[PATCH] cache: don't leave cache_slot fields uninitialized

John Keeping john at keeping.me.uk
Sun Jan 12 17:49:40 CET 2014

Valgrind says:

==18344== Conditional jump or move depends on uninitialised value(s)
==18344==    at 0x406C83: open_slot (cache.c:63)
==18344==    by 0x407478: cache_ls (cache.c:403)
==18344==    by 0x404C9A: process_request (cgit.c:639)
==18344==    by 0x406BD2: fill_slot (cache.c:190)
==18344==    by 0x4071A0: cache_process (cache.c:284)
==18344==    by 0x404461: main (cgit.c:952)
==18344==  Uninitialised value was created by a stack allocation
==18344==    at 0x40738B: cache_ls (cache.c:375)

This is caused by the keylen field being used to calculate whether or
not a slot is matched.  We never then check the value of this and the
length of data read depends on the key length read from the file so this
isn't dangerous, but it's nice to avoid branching based on uninitialized

Signed-off-by: John Keeping <john at keeping.me.uk>
Is there any chance of getting jk/valgrind-tests merged as well?  It's
been sat there for a while now and is quite useful.

 cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cache.c b/cache.c
index d339435..fa83ddc 100644
--- a/cache.c
+++ b/cache.c
@@ -376,7 +376,7 @@ int cache_ls(const char *path)
 	DIR *dir;
 	struct dirent *ent;
 	int err = 0;
-	struct cache_slot slot;
+	struct cache_slot slot = { 0 };
 	struct strbuf fullname = STRBUF_INIT;
 	size_t prefixlen;

More information about the CGit mailing list