[PATCH] Smack: fix a dereference before null check on sock->sk

Colin King
2017-02-09T12:03:01Z

From: Colin Ian King <colin.king@canonical.com>

The initialisation of pointer ssp is from a dereference on sock->sk
before sock-sk is null checked, hence there is a potential for a
null pointer deference. Fix this by moving the assignment of ssp
to just before it is used in the call to smk_ipv6_check.

Detected with CoverityScan, CID#1324196 ("Dereference before null check")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
security/smack/smack_lsm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index fc8fb31..bb17387 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2899,7 +2899,7 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
#endif
#ifdef SMACK_IPV6_SECMARK_LABELING
struct smack_known *rsp;
- struct socket_smack *ssp = sock->sk->sk_security;
+ struct socket_smack *ssp;
#endif

if (sock->sk = NULL)
@@ -2916,9 +2916,11 @@ static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
return -EINVAL;
#ifdef SMACK_IPV6_SECMARK_LABELING
rsp = smack_ipv6host_label(sip);
- if (rsp != NULL)
+ if (rsp != NULL) {
+ ssp = sock->sk->sk_security;
rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
SMK_CONNECTING);
+ }
#endif
#ifdef SMACK_IPV6_PORT_LABELING
rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
--
2.10.2