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ae4745730c
In some situation vlan packets do not have ethernet headers. One example
is packets from tun devices. Users can specify vlan protocol in tun_pi
field instead of IP protocol, and skb_vlan_untag() attempts to untag such
packets.
skb_vlan_untag() (more precisely, skb_reorder_vlan_header() called by it)
however did not expect packets without ethernet headers, so in such a case
size argument for memmove() underflowed and triggered crash.
====
BUG: unable to handle kernel paging request at ffff8801cccb8000
IP: __memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43
PGD 9cee067 P4D 9cee067 PUD 1d9401063 PMD 1cccb7063 PTE 2810100028101
Oops: 000b [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 17663 Comm: syz-executor2 Not tainted 4.16.0-rc7+ #368
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43
RSP: 0018:ffff8801cc046e28 EFLAGS: 00010287
RAX: ffff8801ccc244c4 RBX: fffffffffffffffe RCX: fffffffffff6c4c2
RDX: fffffffffffffffe RSI: ffff8801cccb7ffc RDI: ffff8801cccb8000
RBP: ffff8801cc046e48 R08: ffff8801ccc244be R09: ffffed0039984899
R10: 0000000000000001 R11: ffffed0039984898 R12: ffff8801ccc244c4
R13: ffff8801ccc244c0 R14: ffff8801d96b7c06 R15: ffff8801d96b7b40
FS: 00007febd562d700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8801cccb8000 CR3: 00000001ccb2f006 CR4: 00000000001606e0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
memmove include/linux/string.h:360 [inline]
skb_reorder_vlan_header net/core/skbuff.c:5031 [inline]
skb_vlan_untag+0x470/0xc40 net/core/skbuff.c:5061
__netif_receive_skb_core+0x119c/0x3460 net/core/dev.c:4460
__netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4627
netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4701
netif_receive_skb+0xae/0x390 net/core/dev.c:4725
tun_rx_batched.isra.50+0x5ee/0x870 drivers/net/tun.c:1555
tun_get_user+0x299e/0x3c20 drivers/net/tun.c:1962
tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1990
call_write_iter include/linux/fs.h:1782 [inline]
new_sync_write fs/read_write.c:469 [inline]
__vfs_write+0x684/0x970 fs/read_write.c:482
vfs_write+0x189/0x510 fs/read_write.c:544
SYSC_write fs/read_write.c:589 [inline]
SyS_write+0xef/0x220 fs/read_write.c:581
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x454879
RSP: 002b:00007febd562cc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007febd562d6d4 RCX: 0000000000454879
RDX: 0000000000000157 RSI: 0000000020000180 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000006b0 R14: 00000000006fc120 R15: 0000000000000000
Code: 90 90 90 90 90 90 90 48 89 f8 48 83 fa 20 0f 82 03 01 00 00 48 39 fe 7d 0f 49 89 f0 49 01 d0 49 39 f8 0f 8f 9f 00 00 00 48 89 d1 <f3> a4 c3 48 81 fa a8 02 00 00 72 05 40 38 fe 74 3b 48 83 ea 20
RIP: __memmove+0x24/0x1a0 arch/x86/lib/memmove_64.S:43 RSP: ffff8801cc046e28
CR2: ffff8801cccb8000
====
We don't need to copy headers for packets which do not have preceding
headers of vlan headers, so skip memmove() in that case.
Fixes:
|
||
---|---|---|
.. | ||
6lowpan | ||
9p | ||
802 | ||
8021q | ||
appletalk | ||
atm | ||
ax25 | ||
batman-adv | ||
bluetooth | ||
bpf | ||
bridge | ||
caif | ||
can | ||
ceph | ||
core | ||
dcb | ||
dccp | ||
decnet | ||
dns_resolver | ||
dsa | ||
ethernet | ||
hsr | ||
ieee802154 | ||
ife | ||
ipv4 | ||
ipv6 | ||
iucv | ||
kcm | ||
key | ||
l2tp | ||
l3mdev | ||
lapb | ||
llc | ||
mac80211 | ||
mac802154 | ||
mpls | ||
ncsi | ||
netfilter | ||
netlabel | ||
netlink | ||
netrom | ||
nfc | ||
nsh | ||
openvswitch | ||
packet | ||
phonet | ||
psample | ||
qrtr | ||
rds | ||
rfkill | ||
rose | ||
rxrpc | ||
sched | ||
sctp | ||
smc | ||
strparser | ||
sunrpc | ||
switchdev | ||
tipc | ||
tls | ||
unix | ||
vmw_vsock | ||
wimax | ||
wireless | ||
x25 | ||
xfrm | ||
compat.c | ||
Kconfig | ||
Makefile | ||
socket.c | ||
sysctl_net.c |