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Commit 4b1e27b3 authored by Jia-Ju Bai's avatar Jia-Ju Bai Committed by Greg Kroah-Hartman
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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: default avatarJia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 6001d7e3

security/smack/smack_lsm.c

+2 −0
Original line number Diff line number Diff line
@@ -4031,6 +4031,8 @@ 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;