linux/net
Eric Dumazet 17c25cafd4 gre: fix uninit-value in __iptunnel_pull_header
syzbot found an interesting case of the kernel reading
an uninit-value [1]

Problem is in the handling of ETH_P_WCCP in gre_parse_header()

We look at the byte following GRE options to eventually decide
if the options are four bytes longer.

Use skb_header_pointer() to not pull bytes if we found
that no more bytes were needed.

All callers of gre_parse_header() are properly using pskb_may_pull()
anyway before proceeding to next header.

[1]
BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2303 [inline]
BUG: KMSAN: uninit-value in __iptunnel_pull_header+0x30c/0xbd0 net/ipv4/ip_tunnel_core.c:94
CPU: 1 PID: 11784 Comm: syz-executor940 Not tainted 5.6.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 pskb_may_pull include/linux/skbuff.h:2303 [inline]
 __iptunnel_pull_header+0x30c/0xbd0 net/ipv4/ip_tunnel_core.c:94
 iptunnel_pull_header include/net/ip_tunnels.h:411 [inline]
 gre_rcv+0x15e/0x19c0 net/ipv6/ip6_gre.c:606
 ip6_protocol_deliver_rcu+0x181b/0x22c0 net/ipv6/ip6_input.c:432
 ip6_input_finish net/ipv6/ip6_input.c:473 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip6_input net/ipv6/ip6_input.c:482 [inline]
 ip6_mc_input+0xdf2/0x1460 net/ipv6/ip6_input.c:576
 dst_input include/net/dst.h:442 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ipv6_rcv+0x683/0x710 net/ipv6/ip6_input.c:306
 __netif_receive_skb_one_core net/core/dev.c:5198 [inline]
 __netif_receive_skb net/core/dev.c:5312 [inline]
 netif_receive_skb_internal net/core/dev.c:5402 [inline]
 netif_receive_skb+0x66b/0xf20 net/core/dev.c:5461
 tun_rx_batched include/linux/skbuff.h:4321 [inline]
 tun_get_user+0x6aef/0x6f60 drivers/net/tun.c:1997
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write fs/read_write.c:483 [inline]
 __vfs_write+0xa5a/0xca0 fs/read_write.c:496
 vfs_write+0x44a/0x8f0 fs/read_write.c:558
 ksys_write+0x267/0x450 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __ia32_sys_write+0xdb/0x120 fs/read_write.c:620
 do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
 do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f62d99
Code: 90 e8 0b 00 00 00 f3 90 0f ae e8 eb f9 8d 74 26 00 89 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000fffedb2c EFLAGS: 00000217 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020002580
RDX: 0000000000000fca RSI: 0000000000000036 RDI: 0000000000000004
RBP: 0000000000008914 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82
 slab_alloc_node mm/slub.c:2793 [inline]
 __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4401
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1051 [inline]
 alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5766
 sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2242
 tun_alloc_skb drivers/net/tun.c:1529 [inline]
 tun_get_user+0x10ae/0x6f60 drivers/net/tun.c:1843
 tun_chr_write_iter+0x1f2/0x360 drivers/net/tun.c:2026
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write fs/read_write.c:483 [inline]
 __vfs_write+0xa5a/0xca0 fs/read_write.c:496
 vfs_write+0x44a/0x8f0 fs/read_write.c:558
 ksys_write+0x267/0x450 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __ia32_sys_write+0xdb/0x120 fs/read_write.c:620
 do_syscall_32_irqs_on arch/x86/entry/common.c:339 [inline]
 do_fast_syscall_32+0x3c7/0x6e0 arch/x86/entry/common.c:410
 entry_SYSENTER_compat+0x68/0x77 arch/x86/entry/entry_64_compat.S:139

Fixes: 95f5c64c3c ("gre: Move utility functions to common headers")
Fixes: c544193214 ("GRE: Refactor GRE tunneling code.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-08 21:25:37 -07:00
..
6lowpan
9p
802 treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
8021q Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-09 12:13:43 -08:00
appletalk
atm proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
ax25 net: Make sock protocol value checks more specific 2020-01-09 18:41:40 -08:00
batman-adv Merge ra.kernel.org:/pub/scm/linux/kernel/git/netdev/net 2020-01-19 22:10:04 +01:00
bluetooth Bluetooth: Fix race condition in hci_release_sock() 2020-01-26 10:34:17 +02:00
bpf bpf: Allow to change skb mark in test_run 2019-12-18 17:05:58 -08:00
bpfilter kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
bridge net: bridge: fix stale eth hdr pointer in br_dev_xmit 2020-02-24 11:11:19 -08:00
caif caif_usb: fix spelling mistake "to" -> "too" 2020-01-24 08:12:06 +01:00
can can: j1939: j1939_sk_bind(): take priv after lock is held 2019-12-08 11:52:02 +01:00
ceph Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
core devlink: validate length of region addr/len 2020-03-03 13:28:48 -08:00
dcb
dccp treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
decnet net: Make sock protocol value checks more specific 2020-01-09 18:41:40 -08:00
dns_resolver
dsa net: dsa: fix phylink_start()/phylink_stop() calls 2020-03-03 15:45:49 -08:00
ethernet net: remove eth_change_mtu 2020-01-27 11:09:31 +01:00
ethtool ethtool: limit bitset size 2020-02-26 11:27:31 -08:00
hsr net: hsr: Pass lockdep expression to RCU lists 2020-02-19 10:55:42 -08:00
ieee802154 nl802154: add missing attribute validation for dev_type 2020-03-03 13:28:48 -08:00
ife
ipv4 gre: fix uninit-value in __iptunnel_pull_header 2020-03-08 21:25:37 -07:00
ipv6 net/ipv6: remove the old peer route if change it to a new one 2020-03-03 14:43:16 -08:00
iucv treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kcm
key
l2tp l2tp: Allow duplicate session creation with UDP 2020-02-04 12:35:49 +01:00
l3mdev
lapb
llc llc2: Fix return statement of llc_stat_ev_rx_null_dsap_xid_c (and _test_c) 2019-12-20 21:19:36 -08:00
mac80211 mac80211: rx: avoid RCU list traversal under mutex 2020-02-24 10:42:38 +01:00
mac802154
mpls
mptcp mptcp: always include dack if possible. 2020-03-05 21:34:42 -08:00
ncsi net/ncsi: Support for multi host mellanox card 2020-01-09 18:36:22 -08:00
netfilter netfilter: nft_chain_nat: inet family is missing module ownership 2020-03-06 18:00:43 +01:00
netlabel netlabel_domainhash.c: Use built-in RCU list checking 2020-02-18 12:44:23 -08:00
netlink netlink: Use netlink header as base to calculate bad attribute offset 2020-02-29 21:21:23 -08:00
netrom
nfc net: nfc: fix bounds checking bugs on "pipe" 2020-03-05 21:32:42 -08:00
nsh
openvswitch openvswitch: add missing attribute validation for hash 2020-03-03 13:28:48 -08:00
packet y2038: core, driver and file system changes 2020-01-29 14:55:47 -08:00
phonet net: Remove redundant BUG_ON() check in phonet_pernet 2020-01-03 12:25:50 -08:00
psample
qrtr net: qrtr: Remove receive worker 2020-01-14 18:36:42 -08:00
rds net/rds: Track user mapped pages through special API 2020-02-16 18:37:09 -08:00
rfkill rfkill: Fix incorrect check to avoid NULL pointer dereference 2019-12-16 10:15:49 +01:00
rose Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-26 10:40:21 +01:00
rxrpc rxrpc: Fix call RCU cleanup using non-bh-safe locks 2020-02-07 11:20:57 +01:00
sched net: taprio: add missing attribute validation for txtime delay 2020-03-03 13:28:48 -08:00
sctp sctp: move the format error check out of __sctp_sf_do_9_1_abort 2020-02-17 21:56:03 -08:00
smc net/smc: check for valid ib_client_data 2020-02-26 20:56:25 -08:00
strparser
sunrpc xprtrdma: Fix DMA scatter-gather list mapping imbalance 2020-02-13 15:35:33 -05:00
switchdev
tipc tipc: add missing attribute validation for MTU property 2020-03-03 13:28:49 -08:00
tls net/tls: Fix to avoid gettig invalid tls record 2020-02-19 16:32:06 -08:00
unix unix: It's CONFIG_PROC_FS not CONFIG_PROCFS 2020-02-27 11:52:35 -08:00
vmw_vsock vsock: fix potential deadlock in transport->release() 2020-02-27 12:03:56 -08:00
wimax
wireless nl80211: explicitly include if_vlan.h 2020-02-24 10:41:13 +01:00
x25 net/x25: fix nonblocking connect 2020-01-09 18:39:33 -08:00
xdp xsk: Publish global consumer pointers when NAPI is finished 2020-02-11 15:51:11 +01:00
xfrm xfrm: interface: use icmp_ndo_send helper 2020-02-13 14:19:00 -08:00
compat.c
Kconfig net: disable BRIDGE_NETFILTER by default 2020-02-20 15:02:02 -08:00
Makefile mptcp: Add MPTCP socket stubs 2020-01-24 13:44:07 +01:00
socket.c socket: fix unused-function warning 2020-01-08 15:02:21 -08:00
sysctl_net.c