[PATCH 03/29] fscrypt: Enable partial page encryption
Richard Weinberger
richard at nod.at
Sun Nov 13 13:20:46 PST 2016
From: David Gstir <david at sigma-star.at>
Not all filesystems work on full pages, thus we should allow them to
hand partial pages to fscrypt for en/decryption.
Signed-off-by: David Gstir <david at sigma-star.at>
Signed-off-by: Richard Weinberger <richard at nod.at>
---
fs/crypto/crypto.c | 42 ++++++++++++++++++++++++++----------------
fs/ext4/inode.c | 6 ++++--
fs/ext4/page-io.c | 2 +-
fs/f2fs/data.c | 2 ++
include/linux/fscrypto.h | 16 +++++++++++-----
5 files changed, 44 insertions(+), 24 deletions(-)
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 222a70520565..e170aa05011d 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -149,6 +149,7 @@ typedef enum {
static int do_page_crypto(struct inode *inode,
fscrypt_direction_t rw, pgoff_t index,
struct page *src_page, struct page *dest_page,
+ unsigned int src_len, unsigned int src_offset,
gfp_t gfp_flags)
{
struct {
@@ -179,10 +180,10 @@ static int do_page_crypto(struct inode *inode,
memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
sg_init_table(&dst, 1);
- sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
+ sg_set_page(&dst, dest_page, src_len, src_offset);
sg_init_table(&src, 1);
- sg_set_page(&src, src_page, PAGE_SIZE, 0);
- skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
+ sg_set_page(&src, src_page, src_len, src_offset);
+ skcipher_request_set_crypt(req, &src, &dst, src_len, &xts_tweak);
if (rw == FS_DECRYPT)
res = crypto_skcipher_decrypt(req);
else
@@ -213,9 +214,11 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
/**
* 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.
- * @gfp_flags: The gfp flag for memory allocation
+ * @inode: The inode for which the encryption should take place
+ * @plaintext_page: The page to encrypt. Must be locked.
+ * @plaintext_len: Length of plaintext within page
+ * @plaintext_offset: Offset of plaintext within page
+ * @gfp_flags: The gfp flag for memory allocation
*
* Encrypts plaintext_page using the ctx encryption context. If
* the filesystem supports it, encryption is performed in-place, otherwise a
@@ -229,13 +232,17 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
* error value or NULL.
*/
struct page *fscrypt_encrypt_page(struct inode *inode,
- struct page *plaintext_page, gfp_t gfp_flags)
+ struct page *plaintext_page,
+ unsigned int plaintext_len,
+ unsigned int plaintext_offset,
+ gfp_t gfp_flags)
+
{
struct fscrypt_ctx *ctx;
struct page *ciphertext_page = plaintext_page;
int err;
- BUG_ON(!PageLocked(plaintext_page));
+ BUG_ON(plaintext_len % FS_CRYPTO_BLOCK_SIZE != 0);
ctx = fscrypt_get_ctx(inode, gfp_flags);
if (IS_ERR(ctx))
@@ -251,6 +258,7 @@ struct page *fscrypt_encrypt_page(struct inode *inode,
ctx->w.control_page = plaintext_page;
err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page,
+ plaintext_len, plaintext_offset,
gfp_flags);
if (err) {
ciphertext_page = ERR_PTR(err);
@@ -270,9 +278,11 @@ struct page *fscrypt_encrypt_page(struct inode *inode,
EXPORT_SYMBOL(fscrypt_encrypt_page);
/**
- * f2crypt_decrypt_page() - Decrypts a page in-place
- * @inode: The encrypted inode to decrypt.
+ * fscrypt_decrypt_page() - Decrypts a page in-place
+ * @inode: Encrypted inode to decrypt.
* @page: The page to decrypt. Must be locked.
+ * @len: Number of bytes in @page to be decrypted.
+ * @offs: Start of data in @page.
*
* Decrypts page in-place using the ctx encryption context.
*
@@ -280,11 +290,10 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
*
* Return: Zero on success, non-zero otherwise.
*/
-int fscrypt_decrypt_page(struct inode *inode, struct page *page)
+int fscrypt_decrypt_page(struct inode *inode, struct page *page,
+ unsigned int len, unsigned int offs)
{
- BUG_ON(!PageLocked(page));
-
- return do_page_crypto(inode, FS_DECRYPT, page->index, page, page,
+ return do_page_crypto(inode, FS_DECRYPT, page->index, page, page, len, offs,
GFP_NOFS);
}
EXPORT_SYMBOL(fscrypt_decrypt_page);
@@ -312,7 +321,7 @@ int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
while (len--) {
err = do_page_crypto(inode, FS_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page,
- GFP_NOFS);
+ PAGE_SIZE, 0, GFP_NOFS);
if (err)
goto errout;
@@ -420,7 +429,8 @@ 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);
+ int ret = fscrypt_decrypt_page(page->mapping->host, page,
+ PAGE_SIZE, 0);
if (ret) {
WARN_ON_ONCE(1);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4b7b842ec024..1d498c5e2990 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1166,7 +1166,8 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
if (unlikely(err))
page_zero_new_buffers(page, from, to);
else if (decrypt)
- err = fscrypt_decrypt_page(page->mapping->host, page);
+ err = fscrypt_decrypt_page(page->mapping->host, page,
+ PAGE_SIZE, 0);
return err;
}
#endif
@@ -3743,8 +3744,9 @@ static int __ext4_block_zero_page_range(handle_t *handle,
/* We expect the key to be set. */
BUG_ON(!fscrypt_has_encryption_key(inode));
BUG_ON(blocksize != PAGE_SIZE);
+ BUG_ON(!PageLocked(page));
WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
- page));
+ page, PAGE_SIZE, 0));
}
}
if (ext4_should_journal_data(inode)) {
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 0094923e5ebf..3d1d3d0f4303 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -470,7 +470,7 @@ 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, gfp_flags);
+ data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0, gfp_flags);
if (IS_ERR(data_page)) {
ret = PTR_ERR(data_page);
if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 9ae194fd2fdb..fac207254e8d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1194,7 +1194,9 @@ int do_write_data_page(struct f2fs_io_info *fio)
f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode),
fio->old_blkaddr);
retry_encrypt:
+ BUG_ON(!PageLocked(fio->page));
fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
+ PAGE_SIZE, 0,
gfp_flags);
if (IS_ERR(fio->encrypted_page)) {
err = PTR_ERR(fio->encrypted_page);
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index 8be8e9657c63..e05931272cea 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -248,8 +248,11 @@ int fscrypt_initialize(void);
extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t);
extern void fscrypt_release_ctx(struct fscrypt_ctx *);
-extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t);
-extern int fscrypt_decrypt_page(struct inode *, struct page *);
+extern struct page *fscrypt_encrypt_page(struct inode *, struct page *,
+ unsigned int, unsigned int,
+ gfp_t);
+extern int fscrypt_decrypt_page(struct inode *, struct page *, unsigned int,
+ unsigned int);
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 *);
@@ -293,13 +296,16 @@ static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
}
static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i,
- struct page *p, gfp_t f)
+ struct page *p,
+ unsigned int len,
+ unsigned int offs,
+ gfp_t f)
{
return ERR_PTR(-EOPNOTSUPP);
}
-static inline int fscrypt_notsupp_decrypt_page(struct inode *i,
- struct page *p)
+static inline int fscrypt_notsupp_decrypt_page(struct inode *i, struct page *p,
+ unsigned int len, unsigned int offs)
{
return -EOPNOTSUPP;
}
--
2.7.3
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