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Commit 9c4bb8a3 authored by David Gstir's avatar David Gstir Committed by Theodore Ts'o
Browse files

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: 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 0b93e1b9

fs/crypto/crypto.c

+7 −4
Original line number Diff line number Diff line
@@ -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);

fs/ext4/inode.c

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

fs/ext4/page-io.c

+2 −1
Original line number Diff line number Diff line
@@ -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) {

fs/f2fs/data.c

+3 −2
Original line number Diff line number Diff line
@@ -1197,6 +1197,7 @@ int do_write_data_page(struct f2fs_io_info *fio) 
		BUG_ON(!PageLocked(fio->page));

		fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,

							PAGE_SIZE, 0,

							fio->page->index,

							gfp_flags);

		if (IS_ERR(fio->encrypted_page)) {

			err = PTR_ERR(fio->encrypted_page);

include/linux/fscrypto.h

+5 −4
Original line number Diff line number Diff line
@@ -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;

}