linux/net/core
Eric Dumazet b2504a5dbe net: reduce skb_warn_bad_offload() noise
Dmitry reported warnings occurring in __skb_gso_segment() [1]

All SKB_GSO_DODGY producers can allow user space to feed
packets that trigger the current check.

We could prevent them from doing so, rejecting packets, but
this might add regressions to existing programs.

It turns out our SKB_GSO_DODGY handlers properly set up checksum
information that is needed anyway when packets needs to be segmented.

By checking again skb_needs_check() after skb_mac_gso_segment(),
we should remove these pesky warnings, at a very minor cost.

With help from Willem de Bruijn

[1]
WARNING: CPU: 1 PID: 6768 at net/core/dev.c:2439 skb_warn_bad_offload+0x2af/0x390 net/core/dev.c:2434
lo: caps=(0x000000a2803b7c69, 0x0000000000000000) len=138 data_len=0 gso_size=15883 gso_type=4 ip_summed=0
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 6768 Comm: syz-executor1 Not tainted 4.9.0 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801c063ecd8 ffffffff82346bdf ffffffff00000001 1ffff100380c7d2e
 ffffed00380c7d26 0000000041b58ab3 ffffffff84b37e38 ffffffff823468f1
 ffffffff84820740 ffffffff84f289c0 dffffc0000000000 ffff8801c063ee20
Call Trace:
 [<ffffffff82346bdf>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff82346bdf>] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
 [<ffffffff81827e34>] panic+0x1fb/0x412 kernel/panic.c:179
 [<ffffffff8141f704>] __warn+0x1c4/0x1e0 kernel/panic.c:542
 [<ffffffff8141f7e5>] warn_slowpath_fmt+0xc5/0x100 kernel/panic.c:565
 [<ffffffff8356cbaf>] skb_warn_bad_offload+0x2af/0x390 net/core/dev.c:2434
 [<ffffffff83585cd2>] __skb_gso_segment+0x482/0x780 net/core/dev.c:2706
 [<ffffffff83586f19>] skb_gso_segment include/linux/netdevice.h:3985 [inline]
 [<ffffffff83586f19>] validate_xmit_skb+0x5c9/0xc20 net/core/dev.c:2969
 [<ffffffff835892bb>] __dev_queue_xmit+0xe6b/0x1e70 net/core/dev.c:3383
 [<ffffffff8358a2d7>] dev_queue_xmit+0x17/0x20 net/core/dev.c:3424
 [<ffffffff83ad161d>] packet_snd net/packet/af_packet.c:2930 [inline]
 [<ffffffff83ad161d>] packet_sendmsg+0x32ed/0x4d30 net/packet/af_packet.c:2955
 [<ffffffff834f0aaa>] sock_sendmsg_nosec net/socket.c:621 [inline]
 [<ffffffff834f0aaa>] sock_sendmsg+0xca/0x110 net/socket.c:631
 [<ffffffff834f329a>] ___sys_sendmsg+0x8fa/0x9f0 net/socket.c:1954
 [<ffffffff834f5e58>] __sys_sendmsg+0x138/0x300 net/socket.c:1988
 [<ffffffff834f604d>] SYSC_sendmsg net/socket.c:1999 [inline]
 [<ffffffff834f604d>] SyS_sendmsg+0x2d/0x50 net/socket.c:1995
 [<ffffffff84371941>] entry_SYSCALL_64_fastpath+0x1f/0xc2

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov  <dvyukov@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-01 12:02:48 -05:00
..
datagram.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dev_addr_lists.c net: fix spelling for synchronized 2014-11-18 15:26:32 -05:00
dev_ioctl.c dev_ioctl: use sizeof(x) instead of sizeof x 2014-11-18 15:27:32 -05:00
dev.c net: reduce skb_warn_bad_offload() noise 2017-02-01 12:02:48 -05:00
devlink.c devlink: Add E-Switch inline mode control 2016-11-24 16:01:14 -05:00
drop_monitor.c drop_monitor: consider inserted data in genlmsg_end 2017-01-03 11:09:44 -05:00
dst_cache.c net: dst_cache_per_cpu_dst_set() can be static 2016-03-18 17:45:08 -04:00
dst.c net: add dst_cache to ovs vxlan lwtunnel 2016-02-16 20:21:48 -05:00
ethtool.c net: ethtool: convert large order kmalloc allocations to vzalloc 2017-01-31 13:28:06 -05:00
fib_rules.c net: core: add missing check for uid_range in rule_exists. 2016-11-09 13:28:10 -05:00
filter.c bpf: allow option for setting bpf_l4_csum_replace from scratch 2017-01-24 14:46:06 -05:00
flow_dissector.c flow dissector: check if arp_eth is null rather than arp 2017-01-16 13:48:48 -05:00
flow.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-12 19:25:04 -08:00
gen_estimator.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
gen_stats.c net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -05:00
hwbm.c net: hwbm: Fix unbalanced spinlock in error case 2016-05-25 12:35:09 -07:00
link_watch.c dev: introduce dev_get_iflink() 2015-04-02 14:04:59 -04:00
lwt_bpf.c lwtunnel: remove device arg to lwtunnel_build_state 2017-01-30 15:14:22 -05:00
lwtunnel.c lwtunnel: remove device arg to lwtunnel_build_state 2017-01-30 15:14:22 -05:00
Makefile bpf: BPF for lightweight tunnel infrastructure 2016-12-02 10:51:49 -05:00
neighbour.c neigh: Send netevent after marking neigh as dead 2016-12-23 12:31:18 -05:00
net_namespace.c Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit 2016-12-14 14:06:40 -08:00
net-procfs.c net: remove NETDEV_TX_LOCKED support 2016-04-26 15:53:05 -04:00
net-sysfs.c net: Add support for XPS with QoS via traffic classes 2016-10-31 15:00:48 -04:00
net-sysfs.h
net-traces.c net: IPv6 fib lookup tracepoint 2015-11-22 11:54:10 -05:00
netclassid_cgroup.c core: remove unneded headers for net cgroup controllers. 2016-02-17 15:31:27 -05:00
netevent.c netevent: remove automatic variable in register_netevent_notifier() 2015-05-31 00:03:21 -07:00
netpoll.c netpoll: more efficient locking 2016-11-16 18:32:02 -05:00
netprio_cgroup.c core: remove unneded headers for net cgroup controllers. 2016-02-17 15:31:27 -05:00
pktgen.c net-tc: convert tc_verd to integer bitfields 2017-01-08 20:58:52 -05:00
ptp_classifier.c ptp: Change ptp_class to a proper bitmask 2015-11-03 11:08:22 -05:00
request_sock.c ipv4: Namespaceify tcp_max_syn_backlog knob 2016-12-29 11:38:31 -05:00
rtnetlink.c rtnetlink: Handle IFLA_MASTER parameter when processing rtnl_newlink 2017-02-01 11:53:23 -05:00
scm.c scm: remove use CMSG{_COMPAT}_ALIGN(sizeof(struct {compat_}cmsghdr)) 2017-01-04 13:04:37 -05:00
secure_seq.c secure_seq: fix sparse errors 2017-01-12 15:57:10 -05:00
skbuff.c net: adjust skb->truesize in pskb_expand_head() 2017-01-27 12:03:29 -05:00
sock_diag.c sock_diag: align nlattr properly when needed 2016-04-26 12:00:48 -04:00
sock_reuseport.c soreuseport: do not export reuseport_add_sock() 2016-10-18 14:18:23 -04:00
sock.c net: fix AF_SMC related typo 2017-01-12 09:47:01 -05:00
stream.c net: fix sleeping for sk_wait_event() 2016-11-14 13:17:21 -05:00
sysctl_net_core.c net: dev_weight: TX/RX orthogonality 2016-12-29 15:38:35 -05:00
timestamping.c net: skb_defer_rx_timestamp should check for phydev before setting up classify 2015-07-09 14:17:15 -07:00
tso.c net: tso: add support for IPv6 2015-10-26 22:24:22 -07:00
utils.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00