From: Jia-Ju Bai Date: Tue, 23 Jul 2019 10:00:15 +0000 (+0800) Subject: security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb() X-Git-Tag: v4.9.196~24 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5f0b9f0611eef41eb77ac666a985c40e414f72ae;p=platform%2Fkernel%2Flinux-amlogic.git security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb() [ 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 Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin --- diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index aeb3ba7..19d1702 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4037,6 +4037,8 @@ access_check: 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;