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linux/fs/ext4/crypto.c

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ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
/*
* linux/fs/ext4/crypto.c
*
* Copyright (C) 2015, Google, Inc.
*
* This contains encryption functions for ext4
*
* Written by Michael Halcrow, 2014.
*
* Filename encryption additions
* Uday Savagaonkar, 2014
* Encryption policy handling additions
* Ildar Muslukhov, 2014
*
* 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 <crypto/hash.h>
#include <crypto/sha.h>
#include <keys/user-type.h>
#include <keys/encrypted-type.h>
#include <linux/crypto.h>
#include <linux/ecryptfs.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/key.h>
#include <linux/list.h>
#include <linux/mempool.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <linux/spinlock_types.h>
#include "ext4_extents.h"
#include "xattr.h"
/* Encryption added and removed here! (L: */
static unsigned int num_prealloc_crypto_pages = 32;
static unsigned int num_prealloc_crypto_ctxs = 128;
module_param(num_prealloc_crypto_pages, uint, 0444);
MODULE_PARM_DESC(num_prealloc_crypto_pages,
"Number of crypto pages to preallocate");
module_param(num_prealloc_crypto_ctxs, uint, 0444);
MODULE_PARM_DESC(num_prealloc_crypto_ctxs,
"Number of crypto contexts to preallocate");
static mempool_t *ext4_bounce_page_pool;
static LIST_HEAD(ext4_free_crypto_ctxs);
static DEFINE_SPINLOCK(ext4_crypto_ctx_lock);
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
static struct kmem_cache *ext4_crypto_ctx_cachep;
struct kmem_cache *ext4_crypt_info_cachep;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
/**
* ext4_release_crypto_ctx() - Releases an encryption context
* @ctx: The encryption context to release.
*
* If the encryption context was allocated from the pre-allocated pool, returns
* it to that pool. Else, frees it.
*
* If there's a bounce page in the context, this frees that.
*/
void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
{
unsigned long flags;
ext4 crypto: allocate bounce pages using GFP_NOWAIT Previously we allocated bounce pages using a combination of alloc_page() and mempool_alloc() with the __GFP_WAIT bit set. Instead, use mempool_alloc() with GFP_NOWAIT. The mempool_alloc() function will try using alloc_pages() initially, and then only use the mempool reserve of pages if alloc_pages() is unable to fulfill the request. This minimizes the the impact on the mm layer when we need to do a large amount of writeback of encrypted files, as Jaeguk Kim had reported that under a heavy fio workload on a system with restricted amounts memory (which unfortunately, includes many mobile handsets), he had observed the the OOM killer getting triggered several times. Using GFP_NOWAIT If the mempool_alloc() function fails, we will retry the page writeback at a later time; the function of the mempool is to ensure that we can writeback at least 32 pages at a time, so we can more efficiently dispatch I/O under high memory pressure situations. In the future we should make this be a tunable so we can determine the best tradeoff between permanently sequestering memory and the ability to quickly launder pages so we can free up memory quickly when necessary. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-03 21:32:39 +08:00
if (ctx->flags & EXT4_WRITE_PATH_FL && ctx->w.bounce_page)
mempool_free(ctx->w.bounce_page, ext4_bounce_page_pool);
ext4 crypto: shrink size of the ext4_crypto_ctx structure Some fields are only used when the crypto_ctx is being used on the read path, some are only used on the write path, and some are only used when the structure is on free list. Optimize memory use by using a union. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:31:34 +08:00
ctx->w.bounce_page = NULL;
ctx->w.control_page = NULL;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) {
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
kmem_cache_free(ext4_crypto_ctx_cachep, ctx);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
} else {
spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
}
}
/**
* ext4_get_crypto_ctx() - Gets an encryption context
* @inode: The inode for which we are doing the crypto
*
* Allocates and initializes an encryption context.
*
* Return: An allocated and initialized encryption context on success; error
* value or NULL otherwise.
*/
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
{
struct ext4_crypto_ctx *ctx = NULL;
int res = 0;
unsigned long flags;
ext4 crypto: reorganize how we store keys in the inode This is a pretty massive patch which does a number of different things: 1) The per-inode encryption information is now stored in an allocated data structure, ext4_crypt_info, instead of directly in the node. This reduces the size usage of an in-memory inode when it is not using encryption. 2) We drop the ext4_fname_crypto_ctx entirely, and use the per-inode encryption structure instead. This remove an unnecessary memory allocation and free for the fname_crypto_ctx as well as allowing us to reuse the ctfm in a directory for multiple lookups and file creations. 3) We also cache the inode's policy information in the ext4_crypt_info structure so we don't have to continually read it out of the extended attributes. 4) We now keep the keyring key in the inode's encryption structure instead of releasing it after we are done using it to derive the per-inode key. This allows us to test to see if the key has been revoked; if it has, we prevent the use of the derived key and free it. 5) When an inode is released (or when the derived key is freed), we will use memset_explicit() to zero out the derived key, so it's not left hanging around in memory. This implies that when a user logs out, it is important to first revoke the key, and then unlink it, and then finally, to use "echo 3 > /proc/sys/vm/drop_caches" to release any decrypted pages and dcache entries from the system caches. 6) All this, and we also shrink the number of lines of code by around 100. :-) Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:17:47 +08:00
struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
ext4 crypto: handle unexpected lack of encryption keys Fix up attempts by users to try to write to a file when they don't have access to the encryption key. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:35:39 +08:00
if (ci == NULL)
return ERR_PTR(-ENOKEY);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
/*
* We first try getting the ctx from a free list because in
* the common case the ctx will have an allocated and
* initialized crypto tfm, so it's probably a worthwhile
* optimization. For the bounce page, we first try getting it
* from the kernel allocator because that's just about as fast
* as getting it from a list and because a cache of free pages
* should generally be a "last resort" option for a filesystem
* to be able to do its job.
*/
spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
ctx = list_first_entry_or_null(&ext4_free_crypto_ctxs,
struct ext4_crypto_ctx, free_list);
if (ctx)
list_del(&ctx->free_list);
spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
if (!ctx) {
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
if (!ctx) {
res = -ENOMEM;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
goto out;
}
ctx->flags |= EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
} else {
ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
}
ext4 crypto: shrink size of the ext4_crypto_ctx structure Some fields are only used when the crypto_ctx is being used on the read path, some are only used on the write path, and some are only used when the structure is on free list. Optimize memory use by using a union. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:31:34 +08:00
ctx->flags &= ~EXT4_WRITE_PATH_FL;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
out:
if (res) {
if (!IS_ERR_OR_NULL(ctx))
ext4_release_crypto_ctx(ctx);
ctx = ERR_PTR(res);
}
return ctx;
}
struct workqueue_struct *ext4_read_workqueue;
static DEFINE_MUTEX(crypto_init);
/**
* ext4_exit_crypto() - Shutdown the ext4 encryption system
*/
void ext4_exit_crypto(void)
{
struct ext4_crypto_ctx *pos, *n;
ext4 crypto: use per-inode tfm structure As suggested by Herbert Xu, we shouldn't allocate a new tfm each time we read or write a page. Instead we can use a single tfm hanging off the inode's crypt_info structure for all of our encryption needs for that inode, since the tfm can be used by multiple crypto requests in parallel. Also use cmpxchg() to avoid races that could result in crypt_info structure getting doubly allocated or doubly freed. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:22 +08:00
list_for_each_entry_safe(pos, n, &ext4_free_crypto_ctxs, free_list)
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
kmem_cache_free(ext4_crypto_ctx_cachep, pos);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
INIT_LIST_HEAD(&ext4_free_crypto_ctxs);
if (ext4_bounce_page_pool)
mempool_destroy(ext4_bounce_page_pool);
ext4_bounce_page_pool = NULL;
if (ext4_read_workqueue)
destroy_workqueue(ext4_read_workqueue);
ext4_read_workqueue = NULL;
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
if (ext4_crypto_ctx_cachep)
kmem_cache_destroy(ext4_crypto_ctx_cachep);
ext4_crypto_ctx_cachep = NULL;
if (ext4_crypt_info_cachep)
kmem_cache_destroy(ext4_crypt_info_cachep);
ext4_crypt_info_cachep = NULL;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
}
/**
* ext4_init_crypto() - Set up for ext4 encryption.
*
* We only call this when we start accessing encrypted files, since it
* results in memory getting allocated that wouldn't otherwise be used.
*
* Return: Zero on success, non-zero otherwise.
*/
int ext4_init_crypto(void)
{
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
int i, res = -ENOMEM;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
mutex_lock(&crypto_init);
if (ext4_read_workqueue)
goto already_initialized;
ext4_read_workqueue = alloc_workqueue("ext4_crypto", WQ_HIGHPRI, 0);
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
if (!ext4_read_workqueue)
goto fail;
ext4_crypto_ctx_cachep = KMEM_CACHE(ext4_crypto_ctx,
SLAB_RECLAIM_ACCOUNT);
if (!ext4_crypto_ctx_cachep)
goto fail;
ext4_crypt_info_cachep = KMEM_CACHE(ext4_crypt_info,
SLAB_RECLAIM_ACCOUNT);
if (!ext4_crypt_info_cachep)
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
goto fail;
for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
struct ext4_crypto_ctx *ctx;
ext4 crypto: use slab caches Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for slighly better memory efficiency and debuggability. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-05-19 01:19:47 +08:00
ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
if (!ctx) {
res = -ENOMEM;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
goto fail;
}
list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
}
ext4_bounce_page_pool =
mempool_create_page_pool(num_prealloc_crypto_pages, 0);
if (!ext4_bounce_page_pool) {
res = -ENOMEM;
goto fail;
}
already_initialized:
mutex_unlock(&crypto_init);
return 0;
fail:
ext4_exit_crypto();
mutex_unlock(&crypto_init);
return res;
}
void ext4_restore_control_page(struct page *data_page)
{
struct ext4_crypto_ctx *ctx =
(struct ext4_crypto_ctx *)page_private(data_page);
set_page_private(data_page, (unsigned long)NULL);
ClearPagePrivate(data_page);
unlock_page(data_page);
ext4_release_crypto_ctx(ctx);
}
/**
* ext4_crypt_complete() - The completion callback for page encryption
* @req: The asynchronous encryption request context
* @res: The result of the encryption operation
*/
static void ext4_crypt_complete(struct crypto_async_request *req, int res)
{
struct ext4_completion_result *ecr = req->data;
if (res == -EINPROGRESS)
return;
ecr->res = res;
complete(&ecr->completion);
}
typedef enum {
EXT4_DECRYPT = 0,
EXT4_ENCRYPT,
} ext4_direction_t;
ext4 crypto: ext4_page_crypto() doesn't need a encryption context Since ext4_page_crypto() doesn't need an encryption context (at least not any more), this allows us to simplify a number function signature and also allows us to avoid needing to allocate a context in ext4_block_write_begin(). It also means we no longer need a separate ext4_decrypt_one() function. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-03 22:49:26 +08:00
static int ext4_page_crypto(struct inode *inode,
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
ext4_direction_t rw,
pgoff_t index,
struct page *src_page,
struct page *dest_page)
{
u8 xts_tweak[EXT4_XTS_TWEAK_SIZE];
struct ablkcipher_request *req = NULL;
DECLARE_EXT4_COMPLETION_RESULT(ecr);
struct scatterlist dst, src;
ext4 crypto: use per-inode tfm structure As suggested by Herbert Xu, we shouldn't allocate a new tfm each time we read or write a page. Instead we can use a single tfm hanging off the inode's crypt_info structure for all of our encryption needs for that inode, since the tfm can be used by multiple crypto requests in parallel. Also use cmpxchg() to avoid races that could result in crypt_info structure getting doubly allocated or doubly freed. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:22 +08:00
struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;
struct crypto_ablkcipher *tfm = ci->ci_ctfm;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
int res = 0;
ext4 crypto: use per-inode tfm structure As suggested by Herbert Xu, we shouldn't allocate a new tfm each time we read or write a page. Instead we can use a single tfm hanging off the inode's crypt_info structure for all of our encryption needs for that inode, since the tfm can be used by multiple crypto requests in parallel. Also use cmpxchg() to avoid races that could result in crypt_info structure getting doubly allocated or doubly freed. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:22 +08:00
req = ablkcipher_request_alloc(tfm, GFP_NOFS);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
if (!req) {
printk_ratelimited(KERN_ERR
"%s: crypto_request_alloc() failed\n",
__func__);
return -ENOMEM;
}
ablkcipher_request_set_callback(
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
ext4_crypt_complete, &ecr);
BUILD_BUG_ON(EXT4_XTS_TWEAK_SIZE < sizeof(index));
memcpy(xts_tweak, &index, sizeof(index));
memset(&xts_tweak[sizeof(index)], 0,
EXT4_XTS_TWEAK_SIZE - sizeof(index));
sg_init_table(&dst, 1);
sg_set_page(&dst, dest_page, PAGE_CACHE_SIZE, 0);
sg_init_table(&src, 1);
sg_set_page(&src, src_page, PAGE_CACHE_SIZE, 0);
ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
xts_tweak);
if (rw == EXT4_DECRYPT)
res = crypto_ablkcipher_decrypt(req);
else
res = crypto_ablkcipher_encrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) {
wait_for_completion(&ecr.completion);
res = ecr.res;
}
ablkcipher_request_free(req);
if (res) {
printk_ratelimited(
KERN_ERR
"%s: crypto_ablkcipher_encrypt() returned %d\n",
__func__, res);
return res;
}
return 0;
}
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx)
{
ext4 crypto: allocate bounce pages using GFP_NOWAIT Previously we allocated bounce pages using a combination of alloc_page() and mempool_alloc() with the __GFP_WAIT bit set. Instead, use mempool_alloc() with GFP_NOWAIT. The mempool_alloc() function will try using alloc_pages() initially, and then only use the mempool reserve of pages if alloc_pages() is unable to fulfill the request. This minimizes the the impact on the mm layer when we need to do a large amount of writeback of encrypted files, as Jaeguk Kim had reported that under a heavy fio workload on a system with restricted amounts memory (which unfortunately, includes many mobile handsets), he had observed the the OOM killer getting triggered several times. Using GFP_NOWAIT If the mempool_alloc() function fails, we will retry the page writeback at a later time; the function of the mempool is to ensure that we can writeback at least 32 pages at a time, so we can more efficiently dispatch I/O under high memory pressure situations. In the future we should make this be a tunable so we can determine the best tradeoff between permanently sequestering memory and the ability to quickly launder pages so we can free up memory quickly when necessary. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-03 21:32:39 +08:00
ctx->w.bounce_page = mempool_alloc(ext4_bounce_page_pool, GFP_NOWAIT);
if (ctx->w.bounce_page == NULL)
return ERR_PTR(-ENOMEM);
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
ctx->flags |= EXT4_WRITE_PATH_FL;
ext4 crypto: allocate bounce pages using GFP_NOWAIT Previously we allocated bounce pages using a combination of alloc_page() and mempool_alloc() with the __GFP_WAIT bit set. Instead, use mempool_alloc() with GFP_NOWAIT. The mempool_alloc() function will try using alloc_pages() initially, and then only use the mempool reserve of pages if alloc_pages() is unable to fulfill the request. This minimizes the the impact on the mm layer when we need to do a large amount of writeback of encrypted files, as Jaeguk Kim had reported that under a heavy fio workload on a system with restricted amounts memory (which unfortunately, includes many mobile handsets), he had observed the the OOM killer getting triggered several times. Using GFP_NOWAIT If the mempool_alloc() function fails, we will retry the page writeback at a later time; the function of the mempool is to ensure that we can writeback at least 32 pages at a time, so we can more efficiently dispatch I/O under high memory pressure situations. In the future we should make this be a tunable so we can determine the best tradeoff between permanently sequestering memory and the ability to quickly launder pages so we can free up memory quickly when necessary. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-03 21:32:39 +08:00
return ctx->w.bounce_page;
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
}
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
/**
* ext4_encrypt() - Encrypts a page
* @inode: The inode for which the encryption should take place
* @plaintext_page: The page to encrypt. Must be locked.
*
* Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
* encryption context.
*
* Called on the page write path. The caller must call
* ext4_restore_control_page() on the returned ciphertext page to
* release the bounce buffer and the encryption context.
*
* Return: An allocated page with the encrypted content on success. Else, an
* error value or NULL.
*/
struct page *ext4_encrypt(struct inode *inode,
struct page *plaintext_page)
{
struct ext4_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
int err;
BUG_ON(!PageLocked(plaintext_page));
ctx = ext4_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return (struct page *) ctx;
/* The encryption operation will require a bounce page. */
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page))
goto errout;
ext4 crypto: shrink size of the ext4_crypto_ctx structure Some fields are only used when the crypto_ctx is being used on the read path, some are only used on the write path, and some are only used when the structure is on free list. Optimize memory use by using a union. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:31:34 +08:00
ctx->w.control_page = plaintext_page;
ext4 crypto: ext4_page_crypto() doesn't need a encryption context Since ext4_page_crypto() doesn't need an encryption context (at least not any more), this allows us to simplify a number function signature and also allows us to avoid needing to allocate a context in ext4_block_write_begin(). It also means we no longer need a separate ext4_decrypt_one() function. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-03 22:49:26 +08:00
err = ext4_page_crypto(inode, EXT4_ENCRYPT, plaintext_page->index,
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
plaintext_page, ciphertext_page);
if (err) {
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
ciphertext_page = ERR_PTR(err);
errout:
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
ext4_release_crypto_ctx(ctx);
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
return ciphertext_page;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
}
SetPagePrivate(ciphertext_page);
set_page_private(ciphertext_page, (unsigned long)ctx);
lock_page(ciphertext_page);
return ciphertext_page;
}
/**
* ext4_decrypt() - Decrypts a page in-place
* @ctx: The encryption context.
* @page: The page to decrypt. Must be locked.
*
* Decrypts page in-place using the ctx encryption context.
*
* Called from the read completion callback.
*
* Return: Zero on success, non-zero otherwise.
*/
ext4 crypto: ext4_page_crypto() doesn't need a encryption context Since ext4_page_crypto() doesn't need an encryption context (at least not any more), this allows us to simplify a number function signature and also allows us to avoid needing to allocate a context in ext4_block_write_begin(). It also means we no longer need a separate ext4_decrypt_one() function. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-03 22:49:26 +08:00
int ext4_decrypt(struct page *page)
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
{
BUG_ON(!PageLocked(page));
ext4 crypto: ext4_page_crypto() doesn't need a encryption context Since ext4_page_crypto() doesn't need an encryption context (at least not any more), this allows us to simplify a number function signature and also allows us to avoid needing to allocate a context in ext4_block_write_begin(). It also means we no longer need a separate ext4_decrypt_one() function. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-03 22:49:26 +08:00
return ext4_page_crypto(page->mapping->host,
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
EXT4_DECRYPT, page->index, page, page);
}
ext4: provide ext4_issue_zeroout() Create new function ext4_issue_zeroout() to zeroout contiguous (both logically and physically) part of inode data. We will need to issue zeroout when extent structure is not readily available and this function will allow us to do it without making up fake extent structures. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-08 04:09:35 +08:00
int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
ext4_fsblk_t pblk, ext4_lblk_t len)
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
{
struct ext4_crypto_ctx *ctx;
struct page *ciphertext_page = NULL;
struct bio *bio;
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
int ret, err = 0;
#if 0
ext4_msg(inode->i_sb, KERN_CRIT,
"ext4_encrypted_zeroout ino %lu lblk %u len %u",
(unsigned long) inode->i_ino, lblk, len);
#endif
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
ctx = ext4_get_crypto_ctx(inode);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page)) {
err = PTR_ERR(ciphertext_page);
goto errout;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
}
while (len--) {
ext4 crypto: ext4_page_crypto() doesn't need a encryption context Since ext4_page_crypto() doesn't need an encryption context (at least not any more), this allows us to simplify a number function signature and also allows us to avoid needing to allocate a context in ext4_block_write_begin(). It also means we no longer need a separate ext4_decrypt_one() function. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-10-03 22:49:26 +08:00
err = ext4_page_crypto(inode, EXT4_ENCRYPT, lblk,
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
ZERO_PAGE(0), ciphertext_page);
if (err)
goto errout;
bio = bio_alloc(GFP_KERNEL, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
bio->bi_bdev = inode->i_sb->s_bdev;
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
bio->bi_iter.bi_sector =
pblk << (inode->i_sb->s_blocksize_bits - 9);
ret = bio_add_page(bio, ciphertext_page,
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
inode->i_sb->s_blocksize, 0);
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
if (ret != inode->i_sb->s_blocksize) {
/* should never happen! */
ext4_msg(inode->i_sb, KERN_ERR,
"bio_add_page failed: %d", ret);
WARN_ON(1);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
bio_put(bio);
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
err = -EIO;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
goto errout;
}
err = submit_bio_wait(WRITE, bio);
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
if ((err == 0) && bio->bi_error)
err = -EIO;
ext4 crypto: fix memory leaks in ext4_encrypted_zeroout ext4_encrypted_zeroout() could end up leaking a bio and bounce page. Fortunately it's not used much. While we're fixing things up, refactor out common code into the static function alloc_bounce_page() and fix up error handling if mempool_alloc() fails. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-06-01 01:34:24 +08:00
bio_put(bio);
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
if (err)
goto errout;
ext4 crypto: fix bugs in ext4_encrypted_zeroout() Fix multiple bugs in ext4_encrypted_zeroout(), including one that could cause us to write an encrypted zero page to the wrong location on disk, potentially causing data and file system corruption. Fortunately, this tends to only show up in stress tests, but even with these fixes, we are seeing some test failures with generic/127 --- but these are now caused by data failures instead of metadata corruption. Since ext4_encrypted_zeroout() is only used for some optimizations to keep the extent tree from being too fragmented, and ext4_encrypted_zeroout() itself isn't all that optimized from a time or IOPS perspective, disable the extent tree optimization for encrypted inodes for now. This prevents the data corruption issues reported by generic/127 until we can figure out what's going wrong. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2015-10-03 22:49:29 +08:00
lblk++; pblk++;
ext4 crypto: add ext4 encryption facilities On encrypt, we will re-assign the buffer_heads to point to a bounce page rather than the control_page (which is the original page to write that contains the plaintext). The block I/O occurs against the bounce page. On write completion, we re-assign the buffer_heads to the original plaintext page. On decrypt, we will attach a read completion callback to the bio struct. This read completion will decrypt the read contents in-place prior to setting the page up-to-date. The current encryption mode, AES-256-XTS, lacks cryptographic integrity. AES-256-GCM is in-plan, but we will need to devise a mechanism for handling the integrity data. Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-04-12 12:43:56 +08:00
}
err = 0;
errout:
ext4_release_crypto_ctx(ctx);
return err;
}
bool ext4_valid_contents_enc_mode(uint32_t mode)
{
return (mode == EXT4_ENCRYPTION_MODE_AES_256_XTS);
}
/**
* ext4_validate_encryption_key_size() - Validate the encryption key size
* @mode: The key mode.
* @size: The key size to validate.
*
* Return: The validated key size for @mode. Zero if invalid.
*/
uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size)
{
if (size == ext4_encryption_key_size(mode))
return size;
return 0;
}