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fscrypt: Let fs select encryption index/tweak 

Avoid re-use of page index as tweak for AES-XTS when multiple parts of
same page are encrypted. This will happen on multiple (partial) calls of
fscrypt_encrypt_page on same page.
page->index is only valid for writeback pages.

Signed-off-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
David Gstir 2016-11-13 22:20:48 +01:00 committed by Theodore Ts'o
parent 0b93e1b94b
commit 9c4bb8a3a9
5 changed files with 19 additions and 13 deletions
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11
fs/crypto/crypto.c
View File

@ -218,6 +218,8 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
* @plaintext_page: The page to encrypt. Must be locked.
* @plaintext_len: Length of plaintext within page
* @plaintext_offset: Offset of plaintext within page
* @index: Index for encryption. This is mainly the page index, but
* but might be different for multiple calls on same page.
* @gfp_flags: The gfp flag for memory allocation
*
* Encrypts plaintext_page using the ctx encryption context. If
@ -235,7 +237,7 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
struct page *plaintext_page,
unsigned int plaintext_len,
unsigned int plaintext_offset,
gfp_t gfp_flags)
pgoff_t index, gfp_t gfp_flags)
{
struct fscrypt_ctx *ctx;
@ -256,7 +258,7 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
}
ctx->w.control_page = plaintext_page;
err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
err = do_page_crypto(inode, FS_ENCRYPT, index,
plaintext_page, ciphertext_page,
plaintext_len, plaintext_offset,
gfp_flags);
@ -283,6 +285,7 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
* @page: The page to decrypt. Must be locked.
* @len: Number of bytes in @page to be decrypted.
* @offs: Start of data in @page.
* @index: Index for encryption.
*
* Decrypts page in-place using the ctx encryption context.
*
@ -291,7 +294,7 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
* Return: Zero on success, non-zero otherwise.
*/
int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
unsigned int len, unsigned int offs)
unsigned int len, unsigned int offs, pgoff_t index)
{
return do_page_crypto(inode, FS_DECRYPT, page->index, page, page, len, offs,
GFP_NOFS);
@ -430,7 +433,7 @@ static void completion_pages(struct work_struct *work)
bio_for_each_segment_all(bv, bio, i) {
struct page *page = bv->bv_page;
int ret = fscrypt_decrypt_page(page->mapping->host, page,
PAGE_SIZE, 0);
PAGE_SIZE, 0, page->index);
if (ret) {
WARN_ON_ONCE(1);

4
fs/ext4/inode.c
View File

@ -1167,7 +1167,7 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
page_zero_new_buffers(page, from, to);
else if (decrypt)
err = fscrypt_decrypt_page(page->mapping->host, page,
PAGE_SIZE, 0);
PAGE_SIZE, 0, page->index);
return err;
}
#endif
@ -3746,7 +3746,7 @@ static int __ext4_block_zero_page_range(handle_t *handle,
BUG_ON(blocksize != PAGE_SIZE);
BUG_ON(!PageLocked(page));
WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
page, PAGE_SIZE, 0));
page, PAGE_SIZE, 0, page->index));
}
}
if (ext4_should_journal_data(inode)) {

3
fs/ext4/page-io.c
View File

@ -470,7 +470,8 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
gfp_t gfp_flags = GFP_NOFS;
retry_encrypt:
data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0, gfp_flags);
data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
page->index, gfp_flags);
if (IS_ERR(data_page)) {
ret = PTR_ERR(data_page);
if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {

5
fs/f2fs/data.c
View File

@ -1196,8 +1196,9 @@ int do_write_data_page(struct f2fs_io_info *fio)
retry_encrypt:
BUG_ON(!PageLocked(fio->page));
fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
PAGE_SIZE, 0,
gfp_flags);
PAGE_SIZE, 0,
fio->page->index,
gfp_flags);
if (IS_ERR(fio->encrypted_page)) {
err = PTR_ERR(fio->encrypted_page);
if (err == -ENOMEM) {

9
include/linux/fscrypto.h
View File

@ -250,9 +250,9 @@ extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
extern void fscrypt_release_ctx(struct fscrypt_ctx *);
extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
unsigned int, unsigned int,
gfp_t);
pgoff_t, gfp_t);
extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
unsigned int);
unsigned int, pgoff_t);
extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
extern void fscrypt_pullback_bio_page(struct page **, bool);
extern void fscrypt_restore_control_page(struct page *);
@ -299,13 +299,14 @@ static inline struct page *fscrypt_notsupp_encrypt_page(const struct inode *i,
struct page *p,
unsigned int len,
unsigned int offs,
gfp_t f)
pgoff_t index, gfp_t f)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline int fscrypt_notsupp_decrypt_page(const struct inode *i, struct page *p,
unsigned int len, unsigned int offs)
unsigned int len, unsigned int offs,
pgoff_t index)
{
return -EOPNOTSUPP;
}