __be16 modulus_size; +} __packed; + +/* + * Fill the data with PKCS#1 v1.5 padding. + */ +static int tpm2_pad_pkcs1(const u8 *in, int in_len, u8 *out, int out_len) +{ + unsigned int prefix_len = out_len - in_len - 3; + + if (in_len > out_len - PKCS1_PAD_MIN_SIZE) + return -EBADMSG; + + /* prefix */ + out[0] = 0; + out[1] = 1; + memset(&out[2], 0xff, prefix_len); + out[2 + prefix_len] = 0; + /* payload */ + memcpy(&out[2 + prefix_len + 1], in, in_len); + + return 0; +} + +/* + * RFC 3447 - Section 7.2.2 + * Size of the input data should be checked against public key size by + * the caller. + */ +static const u8 *tpm2_unpad_pkcs1(const u8 *in, int in_len, int *out_len) +{ + int i; + + if (in[0] != 0 || in[1] != 2) + return NULL; + + i = 2; + while (in[i] != 0 && i < in_len) + i++; + + if (i == in_len || i < (PKCS1_PAD_MIN_SIZE - 1)) + return NULL; + + *out_len = in_len - i - 1; + return in + i + 1; +} + +/* + * Outputs the cipher algorithm name on success, and retuns -ENOPKG + * on failure. + */ +static int tpm2_key_get_akcipher(const char *encoding, const char *hash_algo, + char *cipher) +{ + ssize_t ret; + + if (strcmp(encoding, "pkcs1") == 0) { + if (!hash_algo) { + strcpy(cipher, "pkcs1pad(rsa)"); + return 0; + } + + ret = snprintf(cipher, CRYPTO_MAX_ALG_NAME, + "pkcs1pad(rsa,%s)", + hash_algo); + if (ret >= CRYPTO_MAX_ALG_NAME) + return -ENOPKG; + + return 0; + } + + if (strcmp(encoding, "raw") == 0) { + strcpy(cipher, "rsa"); + return 0; + } + + return -ENOPKG; +} + +static int tpm2_key_rsa_encode(const struct tpm2_key *key, u8 *buf) +{ + const off_t o = key->priv_len + 2 + sizeof(*key->desc); + const struct tpm2_rsa_parms *p = + (const struct tpm2_rsa_parms *)&key->data[o]; + const u16 mod_size = be16_to_cpu(p->modulus_size); + const void *mod = &key->data[o + sizeof(*p)]; + + u8 *start = &buf[4]; + u8 *work = &buf[4]; + u32 seq_len; + + work[0] = 0x02; /* INTEGER */ + work[1] = 0x82; /* u16 */ + work[2] = mod_size >> 8; + work[3] = mod_size & 0xff; + work = &work[4]; + memcpy(work, mod, mod_size); + work = &work[mod_size]; + work[0] = 0x02; /* INTEGER */ + work[1] = 3; /* < 128 */ + work[2] = 1; /* 65537 */ + work[3] = 0; + work[4] = 1; + work = &work[5]; + seq_len = work - start; + buf[0] = 0x30; /* SEQUENCE */ + buf[1] = 0x82; /* u16 */ + buf[2] = seq_len >> 8; + buf[3] = seq_len & 0xff; + + /* + * ABI requires this according include/crypto/akcipher.h, which says + * that there is epilogue with algorithm OID and parameters length. + * Neither size nor semantics is documented *anywhere*, and there's no + * struct to hold them. + * + * So zeroing out the last eight bytes after the key blob seems like the + * best bet, given no better (or any) information. The size of the + * parameters (two u32's) was found from crypto/asymmetric/public_key.c. + */ + memset(work, 0, 8); + + return seq_len + 4; +} + +/* + * Encryption operation is performed with the public key. Hence it is done + * in software + */ +static int tpm2_key_rsa_encrypt(struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + char cipher[CRYPTO_MAX_ALG_NAME]; + struct scatterlist in_sg, out_sg; + struct akcipher_request *req; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + u8 *buf; + int ret; + + buf = kzalloc(TPM2_KEY_BYTES_MAX, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = tpm2_key_get_akcipher(params->encoding, params->hash_algo, cipher); + if (ret < 0) + goto err_buf; + + tfm = crypto_alloc_akcipher(cipher, 0, 0); + if (IS_ERR(tfm)) { + ret = PTR_ERR(tfm); + goto err_buf; + } + + ret = tpm2_key_rsa_encode(key, buf); + if (ret < 0) + goto err_tfm; + + ret = crypto_akcipher_set_pub_key(tfm, buf, ret); + if (ret < 0) + goto err_tfm; + + req = akcipher_request_alloc(tfm, GFP_KERNEL); + if (!req) { + ret = -ENOMEM; + goto err_tfm; + } + + sg_init_one(&in_sg, in, params->in_len); + sg_init_one(&out_sg, out, params->out_len); + akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len, + params->out_len); + + crypto_init_wait(&cwait); + akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + + ret = crypto_akcipher_encrypt(req); + if (ret) + goto err_tfm; + + ret = crypto_wait_req(ret, &cwait); + if (!ret) + ret = req->dst_len; + + akcipher_request_free(req); + +err_tfm: + crypto_free_akcipher(tfm); + +err_buf: + kfree(buf); + return ret; +} + +static int __tpm2_key_rsa_decrypt(struct tpm_chip *chip, + struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, int in_len, void *out) +{ + u32 key_handle = 0; + struct tpm_buf buf; + u16 decrypted_len; + u8 *pos; + int ret; + + ret = tpm_try_get_ops(chip); + if (ret) + return ret; + + ret = tpm2_start_auth_session(chip); + if (ret) + goto err_ops; + + ret = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD); + if (ret < 0) + goto err_auth; + + tpm_buf_append_name(chip, &buf, key->parent, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_CONTINUE_SESSION | + TPM2_SA_ENCRYPT, NULL, 0); + tpm_buf_append(&buf, &key->data[0], key->priv_len + key->pub_len); + if (buf.flags & TPM_BUF_OVERFLOW) { + ret = -E2BIG; + goto err_buf; + } + tpm_buf_fill_hmac_session(chip, &buf); + ret = tpm_transmit_cmd(chip, &buf, 4, "TPM2_CC_LOAD"); + ret = tpm_buf_check_hmac_response(chip, &buf, ret); + if (ret) { + ret = -EIO; + goto err_buf; + } + key_handle = be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE]); + + tpm_buf_reset(&buf, TPM2_ST_SESSIONS, TPM2_CC_RSA_DECRYPT); + tpm_buf_append_name(chip, &buf, key_handle, NULL); + tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT, NULL, 0); + tpm_buf_append_u16(&buf, in_len); + tpm_buf_append(&buf, in, in_len); + tpm_buf_append_u16(&buf, TPM_ALG_NULL); + tpm_buf_append_u16(&buf, 0); + tpm_buf_fill_hmac_session(chip, &buf); + ret = tpm_transmit_cmd(chip, &buf, 4, "TPM2_RSA_DECRYPT"); + ret = tpm_buf_check_hmac_response(chip, &buf, ret); + if (ret) { + ret = -EIO; + goto err_blob; + } + + pos = buf.data + TPM_HEADER_SIZE + 4; + decrypted_len = be16_to_cpup((__be16 *)pos); + pos += 2; + + if (params->out_len < decrypted_len) { + ret = -EMSGSIZE; + goto err_blob; + } + + memcpy(out, pos, decrypted_len); + ret = decrypted_len; + +err_blob: + tpm2_flush_context(chip, key_handle); + +err_buf: + tpm_buf_destroy(&buf); + +err_auth: + if (ret < 0) + tpm2_end_auth_session(chip); + +err_ops: + tpm_put_ops(chip); + return ret; +} + +static int tpm2_key_rsa_decrypt(struct tpm_chip *chip, struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + const u8 *ptr; + int out_len; + u8 *work; + int ret; + + work = kzalloc(TPM2_KEY_BYTES_MAX, GFP_KERNEL); + if (!work) + return -ENOMEM; + + ret = __tpm2_key_rsa_decrypt(chip, key, params, in, params->in_len, + work); + if (ret < 0) + goto err; + + ptr = tpm2_unpad_pkcs1(work, ret, &out_len); + if (!ptr) { + ret = -EINVAL; + goto err; + } + + if (out_len > params->out_len) { + ret = -EMSGSIZE; + goto err; + } + + memcpy(out, ptr, out_len); + kfree(work); + return out_len; + +err: + kfree(work); + return ret; +} + +/* + * Sign operation is an encryption using the TPM's private key. With RSA the + * only difference between encryption and decryption is where the padding goes. + * Since own padding can be used, TPM2_RSA_Decrypt can be repurposed to do + * encryption. + */ +static int tpm2_key_rsa_sign(struct tpm_chip *chip, struct tpm2_key *key, + struct kernel_pkey_params *params, + const void *in, void *out) +{ + const off_t o = key->priv_len + 2 + sizeof(*key->desc); + const struct tpm2_rsa_parms *p = + (const struct tpm2_rsa_parms *)&key->data[o]; + const u16 mod_size = be16_to_cpu(p->modulus_size); + const struct rsa_asn1_template *asn1; + u32 in_len = params->in_len; + void *asn1_wrapped = NULL; + u8 *padded; + int ret; + + if (strcmp(params->encoding, "pkcs1") != 0) { + ret = -ENOPKG; + goto err; + } + + if (params->hash_algo) { + asn1 = rsa_lookup_asn1(params->hash_algo); + if (!asn1) { + ret = -ENOPKG; + goto err; + } + + /* Request enough space for the ASN.1 template + input hash */ + asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL); + if (!asn1_wrapped) { + ret = -ENOMEM; + goto err; + } + + /* Copy ASN.1 template, then the input */ + memcpy(asn1_wrapped, asn1->data, asn1->size); + memcpy(asn1_wrapped + asn1->size, in, in_len); + + in = asn1_wrapped; + in_len += asn1->size; + } + + /* with padding: */ + padded = kmalloc(mod_size, GFP_KERNEL); + tpm2_pad_pkcs1(in, in_len, padded, mod_size); + ret = __tpm2_key_rsa_decrypt(chip, key, params, padded, mod_size, out); + kfree(padded); + +err: + kfree(asn1_wrapped); + return ret; +} + +static void tpm2_key_rsa_describe(const struct key *asymmetric_key, + struct seq_file *m) +{ + struct tpm2_key *key = asymmetric_key->payload.data[asym_crypto]; + + if (!key) { + pr_err("key blob missing"); + return; + } + + seq_puts(m, "TPM2/RSA"); +} + +static void tpm2_key_rsa_destroy(void *payload0, void *payload3) +{ + struct tpm2_key *key = payload0; + + if (!key) + return; + + kfree(key); +} + +static int tpm2_key_rsa_eds_op(struct kernel_pkey_params *params, + const void *in, void *out) +{ + struct tpm2_key *key = params->key->payload.data[asym_crypto]; + struct tpm_chip *chip = tpm_default_chip(); + + if (!chip) + return -ENODEV; + + switch (params->op) { + case kernel_pkey_encrypt: + return tpm2_key_rsa_encrypt(key, params, in, out); + case kernel_pkey_decrypt: + return tpm2_key_rsa_decrypt(chip, key, params, in, out); + case kernel_pkey_sign: + return tpm2_key_rsa_sign(chip, key, params, in, out); + default: + return -EOPNOTSUPP; + } +} + +static int tpm2_key_rsa_verify(const struct key *key, + const struct public_key_signature *sig) +{ + const struct tpm2_key *tpm2_key = key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + struct akcipher_request *req; + struct scatterlist src_sg[2]; + struct crypto_akcipher *tfm; + struct crypto_wait cwait; + u8 *buf; + int ret; + + if (!sig->digest) + return -ENOPKG; + + ret = tpm2_key_get_akcipher(sig->encoding, sig->hash_algo, alg_name); + if (ret < 0) + return ret; + + buf = kzalloc(TPM2_KEY_BYTES_MAX, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + tfm = crypto_alloc_akcipher(alg_name, 0, 0); + if (IS_ERR(tfm)) { + ret = PTR_ERR(tfm); + goto err_buf; + } + + ret = tpm2_key_rsa_encode(tpm2_key, buf); + if (ret < 0) + goto err_tfm; + + ret = crypto_akcipher_set_pub_key(tfm, buf, ret); + if (ret < 0) + goto err_tfm; + + ret = -ENOMEM; + req = akcipher_request_alloc(tfm, GFP_KERNEL); + if (!req) + goto err_tfm; + + sg_init_table(src_sg, 2); + sg_set_buf(&src_sg[0], sig->s, sig->s_size); + sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); + akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, + sig->digest_size); + crypto_init_wait(&cwait); + akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | + CRYPTO_TFM_REQ_MAY_SLEEP, + crypto_req_done, &cwait); + ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); + + akcipher_request_free(req); + +err_tfm: + crypto_free_akcipher(tfm); + +err_buf: + kfree(buf); + return ret; +} + +static int tpm2_key_rsa_query(const struct kernel_pkey_params *params, + struct kernel_pkey_query *info) +{ + const struct tpm2_key *key = params->key->payload.data[asym_crypto]; + const off_t o = key->priv_len + 2 + sizeof(*key->desc); + const struct tpm2_rsa_parms *p = + (const struct tpm2_rsa_parms *)&key->data[o]; + const u16 mod_size = be16_to_cpu(p->modulus_size); + char alg_name[CRYPTO_MAX_ALG_NAME]; + struct crypto_akcipher *tfm; + unsigned int len; + u8 *buf; + int ret; + + ret = tpm2_key_get_akcipher(params->encoding, params->hash_algo, alg_name); + if (ret < 0) + return ret; + + buf = kzalloc(TPM2_KEY_BYTES_MAX, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + tfm = crypto_alloc_akcipher(alg_name, 0, 0); + if (IS_ERR(tfm)) { + ret = PTR_ERR(tfm); + goto err_buf; + } + + ret = tpm2_key_rsa_encode(key, buf); + if (ret < 0) + goto err_tfm; + + ret = crypto_akcipher_set_pub_key(tfm, buf, ret); + if (ret < 0) + goto err_tfm; + + len = crypto_akcipher_maxsize(tfm); + + info->key_size = mod_size * 8; + info->max_data_size = mod_size; + info->max_sig_size = len; + info->max_enc_size = len; + info->max_dec_size = mod_size; + + info->supported_ops = KEYCTL_SUPPORTS_SIGN | KEYCTL_SUPPORTS_VERIFY; + + if (!strcmp(params->encoding, "pkcs1")) { + pr_info("pkcs1\n"); + info->supported_ops = + KEYCTL_SUPPORTS_ENCRYPT | KEYCTL_SUPPORTS_DECRYPT; + } + +err_tfm: + crypto_free_akcipher(tfm); + return ret; + +err_buf: + kfree(buf); + return ret; +} + +struct asymmetric_key_subtype tpm2_key_rsa_subtype = { + .owner = THIS_MODULE, + .name = "tpm2_key_rsa", + .name_len = sizeof("tpm2_key_rsa") - 1, + .describe = tpm2_key_rsa_describe, + .destroy = tpm2_key_rsa_destroy, + .query = tpm2_key_rsa_query, + .eds_op = tpm2_key_rsa_eds_op, + .verify_signature = tpm2_key_rsa_verify, +}; +EXPORT_SYMBOL_GPL(tpm2_key_rsa_subtype); + +static int __tpm2_key_rsa_preparse(struct tpm2_key *key) +{ + const off_t o = key->priv_len + 2 + sizeof(*key->desc); + const struct tpm2_rsa_parms *p = + (const struct tpm2_rsa_parms *)&key->data[o]; + + if (tpm2_key_type(key) != TPM_ALG_RSA) + return -EBADMSG; + + if (tpm2_key_policy_size(key) != 0) + return -EBADMSG; + + if (be16_to_cpu(p->symmetric) != TPM_ALG_NULL) + return -EBADMSG; + + if (be16_to_cpu(p->scheme) != TPM_ALG_NULL) + return -EBADMSG; + + if (be16_to_cpu(p->key_bits) != 2048 && + be16_to_cpu(p->key_bits) != 3072 && + be16_to_cpu(p->key_bits) != 4096) + return -EBADMSG; + + if (be32_to_cpu(p->exponent) != 0x00000000 && + be32_to_cpu(p->exponent) != 0x00010001) + return -EBADMSG; + + pr_debug("modulus_size=%u\n", be16_to_cpu(p->modulus_size)); + return 0; +} + +/* + * Attempt to parse a data blob for a key as a TPM private key blob. + */ +static int tpm2_key_rsa_preparse(struct key_preparsed_payload *prep) +{ + struct tpm2_key *key; + int ret; + + key = tpm2_key_decode(prep->data, prep->datalen); + if (IS_ERR(key)) + return ret; + + if (key->oid != OID_TPMLoadableKey) { + kfree(key); + return -EBADMSG; + } + + ret = __tpm2_key_rsa_preparse(key); + if (ret < 0) { + kfree(key); + return ret; + } + + prep->payload.data[asym_subtype] = &tpm2_key_rsa_subtype; + prep->payload.data[asym_key_ids] = NULL; + prep->payload.data[asym_crypto] = key; + prep->payload.data[asym_auth] = NULL; + prep->quotalen = 100; + + return 0; +} + +static struct asymmetric_key_parser tpm2_key_rsa_parser = { + .owner = THIS_MODULE, + .name = "tpm2_key_rsa_parser", + .parse = tpm2_key_rsa_preparse, +}; + +static int __init tpm2_key_rsa_init(void) +{ + return register_asymmetric_key_parser(&tpm2_key_rsa_parser); +} + +static void __exit tpm2_key_rsa_exit(void) +{ + unregister_asymmetric_key_parser(&tpm2_key_rsa_parser); +} + +module_init(tpm2_key_rsa_init); +module_exit(tpm2_key_rsa_exit); + +MODULE_DESCRIPTION("Asymmetric TPM2 RSA key"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 21a67dc9efe8..d0860af7a56d 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -43,6 +43,7 @@ enum tpm2_session_types { /* if you add a new hash to this, increment TPM_MAX_HASHES below */ enum tpm_algorithms { TPM_ALG_ERROR = 0x0000, + TPM_ALG_RSA = 0x0001, TPM_ALG_SHA1 = 0x0004, TPM_ALG_AES = 0x0006, TPM_ALG_KEYEDHASH = 0x0008, @@ -271,6 +272,7 @@ enum tpm2_command_codes { TPM2_CC_NV_READ = 0x014E, TPM2_CC_CREATE = 0x0153, TPM2_CC_LOAD = 0x0157, + TPM2_CC_RSA_DECRYPT = 0x0159, TPM2_CC_SEQUENCE_UPDATE = 0x015C, TPM2_CC_UNSEAL = 0x015E, TPM2_CC_CONTEXT_LOAD = 0x0161,