linux/net
Christoph Paasch 9410d386d0 net: Prevent invalid access to skb->prev in __qdisc_drop_all
__qdisc_drop_all() accesses skb->prev to get to the tail of the
segment-list.

With commit 68d2f84a13 ("net: gro: properly remove skb from list")
the skb-list handling has been changed to set skb->next to NULL and set
the list-poison on skb->prev.

With that change, __qdisc_drop_all() will panic when it tries to
dereference skb->prev.

Since commit 992cba7e27 ("net: Add and use skb_list_del_init().")
__list_del_entry is used, leaving skb->prev unchanged (thus,
pointing to the list-head if it's the first skb of the list).
This will make __qdisc_drop_all modify the next-pointer of the list-head
and result in a panic later on:

[   34.501053] general protection fault: 0000 [#1] SMP KASAN PTI
[   34.501968] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.20.0-rc2.mptcp #108
[   34.502887] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011
[   34.504074] RIP: 0010:dev_gro_receive+0x343/0x1f90
[   34.504751] Code: e0 48 c1 e8 03 42 80 3c 30 00 0f 85 4a 1c 00 00 4d 8b 24 24 4c 39 65 d0 0f 84 0a 04 00 00 49 8d 7c 24 38 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 04
[   34.507060] RSP: 0018:ffff8883af507930 EFLAGS: 00010202
[   34.507761] RAX: 0000000000000007 RBX: ffff8883970b2c80 RCX: 1ffff11072e165a6
[   34.508640] RDX: 1ffff11075867008 RSI: ffff8883ac338040 RDI: 0000000000000038
[   34.509493] RBP: ffff8883af5079d0 R08: ffff8883970b2d40 R09: 0000000000000062
[   34.510346] R10: 0000000000000034 R11: 0000000000000000 R12: 0000000000000000
[   34.511215] R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8883ac338008
[   34.512082] FS:  0000000000000000(0000) GS:ffff8883af500000(0000) knlGS:0000000000000000
[   34.513036] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   34.513741] CR2: 000055ccc3e9d020 CR3: 00000003abf32000 CR4: 00000000000006e0
[   34.514593] Call Trace:
[   34.514893]  <IRQ>
[   34.515157]  napi_gro_receive+0x93/0x150
[   34.515632]  receive_buf+0x893/0x3700
[   34.516094]  ? __netif_receive_skb+0x1f/0x1a0
[   34.516629]  ? virtnet_probe+0x1b40/0x1b40
[   34.517153]  ? __stable_node_chain+0x4d0/0x850
[   34.517684]  ? kfree+0x9a/0x180
[   34.518067]  ? __kasan_slab_free+0x171/0x190
[   34.518582]  ? detach_buf+0x1df/0x650
[   34.519061]  ? lapic_next_event+0x5a/0x90
[   34.519539]  ? virtqueue_get_buf_ctx+0x280/0x7f0
[   34.520093]  virtnet_poll+0x2df/0xd60
[   34.520533]  ? receive_buf+0x3700/0x3700
[   34.521027]  ? qdisc_watchdog_schedule_ns+0xd5/0x140
[   34.521631]  ? htb_dequeue+0x1817/0x25f0
[   34.522107]  ? sch_direct_xmit+0x142/0xf30
[   34.522595]  ? virtqueue_napi_schedule+0x26/0x30
[   34.523155]  net_rx_action+0x2f6/0xc50
[   34.523601]  ? napi_complete_done+0x2f0/0x2f0
[   34.524126]  ? kasan_check_read+0x11/0x20
[   34.524608]  ? _raw_spin_lock+0x7d/0xd0
[   34.525070]  ? _raw_spin_lock_bh+0xd0/0xd0
[   34.525563]  ? kvm_guest_apic_eoi_write+0x6b/0x80
[   34.526130]  ? apic_ack_irq+0x9e/0xe0
[   34.526567]  __do_softirq+0x188/0x4b5
[   34.527015]  irq_exit+0x151/0x180
[   34.527417]  do_IRQ+0xdb/0x150
[   34.527783]  common_interrupt+0xf/0xf
[   34.528223]  </IRQ>

This patch makes sure that skb->prev is set to NULL when entering
netem_enqueue.

Cc: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Fixes: 68d2f84a13 ("net: gro: properly remove skb from list")
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-29 16:27:27 -08:00
..
6lowpan
9p Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-03 10:35:52 -07:00
802
8021q netpoll: allow cleanup to be synchronous 2018-10-19 17:01:43 -07:00
appletalk
atm Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
ax25
batman-adv batman-adv: Expand merged fragment buffer for full packet 2018-11-12 10:41:29 +01:00
bluetooth Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
bpf bpf: add tests for direct packet access from CGROUP_SKB 2018-10-19 13:49:34 -07:00
bpfilter net: bpfilter: Set user mode helper's command line 2018-10-22 19:37:36 -07:00
bridge net: bridge: fix vlan stats use-after-free on destruction 2018-11-17 21:38:44 -08:00
caif Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
can can: raw: check for CAN FD capable netdev in raw_sendmsg() 2018-11-09 17:19:34 +01:00
ceph libceph: fall back to sendmsg for slab pages 2018-11-19 17:59:47 +01:00
core net: fix XPS static_key accounting 2018-11-29 11:06:08 -08:00
dcb net: dcb: Add priority-to-DSCP map getters 2018-07-27 13:17:50 -07:00
dccp Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
decnet decnet: Remove unnecessary check for dev->name 2018-09-21 19:48:36 -07:00
dns_resolver dns: Allow the dns resolver to retrieve a server set 2018-10-04 09:40:52 -07:00
dsa net: dsa: legacy: simplify getting .driver_data 2018-10-22 19:49:04 -07:00
ethernet
hsr
ieee802154 net/ipfrag: let ip[6]frag_high_thresh in ns be higher than in init_net 2018-09-21 19:45:52 -07:00
ife
ipv4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2018-11-28 11:02:45 -08:00
ipv6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2018-11-28 11:02:45 -08:00
iucv Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
kcm Revert "kcm: remove any offset before parsing messages" 2018-09-17 18:43:42 -07:00
key Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2018-07-27 09:33:37 -07:00
l2tp l2tp: fix a sock refcnt leak in l2tp_tunnel_register 2018-11-14 22:49:31 -08:00
l3mdev
lapb
llc llc: do not use sk_eat_skb() 2018-10-22 19:59:20 -07:00
mac80211 mac80211: implement ieee80211_tx_rate_update to update rate 2018-10-12 13:05:40 +02:00
mac802154 mac802154: Remove VLA usage of skcipher 2018-09-28 12:46:07 +08:00
mpls net/mpls: Handle kernel side filtering of route dumps 2018-10-16 00:14:07 -07:00
ncsi net/ncsi: Add NCSI Broadcom OEM command 2018-10-17 22:14:54 -07:00
netfilter netfilter: nf_tables: deactivate expressions in rule replecement routine 2018-11-28 10:56:40 +01:00
netlabel netlabel: check for IPV4MASK in addrinfo_get 2018-09-21 18:58:34 -07:00
netlink netlink: Add answer_flags to netlink_callback 2018-10-16 00:13:12 -07:00
netrom
nfc Merge branch 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-10-24 14:43:41 +01:00
nsh
openvswitch openvswitch: fix linking without CONFIG_NF_CONNTRACK_LABELS 2018-11-03 19:28:44 -07:00
packet packet: copy user buffers before orphan or clone 2018-11-23 11:08:03 -08:00
phonet
psample
qrtr
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-12 21:38:46 -07:00
rfkill Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-09-04 21:33:03 -07:00
rose
rxrpc rxrpc: Fix life check 2018-11-15 11:35:40 -08:00
sched net: Prevent invalid access to skb->prev in __qdisc_drop_all 2018-11-29 16:27:27 -08:00
sctp sctp: increase sk_wmem_alloc when head->truesize is increased 2018-11-27 15:42:31 -08:00
smc net/smc: use after free fix in smc_wr_tx_put_slot() 2018-11-21 16:14:56 -08:00
strparser bpf, sockmap: convert to generic sk_msg interface 2018-10-15 12:23:19 -07:00
sunrpc NFS client bugfixes for Linux 4.20 2018-11-15 10:59:37 -06:00
switchdev
tipc tipc: fix lockdep warning during node delete 2018-11-27 16:30:39 -08:00
tls Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
unix Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
vmw_vsock vsock: split dwork to avoid reinitializations 2018-08-07 12:39:13 -07:00
wimax
wireless nl80211: Add per peer statistics to compute FCS error rate 2018-10-12 12:56:34 +02:00
x25 net/x25: handle call collisions 2018-11-29 14:25:36 -08:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00
xfrm Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-11-03 18:25:17 -07:00
compat.c y2038: socket: Change recvmmsg to use __kernel_timespec 2018-08-29 15:42:24 +02:00
Kconfig bpf, sockmap: convert to generic sk_msg interface 2018-10-15 12:23:19 -07:00
Makefile
socket.c socket: do a generic_file_splice_read when proto_ops has no splice_read 2018-11-17 21:34:11 -08:00
sysctl_net.c