[PATCH] audit: fix memleak in auditd_send_unicast_skb.
From: shuwang
Date: Tue Jul 18 2017 - 02:37:52 EST
From: Shu Wang <shuwang@xxxxxxxxxx>
Found this issue by kmemleak report, auditd_send_unicast_skb
did not free skb if rcu_dereference(auditd_conn) returns null.
unreferenced object 0xffff88082568ce00 (size 256):
comm "auditd", pid 1119, jiffies 4294708499
backtrace:
[<ffffffff8176166a>] kmemleak_alloc+0x4a/0xa0
[<ffffffff8121820c>] kmem_cache_alloc_node+0xcc/0x210
[<ffffffff8161b99d>] __alloc_skb+0x5d/0x290
[<ffffffff8113c614>] audit_make_reply+0x54/0xd0
[<ffffffff8113dfa7>] audit_receive_msg+0x967/0xd70
----------------
(gdb) list *audit_receive_msg+0x967
0xffffffff8113dff7 is in audit_receive_msg (kernel/audit.c:1133).
1132 skb = audit_make_reply(0, AUDIT_REPLACE, 0,
0, &pvnr, sizeof(pvnr));
---------------
[<ffffffff8113e402>] audit_receive+0x52/0xa0
[<ffffffff8166c561>] netlink_unicast+0x181/0x240
[<ffffffff8166c8e2>] netlink_sendmsg+0x2c2/0x3b0
[<ffffffff816112e8>] sock_sendmsg+0x38/0x50
[<ffffffff816117a2>] SYSC_sendto+0x102/0x190
[<ffffffff81612f4e>] SyS_sendto+0xe/0x10
[<ffffffff8176d337>] entry_SYSCALL_64_fastpath+0x1a/0xa5
[<ffffffffffffffff>] 0xffffffffffffffff
Signed-off-by: Shu Wang <shuwang@xxxxxxxxxx>
---
kernel/audit.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/audit.c b/kernel/audit.c
index 833267b..6dd5569 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -641,6 +641,7 @@ static int auditd_send_unicast_skb(struct sk_buff *skb)
ac = rcu_dereference(auditd_conn);
if (!ac) {
rcu_read_unlock();
+ kfree_skb(skb);
rc = -ECONNREFUSED;
goto err;
}
--
2.5.0