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 14402ef6d8269cc8db32f87dd63009da4b9cb7a4..90d73a22f12917d44504b137ea52a3e26d30dabe 100644 (file)
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -91,13 +91,14 @@ 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)