• Xin Long's avatar
    xfrm: fix a warning in xfrm_policy_insert_list · ed17b8d3
    Xin Long authored
    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 7cb8a939 ("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 only (the same value and priority) as the
    same policy in xfrm_policy_mark_match().
    
    Thanks to Yuehaibing, we could make this fix better.
    
    v1->v2:
      - check policy->mark.v == pol->mark.v only without mask.
    
    Fixes: 7cb8a939 ("xfrm: Allow inserting policies with matching mark and different priorities")
    Reported-by: default avatarXiumei Mu <xmu@redhat.com>
    Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
    Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
    ed17b8d3
xfrm_policy.c 106 KB