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Commit 7821d4dd authored by David Gstir's avatar David Gstir Committed by Theodore Ts'o
Browse files

fscrypt: Enable partial page encryption 



Not all filesystems work on full pages, thus we should allow them to
hand partial pages to fscrypt for en/decryption.

Signed-off-by: default avatarDavid Gstir <david@sigma-star.at>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent b50f7b26

fs/crypto/crypto.c

+26 −16
Original line number Diff line number Diff line
@@ -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
@@ -215,6 +216,8 @@ 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.

 * @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
@@ -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);

fs/ext4/inode.c

+4 −2
Original line number Diff line number Diff line
@@ -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)) {

fs/ext4/page-io.c

+1 −1
Original line number Diff line number Diff line
@@ -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) {

fs/f2fs/data.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/fscrypto.h

+11 −5
Original line number Diff line number Diff line
@@ -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;

}