[PATCH AUTOSEL 4.4 03/65] net: drop write-only stack variable

Sasha Levin
2018-10-25T14:17:18Z

From: David Herrmann <dh.herrmann@gmail.com>

[ Upstream commit 3575dbf2cbbc8e598f17ec441aed526dbea0e1bd ]

Remove a write-only stack variable from unix_attach_fds(). This is a
left-over from the security fix in:

commit 712f4aad406bb1ed67f3f98d04c044191f0ff593
Author: willy tarreau <w@1wt.eu>
Date: Sun Jan 10 07:54:56 2016 +0100

unix: properly account for FDs passed over unix sockets

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/unix/af_unix.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index e05ec54ac53f..c6b1eec94911 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1531,7 +1531,6 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
{
int i;
unsigned char max_level = 0;
- int unix_sock_count = 0;

if (too_many_unix_fds(current))
return -ETOOMANYREFS;
@@ -1539,11 +1538,9 @@ static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
for (i = scm->fp->count - 1; i >= 0; i--) {
struct sock *sk = unix_get_socket(scm->fp->fp[i]);

- if (sk) {
- unix_sock_count++;
+ if (sk)
max_level = max(max_level,
unix_sk(sk)->recursion_level);
- }
}
if (unlikely(max_level > MAX_RECURSION_LEVEL))
return -ETOOMANYREFS;
--
2.17.1