On Sun, Apr 28, 2019 at 10:01:18AM +0530, Chandan Rajendra wrote:
> For subpage-sized blocks, this commit now encrypts all blocks mapped by
> a page range.
>
> Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxx>
> ---
> fs/crypto/crypto.c | 37 +++++++++++++++++++++++++------------
> 1 file changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
> index 4f0d832cae71..2d65b431563f 100644
> --- a/fs/crypto/crypto.c
> +++ b/fs/crypto/crypto.c
> @@ -242,18 +242,26 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
Need to update the function comment to clearly explain what this function
actually does now.
> {
> struct fscrypt_ctx *ctx;
> struct page *ciphertext_page = page;
> + int i, page_nr_blks;
> int err;
>
> BUG_ON(len % FS_CRYPTO_BLOCK_SIZE != 0);
>
Make a 'blocksize' variable so you don't have to keep calling i_blocksize().
Also, you need to check whether 'len' and 'offs' are filesystem-block-aligned,
since the code now assumes it.
const unsigned int blocksize = i_blocksize(inode);
if (!IS_ALIGNED(len | offs, blocksize))
return -EINVAL;
However, did you check whether that's always true for ubifs? It looks like it
may expect to encrypt a prefix of a block, that is only padded to the next
16-byte boundary.
> + page_nr_blks = len >> inode->i_blkbits;
> +
> if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
> /* with inplace-encryption we just encrypt the page */
> - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
> - ciphertext_page, len, offs,
> - gfp_flags);
> - if (err)
> - return ERR_PTR(err);
> -
> + for (i = 0; i < page_nr_blks; i++) {
> + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT,
> + lblk_num, page,
> + ciphertext_page,
> + i_blocksize(inode), offs,
> + gfp_flags);
> + if (err)
> + return ERR_PTR(err);
> + ++lblk_num;
> + offs += i_blocksize(inode);
> + }
> return ciphertext_page;
> }
>
> @@ -269,12 +277,17 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
> goto errout;
>
> ctx->control_page = page;
> - err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
> - page, ciphertext_page, len, offs,
> - gfp_flags);
> - if (err) {
> - ciphertext_page = ERR_PTR(err);
> - goto errout;
> +
> + for (i = 0; i < page_nr_blks; i++) {
> + err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
> + page, ciphertext_page,
> + i_blocksize(inode), offs, gfp_flags);
As I mentioned elsewhere, renaming fscrypt_do_page_crypto() to
fscrypt_crypt_block() would make more sense now.
> + if (err) {
> + ciphertext_page = ERR_PTR(err);
> + goto errout;
> + }
> + ++lblk_num;
> + offs += i_blocksize(inode);
> }
> SetPagePrivate(ciphertext_page);
> set_page_private(ciphertext_page, (unsigned long)ctx);
> --
> 2.19.1
>
