From: Jia-Ju Bai baijiaju1990@gmail.com
[ Upstream commit 3f4287e7d98a2954f20bf96c567fdffcd2b63eb9 ]
In smack_socket_sock_rcv_skb(), there is an if statement on line 3920 to check whether skb is NULL: if (skb && skb->secmark != 0)
This check indicates skb can be NULL in some cases.
But on lines 3931 and 3932, skb is used: ad.a.u.net->netif = skb->skb_iif; ipv6_skb_to_auditdata(skb, &ad.a, NULL);
Thus, possible null-pointer dereferences may occur when skb is NULL.
To fix these possible bugs, an if statement is added to check skb.
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai baijiaju1990@gmail.com Signed-off-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/smack/smack_lsm.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index aeb3ba70f9077..19d1702aa9856 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4037,6 +4037,8 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) skp = smack_ipv6host_label(&sadd); if (skp == NULL) skp = smack_net_ambient; + if (skb == NULL) + break; #ifdef CONFIG_AUDIT smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); ad.a.u.net->family = family;