crypto: hash - Fix page length clamping in hash walk

The crypto hash walk code is broken when supplied with an offset greater than or equal to PAGE_SIZE. This patch fixes it by adjusting walk->pg and walk->offset when this happens. Cc: <[email protected]> Reported-by: Steffen Klassert <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
kyagi · May 5, 2016 · 13f4bb7 · 13f4bb7
1 parent 6dc5df7
commit 13f4bb7
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/crypto/ahash.c b/crypto/ahash.c
@@ -69,8 +69,9 @@ static int hash_walk_new_entry(struct crypto_hash_walk *walk)
 	struct scatterlist *sg;
 
 	sg = walk->sg;
-	walk->pg = sg_page(sg);
 	walk->offset = sg->offset;
+	walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
+	walk->offset = offset_in_page(walk->offset);
 	walk->entrylen = sg->length;
 
 	if (walk->entrylen > walk->total)