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Eric Dumazet d9f92772e8 xfrm6: avoid potential infinite loop in _decode_session6()
syzbot found a way to trigger an infinitie loop by overflowing
@offset variable that has been forced to use u16 for some very
obscure reason in the past.

We probably want to look at NEXTHDR_FRAGMENT handling which looks
wrong, in a separate patch.

In net-next, we shall try to use skb_header_pointer() instead of
pskb_may_pull().

watchdog: BUG: soft lockup - CPU#1 stuck for 134s! [syz-executor738:4553]
Modules linked in:
irq event stamp: 13885653
hardirqs last  enabled at (13885652): [<ffffffff878009d5>] restore_regs_and_return_to_kernel+0x0/0x2b
hardirqs last disabled at (13885653): [<ffffffff87800905>] interrupt_entry+0xb5/0xf0 arch/x86/entry/entry_64.S:625
softirqs last  enabled at (13614028): [<ffffffff84df0809>] tun_napi_alloc_frags drivers/net/tun.c:1478 [inline]
softirqs last  enabled at (13614028): [<ffffffff84df0809>] tun_get_user+0x1dd9/0x4290 drivers/net/tun.c:1825
softirqs last disabled at (13614032): [<ffffffff84df1b6f>] tun_get_user+0x313f/0x4290 drivers/net/tun.c:1942
CPU: 1 PID: 4553 Comm: syz-executor738 Not tainted 4.17.0-rc3+ #40
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:check_kcov_mode kernel/kcov.c:67 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:101
RSP: 0018:ffff8801d8cfe250 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff8801d88a8080 RBX: ffff8801d7389e40 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff868da4ad RDI: ffff8801c8a53277
RBP: ffff8801d8cfe250 R08: ffff8801d88a8080 R09: ffff8801d8cfe3e8
R10: ffffed003b19fc87 R11: ffff8801d8cfe43f R12: ffff8801c8a5327f
R13: 0000000000000000 R14: ffff8801c8a4e5fe R15: ffff8801d8cfe3e8
FS:  0000000000d88940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 00000001acab3000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 _decode_session6+0xc1d/0x14f0 net/ipv6/xfrm6_policy.c:150
 __xfrm_decode_session+0x71/0x140 net/xfrm/xfrm_policy.c:2368
 xfrm_decode_session_reverse include/net/xfrm.h:1213 [inline]
 icmpv6_route_lookup+0x395/0x6e0 net/ipv6/icmp.c:372
 icmp6_send+0x1982/0x2da0 net/ipv6/icmp.c:551
 icmpv6_send+0x17a/0x300 net/ipv6/ip6_icmp.c:43
 ip6_input_finish+0x14e1/0x1a30 net/ipv6/ip6_input.c:305
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_input+0xe1/0x5e0 net/ipv6/ip6_input.c:327
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x29c/0xa10 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ipv6_rcv+0xeb8/0x2040 net/ipv6/ip6_input.c:208
 __netif_receive_skb_core+0x2468/0x3650 net/core/dev.c:4646
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4711
 netif_receive_skb_internal+0x126/0x7b0 net/core/dev.c:4785
 napi_frags_finish net/core/dev.c:5226 [inline]
 napi_gro_frags+0x631/0xc40 net/core/dev.c:5299
 tun_get_user+0x3168/0x4290 drivers/net/tun.c:1951
 tun_chr_write_iter+0xb9/0x154 drivers/net/tun.c:1996
 call_write_iter include/linux/fs.h:1784 [inline]
 do_iter_readv_writev+0x859/0xa50 fs/read_write.c:680
 do_iter_write+0x185/0x5f0 fs/read_write.c:959
 vfs_writev+0x1c7/0x330 fs/read_write.c:1004
 do_writev+0x112/0x2f0 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1109
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reported-by: syzbot+0053c8...@syzkaller.appspotmail.com
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
2018-05-14 09:42:07 +02:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-03 18:57:03 -10:00
block Revert "blk-mq: remove code for dealing with remapping queue" 2018-04-25 09:49:22 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-03 18:57:03 -10:00
drivers net: aquantia: Limit number of vectors to actually allocated irqs 2018-05-08 00:06:44 -04:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Changes since last update: 2018-05-01 09:11:45 -07:00
include Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2018-05-07 23:51:30 -04:00
init Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2018-05-04 19:50:10 -04:00
lib swiotlb: fix inversed DMA_ATTR_NO_WARN test 2018-05-02 14:48:55 +02:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm x86/pti: Filter at vma->vm_page_prot population 2018-04-25 11:02:51 +02:00
net xfrm6: avoid potential infinite loop in _decode_session6() 2018-05-14 09:42:07 +02:00
samples bpf: sockmap sample use clang flag, -target bpf 2018-04-23 23:42:21 +02:00
scripts Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: dice: fix error path to destroy initialized stream data 2018-04-26 15:24:54 +02:00
tools selftests: net: use TEST_PROGS_EXTENDED 2018-05-07 23:28:40 -04:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM fixes for v4.17-rc3 2018-04-27 16:13:31 -07:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MAINTAINERS: Update the 3c59x network driver entry 2018-05-08 00:04:18 -04:00
Makefile Linux v4.17-rc3 2018-04-29 14:17:42 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.