• Eric Dumazet's avatar
    net: introduce DST_NOPEER dst flag · e688a604
    Eric Dumazet authored
    Chris Boot reported crashes occurring in ipv6_select_ident().
    
    [  461.457562] RIP: 0010:[<ffffffff812dde61>]  [<ffffffff812dde61>]
    ipv6_select_ident+0x31/0xa7
    
    [  461.578229] Call Trace:
    [  461.580742] <IRQ>
    [  461.582870]  [<ffffffff812efa7f>] ? udp6_ufo_fragment+0x124/0x1a2
    [  461.589054]  [<ffffffff812dbfe0>] ? ipv6_gso_segment+0xc0/0x155
    [  461.595140]  [<ffffffff812700c6>] ? skb_gso_segment+0x208/0x28b
    [  461.601198]  [<ffffffffa03f236b>] ? ipv6_confirm+0x146/0x15e
    [nf_conntrack_ipv6]
    [  461.608786]  [<ffffffff81291c4d>] ? nf_iterate+0x41/0x77
    [  461.614227]  [<ffffffff81271d64>] ? dev_hard_start_xmit+0x357/0x543
    [  461.620659]  [<ffffffff81291cf6>] ? nf_hook_slow+0x73/0x111
    [  461.626440]  [<ffffffffa0379745>] ? br_parse_ip_options+0x19a/0x19a
    [bridge]
    [  461.633581]  [<ffffffff812722ff>] ? dev_queue_xmit+0x3af/0x459
    [  461.639577]  [<ffffffffa03747d2>] ? br_dev_queue_push_xmit+0x72/0x76
    [bridge]
    [  461.646887]  [<ffffffffa03791e3>] ? br_nf_post_routing+0x17d/0x18f
    [bridge]
    [  461.653997]  [<ffffffff81291c4d>] ? nf_iterate+0x41/0x77
    [  461.659473]  [<ffffffffa0374760>] ? br_flood+0xfa/0xfa [bridge]
    [  461.665485]  [<ffffffff81291cf6>] ? nf_hook_slow+0x73/0x111
    [  461.671234]  [<ffffffffa0374760>] ? br_flood+0xfa/0xfa [bridge]
    [  461.677299]  [<ffffffffa0379215>] ?
    nf_bridge_update_protocol+0x20/0x20 [bridge]
    [  461.684891]  [<ffffffffa03bb0e5>] ? nf_ct_zone+0xa/0x17 [nf_conntrack]
    [  461.691520]  [<ffffffffa0374760>] ? br_flood+0xfa/0xfa [bridge]
    [  461.697572]  [<ffffffffa0374812>] ? NF_HOOK.constprop.8+0x3c/0x56
    [bridge]
    [  461.704616]  [<ffffffffa0379031>] ?
    nf_bridge_push_encap_header+0x1c/0x26 [bridge]
    [  461.712329]  [<ffffffffa037929f>] ? br_nf_forward_finish+0x8a/0x95
    [bridge]
    [  461.719490]  [<ffffffffa037900a>] ?
    nf_bridge_pull_encap_header+0x1c/0x27 [bridge]
    [  461.727223]  [<ffffffffa0379974>] ? br_nf_forward_ip+0x1c0/0x1d4 [bridge]
    [  461.734292]  [<ffffffff81291c4d>] ? nf_iterate+0x41/0x77
    [  461.739758]  [<ffffffffa03748cc>] ? __br_deliver+0xa0/0xa0 [bridge]
    [  461.746203]  [<ffffffff81291cf6>] ? nf_hook_slow+0x73/0x111
    [  461.751950]  [<ffffffffa03748cc>] ? __br_deliver+0xa0/0xa0 [bridge]
    [  461.758378]  [<ffffffffa037533a>] ? NF_HOOK.constprop.4+0x56/0x56
    [bridge]
    
    This is caused by bridge netfilter special dst_entry (fake_rtable), a
    special shared entry, where attaching an inetpeer makes no sense.
    
    Problem is present since commit 87c48fa3 (ipv6: make fragment
    identifications less predictable)
    
    Introduce DST_NOPEER dst flag and make sure ipv6_select_ident() and
    __ip_select_ident() fallback to the 'no peer attached' handling.
    Reported-by: default avatarChris Boot <bootc@bootc.net>
    Tested-by: default avatarChris Boot <bootc@bootc.net>
    Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    e688a604
dst.h 10.7 KB