From 52491c7607c5527138095edf44c53169dc1ddb82 Mon Sep 17 00:00:00 2001 From: Etienne Noss Date: Fri, 10 Mar 2017 16:55:32 +0100 Subject: [PATCH] act_connmark: avoid crashing on malformed nlattrs with null parms MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit tcf_connmark_init does not check in its configuration if TCA_CONNMARK_PARMS is set, resulting in a null pointer dereference when trying to access it. [501099.043007] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 [501099.043039] IP: [] tcf_connmark_init+0x8b/0x180 [act_connmark] ... [501099.044334] Call Trace: [501099.044345] [] ? tcf_action_init_1+0x198/0x1b0 [501099.044363] [] ? tcf_action_init+0xb0/0x120 [501099.044380] [] ? tcf_exts_validate+0xc4/0x110 [501099.044398] [] ? u32_set_parms+0xa7/0x270 [cls_u32] [501099.044417] [] ? u32_change+0x680/0x87b [cls_u32] [501099.044436] [] ? tc_ctl_tfilter+0x4dd/0x8a0 [501099.044454] [] ? security_capable+0x41/0x60 [501099.044471] [] ? rtnetlink_rcv_msg+0xe1/0x220 [501099.044490] [] ? rtnl_newlink+0x870/0x870 [501099.044507] [] ? netlink_rcv_skb+0xa1/0xc0 [501099.044524] [] ? rtnetlink_rcv+0x24/0x30 [501099.044541] [] ? netlink_unicast+0x184/0x230 [501099.044558] [] ? netlink_sendmsg+0x2f8/0x3b0 [501099.044576] [] ? sock_sendmsg+0x30/0x40 [501099.044592] [] ? SYSC_sendto+0xd3/0x150 [501099.044608] [] ? __do_page_fault+0x2d1/0x510 [501099.044626] [] ? system_call_fast_compare_end+0xc/0x9b Fixes: 22a5dc0e5e3e ("net: sched: Introduce connmark action") Signed-off-by: Étienne Noss Signed-off-by: Victorien Molle Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/act_connmark.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c index ab8062909962..f9bb43c25697 100644 --- a/net/sched/act_connmark.c +++ b/net/sched/act_connmark.c @@ -113,6 +113,9 @@ static int tcf_connmark_init(struct net *net, struct nlattr *nla, if (ret < 0) return ret; + if (!tb[TCA_CONNMARK_PARMS]) + return -EINVAL; + parm = nla_data(tb[TCA_CONNMARK_PARMS]); if (!tcf_hash_check(tn, parm->index, a, bind)) { -- 2.20.1