From: Jia-Ju Bai <baijiaju1990@gmail.com>
Date: Tue, 23 Jul 2019 18:00:15 +0800
Subject: security: smack: Fix possible null-pointer dereferences in
smack_socket_sock_rcv_skb()
Git-commit: 3f4287e7d98a2954f20bf96c567fdffcd2b63eb9
Patch-mainline: 5.4-rc1
References: bnc#1151927 5.3.5
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: Jiri Slaby <jslaby@suse.cz>
---
security/smack/smack_lsm.c | 2 ++
1 file changed, 2 insertions(+)
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3926,6 +3926,8 @@ 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;