From 900a081f6912a8985dc15380ec912752cb66025a Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 26 Mar 2018 08:53:25 +0800
Subject: [PATCH] crypto: ahash - Fix early termination in hash walk
Git-commit: 900a081f6912a8985dc15380ec912752cb66025a
Patch-mainline: v4.17-rc1
References: bsc#1051510

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 crypto/ahash.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -92,13 +92,14 @@ int crypto_hash_walk_done(struct crypto_
 
 	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)