crypto: ahash - Fix early termination in hash walk

BugLink: http://bugs.launchpad.net/bugs/1762370
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>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/crypto/ahash.c b/crypto/ahash.c
index 266fc1d64f61d537430059f38f3234be7f3a17e1..c03cc177870bba1c739770517d03f4ca80cf4500 100644 (file)
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -92,13 +92,14 @@ 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)