linux-stable.git/net/ipv4/ip_tunnel.c, branch linux-5.7.y Linux kernel stable tree ip_tunnel: fix use-after-free in ip_tunnel_lookup() 2020-06-30T19:35:49+00:00 Taehee Yoo ap420073@gmail.com 2020-06-16T16:51:51+00:00 58b1dabf1ae9e27f0fd9f9528b0a366c96e33b38 [ Upstream commit ba61539c6ae57f4146284a5cb4f7b7ed8d42bf45 ] In the datapath, the ip_tunnel_lookup() is used and it internally uses fallback tunnel device pointer, which is fb_tunnel_dev. This pointer variable should be set to NULL when a fb interface is deleted. But there is no routine to set fb_tunnel_dev pointer to NULL. So, this pointer will be still used after interface is deleted and it eventually results in the use-after-free problem. Test commands: ip netns add A ip netns add B ip link add eth0 type veth peer name eth1 ip link set eth0 netns A ip link set eth1 netns B ip netns exec A ip link set lo up ip netns exec A ip link set eth0 up ip netns exec A ip link add gre1 type gre local 10.0.0.1 \ remote 10.0.0.2 ip netns exec A ip link set gre1 up ip netns exec A ip a a 10.0.100.1/24 dev gre1 ip netns exec A ip a a 10.0.0.1/24 dev eth0 ip netns exec B ip link set lo up ip netns exec B ip link set eth1 up ip netns exec B ip link add gre1 type gre local 10.0.0.2 \ remote 10.0.0.1 ip netns exec B ip link set gre1 up ip netns exec B ip a a 10.0.100.2/24 dev gre1 ip netns exec B ip a a 10.0.0.2/24 dev eth1 ip netns exec A hping3 10.0.100.2 -2 --flood -d 60000 & ip netns del B Splat looks like: [ 77.793450][ C3] ================================================================== [ 77.794702][ C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0xcc4/0xf30 [ 77.795573][ C3] Read of size 4 at addr ffff888060bd9c84 by task hping3/2905 [ 77.796398][ C3] [ 77.796664][ C3] CPU: 3 PID: 2905 Comm: hping3 Not tainted 5.8.0-rc1+ #616 [ 77.797474][ C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 77.798453][ C3] Call Trace: [ 77.798815][ C3] <IRQ> [ 77.799142][ C3] dump_stack+0x9d/0xdb [ 77.799605][ C3] print_address_description.constprop.7+0x2cc/0x450 [ 77.800365][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.800908][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.801517][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.802145][ C3] kasan_report+0x154/0x190 [ 77.802821][ C3] ? ip_tunnel_lookup+0xcc4/0xf30 [ 77.803503][ C3] ip_tunnel_lookup+0xcc4/0xf30 [ 77.804165][ C3] __ipgre_rcv+0x1ab/0xaa0 [ip_gre] [ 77.804862][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0 [ 77.805621][ C3] gre_rcv+0x304/0x1910 [ip_gre] [ 77.806293][ C3] ? lock_acquire+0x1a9/0x870 [ 77.806925][ C3] ? gre_rcv+0xfe/0x354 [gre] [ 77.807559][ C3] ? erspan_xmit+0x2e60/0x2e60 [ip_gre] [ 77.808305][ C3] ? rcu_read_lock_sched_held+0xc0/0xc0 [ 77.809032][ C3] ? rcu_read_lock_held+0x90/0xa0 [ 77.809713][ C3] gre_rcv+0x1b8/0x354 [gre] [ ... ] Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit ba61539c6ae57f4146284a5cb4f7b7ed8d42bf45 ]

In the datapath, the ip_tunnel_lookup() is used and it internally uses
fallback tunnel device pointer, which is fb_tunnel_dev.
This pointer variable should be set to NULL when a fb interface is deleted.
But there is no routine to set fb_tunnel_dev pointer to NULL.
So, this pointer will be still used after interface is deleted and
it eventually results in the use-after-free problem.

Test commands:
    ip netns add A
    ip netns add B
    ip link add eth0 type veth peer name eth1
    ip link set eth0 netns A
    ip link set eth1 netns B

    ip netns exec A ip link set lo up
    ip netns exec A ip link set eth0 up
    ip netns exec A ip link add gre1 type gre local 10.0.0.1 \
	    remote 10.0.0.2
    ip netns exec A ip link set gre1 up
    ip netns exec A ip a a 10.0.100.1/24 dev gre1
    ip netns exec A ip a a 10.0.0.1/24 dev eth0

    ip netns exec B ip link set lo up
    ip netns exec B ip link set eth1 up
    ip netns exec B ip link add gre1 type gre local 10.0.0.2 \
	    remote 10.0.0.1
    ip netns exec B ip link set gre1 up
    ip netns exec B ip a a 10.0.100.2/24 dev gre1
    ip netns exec B ip a a 10.0.0.2/24 dev eth1
    ip netns exec A hping3 10.0.100.2 -2 --flood -d 60000 &
    ip netns del B

Splat looks like:
[   77.793450][    C3] ==================================================================
[   77.794702][    C3] BUG: KASAN: use-after-free in ip_tunnel_lookup+0xcc4/0xf30
[   77.795573][    C3] Read of size 4 at addr ffff888060bd9c84 by task hping3/2905
[   77.796398][    C3]
[   77.796664][    C3] CPU: 3 PID: 2905 Comm: hping3 Not tainted 5.8.0-rc1+ #616
[   77.797474][    C3] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[   77.798453][    C3] Call Trace:
[   77.798815][    C3]  <IRQ>
[   77.799142][    C3]  dump_stack+0x9d/0xdb
[   77.799605][    C3]  print_address_description.constprop.7+0x2cc/0x450
[   77.800365][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.800908][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.801517][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.802145][    C3]  kasan_report+0x154/0x190
[   77.802821][    C3]  ? ip_tunnel_lookup+0xcc4/0xf30
[   77.803503][    C3]  ip_tunnel_lookup+0xcc4/0xf30
[   77.804165][    C3]  __ipgre_rcv+0x1ab/0xaa0 [ip_gre]
[   77.804862][    C3]  ? rcu_read_lock_sched_held+0xc0/0xc0
[   77.805621][    C3]  gre_rcv+0x304/0x1910 [ip_gre]
[   77.806293][    C3]  ? lock_acquire+0x1a9/0x870
[   77.806925][    C3]  ? gre_rcv+0xfe/0x354 [gre]
[   77.807559][    C3]  ? erspan_xmit+0x2e60/0x2e60 [ip_gre]
[   77.808305][    C3]  ? rcu_read_lock_sched_held+0xc0/0xc0
[   77.809032][    C3]  ? rcu_read_lock_held+0x90/0xa0
[   77.809713][    C3]  gre_rcv+0x1b8/0x354 [gre]
[ ... ]

Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net, ip_tunnel: fix interface lookup with no key 2020-03-30T05:16:27+00:00 William Dauchy w.dauchy@criteo.com 2020-03-27T18:56:39+00:00 25629fdaff2ff509dd0b3f5ff93d70a75e79e0a1 when creating a new ipip interface with no local/remote configuration, the lookup is done with TUNNEL_NO_KEY flag, making it impossible to match the new interface (only possible match being fallback or metada case interface); e.g: `ip link add tunl1 type ipip dev eth0` To fix this case, adding a flag check before the key comparison so we permit to match an interface with no local/remote config; it also avoids breaking possible userland tools relying on TUNNEL_NO_KEY flag and uninitialised key. context being on my side, I'm creating an extra ipip interface attached to the physical one, and moving it to a dedicated namespace. Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Signed-off-by: William Dauchy <w.dauchy@criteo.com> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
when creating a new ipip interface with no local/remote configuration,
the lookup is done with TUNNEL_NO_KEY flag, making it impossible to
match the new interface (only possible match being fallback or metada
case interface); e.g: `ip link add tunl1 type ipip dev eth0`

To fix this case, adding a flag check before the key comparison so we
permit to match an interface with no local/remote config; it also avoids
breaking possible userland tools relying on TUNNEL_NO_KEY flag and
uninitialised key.

context being on my side, I'm creating an extra ipip interface attached
to the physical one, and moving it to a dedicated namespace.

Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: William Dauchy <w.dauchy@criteo.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net, ip_tunnel: fix namespaces move 2020-01-21T15:05:21+00:00 William Dauchy w.dauchy@criteo.com 2020-01-21T14:26:24+00:00 d0f418516022c32ecceaf4275423e5bd3f8743a9 in the same manner as commit 690afc165bb3 ("net: ip6_gre: fix moving ip6gre between namespaces"), fix namespace moving as it was broken since commit 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata."). Indeed, the ip6_gre commit removed the local flag for collect_md condition, so there is no reason to keep it for ip_gre/ip_tunnel. this patch will fix both ip_tunnel and ip_gre modules. Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.") Signed-off-by: William Dauchy <w.dauchy@criteo.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
in the same manner as commit 690afc165bb3 ("net: ip6_gre: fix moving
ip6gre between namespaces"), fix namespace moving as it was broken since
commit 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.").
Indeed, the ip6_gre commit removed the local flag for collect_md
condition, so there is no reason to keep it for ip_gre/ip_tunnel.

this patch will fix both ip_tunnel and ip_gre modules.

Fixes: 2e15ea390e6f ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: William Dauchy <w.dauchy@criteo.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tunnel: do not confirm neighbor when do pmtu update 2019-12-25T06:28:55+00:00 Hangbin Liu liuhangbin@gmail.com 2019-12-22T02:51:13+00:00 7a1592bcb15d71400a98632727791d1e68ea0ee8 When do tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end, we should not call dst_confirm_neigh() as there is no two-way communication. v5: No Change. v4: Update commit description v3: Do not remove dst_confirm_neigh, but add a new bool parameter in dst_ops.update_pmtu to control whether we should do neighbor confirm. Also split the big patch to small ones for each area. v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu. Fixes: 0dec879f636f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP") Reviewed-by: Guillaume Nault <gnault@redhat.com> Tested-by: Guillaume Nault <gnault@redhat.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When do tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.

v5: No Change.
v4: Update commit description
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Fixes: 0dec879f636f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 269 2019-06-05T15:30:29+00:00 Thomas Gleixner tglx@linutronix.de 2019-05-29T14:12:43+00:00 c942299924a70b458320846e53b742ba11e985b3 Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of version 2 of the gnu general public license as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 21 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141334.228102212@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin street fifth floor boston ma
  02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 21 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141334.228102212@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
iptunnel: NULL pointer deref for ip_md_tunnel_xmit 2019-03-06T18:43:06+00:00 Alan Maguire alan.maguire@oracle.com 2019-03-06T10:25:42+00:00 f4b3ec4e6aa1a2ca437905a519ae08e8cf6af754 Naresh Kamboju noted the following oops during execution of selftest tools/testing/selftests/bpf/test_tunnel.sh on x86_64: [ 274.120445] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [ 274.128285] #PF error: [INSTR] [ 274.131351] PGD 8000000414a0e067 P4D 8000000414a0e067 PUD 3b6334067 PMD 0 [ 274.138241] Oops: 0010 [#1] SMP PTI [ 274.141734] CPU: 1 PID: 11464 Comm: ping Not tainted 5.0.0-rc4-next-20190129 #1 [ 274.149046] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 274.156526] RIP: 0010: (null) [ 274.160280] Code: Bad RIP value. [ 274.163509] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286 [ 274.168726] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000 [ 274.175851] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0 [ 274.182974] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c [ 274.190098] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000 [ 274.197222] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400 [ 274.204346] FS: 00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000) knlGS:0000000000000000 [ 274.212424] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 274.218162] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0 [ 274.225292] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 274.232416] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 274.239541] Call Trace: [ 274.241988] ? tnl_update_pmtu+0x296/0x3b0 [ 274.246085] ip_md_tunnel_xmit+0x1bc/0x520 [ 274.250176] gre_fb_xmit+0x330/0x390 [ 274.253754] gre_tap_xmit+0x128/0x180 [ 274.257414] dev_hard_start_xmit+0xb7/0x300 [ 274.261598] sch_direct_xmit+0xf6/0x290 [ 274.265430] __qdisc_run+0x15d/0x5e0 [ 274.269007] __dev_queue_xmit+0x2c5/0xc00 [ 274.273011] ? dev_queue_xmit+0x10/0x20 [ 274.276842] ? eth_header+0x2b/0xc0 [ 274.280326] dev_queue_xmit+0x10/0x20 [ 274.283984] ? dev_queue_xmit+0x10/0x20 [ 274.287813] arp_xmit+0x1a/0xf0 [ 274.290952] arp_send_dst.part.19+0x46/0x60 [ 274.295138] arp_solicit+0x177/0x6b0 [ 274.298708] ? mod_timer+0x18e/0x440 [ 274.302281] neigh_probe+0x57/0x70 [ 274.305684] __neigh_event_send+0x197/0x2d0 [ 274.309862] neigh_resolve_output+0x18c/0x210 [ 274.314212] ip_finish_output2+0x257/0x690 [ 274.318304] ip_finish_output+0x219/0x340 [ 274.322314] ? ip_finish_output+0x219/0x340 [ 274.326493] ip_output+0x76/0x240 [ 274.329805] ? ip_fragment.constprop.53+0x80/0x80 [ 274.334510] ip_local_out+0x3f/0x70 [ 274.337992] ip_send_skb+0x19/0x40 [ 274.341391] ip_push_pending_frames+0x33/0x40 [ 274.345740] raw_sendmsg+0xc15/0x11d0 [ 274.349403] ? __might_fault+0x85/0x90 [ 274.353151] ? _copy_from_user+0x6b/0xa0 [ 274.357070] ? rw_copy_check_uvector+0x54/0x130 [ 274.361604] inet_sendmsg+0x42/0x1c0 [ 274.365179] ? inet_sendmsg+0x42/0x1c0 [ 274.368937] sock_sendmsg+0x3e/0x50 [ 274.372460] ___sys_sendmsg+0x26f/0x2d0 [ 274.376293] ? lock_acquire+0x95/0x190 [ 274.380043] ? __handle_mm_fault+0x7ce/0xb70 [ 274.384307] ? lock_acquire+0x95/0x190 [ 274.388053] ? __audit_syscall_entry+0xdd/0x130 [ 274.392586] ? ktime_get_coarse_real_ts64+0x64/0xc0 [ 274.397461] ? __audit_syscall_entry+0xdd/0x130 [ 274.401989] ? trace_hardirqs_on+0x4c/0x100 [ 274.406173] __sys_sendmsg+0x63/0xa0 [ 274.409744] ? __sys_sendmsg+0x63/0xa0 [ 274.413488] __x64_sys_sendmsg+0x1f/0x30 [ 274.417405] do_syscall_64+0x55/0x190 [ 274.421064] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 274.426113] RIP: 0033:0x7ff4ae0e6e87 [ 274.429686] Code: 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 80 00 00 00 00 8b 05 ca d9 2b 00 48 63 d2 48 63 ff 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 53 48 89 f3 48 83 ec 10 48 89 7c 24 08 [ 274.448422] RSP: 002b:00007ffcd9b76db8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 274.455978] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007ff4ae0e6e87 [ 274.463104] RDX: 0000000000000000 RSI: 00000000006092e0 RDI: 0000000000000003 [ 274.470228] RBP: 0000000000000000 R08: 00007ffcd9bc40a0 R09: 00007ffcd9bc4080 [ 274.477349] R10: 000000000000060a R11: 0000000000000246 R12: 0000000000000003 [ 274.484475] R13: 0000000000000016 R14: 00007ffcd9b77fa0 R15: 00007ffcd9b78da4 [ 274.491602] Modules linked in: cls_bpf sch_ingress iptable_filter ip_tables algif_hash af_alg x86_pkg_temp_thermal fuse [last unloaded: test_bpf] [ 274.504634] CR2: 0000000000000000 [ 274.507976] ---[ end trace 196d18386545eae1 ]--- [ 274.512588] RIP: 0010: (null) [ 274.516334] Code: Bad RIP value. [ 274.519557] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286 [ 274.524775] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000 [ 274.531921] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0 [ 274.539082] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c [ 274.546205] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000 [ 274.553329] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400 [ 274.560456] FS: 00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000) knlGS:0000000000000000 [ 274.568541] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 274.574277] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0 [ 274.581403] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 274.588535] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 274.595658] Kernel panic - not syncing: Fatal exception in interrupt [ 274.602046] Kernel Offset: 0x14400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 274.612827] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- [ 274.620387] ------------[ cut here ]------------ I'm also seeing the same failure on x86_64, and it reproduces consistently. >From poking around it looks like the skb's dst entry is being used to calculate the mtu in: mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; ...but because that dst_entry has an "ops" value set to md_dst_ops, the various ops (including mtu) are not set: crash> struct sk_buff._skb_refdst ffff928f87447700 -x _skb_refdst = 0xffffcd6fbf5ea590 crash> struct dst_entry.ops 0xffffcd6fbf5ea590 ops = 0xffffffffa0193800 crash> struct dst_ops.mtu 0xffffffffa0193800 mtu = 0x0 crash> I confirmed that the dst entry also has dst->input set to dst_md_discard, so it looks like it's an entry that's been initialized via __metadata_dst_init alright. I think the fix here is to use skb_valid_dst(skb) - it checks for DST_METADATA also, and with that fix in place, the problem - which was previously 100% reproducible - disappears. The below patch resolves the panic and all bpf tunnel tests pass without incident. Fixes: c8b34e680a09 ("ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit") Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Anders Roxell <anders.roxell@linaro.org> Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Naresh Kamboju noted the following oops during execution of selftest
tools/testing/selftests/bpf/test_tunnel.sh on x86_64:

[  274.120445] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000000
[  274.128285] #PF error: [INSTR]
[  274.131351] PGD 8000000414a0e067 P4D 8000000414a0e067 PUD 3b6334067 PMD 0
[  274.138241] Oops: 0010 [#1] SMP PTI
[  274.141734] CPU: 1 PID: 11464 Comm: ping Not tainted
5.0.0-rc4-next-20190129 #1
[  274.149046] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[  274.156526] RIP: 0010:          (null)
[  274.160280] Code: Bad RIP value.
[  274.163509] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286
[  274.168726] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000
[  274.175851] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0
[  274.182974] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c
[  274.190098] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000
[  274.197222] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400
[  274.204346] FS:  00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000)
knlGS:0000000000000000
[  274.212424] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  274.218162] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0
[  274.225292] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  274.232416] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  274.239541] Call Trace:
[  274.241988]  ? tnl_update_pmtu+0x296/0x3b0
[  274.246085]  ip_md_tunnel_xmit+0x1bc/0x520
[  274.250176]  gre_fb_xmit+0x330/0x390
[  274.253754]  gre_tap_xmit+0x128/0x180
[  274.257414]  dev_hard_start_xmit+0xb7/0x300
[  274.261598]  sch_direct_xmit+0xf6/0x290
[  274.265430]  __qdisc_run+0x15d/0x5e0
[  274.269007]  __dev_queue_xmit+0x2c5/0xc00
[  274.273011]  ? dev_queue_xmit+0x10/0x20
[  274.276842]  ? eth_header+0x2b/0xc0
[  274.280326]  dev_queue_xmit+0x10/0x20
[  274.283984]  ? dev_queue_xmit+0x10/0x20
[  274.287813]  arp_xmit+0x1a/0xf0
[  274.290952]  arp_send_dst.part.19+0x46/0x60
[  274.295138]  arp_solicit+0x177/0x6b0
[  274.298708]  ? mod_timer+0x18e/0x440
[  274.302281]  neigh_probe+0x57/0x70
[  274.305684]  __neigh_event_send+0x197/0x2d0
[  274.309862]  neigh_resolve_output+0x18c/0x210
[  274.314212]  ip_finish_output2+0x257/0x690
[  274.318304]  ip_finish_output+0x219/0x340
[  274.322314]  ? ip_finish_output+0x219/0x340
[  274.326493]  ip_output+0x76/0x240
[  274.329805]  ? ip_fragment.constprop.53+0x80/0x80
[  274.334510]  ip_local_out+0x3f/0x70
[  274.337992]  ip_send_skb+0x19/0x40
[  274.341391]  ip_push_pending_frames+0x33/0x40
[  274.345740]  raw_sendmsg+0xc15/0x11d0
[  274.349403]  ? __might_fault+0x85/0x90
[  274.353151]  ? _copy_from_user+0x6b/0xa0
[  274.357070]  ? rw_copy_check_uvector+0x54/0x130
[  274.361604]  inet_sendmsg+0x42/0x1c0
[  274.365179]  ? inet_sendmsg+0x42/0x1c0
[  274.368937]  sock_sendmsg+0x3e/0x50
[  274.372460]  ___sys_sendmsg+0x26f/0x2d0
[  274.376293]  ? lock_acquire+0x95/0x190
[  274.380043]  ? __handle_mm_fault+0x7ce/0xb70
[  274.384307]  ? lock_acquire+0x95/0x190
[  274.388053]  ? __audit_syscall_entry+0xdd/0x130
[  274.392586]  ? ktime_get_coarse_real_ts64+0x64/0xc0
[  274.397461]  ? __audit_syscall_entry+0xdd/0x130
[  274.401989]  ? trace_hardirqs_on+0x4c/0x100
[  274.406173]  __sys_sendmsg+0x63/0xa0
[  274.409744]  ? __sys_sendmsg+0x63/0xa0
[  274.413488]  __x64_sys_sendmsg+0x1f/0x30
[  274.417405]  do_syscall_64+0x55/0x190
[  274.421064]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  274.426113] RIP: 0033:0x7ff4ae0e6e87
[  274.429686] Code: 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 80 00
00 00 00 8b 05 ca d9 2b 00 48 63 d2 48 63 ff 85 c0 75 10 b8 2e 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 53 48 89 f3 48 83 ec 10 48 89 7c
24 08
[  274.448422] RSP: 002b:00007ffcd9b76db8 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[  274.455978] RAX: ffffffffffffffda RBX: 0000000000000040 RCX: 00007ff4ae0e6e87
[  274.463104] RDX: 0000000000000000 RSI: 00000000006092e0 RDI: 0000000000000003
[  274.470228] RBP: 0000000000000000 R08: 00007ffcd9bc40a0 R09: 00007ffcd9bc4080
[  274.477349] R10: 000000000000060a R11: 0000000000000246 R12: 0000000000000003
[  274.484475] R13: 0000000000000016 R14: 00007ffcd9b77fa0 R15: 00007ffcd9b78da4
[  274.491602] Modules linked in: cls_bpf sch_ingress iptable_filter
ip_tables algif_hash af_alg x86_pkg_temp_thermal fuse [last unloaded:
test_bpf]
[  274.504634] CR2: 0000000000000000
[  274.507976] ---[ end trace 196d18386545eae1 ]---
[  274.512588] RIP: 0010:          (null)
[  274.516334] Code: Bad RIP value.
[  274.519557] RSP: 0018:ffffbc9681f83540 EFLAGS: 00010286
[  274.524775] RAX: 0000000000000000 RBX: ffffdc967fa80a18 RCX: 0000000000000000
[  274.531921] RDX: ffff9db2ee08b540 RSI: 000000000000000e RDI: ffffdc967fa809a0
[  274.539082] RBP: ffffbc9681f83580 R08: ffff9db2c4d62690 R09: 000000000000000c
[  274.546205] R10: 0000000000000000 R11: ffff9db2ee08b540 R12: ffff9db31ce7c000
[  274.553329] R13: 0000000000000001 R14: 000000000000000c R15: ffff9db3179cf400
[  274.560456] FS:  00007ff4ae7c5740(0000) GS:ffff9db31fa80000(0000)
knlGS:0000000000000000
[  274.568541] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  274.574277] CR2: ffffffffffffffd6 CR3: 00000004574da004 CR4: 00000000003606e0
[  274.581403] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  274.588535] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  274.595658] Kernel panic - not syncing: Fatal exception in interrupt
[  274.602046] Kernel Offset: 0x14400000 from 0xffffffff81000000
(relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[  274.612827] ---[ end Kernel panic - not syncing: Fatal exception in
interrupt ]---
[  274.620387] ------------[ cut here ]------------

I'm also seeing the same failure on x86_64, and it reproduces
consistently.

>From poking around it looks like the skb's dst entry is being used
to calculate the mtu in:

mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;

...but because that dst_entry  has an "ops" value set to md_dst_ops,
the various ops (including mtu) are not set:

crash> struct sk_buff._skb_refdst ffff928f87447700 -x
      _skb_refdst = 0xffffcd6fbf5ea590
crash> struct dst_entry.ops 0xffffcd6fbf5ea590
  ops = 0xffffffffa0193800
crash> struct dst_ops.mtu 0xffffffffa0193800
  mtu = 0x0
crash>

I confirmed that the dst entry also has dst->input set to
dst_md_discard, so it looks like it's an entry that's been
initialized via __metadata_dst_init alright.

I think the fix here is to use skb_valid_dst(skb) - it checks
for  DST_METADATA also, and with that fix in place, the
problem - which was previously 100% reproducible - disappears.

The below patch resolves the panic and all bpf tunnel tests pass
without incident.

Fixes: c8b34e680a09 ("ip_tunnel: Add tnl_update_pmtu in ip_md_tunnel_xmit")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Reported-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Tested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
route: Add multipath_hash in flowi_common to make user-define hash 2019-02-27T20:50:17+00:00 wenxu wenxu@ucloud.cn 2019-02-24T03:36:20+00:00 24ba14406c5c8e33fcbe064f77b3ab01b84ec830 Current fib_multipath_hash_policy can make hash based on the L3 or L4. But it only work on the outer IP. So a specific tunnel always has the same hash value. But a specific tunnel may contain so many inner connections. This patch provide a generic multipath_hash in floi_common. It can make a user-define hash which can mix with L3 or L4 hash. Signed-off-by: wenxu <wenxu@ucloud.cn> Signed-off-by: David S. Miller <davem@davemloft.net> 
Current fib_multipath_hash_policy can make hash based on the L3 or
L4. But it only work on the outer IP. So a specific tunnel always
has the same hash value. But a specific tunnel may contain so many
inner connections.

This patch provide a generic multipath_hash in floi_common. It can
make a user-define hash which can mix with L3 or L4 hash.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_tunnel: Add ip tunnel tun_info type dst_cache in ip_tunnel_xmit 2019-02-25T06:22:33+00:00 wenxu wenxu@ucloud.cn 2019-02-24T00:24:45+00:00 186d93669fe0cba252d42a42ddcfdbe9f2ee101d ip l add dev tun type gretap key 1000 Non-tunnel-dst ip tunnel device can send packet through lwtunnel This patch provide the tun_inf dst cache support for this mode. Signed-off-by: wenxu <wenxu@ucloud.cn> Signed-off-by: David S. Miller <davem@davemloft.net> 
ip l add dev tun type gretap key 1000

Non-tunnel-dst ip tunnel device can send packet through lwtunnel
This patch provide the tun_inf dst cache support for this mode.

Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-27T18:43:17+00:00 David S. Miller davem@davemloft.net 2019-01-27T18:43:17+00:00 1d68101367a92336e633d0c3681bf8c86644e124 






ip_tunnel: Fix route fl4 init in ip_md_tunnel_xmit
2019-01-26T17:43:03+00:00

wenxu
wenxu@ucloud.cn

2019-01-22T10:39:51+00:00

6e6b904ad4f9aed43ec320afbd5a52ed8461ab41

Init the gre_key from tuninfo->key.tun_id and init the mark
from the skb->mark, set the oif to zero in the collect metadata
mode.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>





Init the gre_key from tuninfo->key.tun_id and init the mark
from the skb->mark, set the oif to zero in the collect metadata
mode.

Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel")
Signed-off-by: wenxu <wenxu@ucloud.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>