netdev - [PATCH ipsec] xfrm: fix a warning in xfrm_policy_insert

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <b328381f956215debcaa2fb70c6a10159ba1f5db.1587459464.git.lucien.xin@gmail.com>
Date:   Tue, 21 Apr 2020 16:57:44 +0800
From:   Xin Long <lucien.xin@...il.com>
To:     netdev@...r.kernel.org
Cc:     Steffen Klassert <steffen.klassert@...unet.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Sabrina Dubroca <sd@...asysnail.net>
Subject: [PATCH ipsec] xfrm: fix a warning in xfrm_policy_insert_list

This waring can be triggered simply by:

  # ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \
    priority 1 mark 0 mask 0x10  #[1]
  # ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \
    priority 2 mark 0 mask 0x1   #[2]
  # ip xfrm policy update src 192.168.1.1/24 dst 192.168.1.2/24 dir in \
    priority 2 mark 0 mask 0x10  #[3]

Then dmesg shows:

  [ ] WARNING: CPU: 1 PID: 7265 at net/xfrm/xfrm_policy.c:1548
  [ ] RIP: 0010:xfrm_policy_insert_list+0x2f2/0x1030
  [ ] Call Trace:
  [ ]  xfrm_policy_inexact_insert+0x85/0xe50
  [ ]  xfrm_policy_insert+0x4ba/0x680
  [ ]  xfrm_add_policy+0x246/0x4d0
  [ ]  xfrm_user_rcv_msg+0x331/0x5c0
  [ ]  netlink_rcv_skb+0x121/0x350
  [ ]  xfrm_netlink_rcv+0x66/0x80
  [ ]  netlink_unicast+0x439/0x630
  [ ]  netlink_sendmsg+0x714/0xbf0
  [ ]  sock_sendmsg+0xe2/0x110

The issue was introduced by Commit 7cb8a93968e3 ("xfrm: Allow inserting
policies with matching mark and different priorities"). After that, the
policies [1] and [2] would be able to be added with different priorities.

However, policy [3] will actually match both [1] and [2]. Policy [1]
was matched due to the 1st 'return true' in xfrm_policy_mark_match(),
and policy [2] was matched due to the 2nd 'return true' in there. It
caused WARN_ON() in xfrm_policy_insert_list().

This patch is to fix it by removing the 1st 'return true', as it should
not be how value and mask work.

Fixes: 7cb8a93968e3 ("xfrm: Allow inserting policies with matching mark and different priorities")
Reported-by: Xiumei Mu <xmu@...hat.com>
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
 net/xfrm/xfrm_policy.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 297b2fd..3db2db6 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1438,9 +1438,6 @@ static bool xfrm_policy_mark_match(struct xfrm_policy *policy,
 {
 	u32 mark = policy->mark.v & policy->mark.m;
 
-	if (policy->mark.v == pol->mark.v && policy->mark.m == pol->mark.m)
-		return true;
-
 	if ((mark & pol->mark.m) == pol->mark.v &&
 	    policy->priority == pol->priority)
 		return true;
-- 
2.1.0