[PATCH v4 04/12] cache: clear whole hash buffer with oidclr

From: Patryk Obara <patryk.obara@gmail.com>
Date: Jan 28, 2018, 00:13 UTC
Message-ID: <ca4fac44f11c767c6042404ed9ed0c2e1b2f5369.1517097306.git.patryk.obara@gmail.com>
In-Reply-To: <cover.1517097306.git.patryk.obara@gmail.com>

As long as GIT_SHA1_RAWSZ is equal to GIT_MAX_RAWSZ there's no problem, but when new hashing algorithm will be in place this memset will clear only 20-byte prefix of hash buffer.

Alternatively, hashclr implementation could be adjusted, but this function is almost removed from codebase already. Separate implementation of oidclr prevents potential buffer overrun in case someone incorrectly used hashclr on object_id in future.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
---
 cache.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cache.h b/cache.h
index 08f2b81e1b..d5d78d6a51 100644
--- a/cache.h
+++ b/cache.h
@@ -1029,7 +1029,7 @@ static inline void hashclr(unsigned char *hash)
 
 static inline void oidclr(struct object_id *oid)
 {
-	hashclr(oid->hash);
+	memset(oid->hash, 0, GIT_MAX_RAWSZ);
 }

-- 
2.14.3