xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge tag 'for-f2fs-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Browse Source 
Pull f2fs updates from Jaegeuk Kim:
 "New Features:
   - uplift filesystem encryption into fs/crypto/
   - give sysfs entries to control memroy consumption

  Enhancements:
   - aio performance by preallocating blocks in ->write_iter
   - use writepages lock for only WB_SYNC_ALL
   - avoid redundant inline_data conversion
   - enhance forground GC
   - use wait_for_stable_page as possible
   - speed up SEEK_DATA and fiiemap

  Bug Fixes:
   - corner case in terms of -ENOSPC for inline_data
   - hung task caused by long latency in shrinker
   - corruption between atomic write and f2fs_trace_pid
   - avoid garbage lengths in dentries
   - revoke atomicly written pages if an error occurs

  In addition, there are various minor bug fixes and clean-ups"

* tag 'for-f2fs-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (81 commits)
  f2fs: submit node page write bios when really required
  f2fs: add missing argument to f2fs_setxattr stub
  f2fs: fix to avoid unneeded unlock_new_inode
  f2fs: clean up opened code with f2fs_update_dentry
  f2fs: declare static functions
  f2fs: use cryptoapi crc32 functions
  f2fs: modify the readahead method in ra_node_page()
  f2fs crypto: sync ext4_lookup and ext4_file_open
  fs crypto: move per-file encryption from f2fs tree to fs/crypto
  f2fs: mutex can't be used by down_write_nest_lock()
  f2fs: recovery missing dot dentries in root directory
  f2fs: fix to avoid deadlock when merging inline data
  f2fs: introduce f2fs_flush_merged_bios for cleanup
  f2fs: introduce f2fs_update_data_blkaddr for cleanup
  f2fs crypto: fix incorrect positioning for GCing encrypted data page
  f2fs: fix incorrect upper bound when iterating inode mapping tree
  f2fs: avoid hungtask problem caused by losing wake_up
  f2fs: trace old block address for CoWed page
  f2fs: try to flush inode after merging inline data
  f2fs: show more info about superblock recovery
  ...
This commit is contained in:
Linus Torvalds
2016-03-21 11:03:02 -07:00
parent 5518f66b5a 12bb0a8fd4
commit d407574e79
40 changed files with 3148 additions and 2385 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
fs/crypto/Kconfig Normal file
View File

@@ -0,0 +1,18 @@
config FS_ENCRYPTION
tristate "FS Encryption (Per-file encryption)"
depends on BLOCK
select CRYPTO
select CRYPTO_AES
select CRYPTO_CBC
select CRYPTO_ECB
select CRYPTO_XTS
select CRYPTO_CTS
select CRYPTO_CTR
select CRYPTO_SHA256
select KEYS
select ENCRYPTED_KEYS
help
Enable encryption of files and directories. This
feature is similar to ecryptfs, but it is more memory
efficient since it avoids caching the encrypted and
decrypted pages in the page cache.

3
fs/crypto/Makefile Normal file
View File

@@ -0,0 +1,3 @@
obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o
fscrypto-y := crypto.o fname.o policy.o keyinfo.o

555
fs/crypto/crypto.c Normal file
View File

@@ -0,0 +1,555 @@
/*
* 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 <linux/bio.h>
#include <linux/dcache.h>
#include <linux/fscrypto.h>
#include <linux/ecryptfs.h>
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 *fscrypt_bounce_page_pool = NULL;
static LIST_HEAD(fscrypt_free_ctxs);
static DEFINE_SPINLOCK(fscrypt_ctx_lock);
static struct workqueue_struct *fscrypt_read_workqueue;
static DEFINE_MUTEX(fscrypt_init_mutex);
static struct kmem_cache *fscrypt_ctx_cachep;
struct kmem_cache *fscrypt_info_cachep;
/**
* fscrypt_release_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 fscrypt_release_ctx(struct fscrypt_ctx *ctx)
{
unsigned long flags;
if (ctx->flags & FS_WRITE_PATH_FL && ctx->w.bounce_page) {
mempool_free(ctx->w.bounce_page, fscrypt_bounce_page_pool);
ctx->w.bounce_page = NULL;
}
ctx->w.control_page = NULL;
if (ctx->flags & FS_CTX_REQUIRES_FREE_ENCRYPT_FL) {
kmem_cache_free(fscrypt_ctx_cachep, ctx);
} else {
spin_lock_irqsave(&fscrypt_ctx_lock, flags);
list_add(&ctx->free_list, &fscrypt_free_ctxs);
spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
}
}
EXPORT_SYMBOL(fscrypt_release_ctx);
/**
* fscrypt_get_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 fscrypt_ctx *fscrypt_get_ctx(struct inode *inode)
{
struct fscrypt_ctx *ctx = NULL;
struct fscrypt_info *ci = inode->i_crypt_info;
unsigned long flags;
if (ci == NULL)
return ERR_PTR(-ENOKEY);
/*
* 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(&fscrypt_ctx_lock, flags);
ctx = list_first_entry_or_null(&fscrypt_free_ctxs,
struct fscrypt_ctx, free_list);
if (ctx)
list_del(&ctx->free_list);
spin_unlock_irqrestore(&fscrypt_ctx_lock, flags);
if (!ctx) {
ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, GFP_NOFS);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->flags |= FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
} else {
ctx->flags &= ~FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
}
ctx->flags &= ~FS_WRITE_PATH_FL;
return ctx;
}
EXPORT_SYMBOL(fscrypt_get_ctx);
/**
* fscrypt_complete() - The completion callback for page encryption
* @req: The asynchronous encryption request context
* @res: The result of the encryption operation
*/
static void fscrypt_complete(struct crypto_async_request *req, int res)
{
struct fscrypt_completion_result *ecr = req->data;
if (res == -EINPROGRESS)
return;
ecr->res = res;
complete(&ecr->completion);
}
typedef enum {
FS_DECRYPT = 0,
FS_ENCRYPT,
} fscrypt_direction_t;
static int do_page_crypto(struct inode *inode,
fscrypt_direction_t rw, pgoff_t index,
struct page *src_page, struct page *dest_page)
{
u8 xts_tweak[FS_XTS_TWEAK_SIZE];
struct skcipher_request *req = NULL;
DECLARE_FS_COMPLETION_RESULT(ecr);
struct scatterlist dst, src;
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
int res = 0;
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
printk_ratelimited(KERN_ERR
"%s: crypto_request_alloc() failed\n",
__func__);
return -ENOMEM;
}
skcipher_request_set_callback(
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
fscrypt_complete, &ecr);
BUILD_BUG_ON(FS_XTS_TWEAK_SIZE < sizeof(index));
memcpy(xts_tweak, &inode->i_ino, sizeof(index));
memset(&xts_tweak[sizeof(index)], 0,
FS_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);
skcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
xts_tweak);
if (rw == FS_DECRYPT)
res = crypto_skcipher_decrypt(req);
else
res = crypto_skcipher_encrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) {
BUG_ON(req->base.data != &ecr);
wait_for_completion(&ecr.completion);
res = ecr.res;
}
skcipher_request_free(req);
if (res) {
printk_ratelimited(KERN_ERR
"%s: crypto_skcipher_encrypt() returned %d\n",
__func__, res);
return res;
}
return 0;
}
static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx)
{
ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool,
GFP_NOWAIT);
if (ctx->w.bounce_page == NULL)
return ERR_PTR(-ENOMEM);
ctx->flags |= FS_WRITE_PATH_FL;
return ctx->w.bounce_page;
}
/**
* fscypt_encrypt_page() - 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
* fscrypt_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 *fscrypt_encrypt_page(struct inode *inode,
struct page *plaintext_page)
{
struct fscrypt_ctx *ctx;
struct page *ciphertext_page = NULL;
int err;
BUG_ON(!PageLocked(plaintext_page));
ctx = fscrypt_get_ctx(inode);
if (IS_ERR(ctx))
return (struct page *)ctx;
/* The encryption operation will require a bounce page. */
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page))
goto errout;
ctx->w.control_page = plaintext_page;
err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page);
if (err) {
ciphertext_page = ERR_PTR(err);
goto errout;
}
SetPagePrivate(ciphertext_page);
set_page_private(ciphertext_page, (unsigned long)ctx);
lock_page(ciphertext_page);
return ciphertext_page;
errout:
fscrypt_release_ctx(ctx);
return ciphertext_page;
}
EXPORT_SYMBOL(fscrypt_encrypt_page);
/**
* f2crypt_decrypt_page() - Decrypts a page in-place
* @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.
*/
int fscrypt_decrypt_page(struct page *page)
{
BUG_ON(!PageLocked(page));
return do_page_crypto(page->mapping->host,
FS_DECRYPT, page->index, page, page);
}
EXPORT_SYMBOL(fscrypt_decrypt_page);
int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len)
{
struct fscrypt_ctx *ctx;
struct page *ciphertext_page = NULL;
struct bio *bio;
int ret, err = 0;
BUG_ON(inode->i_sb->s_blocksize != PAGE_CACHE_SIZE);
ctx = fscrypt_get_ctx(inode);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ciphertext_page = alloc_bounce_page(ctx);
if (IS_ERR(ciphertext_page)) {
err = PTR_ERR(ciphertext_page);
goto errout;
}
while (len--) {
err = do_page_crypto(inode, FS_ENCRYPT, lblk,
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;
bio->bi_iter.bi_sector =
pblk << (inode->i_sb->s_blocksize_bits - 9);
ret = bio_add_page(bio, ciphertext_page,
inode->i_sb->s_blocksize, 0);
if (ret != inode->i_sb->s_blocksize) {
/* should never happen! */
WARN_ON(1);
bio_put(bio);
err = -EIO;
goto errout;
}
err = submit_bio_wait(WRITE, bio);
if ((err == 0) && bio->bi_error)
err = -EIO;
bio_put(bio);
if (err)
goto errout;
lblk++;
pblk++;
}
err = 0;
errout:
fscrypt_release_ctx(ctx);
return err;
}
EXPORT_SYMBOL(fscrypt_zeroout_range);
/*
* Validate dentries for encrypted directories to make sure we aren't
* potentially caching stale data after a key has been added or
* removed.
*/
static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
{
struct inode *dir = d_inode(dentry->d_parent);
struct fscrypt_info *ci = dir->i_crypt_info;
int dir_has_key, cached_with_key;
if (!dir->i_sb->s_cop->is_encrypted(dir))
return 0;
if (ci && ci->ci_keyring_key &&
(ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
(1 << KEY_FLAG_REVOKED) |
(1 << KEY_FLAG_DEAD))))
ci = NULL;
/* this should eventually be an flag in d_flags */
spin_lock(&dentry->d_lock);
cached_with_key = dentry->d_flags & DCACHE_ENCRYPTED_WITH_KEY;
spin_unlock(&dentry->d_lock);
dir_has_key = (ci != NULL);
/*
* If the dentry was cached without the key, and it is a
* negative dentry, it might be a valid name. We can't check
* if the key has since been made available due to locking
* reasons, so we fail the validation so ext4_lookup() can do
* this check.
*
* We also fail the validation if the dentry was created with
* the key present, but we no longer have the key, or vice versa.
*/
if ((!cached_with_key && d_is_negative(dentry)) ||
(!cached_with_key && dir_has_key) ||
(cached_with_key && !dir_has_key))
return 0;
return 1;
}
const struct dentry_operations fscrypt_d_ops = {
.d_revalidate = fscrypt_d_revalidate,
};
EXPORT_SYMBOL(fscrypt_d_ops);
/*
* Call fscrypt_decrypt_page on every single page, reusing the encryption
* context.
*/
static void completion_pages(struct work_struct *work)
{
struct fscrypt_ctx *ctx =
container_of(work, struct fscrypt_ctx, r.work);
struct bio *bio = ctx->r.bio;
struct bio_vec *bv;
int i;
bio_for_each_segment_all(bv, bio, i) {
struct page *page = bv->bv_page;
int ret = fscrypt_decrypt_page(page);
if (ret) {
WARN_ON_ONCE(1);
SetPageError(page);
} else {
SetPageUptodate(page);
}
unlock_page(page);
}
fscrypt_release_ctx(ctx);
bio_put(bio);
}
void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
{
INIT_WORK(&ctx->r.work, completion_pages);
ctx->r.bio = bio;
queue_work(fscrypt_read_workqueue, &ctx->r.work);
}
EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
void fscrypt_pullback_bio_page(struct page **page, bool restore)
{
struct fscrypt_ctx *ctx;
struct page *bounce_page;
/* The bounce data pages are unmapped. */
if ((*page)->mapping)
return;
/* The bounce data page is unmapped. */
bounce_page = *page;
ctx = (struct fscrypt_ctx *)page_private(bounce_page);
/* restore control page */
*page = ctx->w.control_page;
if (restore)
fscrypt_restore_control_page(bounce_page);
}
EXPORT_SYMBOL(fscrypt_pullback_bio_page);
void fscrypt_restore_control_page(struct page *page)
{
struct fscrypt_ctx *ctx;
ctx = (struct fscrypt_ctx *)page_private(page);
set_page_private(page, (unsigned long)NULL);
ClearPagePrivate(page);
unlock_page(page);
fscrypt_release_ctx(ctx);
}
EXPORT_SYMBOL(fscrypt_restore_control_page);
static void fscrypt_destroy(void)
{
struct fscrypt_ctx *pos, *n;
list_for_each_entry_safe(pos, n, &fscrypt_free_ctxs, free_list)
kmem_cache_free(fscrypt_ctx_cachep, pos);
INIT_LIST_HEAD(&fscrypt_free_ctxs);
mempool_destroy(fscrypt_bounce_page_pool);
fscrypt_bounce_page_pool = NULL;
}
/**
* fscrypt_initialize() - allocate major buffers for fs 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 fscrypt_initialize(void)
{
int i, res = -ENOMEM;
if (fscrypt_bounce_page_pool)
return 0;
mutex_lock(&fscrypt_init_mutex);
if (fscrypt_bounce_page_pool)
goto already_initialized;
for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
struct fscrypt_ctx *ctx;
ctx = kmem_cache_zalloc(fscrypt_ctx_cachep, GFP_NOFS);
if (!ctx)
goto fail;
list_add(&ctx->free_list, &fscrypt_free_ctxs);
}
fscrypt_bounce_page_pool =
mempool_create_page_pool(num_prealloc_crypto_pages, 0);
if (!fscrypt_bounce_page_pool)
goto fail;
already_initialized:
mutex_unlock(&fscrypt_init_mutex);
return 0;
fail:
fscrypt_destroy();
mutex_unlock(&fscrypt_init_mutex);
return res;
}
EXPORT_SYMBOL(fscrypt_initialize);
/**
* fscrypt_init() - Set up for fs encryption.
*/
static int __init fscrypt_init(void)
{
fscrypt_read_workqueue = alloc_workqueue("fscrypt_read_queue",
WQ_HIGHPRI, 0);
if (!fscrypt_read_workqueue)
goto fail;
fscrypt_ctx_cachep = KMEM_CACHE(fscrypt_ctx, SLAB_RECLAIM_ACCOUNT);
if (!fscrypt_ctx_cachep)
goto fail_free_queue;
fscrypt_info_cachep = KMEM_CACHE(fscrypt_info, SLAB_RECLAIM_ACCOUNT);
if (!fscrypt_info_cachep)
goto fail_free_ctx;
return 0;
fail_free_ctx:
kmem_cache_destroy(fscrypt_ctx_cachep);
fail_free_queue:
destroy_workqueue(fscrypt_read_workqueue);
fail:
return -ENOMEM;
}
module_init(fscrypt_init)
/**
* fscrypt_exit() - Shutdown the fs encryption system
*/
static void __exit fscrypt_exit(void)
{
fscrypt_destroy();
if (fscrypt_read_workqueue)
destroy_workqueue(fscrypt_read_workqueue);
kmem_cache_destroy(fscrypt_ctx_cachep);
kmem_cache_destroy(fscrypt_info_cachep);
}
module_exit(fscrypt_exit);
MODULE_LICENSE("GPL");

424
fs/crypto/fname.c Normal file
View File

@@ -0,0 +1,424 @@
/*
* This contains functions for filename crypto management
*
* Copyright (C) 2015, Google, Inc.
* Copyright (C) 2015, Motorola Mobility
*
* Written by Uday Savagaonkar, 2014.
* Modified by Jaegeuk Kim, 2015.
*
* This has not yet undergone a rigorous security audit.
*/
#include <keys/encrypted-type.h>
#include <keys/user-type.h>
#include <linux/scatterlist.h>
#include <linux/ratelimit.h>
#include <linux/fscrypto.h>
static u32 size_round_up(size_t size, size_t blksize)
{
return ((size + blksize - 1) / blksize) * blksize;
}
/**
* dir_crypt_complete() -
*/
static void dir_crypt_complete(struct crypto_async_request *req, int res)
{
struct fscrypt_completion_result *ecr = req->data;
if (res == -EINPROGRESS)
return;
ecr->res = res;
complete(&ecr->completion);
}
/**
* fname_encrypt() -
*
* This function encrypts the input filename, and returns the length of the
* ciphertext. Errors are returned as negative numbers. We trust the caller to
* allocate sufficient memory to oname string.
*/
static int fname_encrypt(struct inode *inode,
const struct qstr *iname, struct fscrypt_str *oname)
{
u32 ciphertext_len;
struct skcipher_request *req = NULL;
DECLARE_FS_COMPLETION_RESULT(ecr);
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
int res = 0;
char iv[FS_CRYPTO_BLOCK_SIZE];
struct scatterlist src_sg, dst_sg;
int padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK);
char *workbuf, buf[32], *alloc_buf = NULL;
unsigned lim;
lim = inode->i_sb->s_cop->max_namelen(inode);
if (iname->len <= 0 || iname->len > lim)
return -EIO;
ciphertext_len = (iname->len < FS_CRYPTO_BLOCK_SIZE) ?
FS_CRYPTO_BLOCK_SIZE : iname->len;
ciphertext_len = size_round_up(ciphertext_len, padding);
ciphertext_len = (ciphertext_len > lim) ? lim : ciphertext_len;
if (ciphertext_len <= sizeof(buf)) {
workbuf = buf;
} else {
alloc_buf = kmalloc(ciphertext_len, GFP_NOFS);
if (!alloc_buf)
return -ENOMEM;
workbuf = alloc_buf;
}
/* Allocate request */
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
printk_ratelimited(KERN_ERR
"%s: crypto_request_alloc() failed\n", __func__);
kfree(alloc_buf);
return -ENOMEM;
}
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
dir_crypt_complete, &ecr);
/* Copy the input */
memcpy(workbuf, iname->name, iname->len);
if (iname->len < ciphertext_len)
memset(workbuf + iname->len, 0, ciphertext_len - iname->len);
/* Initialize IV */
memset(iv, 0, FS_CRYPTO_BLOCK_SIZE);
/* Create encryption request */
sg_init_one(&src_sg, workbuf, ciphertext_len);
sg_init_one(&dst_sg, oname->name, ciphertext_len);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
res = crypto_skcipher_encrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) {
wait_for_completion(&ecr.completion);
res = ecr.res;
}
kfree(alloc_buf);
skcipher_request_free(req);
if (res < 0)
printk_ratelimited(KERN_ERR
"%s: Error (error code %d)\n", __func__, res);
oname->len = ciphertext_len;
return res;
}
/*
* fname_decrypt()
* This function decrypts the input filename, and returns
* the length of the plaintext.
* Errors are returned as negative numbers.
* We trust the caller to allocate sufficient memory to oname string.
*/
static int fname_decrypt(struct inode *inode,
const struct fscrypt_str *iname,
struct fscrypt_str *oname)
{
struct skcipher_request *req = NULL;
DECLARE_FS_COMPLETION_RESULT(ecr);
struct scatterlist src_sg, dst_sg;
struct fscrypt_info *ci = inode->i_crypt_info;
struct crypto_skcipher *tfm = ci->ci_ctfm;
int res = 0;
char iv[FS_CRYPTO_BLOCK_SIZE];
unsigned lim;
lim = inode->i_sb->s_cop->max_namelen(inode);
if (iname->len <= 0 || iname->len > lim)
return -EIO;
/* Allocate request */
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
printk_ratelimited(KERN_ERR
"%s: crypto_request_alloc() failed\n", __func__);
return -ENOMEM;
}
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
dir_crypt_complete, &ecr);
/* Initialize IV */
memset(iv, 0, FS_CRYPTO_BLOCK_SIZE);
/* Create decryption request */
sg_init_one(&src_sg, iname->name, iname->len);
sg_init_one(&dst_sg, oname->name, oname->len);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, iv);
res = crypto_skcipher_decrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) {
wait_for_completion(&ecr.completion);
res = ecr.res;
}
skcipher_request_free(req);
if (res < 0) {
printk_ratelimited(KERN_ERR
"%s: Error (error code %d)\n", __func__, res);
return res;
}
oname->len = strnlen(oname->name, iname->len);
return oname->len;
}
static const char *lookup_table =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
/**
* digest_encode() -
*
* Encodes the input digest using characters from the set [a-zA-Z0-9_+].
* The encoded string is roughly 4/3 times the size of the input string.
*/
static int digest_encode(const char *src, int len, char *dst)
{
int i = 0, bits = 0, ac = 0;
char *cp = dst;
while (i < len) {
ac += (((unsigned char) src[i]) << bits);
bits += 8;
do {
*cp++ = lookup_table[ac & 0x3f];
ac >>= 6;
bits -= 6;
} while (bits >= 6);
i++;
}
if (bits)
*cp++ = lookup_table[ac & 0x3f];
return cp - dst;
}
static int digest_decode(const char *src, int len, char *dst)
{
int i = 0, bits = 0, ac = 0;
const char *p;
char *cp = dst;
while (i < len) {
p = strchr(lookup_table, src[i]);
if (p == NULL || src[i] == 0)
return -2;
ac += (p - lookup_table) << bits;
bits += 6;
if (bits >= 8) {
*cp++ = ac & 0xff;
ac >>= 8;
bits -= 8;
}
i++;
}
if (ac)
return -1;
return cp - dst;
}
u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen)
{
int padding = 32;
struct fscrypt_info *ci = inode->i_crypt_info;
if (ci)
padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK);
if (ilen < FS_CRYPTO_BLOCK_SIZE)
ilen = FS_CRYPTO_BLOCK_SIZE;
return size_round_up(ilen, padding);
}
EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
/**
* fscrypt_fname_crypto_alloc_obuff() -
*
* Allocates an output buffer that is sufficient for the crypto operation
* specified by the context and the direction.
*/
int fscrypt_fname_alloc_buffer(struct inode *inode,
u32 ilen, struct fscrypt_str *crypto_str)
{
unsigned int olen = fscrypt_fname_encrypted_size(inode, ilen);
crypto_str->len = olen;
if (olen < FS_FNAME_CRYPTO_DIGEST_SIZE * 2)
olen = FS_FNAME_CRYPTO_DIGEST_SIZE * 2;
/*
* Allocated buffer can hold one more character to null-terminate the
* string
*/
crypto_str->name = kmalloc(olen + 1, GFP_NOFS);
if (!(crypto_str->name))
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(fscrypt_fname_alloc_buffer);
/**
* fscrypt_fname_crypto_free_buffer() -
*
* Frees the buffer allocated for crypto operation.
*/
void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
{
if (!crypto_str)
return;
kfree(crypto_str->name);
crypto_str->name = NULL;
}
EXPORT_SYMBOL(fscrypt_fname_free_buffer);
/**
* fscrypt_fname_disk_to_usr() - converts a filename from disk space to user
* space
*/
int fscrypt_fname_disk_to_usr(struct inode *inode,
u32 hash, u32 minor_hash,
const struct fscrypt_str *iname,
struct fscrypt_str *oname)
{
const struct qstr qname = FSTR_TO_QSTR(iname);
char buf[24];
int ret;
if (fscrypt_is_dot_dotdot(&qname)) {
oname->name[0] = '.';
oname->name[iname->len - 1] = '.';
oname->len = iname->len;
return oname->len;
}
if (iname->len < FS_CRYPTO_BLOCK_SIZE)
return -EUCLEAN;
if (inode->i_crypt_info)
return fname_decrypt(inode, iname, oname);
if (iname->len <= FS_FNAME_CRYPTO_DIGEST_SIZE) {
ret = digest_encode(iname->name, iname->len, oname->name);
oname->len = ret;
return ret;
}
if (hash) {
memcpy(buf, &hash, 4);
memcpy(buf + 4, &minor_hash, 4);
} else {
memset(buf, 0, 8);
}
memcpy(buf + 8, iname->name + iname->len - 16, 16);
oname->name[0] = '_';
ret = digest_encode(buf, 24, oname->name + 1);
oname->len = ret + 1;
return ret + 1;
}
EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
/**
* fscrypt_fname_usr_to_disk() - converts a filename from user space to disk
* space
*/
int fscrypt_fname_usr_to_disk(struct inode *inode,
const struct qstr *iname,
struct fscrypt_str *oname)
{
if (fscrypt_is_dot_dotdot(iname)) {
oname->name[0] = '.';
oname->name[iname->len - 1] = '.';
oname->len = iname->len;
return oname->len;
}
if (inode->i_crypt_info)
return fname_encrypt(inode, iname, oname);
/*
* Without a proper key, a user is not allowed to modify the filenames
* in a directory. Consequently, a user space name cannot be mapped to
* a disk-space name
*/
return -EACCES;
}
EXPORT_SYMBOL(fscrypt_fname_usr_to_disk);
int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
int lookup, struct fscrypt_name *fname)
{
int ret = 0, bigname = 0;
memset(fname, 0, sizeof(struct fscrypt_name));
fname->usr_fname = iname;
if (!dir->i_sb->s_cop->is_encrypted(dir) ||
fscrypt_is_dot_dotdot(iname)) {
fname->disk_name.name = (unsigned char *)iname->name;
fname->disk_name.len = iname->len;
return 0;
}
ret = get_crypt_info(dir);
if (ret && ret != -EOPNOTSUPP)
return ret;
if (dir->i_crypt_info) {
ret = fscrypt_fname_alloc_buffer(dir, iname->len,
&fname->crypto_buf);
if (ret < 0)
return ret;
ret = fname_encrypt(dir, iname, &fname->crypto_buf);
if (ret < 0)
goto errout;
fname->disk_name.name = fname->crypto_buf.name;
fname->disk_name.len = fname->crypto_buf.len;
return 0;
}
if (!lookup)
return -EACCES;
/*
* We don't have the key and we are doing a lookup; decode the
* user-supplied name
*/
if (iname->name[0] == '_')
bigname = 1;
if ((bigname && (iname->len != 33)) || (!bigname && (iname->len > 43)))
return -ENOENT;
fname->crypto_buf.name = kmalloc(32, GFP_KERNEL);
if (fname->crypto_buf.name == NULL)
return -ENOMEM;
ret = digest_decode(iname->name + bigname, iname->len - bigname,
fname->crypto_buf.name);
if (ret < 0) {
ret = -ENOENT;
goto errout;
}
fname->crypto_buf.len = ret;
if (bigname) {
memcpy(&fname->hash, fname->crypto_buf.name, 4);
memcpy(&fname->minor_hash, fname->crypto_buf.name + 4, 4);
} else {
fname->disk_name.name = fname->crypto_buf.name;
fname->disk_name.len = fname->crypto_buf.len;
}
return 0;
errout:
fscrypt_fname_free_buffer(&fname->crypto_buf);
return ret;
}
EXPORT_SYMBOL(fscrypt_setup_filename);
void fscrypt_free_filename(struct fscrypt_name *fname)
{
kfree(fname->crypto_buf.name);
fname->crypto_buf.name = NULL;
fname->usr_fname = NULL;
fname->disk_name.name = NULL;
}
EXPORT_SYMBOL(fscrypt_free_filename);

272
fs/crypto/keyinfo.c Normal file
View File

@@ -0,0 +1,272 @@
/*
* key management facility for FS encryption support.
*
* Copyright (C) 2015, Google, Inc.
*
* This contains encryption key functions.
*
* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
*/
#include <keys/encrypted-type.h>
#include <keys/user-type.h>
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <uapi/linux/keyctl.h>
#include <linux/fscrypto.h>
static void derive_crypt_complete(struct crypto_async_request *req, int rc)
{
struct fscrypt_completion_result *ecr = req->data;
if (rc == -EINPROGRESS)
return;
ecr->res = rc;
complete(&ecr->completion);
}
/**
* derive_key_aes() - Derive a key using AES-128-ECB
* @deriving_key: Encryption key used for derivation.
* @source_key: Source key to which to apply derivation.
* @derived_key: Derived key.
*
* Return: Zero on success; non-zero otherwise.
*/
static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
u8 source_key[FS_AES_256_XTS_KEY_SIZE],
u8 derived_key[FS_AES_256_XTS_KEY_SIZE])
{
int res = 0;
struct skcipher_request *req = NULL;
DECLARE_FS_COMPLETION_RESULT(ecr);
struct scatterlist src_sg, dst_sg;
struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
if (IS_ERR(tfm)) {
res = PTR_ERR(tfm);
tfm = NULL;
goto out;
}
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_WEAK_KEY);
req = skcipher_request_alloc(tfm, GFP_NOFS);
if (!req) {
res = -ENOMEM;
goto out;
}
skcipher_request_set_callback(req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
derive_crypt_complete, &ecr);
res = crypto_skcipher_setkey(tfm, deriving_key,
FS_AES_128_ECB_KEY_SIZE);
if (res < 0)
goto out;
sg_init_one(&src_sg, source_key, FS_AES_256_XTS_KEY_SIZE);
sg_init_one(&dst_sg, derived_key, FS_AES_256_XTS_KEY_SIZE);
skcipher_request_set_crypt(req, &src_sg, &dst_sg,
FS_AES_256_XTS_KEY_SIZE, NULL);
res = crypto_skcipher_encrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) {
wait_for_completion(&ecr.completion);
res = ecr.res;
}
out:
skcipher_request_free(req);
crypto_free_skcipher(tfm);
return res;
}
static void put_crypt_info(struct fscrypt_info *ci)
{
if (!ci)
return;
key_put(ci->ci_keyring_key);
crypto_free_skcipher(ci->ci_ctfm);
kmem_cache_free(fscrypt_info_cachep, ci);
}
int get_crypt_info(struct inode *inode)
{
struct fscrypt_info *crypt_info;
u8 full_key_descriptor[FS_KEY_DESC_PREFIX_SIZE +
(FS_KEY_DESCRIPTOR_SIZE * 2) + 1];
struct key *keyring_key = NULL;
struct fscrypt_key *master_key;
struct fscrypt_context ctx;
const struct user_key_payload *ukp;
struct crypto_skcipher *ctfm;
const char *cipher_str;
u8 raw_key[FS_MAX_KEY_SIZE];
u8 mode;
int res;
res = fscrypt_initialize();
if (res)
return res;
if (!inode->i_sb->s_cop->get_context)
return -EOPNOTSUPP;
retry:
crypt_info = ACCESS_ONCE(inode->i_crypt_info);
if (crypt_info) {
if (!crypt_info->ci_keyring_key ||
key_validate(crypt_info->ci_keyring_key) == 0)
return 0;
fscrypt_put_encryption_info(inode, crypt_info);
goto retry;
}
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
if (!fscrypt_dummy_context_enabled(inode))
return res;
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
ctx.flags = 0;
} else if (res != sizeof(ctx)) {
return -EINVAL;
}
res = 0;
crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
if (!crypt_info)
return -ENOMEM;
crypt_info->ci_flags = ctx.flags;
crypt_info->ci_data_mode = ctx.contents_encryption_mode;
crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
crypt_info->ci_ctfm = NULL;
crypt_info->ci_keyring_key = NULL;
memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
sizeof(crypt_info->ci_master_key));
if (S_ISREG(inode->i_mode))
mode = crypt_info->ci_data_mode;
else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
mode = crypt_info->ci_filename_mode;
else
BUG();
switch (mode) {
case FS_ENCRYPTION_MODE_AES_256_XTS:
cipher_str = "xts(aes)";
break;
case FS_ENCRYPTION_MODE_AES_256_CTS:
cipher_str = "cts(cbc(aes))";
break;
default:
printk_once(KERN_WARNING
"%s: unsupported key mode %d (ino %u)\n",
__func__, mode, (unsigned) inode->i_ino);
res = -ENOKEY;
goto out;
}
if (fscrypt_dummy_context_enabled(inode)) {
memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE);
goto got_key;
}
memcpy(full_key_descriptor, FS_KEY_DESC_PREFIX,
FS_KEY_DESC_PREFIX_SIZE);
sprintf(full_key_descriptor + FS_KEY_DESC_PREFIX_SIZE,
"%*phN", FS_KEY_DESCRIPTOR_SIZE,
ctx.master_key_descriptor);
full_key_descriptor[FS_KEY_DESC_PREFIX_SIZE +
(2 * FS_KEY_DESCRIPTOR_SIZE)] = '\0';
keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
if (IS_ERR(keyring_key)) {
res = PTR_ERR(keyring_key);
keyring_key = NULL;
goto out;
}
crypt_info->ci_keyring_key = keyring_key;
if (keyring_key->type != &key_type_logon) {
printk_once(KERN_WARNING
"%s: key type must be logon\n", __func__);
res = -ENOKEY;
goto out;
}
down_read(&keyring_key->sem);
ukp = user_key_payload(keyring_key);
if (ukp->datalen != sizeof(struct fscrypt_key)) {
res = -EINVAL;
up_read(&keyring_key->sem);
goto out;
}
master_key = (struct fscrypt_key *)ukp->data;
BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
printk_once(KERN_WARNING
"%s: key size incorrect: %d\n",
__func__, master_key->size);
res = -ENOKEY;
up_read(&keyring_key->sem);
goto out;
}
res = derive_key_aes(ctx.nonce, master_key->raw, raw_key);
up_read(&keyring_key->sem);
if (res)
goto out;
got_key:
ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
if (!ctfm || IS_ERR(ctfm)) {
res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
printk(KERN_DEBUG
"%s: error %d (inode %u) allocating crypto tfm\n",
__func__, res, (unsigned) inode->i_ino);
goto out;
}
crypt_info->ci_ctfm = ctfm;
crypto_skcipher_clear_flags(ctfm, ~0);
crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
res = crypto_skcipher_setkey(ctfm, raw_key, fscrypt_key_size(mode));
if (res)
goto out;
memzero_explicit(raw_key, sizeof(raw_key));
if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
put_crypt_info(crypt_info);
goto retry;
}
return 0;
out:
if (res == -ENOKEY)
res = 0;
put_crypt_info(crypt_info);
memzero_explicit(raw_key, sizeof(raw_key));
return res;
}
void fscrypt_put_encryption_info(struct inode *inode, struct fscrypt_info *ci)
{
struct fscrypt_info *prev;
if (ci == NULL)
ci = ACCESS_ONCE(inode->i_crypt_info);
if (ci == NULL)
return;
prev = cmpxchg(&inode->i_crypt_info, ci, NULL);
if (prev != ci)
return;
put_crypt_info(ci);
}
EXPORT_SYMBOL(fscrypt_put_encryption_info);
int fscrypt_get_encryption_info(struct inode *inode)
{
struct fscrypt_info *ci = inode->i_crypt_info;
if (!ci ||
(ci->ci_keyring_key &&
(ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
(1 << KEY_FLAG_REVOKED) |
(1 << KEY_FLAG_DEAD)))))
return get_crypt_info(inode);
return 0;
}
EXPORT_SYMBOL(fscrypt_get_encryption_info);

229
fs/crypto/policy.c Normal file
View File

@@ -0,0 +1,229 @@
/*
* Encryption policy functions for per-file encryption support.
*
* Copyright (C) 2015, Google, Inc.
* Copyright (C) 2015, Motorola Mobility.
*
* Written by Michael Halcrow, 2015.
* Modified by Jaegeuk Kim, 2015.
*/
#include <linux/random.h>
#include <linux/string.h>
#include <linux/fscrypto.h>
static int inode_has_encryption_context(struct inode *inode)
{
if (!inode->i_sb->s_cop->get_context)
return 0;
return (inode->i_sb->s_cop->get_context(inode, NULL, 0L) > 0);
}
/*
* check whether the policy is consistent with the encryption context
* for the inode
*/
static int is_encryption_context_consistent_with_policy(struct inode *inode,
const struct fscrypt_policy *policy)
{
struct fscrypt_context ctx;
int res;
if (!inode->i_sb->s_cop->get_context)
return 0;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res != sizeof(ctx))
return 0;
return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE) == 0 &&
(ctx.flags == policy->flags) &&
(ctx.contents_encryption_mode ==
policy->contents_encryption_mode) &&
(ctx.filenames_encryption_mode ==
policy->filenames_encryption_mode));
}
static int create_encryption_context_from_policy(struct inode *inode,
const struct fscrypt_policy *policy)
{
struct fscrypt_context ctx;
int res;
if (!inode->i_sb->s_cop->set_context)
return -EOPNOTSUPP;
if (inode->i_sb->s_cop->prepare_context) {
res = inode->i_sb->s_cop->prepare_context(inode);
if (res)
return res;
}
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
if (!fscrypt_valid_contents_enc_mode(
policy->contents_encryption_mode)) {
printk(KERN_WARNING
"%s: Invalid contents encryption mode %d\n", __func__,
policy->contents_encryption_mode);
return -EINVAL;
}
if (!fscrypt_valid_filenames_enc_mode(
policy->filenames_encryption_mode)) {
printk(KERN_WARNING
"%s: Invalid filenames encryption mode %d\n", __func__,
policy->filenames_encryption_mode);
return -EINVAL;
}
if (policy->flags & ~FS_POLICY_FLAGS_VALID)
return -EINVAL;
ctx.contents_encryption_mode = policy->contents_encryption_mode;
ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
ctx.flags = policy->flags;
BUILD_BUG_ON(sizeof(ctx.nonce) != FS_KEY_DERIVATION_NONCE_SIZE);
get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
return inode->i_sb->s_cop->set_context(inode, &ctx, sizeof(ctx), NULL);
}
int fscrypt_process_policy(struct inode *inode,
const struct fscrypt_policy *policy)
{
if (policy->version != 0)
return -EINVAL;
if (!inode_has_encryption_context(inode)) {
if (!inode->i_sb->s_cop->empty_dir)
return -EOPNOTSUPP;
if (!inode->i_sb->s_cop->empty_dir(inode))
return -ENOTEMPTY;
return create_encryption_context_from_policy(inode, policy);
}
if (is_encryption_context_consistent_with_policy(inode, policy))
return 0;
printk(KERN_WARNING "%s: Policy inconsistent with encryption context\n",
__func__);
return -EINVAL;
}
EXPORT_SYMBOL(fscrypt_process_policy);
int fscrypt_get_policy(struct inode *inode, struct fscrypt_policy *policy)
{
struct fscrypt_context ctx;
int res;
if (!inode->i_sb->s_cop->get_context ||
!inode->i_sb->s_cop->is_encrypted(inode))
return -ENODATA;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res != sizeof(ctx))
return -ENODATA;
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
return -EINVAL;
policy->version = 0;
policy->contents_encryption_mode = ctx.contents_encryption_mode;
policy->filenames_encryption_mode = ctx.filenames_encryption_mode;
policy->flags = ctx.flags;
memcpy(&policy->master_key_descriptor, ctx.master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE);
return 0;
}
EXPORT_SYMBOL(fscrypt_get_policy);
int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
{
struct fscrypt_info *parent_ci, *child_ci;
int res;
if ((parent == NULL) || (child == NULL)) {
printk(KERN_ERR "parent %p child %p\n", parent, child);
BUG_ON(1);
}
/* no restrictions if the parent directory is not encrypted */
if (!parent->i_sb->s_cop->is_encrypted(parent))
return 1;
/* if the child directory is not encrypted, this is always a problem */
if (!parent->i_sb->s_cop->is_encrypted(child))
return 0;
res = fscrypt_get_encryption_info(parent);
if (res)
return 0;
res = fscrypt_get_encryption_info(child);
if (res)
return 0;
parent_ci = parent->i_crypt_info;
child_ci = child->i_crypt_info;
if (!parent_ci && !child_ci)
return 1;
if (!parent_ci || !child_ci)
return 0;
return (memcmp(parent_ci->ci_master_key,
child_ci->ci_master_key,
FS_KEY_DESCRIPTOR_SIZE) == 0 &&
(parent_ci->ci_data_mode == child_ci->ci_data_mode) &&
(parent_ci->ci_filename_mode == child_ci->ci_filename_mode) &&
(parent_ci->ci_flags == child_ci->ci_flags));
}
EXPORT_SYMBOL(fscrypt_has_permitted_context);
/**
* fscrypt_inherit_context() - Sets a child context from its parent
* @parent: Parent inode from which the context is inherited.
* @child: Child inode that inherits the context from @parent.
* @fs_data: private data given by FS.
* @preload: preload child i_crypt_info
*
* Return: Zero on success, non-zero otherwise
*/
int fscrypt_inherit_context(struct inode *parent, struct inode *child,
void *fs_data, bool preload)
{
struct fscrypt_context ctx;
struct fscrypt_info *ci;
int res;
if (!parent->i_sb->s_cop->set_context)
return -EOPNOTSUPP;
res = fscrypt_get_encryption_info(parent);
if (res < 0)
return res;
ci = parent->i_crypt_info;
if (ci == NULL)
return -ENOKEY;
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
if (fscrypt_dummy_context_enabled(parent)) {
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
ctx.flags = 0;
memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
res = 0;
} else {
ctx.contents_encryption_mode = ci->ci_data_mode;
ctx.filenames_encryption_mode = ci->ci_filename_mode;
ctx.flags = ci->ci_flags;
memcpy(ctx.master_key_descriptor, ci->ci_master_key,
FS_KEY_DESCRIPTOR_SIZE);
}
get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
res = parent->i_sb->s_cop->set_context(child, &ctx,
sizeof(ctx), fs_data);
if (res)
return res;
return preload ? fscrypt_get_encryption_info(child): 0;
}
EXPORT_SYMBOL(fscrypt_inherit_context);