syzbot triggered various splats (see [0] and links) by a crafted GSO
packet of VIRTIO_NET_HDR_GSO_UDP layering the following protocols:
ETH_P_8021AD + ETH_P_NSH + ETH_P_IPV6 + IPPROTO_UDP
NSH can encapsulate IPv4, IPv6, Ethernet, NSH, and MPLS. As the inner
protocol can be Ethernet, NSH GSO handler, nsh_gso_segment(), calls
skb_mac_gso_segment() to invoke inner protocol GSO handlers.
nsh_gso_segment() does the following for the original skb before
calling skb_mac_gso_segment()
1. reset skb->network_header
2. save the original skb->{mac_heaeder,mac_len} in a local variable
3. pull the NSH header
4. resets skb->mac_header
5. set up skb->mac_len and skb->protocol for the inner protocol.
and does the following for the segmented skb
6. set ntohs(ETH_P_NSH) to skb->protocol
7. push the NSH header
8. restore skb->mac_header
9. set skb->mac_header + mac_len to skb->network_header
10. restore skb->mac_len
There are two problems in 6-7 and 8-9.
(a)
After 6 & 7, skb->data points to the NSH header, so the outer header
(ETH_P_8021AD in this case) is stripped when skb is sent out of netdev.
Also, if NSH is encapsulated by NSH + Ethernet (so NSH-Ethernet-NSH),
skb_pull() in the first nsh_gso_segment() will make skb->data point
to the middle of the outer NSH or Ethernet header because the Ethernet
header is not pulled by the second nsh_gso_segment().
(b)
While restoring skb->{mac_header,network_header} in 8 & 9,
nsh_gso_segment() does not assume that the data in the linear
buffer is shifted.
However, udp6_ufo_fragment() could shift the data and change
skb->mac_header accordingly as demonstrated by syzbot.
If this happens, even the restored skb->mac_header points to
the middle of the outer header.
It seems nsh_gso_segment() has never worked with outer headers so far.
At the end of nsh_gso_segment(), the outer header must be restored for
the segmented skb, instead of the NSH header.
To do that, let's calculate the outer header position relatively from
the inner header and set skb->{data,mac_header,protocol} properly.
[0]:
BUG: KMSAN: uninit-value in ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:524 [inline]
BUG: KMSAN: uninit-value in ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
BUG: KMSAN: uninit-value in ipvlan_queue_xmit+0xf44/0x16b0 drivers/net/ipvlan/ipvlan_core.c:668
ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:524 [inline]
ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:602 [inline]
ipvlan_queue_xmit+0xf44/0x16b0 drivers/net/ipvlan/ipvlan_core.c:668
ipvlan_start_xmit+0x5c/0x1a0 drivers/net/ipvlan/ipvlan_main.c:222
__netdev_start_xmit include/linux/netdevice.h:4989 [inline]
netdev_start_xmit include/linux/netdevice.h:5003 [inline]
xmit_one net/core/dev.c:3547 [inline]
dev_hard_start_xmit+0x244/0xa10 net/core/dev.c:3563
__dev_queue_xmit+0x33ed/0x51c0 net/core/dev.c:4351
dev_queue_xmit include/linux/netdevice.h:3171 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3081 [inline]
packet_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Uninit was created at:
slab_post_alloc_hook mm/slub.c:3819 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
__do_kmalloc_node mm/slub.c:3980 [inline]
__kmalloc_node_track_caller+0x705/0x1000 mm/slub.c:4001
kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
__alloc_skb+0x352/0x790 net/core/skbuff.c:651
skb_segment+0x20aa/0x7080 net/core/skbuff.c:4647
udp6_ufo_fragment+0xcab/0x1150 net/ipv6/udp_offload.c:109
ipv6_gso_segment+0x14be/0x2ca0 net/ipv6/ip6_offload.c:152
skb_mac_gso_segment+0x3e8/0x760 net/core/gso.c:53
nsh_gso_segment+0x6f4/0xf70 net/nsh/nsh.c:108
skb_mac_gso_segment+0x3e8/0x760 net/core/gso.c:53
__skb_gso_segment+0x4b0/0x730 net/core/gso.c:124
skb_gso_segment include/net/gso.h:83 [inline]
validate_xmit_skb+0x107f/0x1930 net/core/dev.c:3628
__dev_queue_xmit+0x1f28/0x51c0 net/core/dev.c:4343
dev_queue_xmit include/linux/netdevice.h:3171 [inline]
packet_xmit+0x9c/0x6b0 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3081 [inline]
packet_sendmsg+0x8aef/0x9f10 net/packet/af_packet.c:3113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x735/0xa10 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0x125/0x1c0 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
CPU: 1 PID: 5101 Comm: syz-executor421 Not tainted 6.8.0-rc5-syzkaller-00297-gf2e367d6ad3b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Fixes: c411ed8545 ("nsh: add GSO support")
Reported-and-tested-by: syzbot+42a0dc856239de4de60e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=42a0dc856239de4de60e
Reported-and-tested-by: syzbot+c298c9f0e46a3c86332b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c298c9f0e46a3c86332b
Link: https://lore.kernel.org/netdev/20240415222041.18537-1-kuniyu@amazon.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240424023549.21862-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Move declarations into include/net/gso.h and code into net/core/gso.c
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230608191738.3947077-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As the call trace shows, skb_panic was caused by wrong skb->mac_header
in nsh_gso_segment():
invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 3 PID: 2737 Comm: syz Not tainted 6.3.0-next-20230505 #1
RIP: 0010:skb_panic+0xda/0xe0
call Trace:
skb_push+0x91/0xa0
nsh_gso_segment+0x4f3/0x570
skb_mac_gso_segment+0x19e/0x270
__skb_gso_segment+0x1e8/0x3c0
validate_xmit_skb+0x452/0x890
validate_xmit_skb_list+0x99/0xd0
sch_direct_xmit+0x294/0x7c0
__dev_queue_xmit+0x16f0/0x1d70
packet_xmit+0x185/0x210
packet_snd+0xc15/0x1170
packet_sendmsg+0x7b/0xa0
sock_sendmsg+0x14f/0x160
The root cause is:
nsh_gso_segment() use skb->network_header - nhoff to reset mac_header
in skb_gso_error_unwind() if inner-layer protocol gso fails.
However, skb->network_header may be reset by inner-layer protocol
gso function e.g. mpls_gso_segment. skb->mac_header reset by the
inaccurate network_header will be larger than skb headroom.
nsh_gso_segment
nhoff = skb->network_header - skb->mac_header;
__skb_pull(skb,nsh_len)
skb_mac_gso_segment
mpls_gso_segment
skb_reset_network_header(skb);//skb->network_header+=nsh_len
return -EINVAL;
skb_gso_error_unwind
skb_push(skb, nsh_len);
skb->mac_header = skb->network_header - nhoff;
// skb->mac_header > skb->headroom, cause skb_push panic
Use correct mac_offset to restore mac_header and get rid of nhoff.
Fixes: c411ed8545 ("nsh: add GSO support")
Reported-by: syzbot+632b5d9964208bfef8c0@syzkaller.appspotmail.com
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When pulling the NSH header in nsh_gso_segment, set the mac length
based on the encapsulated packet type.
skb_reset_mac_len computes an offset to the network header, which
here still points to the outer packet:
> skb_reset_network_header(skb);
> [...]
> __skb_pull(skb, nsh_len);
> skb_reset_mac_header(skb); // now mac hdr starts nsh_len == 8B after net hdr
> skb_reset_mac_len(skb); // mac len = net hdr - mac hdr == (u16) -8 == 65528
> [..]
> skb_mac_gso_segment(skb, ..)
Link: http://lkml.kernel.org/r/CAF=yD-KeAcTSOn4AxirAxL8m7QAS8GBBe1w09eziYwvPbbUeYA@mail.gmail.com
Reported-by: syzbot+7b9ed9872dab8c32305d@syzkaller.appspotmail.com
Fixes: c411ed8545 ("nsh: add GSO support")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
v16->17
- Fixed disputed check code: keep them in nsh_push and nsh_pop
but also add them in __ovs_nla_copy_actions
v15->v16
- Add csum recalculation for nsh_push, nsh_pop and set_nsh
pointed out by Pravin
- Move nsh key into the union with ipv4 and ipv6 and add
check for nsh key in match_validate pointed out by Pravin
- Add nsh check in validate_set and __ovs_nla_copy_actions
v14->v15
- Check size in nsh_hdr_from_nlattr
- Fixed four small issues pointed out By Jiri and Eric
v13->v14
- Rename skb_push_nsh to nsh_push per Dave's comment
- Rename skb_pop_nsh to nsh_pop per Dave's comment
v12->v13
- Fix NSH header length check in set_nsh
v11->v12
- Fix missing changes old comments pointed out
- Fix new comments for v11
v10->v11
- Fix the left three disputable comments for v9
but not fixed in v10.
v9->v10
- Change struct ovs_key_nsh to
struct ovs_nsh_key_base base;
__be32 context[NSH_MD1_CONTEXT_SIZE];
- Fix new comments for v9
v8->v9
- Fix build error reported by daily intel build
because nsh module isn't selected by openvswitch
v7->v8
- Rework nested value and mask for OVS_KEY_ATTR_NSH
- Change pop_nsh to adapt to nsh kernel module
- Fix many issues per comments from Jiri Benc
v6->v7
- Remove NSH GSO patches in v6 because Jiri Benc
reworked it as another patch series and they have
been merged.
- Change it to adapt to nsh kernel module added by NSH
GSO patch series
v5->v6
- Fix the rest comments for v4.
- Add NSH GSO support for VxLAN-gpe + NSH and
Eth + NSH.
v4->v5
- Fix many comments by Jiri Benc and Eric Garver
for v4.
v3->v4
- Add new NSH match field ttl
- Update NSH header to the latest format
which will be final format and won't change
per its author's confirmation.
- Fix comments for v3.
v2->v3
- Change OVS_KEY_ATTR_NSH to nested key to handle
length-fixed attributes and length-variable
attriubte more flexibly.
- Remove struct ovs_action_push_nsh completely
- Add code to handle nested attribute for SET_MASKED
- Change PUSH_NSH to use the nested OVS_KEY_ATTR_NSH
to transfer NSH header data.
- Fix comments and coding style issues by Jiri and Eric
v1->v2
- Change encap_nsh and decap_nsh to push_nsh and pop_nsh
- Dynamically allocate struct ovs_action_push_nsh for
length-variable metadata.
OVS master and 2.8 branch has merged NSH userspace
patch series, this patch is to enable NSH support
in kernel data path in order that OVS can support
NSH in compat mode by porting this.
Signed-off-by: Yi Yang <yi.y.yang@intel.com>
Acked-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Eric Garver <e@erig.me>
Acked-by: Pravin Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new nsh/ directory. It currently holds only GSO functions but more
will come: in particular, code shared by openvswitch and tc to manipulate
NSH headers.
For now, assume there's no hardware support for NSH segmentation. We can
always introduce netdev->nsh_features later.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Kuniyuki Iwashima