From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Wed, 31 Jan 2018 23:02:47 +0000 (-0800)
Subject: netfilter: xt_cgroup: initialize info->priv in cgroup_mt_check_v1()
X-Git-Tag: android-x86-7.1-r2~1^2~110^2~120
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;ds=sidebyside;h=c6f3be756b784b69253a1d4bcd72c2e891f87a74;p=android-x86%2Fkernel.git

netfilter: xt_cgroup: initialize info->priv in cgroup_mt_check_v1()

commit ba7cd5d95f25cc6005f687dabdb4e7a6063adda9 upstream.

xt_cgroup_info_v1->priv is an internal pointer only used for kernel,
we should not trust what user-space provides.

Reported-by: <syzbot+4fbcfcc0d2e6592bd641@syzkaller.appspotmail.com>
Fixes: c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match")
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
index a086a914865f..0eddbd5328af 100644
--- a/net/netfilter/xt_cgroup.c
+++ b/net/netfilter/xt_cgroup.c
@@ -52,6 +52,7 @@ static int cgroup_mt_check_v1(const struct xt_mtchk_param *par)
 		return -EINVAL;
 	}
 
+	info->priv = NULL;
 	if (info->has_path) {
 		cgrp = cgroup_get_from_path(info->path);
 		if (IS_ERR(cgrp)) {