crypto: ahash - Fix early termination in hash walk

commit 900a081f6912a8985dc15380ec912752cb66025a upstream.

When we have an unaligned SG list entry where there is no leftover
aligned data, the hash walk code will incorrectly return zero as if
the entire SG list has been processed.

This patch fixes it by moving onto the next page instead.

Reported-by: Eli Cooper <elicooper@gmx.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/crypto/ahash.c b/crypto/ahash.c
index 0735529ea082bad04b1dde22f8d2f0b58012f123..6ae2b2fd72bac79f7e29fbd3ed8d2d2a54c47d2e 100644 (file)
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -90,13 +90,14 @@ int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
 
        if (nbytes && walk->offset & alignmask && !err) {
                walk->offset = ALIGN(walk->offset, alignmask + 1);
-               walk->data += walk->offset;
-
                nbytes = min(nbytes,
                             ((unsigned int)(PAGE_SIZE)) - walk->offset);
                walk->entrylen -= nbytes;
 
-               return nbytes;
+               if (nbytes) {
+                       walk->data += walk->offset;
+                       return nbytes;
+               }
        }
 
        if (walk->flags & CRYPTO_ALG_ASYNC)