[06/10] PM: hibernate: Add kernel-based encryption

Message ID	20220504161439.6.Ifff11e11797a1bde0297577ecb2f7ebb3f9e2b04@changeid (mailing list archive)
State	Superseded, archived
Headers	show Return-Path: <linux-pm-owner@kernel.org> From: Evan Green <evgreen@chromium.org> To: linux-kernel@vger.kernel.org Cc: Matthew Garrett <mgarrett@aurora.tech>, dlunev@google.com, zohar@linux.ibm.com, jejb@linux.ibm.com, linux-integrity@vger.kernel.org, corbet@lwn.net, rjw@rjwysocki.net, gwendal@chromium.org, jarkko@kernel.org, linux-pm@vger.kernel.org, Evan Green <evgreen@chromium.org>, Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>, "Rafael J. Wysocki" <rafael@kernel.org> Subject: [PATCH 06/10] PM: hibernate: Add kernel-based encryption Date: Wed, 4 May 2022 16:20:58 -0700 Message-Id: <20220504161439.6.Ifff11e11797a1bde0297577ecb2f7ebb3f9e2b04@changeid> In-Reply-To: <20220504232102.469959-1-evgreen@chromium.org> References: <20220504232102.469959-1-evgreen@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Encrypted Hibernation \| expand [00/10] Encrypted Hibernation [01/10] tpm: Add support for in-kernel resetting of PCRs [02/10] tpm: Allow PCR 23 to be restricted to kernel-only use [03/10] security: keys: trusted: Parse out individual components of the key blob [04/10] security: keys: trusted: Allow storage of PCR values in creation data [05/10] security: keys: trusted: Verify creation data [06/10] PM: hibernate: Add kernel-based encryption [07/10] PM: hibernate: Use TPM-backed keys to encrypt image [08/10] PM: hibernate: Mix user key in encrypted hibernate [09/10] PM: hibernate: Verify the digest encryption key [10/10] PM: hibernate: seal the encryption key with a PCR policy

diff --git a/Documentation/power/userland-swsusp.rst b/Documentation/power/userland-swsusp.rst index 1cf62d80a9ca10..f759915a78ce98 100644 --- a/Documentation/power/userland-swsusp.rst +++ b/Documentation/power/userland-swsusp.rst @@ -115,6 +115,14 @@ SNAPSHOT_S2RAM to resume the system from RAM if there's enough battery power or restore its state on the basis of the saved suspend image otherwise) +SNAPSHOT_ENABLE_ENCRYPTION + Enables encryption of the hibernate image within the kernel. Upon suspend + (ie when the snapshot device was opened for reading), returns a blob + representing the random encryption key the kernel created to encrypt the + hibernate image with. Upon resume (ie when the snapshot device was opened + for writing), receives a blob from usermode containing the key material + previously returned during hibernate. + The device's read() operation can be used to transfer the snapshot image from the kernel. It has the following limitations: diff --git a/include/uapi/linux/suspend_ioctls.h b/include/uapi/linux/suspend_ioctls.h index bcce04e21c0dce..b73026ef824bb9 100644 --- a/include/uapi/linux/suspend_ioctls.h +++ b/include/uapi/linux/suspend_ioctls.h @@ -13,6 +13,18 @@ struct resume_swap_area { __u32 dev; } __attribute__((packed)); +#define USWSUSP_KEY_NONCE_SIZE 16 + +/* + * This structure is used to pass the kernel's hibernate encryption key in + * either direction. + */ +struct uswsusp_key_blob { + __u32 blob_len; + __u8 blob[512]; + __u8 nonce[USWSUSP_KEY_NONCE_SIZE]; +} __attribute__((packed)); + #define SNAPSHOT_IOC_MAGIC '3' #define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1) #define SNAPSHOT_UNFREEZE _IO(SNAPSHOT_IOC_MAGIC, 2) @@ -29,6 +41,7 @@ struct resume_swap_area { #define SNAPSHOT_PREF_IMAGE_SIZE _IO(SNAPSHOT_IOC_MAGIC, 18) #define SNAPSHOT_AVAIL_SWAP_SIZE _IOR(SNAPSHOT_IOC_MAGIC, 19, __kernel_loff_t) #define SNAPSHOT_ALLOC_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 20, __kernel_loff_t) -#define SNAPSHOT_IOC_MAXNR 20 +#define SNAPSHOT_ENABLE_ENCRYPTION _IOWR(SNAPSHOT_IOC_MAGIC, 21, struct uswsusp_key_blob) +#define SNAPSHOT_IOC_MAXNR 21 #endif /* _LINUX_SUSPEND_IOCTLS_H */ diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index a12779650f1529..8249968962bcd5 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -92,6 +92,19 @@ config HIBERNATION_SNAPSHOT_DEV If in doubt, say Y. +config ENCRYPTED_HIBERNATION + bool "Encryption support for userspace snapshots" + depends on HIBERNATION_SNAPSHOT_DEV + depends on CRYPTO_AEAD2=y + default n + help + Enable support for kernel-based encryption of hibernation snapshots + created by uswsusp tools. + + Say N if userspace handles the image encryption. + + If in doubt, say N. + config PM_STD_PARTITION string "Default resume partition" depends on HIBERNATION diff --git a/kernel/power/Makefile b/kernel/power/Makefile index 874ad834dc8daf..7be08f2e0e3b68 100644 --- a/kernel/power/Makefile +++ b/kernel/power/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_SUSPEND) += suspend.o obj-$(CONFIG_PM_TEST_SUSPEND) += suspend_test.o obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o swap.o obj-$(CONFIG_HIBERNATION_SNAPSHOT_DEV) += user.o +obj-$(CONFIG_ENCRYPTED_HIBERNATION) += snapenc.o obj-$(CONFIG_PM_AUTOSLEEP) += autosleep.o obj-$(CONFIG_PM_WAKELOCKS) += wakelock.o diff --git a/kernel/power/snapenc.c b/kernel/power/snapenc.c new file mode 100644 index 00000000000000..cb90692d6ab83a --- /dev/null +++ b/kernel/power/snapenc.c @@ -0,0 +1,491 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* This file provides encryption support for system snapshots. */ + +#include <linux/crypto.h> +#include <crypto/aead.h> +#include <crypto/gcm.h> +#include <linux/random.h> +#include <linux/mm.h> +#include <linux/uaccess.h> + +#include "power.h" +#include "user.h" + +/* Encrypt more data from the snapshot into the staging area. */ +static int snapshot_encrypt_refill(struct snapshot_data *data) +{ + + u8 nonce[GCM_AES_IV_SIZE]; + int pg_idx; + int res; + struct aead_request *req = data->aead_req; + DECLARE_CRYPTO_WAIT(wait); + size_t total = 0; + + /* + * The first buffer is the associated data, set to the offset to prevent + * attacks that rearrange chunks. + */ + sg_set_buf(&data->sg[0], &data->crypt_total, sizeof(data->crypt_total)); + + /* Load the crypt buffer with snapshot pages. */ + for (pg_idx = 0; pg_idx < CHUNK_SIZE; pg_idx++) { + void *buf = data->crypt_pages[pg_idx]; + + res = snapshot_read_next(&data->handle); + if (res < 0) + return res; + if (res == 0) + break; + + WARN_ON(res != PAGE_SIZE); + + /* + * Copy the page into the staging area. A future optimization + * could potentially skip this copy for lowmem pages. + */ + memcpy(buf, data_of(data->handle), PAGE_SIZE); + sg_set_buf(&data->sg[1 + pg_idx], buf, PAGE_SIZE); + total += PAGE_SIZE; + } + + sg_set_buf(&data->sg[1 + pg_idx], &data->auth_tag, SNAPSHOT_AUTH_TAG_SIZE); + aead_request_set_callback(req, 0, crypto_req_done, &wait); + /* + * Use incrementing nonces for each chunk, since a 64 bit value won't + * roll into re-use for any given hibernate image. + */ + memcpy(&nonce[0], &data->nonce_low, sizeof(data->nonce_low)); + memcpy(&nonce[sizeof(data->nonce_low)], + &data->nonce_high, + sizeof(nonce) - sizeof(data->nonce_low)); + + data->nonce_low += 1; + /* Total does not include AAD or the auth tag. */ + aead_request_set_crypt(req, data->sg, data->sg, total, nonce); + res = crypto_wait_req(crypto_aead_encrypt(req), &wait); + if (res) + return res; + + data->crypt_size = total; + data->crypt_total += total; + return 0; +} + +/* Decrypt data from the staging area and push it to the snapshot. */ +static int snapshot_decrypt_drain(struct snapshot_data *data) +{ + u8 nonce[GCM_AES_IV_SIZE]; + int page_count; + int pg_idx; + int res; + struct aead_request *req = data->aead_req; + DECLARE_CRYPTO_WAIT(wait); + size_t total; + + /* Set up the associated data. */ + sg_set_buf(&data->sg[0], &data->crypt_total, sizeof(data->crypt_total)); + + /* + * Get the number of full pages, which could be short at the end. There + * should also be a tag at the end, so the offset won't be an even page. + */ + page_count = data->crypt_offset >> PAGE_SHIFT; + total = page_count << PAGE_SHIFT; + if ((total == 0) || (total == data->crypt_offset)) + return -EINVAL; + + /* + * Load the sg list with the crypt buffer. Inline decrypt back into the + * staging buffer. A future optimization could decrypt directly into + * lowmem pages. + */ + for (pg_idx = 0; pg_idx < page_count; pg_idx++) + sg_set_buf(&data->sg[1 + pg_idx], data->crypt_pages[pg_idx], PAGE_SIZE); + + /* + * It's possible this is the final decrypt, and there are fewer than + * CHUNK_SIZE pages. If this is the case we would have just written the + * auth tag into the first few bytes of a new page. Copy to the tag if + * so. + */ + if ((page_count < CHUNK_SIZE) && + (data->crypt_offset - total) == sizeof(data->auth_tag)) { + + memcpy(data->auth_tag, + data->crypt_pages[pg_idx], + sizeof(data->auth_tag)); + + } else if (data->crypt_offset != + ((CHUNK_SIZE << PAGE_SHIFT) + SNAPSHOT_AUTH_TAG_SIZE)) { + + return -EINVAL; + } + + sg_set_buf(&data->sg[1 + pg_idx], &data->auth_tag, SNAPSHOT_AUTH_TAG_SIZE); + aead_request_set_callback(req, 0, crypto_req_done, &wait); + memcpy(&nonce[0], &data->nonce_low, sizeof(data->nonce_low)); + memcpy(&nonce[sizeof(data->nonce_low)], + &data->nonce_high, + sizeof(nonce) - sizeof(data->nonce_low)); + + data->nonce_low += 1; + aead_request_set_crypt(req, data->sg, data->sg, total + SNAPSHOT_AUTH_TAG_SIZE, nonce); + res = crypto_wait_req(crypto_aead_decrypt(req), &wait); + if (res) + return res; + + data->crypt_size = 0; + data->crypt_offset = 0; + + /* Push the decrypted pages further down the stack. */ + total = 0; + for (pg_idx = 0; pg_idx < page_count; pg_idx++) { + void *buf = data->crypt_pages[pg_idx]; + + res = snapshot_write_next(&data->handle); + if (res < 0) + return res; + if (res == 0) + break; + + if (!data_of(data->handle)) + return -EINVAL; + + WARN_ON(res != PAGE_SIZE); + + /* + * Copy the page into the staging area. A future optimization + * could potentially skip this copy for lowmem pages. + */ + memcpy(data_of(data->handle), buf, PAGE_SIZE); + total += PAGE_SIZE; + } + + data->crypt_total += total; + return 0; +} + +static ssize_t snapshot_read_next_encrypted(struct snapshot_data *data, + void **buf) +{ + size_t tag_off; + + /* Refill the encrypted buffer if it's empty. */ + if ((data->crypt_size == 0) || + (data->crypt_offset >= + (data->crypt_size + SNAPSHOT_AUTH_TAG_SIZE))) { + + int rc; + + data->crypt_size = 0; + data->crypt_offset = 0; + rc = snapshot_encrypt_refill(data); + if (rc < 0) + return rc; + } + + /* Return data pages if the offset is in that region. */ + if (data->crypt_offset < data->crypt_size) { + size_t pg_idx = data->crypt_offset >> PAGE_SHIFT; + size_t pg_off = data->crypt_offset & (PAGE_SIZE - 1); + *buf = data->crypt_pages[pg_idx] + pg_off; + return PAGE_SIZE - pg_off; + } + + /* Use offsets just beyond the size to return the tag. */ + tag_off = data->crypt_offset - data->crypt_size; + if (tag_off > SNAPSHOT_AUTH_TAG_SIZE) + tag_off = SNAPSHOT_AUTH_TAG_SIZE; + + *buf = data->auth_tag + tag_off; + return SNAPSHOT_AUTH_TAG_SIZE - tag_off; +} + +static ssize_t snapshot_write_next_encrypted(struct snapshot_data *data, + void **buf) +{ + size_t tag_off; + + /* Return data pages if the offset is in that region. */ + if (data->crypt_offset < (PAGE_SIZE * CHUNK_SIZE)) { + size_t pg_idx = data->crypt_offset >> PAGE_SHIFT; + size_t pg_off = data->crypt_offset & (PAGE_SIZE - 1); + *buf = data->crypt_pages[pg_idx] + pg_off; + return PAGE_SIZE - pg_off; + } + + /* Use offsets just beyond the size to return the tag. */ + tag_off = data->crypt_offset - (PAGE_SIZE * CHUNK_SIZE); + if (tag_off > SNAPSHOT_AUTH_TAG_SIZE) + tag_off = SNAPSHOT_AUTH_TAG_SIZE; + + *buf = data->auth_tag + tag_off; + return SNAPSHOT_AUTH_TAG_SIZE - tag_off; +} + +ssize_t snapshot_read_encrypted(struct snapshot_data *data, + char __user *buf, size_t count, loff_t *offp) +{ + ssize_t total = 0; + + /* Loop getting buffers of varying sizes and copying to userspace. */ + while (count) { + size_t copy_size; + size_t not_done; + void *src; + ssize_t src_size = snapshot_read_next_encrypted(data, &src); + + if (src_size <= 0) { + if (total == 0) + return src_size; + + break; + } + + copy_size = min(count, (size_t)src_size); + not_done = copy_to_user(buf + total, src, copy_size); + copy_size -= not_done; + total += copy_size; + count -= copy_size; + data->crypt_offset += copy_size; + if (copy_size == 0) { + if (total == 0) + return -EFAULT; + + break; + } + } + + *offp += total; + return total; +} + +ssize_t snapshot_write_encrypted(struct snapshot_data *data, + const char __user *buf, size_t count, loff_t *offp) +{ + ssize_t total = 0; + + /* Loop getting buffers of varying sizes and copying from. */ + while (count) { + size_t copy_size; + size_t not_done; + void *dst; + ssize_t dst_size = snapshot_write_next_encrypted(data, &dst); + + if (dst_size <= 0) { + if (total == 0) + return dst_size; + + break; + } + + copy_size = min(count, (size_t)dst_size); + not_done = copy_from_user(dst, buf + total, copy_size); + copy_size -= not_done; + total += copy_size; + count -= copy_size; + data->crypt_offset += copy_size; + if (copy_size == 0) { + if (total == 0) + return -EFAULT; + + break; + } + + /* Drain the encrypted buffer if it's full. */ + if ((data->crypt_offset >= + ((PAGE_SIZE * CHUNK_SIZE) + SNAPSHOT_AUTH_TAG_SIZE))) { + + int rc; + + rc = snapshot_decrypt_drain(data); + if (rc < 0) + return rc; + } + } + + *offp += total; + return total; +} + +void snapshot_teardown_encryption(struct snapshot_data *data) +{ + int i; + + if (data->aead_req) { + aead_request_free(data->aead_req); + data->aead_req = NULL; + } + + if (data->aead_tfm) { + crypto_free_aead(data->aead_tfm); + data->aead_tfm = NULL; + } + + for (i = 0; i < CHUNK_SIZE; i++) { + if (data->crypt_pages[i]) { + free_page((unsigned long)data->crypt_pages[i]); + data->crypt_pages[i] = NULL; + } + } +} + +static int snapshot_setup_encryption_common(struct snapshot_data *data) +{ + int i, rc; + + data->crypt_total = 0; + data->crypt_offset = 0; + data->crypt_size = 0; + memset(data->crypt_pages, 0, sizeof(data->crypt_pages)); + /* This only works once per hibernate. */ + if (data->aead_tfm) + return -EINVAL; + + /* Set up the encryption transform */ + data->aead_tfm = crypto_alloc_aead("gcm(aes)", 0, 0); + if (IS_ERR(data->aead_tfm)) { + rc = PTR_ERR(data->aead_tfm); + data->aead_tfm = NULL; + return rc; + } + + rc = -ENOMEM; + data->aead_req = aead_request_alloc(data->aead_tfm, GFP_KERNEL); + if (data->aead_req == NULL) + goto setup_fail; + + /* Allocate the staging area */ + for (i = 0; i < CHUNK_SIZE; i++) { + data->crypt_pages[i] = (void *)__get_free_page(GFP_ATOMIC); + if (data->crypt_pages[i] == NULL) + goto setup_fail; + } + + sg_init_table(data->sg, CHUNK_SIZE + 2); + + /* + * The associated data will be the offset so that blocks can't be + * rearranged. + */ + aead_request_set_ad(data->aead_req, sizeof(data->crypt_total)); + rc = crypto_aead_setauthsize(data->aead_tfm, SNAPSHOT_AUTH_TAG_SIZE); + if (rc) + goto setup_fail; + + return 0; + +setup_fail: + snapshot_teardown_encryption(data); + return rc; +} + +int snapshot_get_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key) +{ + u8 aead_key[SNAPSHOT_ENCRYPTION_KEY_SIZE]; + u8 nonce[USWSUSP_KEY_NONCE_SIZE]; + int rc; + /* Don't pull a random key from a world that can be reset. */ + if (data->ready) + return -EPIPE; + + rc = snapshot_setup_encryption_common(data); + if (rc) + return rc; + + /* Build a random starting nonce. */ + get_random_bytes(nonce, sizeof(nonce)); + memcpy(&data->nonce_low, &nonce[0], sizeof(data->nonce_low)); + memcpy(&data->nonce_high, &nonce[8], sizeof(data->nonce_high)); + /* Build a random key */ + get_random_bytes(aead_key, sizeof(aead_key)); + rc = crypto_aead_setkey(data->aead_tfm, aead_key, sizeof(aead_key)); + if (rc) + goto fail; + + /* Hand the key back to user mode (to be changed!) */ + rc = put_user(sizeof(struct uswsusp_key_blob), &key->blob_len); + if (rc) + goto fail; + + rc = copy_to_user(&key->blob, &aead_key, sizeof(aead_key)); + if (rc) + goto fail; + + rc = copy_to_user(&key->nonce, &nonce, sizeof(nonce)); + if (rc) + goto fail; + + return 0; + +fail: + snapshot_teardown_encryption(data); + return rc; +} + +int snapshot_set_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key) +{ + struct uswsusp_key_blob blob; + int rc; + + /* It's too late if data's been pushed in. */ + if (data->handle.cur) + return -EPIPE; + + rc = snapshot_setup_encryption_common(data); + if (rc) + return rc; + + /* Load the key from user mode. */ + rc = copy_from_user(&blob, key, sizeof(struct uswsusp_key_blob)); + if (rc) + goto crypto_setup_fail; + + if (blob.blob_len != sizeof(struct uswsusp_key_blob)) { + rc = -EINVAL; + goto crypto_setup_fail; + } + + rc = crypto_aead_setkey(data->aead_tfm, + blob.blob, + SNAPSHOT_ENCRYPTION_KEY_SIZE); + + if (rc) + goto crypto_setup_fail; + + /* Load the starting nonce. */ + memcpy(&data->nonce_low, &blob.nonce[0], sizeof(data->nonce_low)); + memcpy(&data->nonce_high, &blob.nonce[8], sizeof(data->nonce_high)); + return 0; + +crypto_setup_fail: + snapshot_teardown_encryption(data); + return rc; +} + +loff_t snapshot_get_encrypted_image_size(loff_t raw_size) +{ + loff_t pages = raw_size >> PAGE_SHIFT; + loff_t chunks = (pages + (CHUNK_SIZE - 1)) / CHUNK_SIZE; + /* + * The encrypted size is the normal size, plus a stitched in + * authentication tag for every chunk of pages. + */ + return raw_size + (chunks * SNAPSHOT_AUTH_TAG_SIZE); +} + +int snapshot_finalize_decrypted_image(struct snapshot_data *data) +{ + int rc; + + if (data->crypt_offset != 0) { + rc = snapshot_decrypt_drain(data); + if (rc) + return rc; + } + + return 0; +} diff --git a/kernel/power/user.c b/kernel/power/user.c index ad241b4ff64c58..52ad25df4518dc 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -25,18 +25,9 @@ #include <linux/uaccess.h> #include "power.h" +#include "user.h" - -static struct snapshot_data { - struct snapshot_handle handle; - int swap; - int mode; - bool frozen; - bool ready; - bool platform_support; - bool free_bitmaps; - dev_t dev; -} snapshot_state; +struct snapshot_data snapshot_state; int is_hibernate_resume_dev(dev_t dev) { @@ -119,6 +110,7 @@ static int snapshot_release(struct inode *inode, struct file *filp) } else if (data->free_bitmaps) { free_basic_memory_bitmaps(); } + snapshot_teardown_encryption(data); pm_notifier_call_chain(data->mode == O_RDONLY ? PM_POST_HIBERNATION : PM_POST_RESTORE); hibernate_release(); @@ -142,6 +134,12 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf, res = -ENODATA; goto Unlock; } + + if (snapshot_encryption_enabled(data)) { + res = snapshot_read_encrypted(data, buf, count, offp); + goto Unlock; + } + if (!pg_offp) { /* on page boundary? */ res = snapshot_read_next(&data->handle); if (res <= 0) @@ -172,6 +170,11 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf, data = filp->private_data; + if (snapshot_encryption_enabled(data)) { + res = snapshot_write_encrypted(data, buf, count, offp); + goto unlock; + } + if (!pg_offp) { res = snapshot_write_next(&data->handle); if (res <= 0) @@ -302,6 +305,12 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, break; case SNAPSHOT_ATOMIC_RESTORE: + if (snapshot_encryption_enabled(data)) { + error = snapshot_finalize_decrypted_image(data); + if (error) + break; + } + snapshot_write_finalize(&data->handle); if (data->mode != O_WRONLY || !data->frozen || !snapshot_image_loaded(&data->handle)) { @@ -337,6 +346,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, } size = snapshot_get_image_size(); size <<= PAGE_SHIFT; + if (snapshot_encryption_enabled(data)) + size = snapshot_get_encrypted_image_size(size); error = put_user(size, (loff_t __user *)arg); break; @@ -394,6 +405,13 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, error = snapshot_set_swap_area(data, (void __user *)arg); break; + case SNAPSHOT_ENABLE_ENCRYPTION: + if (data->mode == O_RDONLY) + error = snapshot_get_encryption_key(data, (void __user *)arg); + else + error = snapshot_set_encryption_key(data, (void __user *)arg); + break; + default: error = -ENOTTY; diff --git a/kernel/power/user.h b/kernel/power/user.h new file mode 100644 index 00000000000000..6823e2eba7ec53 --- /dev/null +++ b/kernel/power/user.h @@ -0,0 +1,101 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/crypto.h> +#include <crypto/aead.h> +#include <crypto/aes.h> + +#define SNAPSHOT_ENCRYPTION_KEY_SIZE AES_KEYSIZE_128 +#define SNAPSHOT_AUTH_TAG_SIZE 16 + +/* Define the number of pages in a single AEAD encryption chunk. */ +#define CHUNK_SIZE 16 + +struct snapshot_data { + struct snapshot_handle handle; + int swap; + int mode; + bool frozen; + bool ready; + bool platform_support; + bool free_bitmaps; + dev_t dev; + +#if defined(CONFIG_ENCRYPTED_HIBERNATION) + struct crypto_aead *aead_tfm; + struct aead_request *aead_req; + void *crypt_pages[CHUNK_SIZE]; + u8 auth_tag[SNAPSHOT_AUTH_TAG_SIZE]; + struct scatterlist sg[CHUNK_SIZE + 2]; /* Add room for AD and auth tag. */ + size_t crypt_offset; + size_t crypt_size; + uint64_t crypt_total; + uint64_t nonce_low; + uint64_t nonce_high; +#endif + +}; + +extern struct snapshot_data snapshot_state; + +/* kernel/power/swapenc.c routines */ +#if defined(CONFIG_ENCRYPTED_HIBERNATION) + +ssize_t snapshot_read_encrypted(struct snapshot_data *data, + char __user *buf, size_t count, loff_t *offp); + +ssize_t snapshot_write_encrypted(struct snapshot_data *data, + const char __user *buf, size_t count, loff_t *offp); + +void snapshot_teardown_encryption(struct snapshot_data *data); +int snapshot_get_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key); + +int snapshot_set_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key); + +loff_t snapshot_get_encrypted_image_size(loff_t raw_size); + +int snapshot_finalize_decrypted_image(struct snapshot_data *data); + +#define snapshot_encryption_enabled(data) (!!(data)->aead_tfm) + +#else + +ssize_t snapshot_read_encrypted(struct snapshot_data *data, + char __user *buf, size_t count, loff_t *offp) +{ + return -ENOTTY; +} + +ssize_t snapshot_write_encrypted(struct snapshot_data *data, + const char __user *buf, size_t count, loff_t *offp) +{ + return -ENOTTY; +} + +static void snapshot_teardown_encryption(struct snapshot_data *data) {} +static int snapshot_get_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key) +{ + return -ENOTTY; +} + +static int snapshot_set_encryption_key(struct snapshot_data *data, + struct uswsusp_key_blob __user *key) +{ + return -ENOTTY; +} + +static loff_t snapshot_get_encrypted_image_size(loff_t raw_size) +{ + return raw_size; +} + +static int snapshot_finalize_decrypted_image(struct snapshot_data *data) +{ + return -ENOTTY; +} + +#define snapshot_encryption_enabled(data) (0) + +#endif

[06/10] PM: hibernate: Add kernel-based encryption

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