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Message-Id: <20190723100015.5400-1-baijiaju1990@gmail.com>
Date: Tue, 23 Jul 2019 18:00:15 +0800
From: Jia-Ju Bai <baijiaju1990@...il.com>
To: casey@...aufler-ca.com, jmorris@...ei.org, serge@...lyn.com
Cc: linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] security: smack: Fix possible null-pointer dereferences in smack_socket_sock_rcv_skb()
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@...il.com>
---
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 4c5e5a438f8b..5c9fc8ba6e57 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3925,6 +3925,8 @@ 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;
--
2.17.0
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