mirror of
https://github.com/torvalds/linux.git
synced 2024-12-27 05:11:48 +00:00
3e7807d5a7
We are going to track per-extent information, so it'll be necessary to distinguish between inode infos and extent infos. Rename fscrypt_info to fscrypt_inode_info, adjusting any lines that now exceed 80 characters. Signed-off-by: Josef Bacik <josef@toxicpanda.com> [ebiggers: rebased onto fscrypt tree, renamed fscrypt_get_info(), adjusted two comments, and fixed some lines over 80 characters] Link: https://lore.kernel.org/r/20231005025757.33521-1-ebiggers@kernel.org Reviewed-by: Neal Gompa <neal@gompa.dev> Signed-off-by: Eric Biggers <ebiggers@google.com>
431 lines
14 KiB
C
431 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* This contains encryption functions for per-file encryption.
|
|
*
|
|
* Copyright (C) 2015, Google, Inc.
|
|
* Copyright (C) 2015, Motorola Mobility
|
|
*
|
|
* Written by Michael Halcrow, 2014.
|
|
*
|
|
* Filename encryption additions
|
|
* Uday Savagaonkar, 2014
|
|
* Encryption policy handling additions
|
|
* Ildar Muslukhov, 2014
|
|
* Add fscrypt_pullback_bio_page()
|
|
* Jaegeuk Kim, 2015.
|
|
*
|
|
* This has not yet undergone a rigorous security audit.
|
|
*
|
|
* The usage of AES-XTS should conform to recommendations in NIST
|
|
* Special Publication 800-38E and IEEE P1619/D16.
|
|
*/
|
|
|
|
#include <linux/pagemap.h>
|
|
#include <linux/mempool.h>
|
|
#include <linux/module.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <crypto/skcipher.h>
|
|
#include "fscrypt_private.h"
|
|
|
|
static unsigned int num_prealloc_crypto_pages = 32;
|
|
|
|
module_param(num_prealloc_crypto_pages, uint, 0444);
|
|
MODULE_PARM_DESC(num_prealloc_crypto_pages,
|
|
"Number of crypto pages to preallocate");
|
|
|
|
static mempool_t *fscrypt_bounce_page_pool = NULL;
|
|
|
|
static struct workqueue_struct *fscrypt_read_workqueue;
|
|
static DEFINE_MUTEX(fscrypt_init_mutex);
|
|
|
|
struct kmem_cache *fscrypt_inode_info_cachep;
|
|
|
|
void fscrypt_enqueue_decrypt_work(struct work_struct *work)
|
|
{
|
|
queue_work(fscrypt_read_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_enqueue_decrypt_work);
|
|
|
|
struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags)
|
|
{
|
|
if (WARN_ON_ONCE(!fscrypt_bounce_page_pool)) {
|
|
/*
|
|
* Oops, the filesystem called a function that uses the bounce
|
|
* page pool, but it didn't set needs_bounce_pages.
|
|
*/
|
|
return NULL;
|
|
}
|
|
return mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
|
|
}
|
|
|
|
/**
|
|
* fscrypt_free_bounce_page() - free a ciphertext bounce page
|
|
* @bounce_page: the bounce page to free, or NULL
|
|
*
|
|
* Free a bounce page that was allocated by fscrypt_encrypt_pagecache_blocks(),
|
|
* or by fscrypt_alloc_bounce_page() directly.
|
|
*/
|
|
void fscrypt_free_bounce_page(struct page *bounce_page)
|
|
{
|
|
if (!bounce_page)
|
|
return;
|
|
set_page_private(bounce_page, (unsigned long)NULL);
|
|
ClearPagePrivate(bounce_page);
|
|
mempool_free(bounce_page, fscrypt_bounce_page_pool);
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_free_bounce_page);
|
|
|
|
/*
|
|
* Generate the IV for the given data unit index within the given file.
|
|
* For filenames encryption, index == 0.
|
|
*
|
|
* Keep this in sync with fscrypt_limit_io_blocks(). fscrypt_limit_io_blocks()
|
|
* needs to know about any IV generation methods where the low bits of IV don't
|
|
* simply contain the data unit index (e.g., IV_INO_LBLK_32).
|
|
*/
|
|
void fscrypt_generate_iv(union fscrypt_iv *iv, u64 index,
|
|
const struct fscrypt_inode_info *ci)
|
|
{
|
|
u8 flags = fscrypt_policy_flags(&ci->ci_policy);
|
|
|
|
memset(iv, 0, ci->ci_mode->ivsize);
|
|
|
|
if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) {
|
|
WARN_ON_ONCE(index > U32_MAX);
|
|
WARN_ON_ONCE(ci->ci_inode->i_ino > U32_MAX);
|
|
index |= (u64)ci->ci_inode->i_ino << 32;
|
|
} else if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) {
|
|
WARN_ON_ONCE(index > U32_MAX);
|
|
index = (u32)(ci->ci_hashed_ino + index);
|
|
} else if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) {
|
|
memcpy(iv->nonce, ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE);
|
|
}
|
|
iv->index = cpu_to_le64(index);
|
|
}
|
|
|
|
/* Encrypt or decrypt a single "data unit" of file contents. */
|
|
int fscrypt_crypt_data_unit(const struct fscrypt_inode_info *ci,
|
|
fscrypt_direction_t rw, u64 index,
|
|
struct page *src_page, struct page *dest_page,
|
|
unsigned int len, unsigned int offs,
|
|
gfp_t gfp_flags)
|
|
{
|
|
union fscrypt_iv iv;
|
|
struct skcipher_request *req = NULL;
|
|
DECLARE_CRYPTO_WAIT(wait);
|
|
struct scatterlist dst, src;
|
|
struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
|
|
int res = 0;
|
|
|
|
if (WARN_ON_ONCE(len <= 0))
|
|
return -EINVAL;
|
|
if (WARN_ON_ONCE(len % FSCRYPT_CONTENTS_ALIGNMENT != 0))
|
|
return -EINVAL;
|
|
|
|
fscrypt_generate_iv(&iv, index, ci);
|
|
|
|
req = skcipher_request_alloc(tfm, gfp_flags);
|
|
if (!req)
|
|
return -ENOMEM;
|
|
|
|
skcipher_request_set_callback(
|
|
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
|
crypto_req_done, &wait);
|
|
|
|
sg_init_table(&dst, 1);
|
|
sg_set_page(&dst, dest_page, len, offs);
|
|
sg_init_table(&src, 1);
|
|
sg_set_page(&src, src_page, len, offs);
|
|
skcipher_request_set_crypt(req, &src, &dst, len, &iv);
|
|
if (rw == FS_DECRYPT)
|
|
res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
|
|
else
|
|
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
|
|
skcipher_request_free(req);
|
|
if (res) {
|
|
fscrypt_err(ci->ci_inode,
|
|
"%scryption failed for data unit %llu: %d",
|
|
(rw == FS_DECRYPT ? "De" : "En"), index, res);
|
|
return res;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_encrypt_pagecache_blocks() - Encrypt data from a pagecache page
|
|
* @page: the locked pagecache page containing the data to encrypt
|
|
* @len: size of the data to encrypt, in bytes
|
|
* @offs: offset within @page of the data to encrypt, in bytes
|
|
* @gfp_flags: memory allocation flags; see details below
|
|
*
|
|
* This allocates a new bounce page and encrypts the given data into it. The
|
|
* length and offset of the data must be aligned to the file's crypto data unit
|
|
* size. Alignment to the filesystem block size fulfills this requirement, as
|
|
* the filesystem block size is always a multiple of the data unit size.
|
|
*
|
|
* In the bounce page, the ciphertext data will be located at the same offset at
|
|
* which the plaintext data was located in the source page. Any other parts of
|
|
* the bounce page will be left uninitialized.
|
|
*
|
|
* This is for use by the filesystem's ->writepages() method.
|
|
*
|
|
* The bounce page allocation is mempool-backed, so it will always succeed when
|
|
* @gfp_flags includes __GFP_DIRECT_RECLAIM, e.g. when it's GFP_NOFS. However,
|
|
* only the first page of each bio can be allocated this way. To prevent
|
|
* deadlocks, for any additional pages a mask like GFP_NOWAIT must be used.
|
|
*
|
|
* Return: the new encrypted bounce page on success; an ERR_PTR() on failure
|
|
*/
|
|
struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
|
|
unsigned int len,
|
|
unsigned int offs,
|
|
gfp_t gfp_flags)
|
|
|
|
{
|
|
const struct inode *inode = page->mapping->host;
|
|
const struct fscrypt_inode_info *ci = inode->i_crypt_info;
|
|
const unsigned int du_bits = ci->ci_data_unit_bits;
|
|
const unsigned int du_size = 1U << du_bits;
|
|
struct page *ciphertext_page;
|
|
u64 index = ((u64)page->index << (PAGE_SHIFT - du_bits)) +
|
|
(offs >> du_bits);
|
|
unsigned int i;
|
|
int err;
|
|
|
|
if (WARN_ON_ONCE(!PageLocked(page)))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size)))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
ciphertext_page = fscrypt_alloc_bounce_page(gfp_flags);
|
|
if (!ciphertext_page)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
for (i = offs; i < offs + len; i += du_size, index++) {
|
|
err = fscrypt_crypt_data_unit(ci, FS_ENCRYPT, index,
|
|
page, ciphertext_page,
|
|
du_size, i, gfp_flags);
|
|
if (err) {
|
|
fscrypt_free_bounce_page(ciphertext_page);
|
|
return ERR_PTR(err);
|
|
}
|
|
}
|
|
SetPagePrivate(ciphertext_page);
|
|
set_page_private(ciphertext_page, (unsigned long)page);
|
|
return ciphertext_page;
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_encrypt_pagecache_blocks);
|
|
|
|
/**
|
|
* fscrypt_encrypt_block_inplace() - Encrypt a filesystem block in-place
|
|
* @inode: The inode to which this block belongs
|
|
* @page: The page containing the block to encrypt
|
|
* @len: Size of block to encrypt. This must be a multiple of
|
|
* FSCRYPT_CONTENTS_ALIGNMENT.
|
|
* @offs: Byte offset within @page at which the block to encrypt begins
|
|
* @lblk_num: Filesystem logical block number of the block, i.e. the 0-based
|
|
* number of the block within the file
|
|
* @gfp_flags: Memory allocation flags
|
|
*
|
|
* Encrypt a possibly-compressed filesystem block that is located in an
|
|
* arbitrary page, not necessarily in the original pagecache page. The @inode
|
|
* and @lblk_num must be specified, as they can't be determined from @page.
|
|
*
|
|
* This is not compatible with fscrypt_operations::supports_subblock_data_units.
|
|
*
|
|
* Return: 0 on success; -errno on failure
|
|
*/
|
|
int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
|
|
unsigned int len, unsigned int offs,
|
|
u64 lblk_num, gfp_t gfp_flags)
|
|
{
|
|
if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units))
|
|
return -EOPNOTSUPP;
|
|
return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_ENCRYPT,
|
|
lblk_num, page, page, len, offs,
|
|
gfp_flags);
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_encrypt_block_inplace);
|
|
|
|
/**
|
|
* fscrypt_decrypt_pagecache_blocks() - Decrypt data from a pagecache folio
|
|
* @folio: the pagecache folio containing the data to decrypt
|
|
* @len: size of the data to decrypt, in bytes
|
|
* @offs: offset within @folio of the data to decrypt, in bytes
|
|
*
|
|
* Decrypt data that has just been read from an encrypted file. The data must
|
|
* be located in a pagecache folio that is still locked and not yet uptodate.
|
|
* The length and offset of the data must be aligned to the file's crypto data
|
|
* unit size. Alignment to the filesystem block size fulfills this requirement,
|
|
* as the filesystem block size is always a multiple of the data unit size.
|
|
*
|
|
* Return: 0 on success; -errno on failure
|
|
*/
|
|
int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len,
|
|
size_t offs)
|
|
{
|
|
const struct inode *inode = folio->mapping->host;
|
|
const struct fscrypt_inode_info *ci = inode->i_crypt_info;
|
|
const unsigned int du_bits = ci->ci_data_unit_bits;
|
|
const unsigned int du_size = 1U << du_bits;
|
|
u64 index = ((u64)folio->index << (PAGE_SHIFT - du_bits)) +
|
|
(offs >> du_bits);
|
|
size_t i;
|
|
int err;
|
|
|
|
if (WARN_ON_ONCE(!folio_test_locked(folio)))
|
|
return -EINVAL;
|
|
|
|
if (WARN_ON_ONCE(len <= 0 || !IS_ALIGNED(len | offs, du_size)))
|
|
return -EINVAL;
|
|
|
|
for (i = offs; i < offs + len; i += du_size, index++) {
|
|
struct page *page = folio_page(folio, i >> PAGE_SHIFT);
|
|
|
|
err = fscrypt_crypt_data_unit(ci, FS_DECRYPT, index, page,
|
|
page, du_size, i & ~PAGE_MASK,
|
|
GFP_NOFS);
|
|
if (err)
|
|
return err;
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_decrypt_pagecache_blocks);
|
|
|
|
/**
|
|
* fscrypt_decrypt_block_inplace() - Decrypt a filesystem block in-place
|
|
* @inode: The inode to which this block belongs
|
|
* @page: The page containing the block to decrypt
|
|
* @len: Size of block to decrypt. This must be a multiple of
|
|
* FSCRYPT_CONTENTS_ALIGNMENT.
|
|
* @offs: Byte offset within @page at which the block to decrypt begins
|
|
* @lblk_num: Filesystem logical block number of the block, i.e. the 0-based
|
|
* number of the block within the file
|
|
*
|
|
* Decrypt a possibly-compressed filesystem block that is located in an
|
|
* arbitrary page, not necessarily in the original pagecache page. The @inode
|
|
* and @lblk_num must be specified, as they can't be determined from @page.
|
|
*
|
|
* This is not compatible with fscrypt_operations::supports_subblock_data_units.
|
|
*
|
|
* Return: 0 on success; -errno on failure
|
|
*/
|
|
int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
|
|
unsigned int len, unsigned int offs,
|
|
u64 lblk_num)
|
|
{
|
|
if (WARN_ON_ONCE(inode->i_sb->s_cop->supports_subblock_data_units))
|
|
return -EOPNOTSUPP;
|
|
return fscrypt_crypt_data_unit(inode->i_crypt_info, FS_DECRYPT,
|
|
lblk_num, page, page, len, offs,
|
|
GFP_NOFS);
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_decrypt_block_inplace);
|
|
|
|
/**
|
|
* fscrypt_initialize() - allocate major buffers for fs encryption.
|
|
* @sb: the filesystem superblock
|
|
*
|
|
* We only call this when we start accessing encrypted files, since it
|
|
* results in memory getting allocated that wouldn't otherwise be used.
|
|
*
|
|
* Return: 0 on success; -errno on failure
|
|
*/
|
|
int fscrypt_initialize(struct super_block *sb)
|
|
{
|
|
int err = 0;
|
|
mempool_t *pool;
|
|
|
|
/* pairs with smp_store_release() below */
|
|
if (likely(smp_load_acquire(&fscrypt_bounce_page_pool)))
|
|
return 0;
|
|
|
|
/* No need to allocate a bounce page pool if this FS won't use it. */
|
|
if (!sb->s_cop->needs_bounce_pages)
|
|
return 0;
|
|
|
|
mutex_lock(&fscrypt_init_mutex);
|
|
if (fscrypt_bounce_page_pool)
|
|
goto out_unlock;
|
|
|
|
err = -ENOMEM;
|
|
pool = mempool_create_page_pool(num_prealloc_crypto_pages, 0);
|
|
if (!pool)
|
|
goto out_unlock;
|
|
/* pairs with smp_load_acquire() above */
|
|
smp_store_release(&fscrypt_bounce_page_pool, pool);
|
|
err = 0;
|
|
out_unlock:
|
|
mutex_unlock(&fscrypt_init_mutex);
|
|
return err;
|
|
}
|
|
|
|
void fscrypt_msg(const struct inode *inode, const char *level,
|
|
const char *fmt, ...)
|
|
{
|
|
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
|
|
DEFAULT_RATELIMIT_BURST);
|
|
struct va_format vaf;
|
|
va_list args;
|
|
|
|
if (!__ratelimit(&rs))
|
|
return;
|
|
|
|
va_start(args, fmt);
|
|
vaf.fmt = fmt;
|
|
vaf.va = &args;
|
|
if (inode && inode->i_ino)
|
|
printk("%sfscrypt (%s, inode %lu): %pV\n",
|
|
level, inode->i_sb->s_id, inode->i_ino, &vaf);
|
|
else if (inode)
|
|
printk("%sfscrypt (%s): %pV\n", level, inode->i_sb->s_id, &vaf);
|
|
else
|
|
printk("%sfscrypt: %pV\n", level, &vaf);
|
|
va_end(args);
|
|
}
|
|
|
|
/**
|
|
* fscrypt_init() - Set up for fs encryption.
|
|
*
|
|
* Return: 0 on success; -errno on failure
|
|
*/
|
|
static int __init fscrypt_init(void)
|
|
{
|
|
int err = -ENOMEM;
|
|
|
|
/*
|
|
* Use an unbound workqueue to allow bios to be decrypted in parallel
|
|
* even when they happen to complete on the same CPU. This sacrifices
|
|
* locality, but it's worthwhile since decryption is CPU-intensive.
|
|
*
|
|
* Also use a high-priority workqueue to prioritize decryption work,
|
|
* which blocks reads from completing, over regular application tasks.
|
|
*/
|
|
fscrypt_read_workqueue = alloc_workqueue("fscrypt_read_queue",
|
|
WQ_UNBOUND | WQ_HIGHPRI,
|
|
num_online_cpus());
|
|
if (!fscrypt_read_workqueue)
|
|
goto fail;
|
|
|
|
fscrypt_inode_info_cachep = KMEM_CACHE(fscrypt_inode_info,
|
|
SLAB_RECLAIM_ACCOUNT);
|
|
if (!fscrypt_inode_info_cachep)
|
|
goto fail_free_queue;
|
|
|
|
err = fscrypt_init_keyring();
|
|
if (err)
|
|
goto fail_free_inode_info;
|
|
|
|
return 0;
|
|
|
|
fail_free_inode_info:
|
|
kmem_cache_destroy(fscrypt_inode_info_cachep);
|
|
fail_free_queue:
|
|
destroy_workqueue(fscrypt_read_workqueue);
|
|
fail:
|
|
return err;
|
|
}
|
|
late_initcall(fscrypt_init)
|