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Eric Dumazet b855ff8274 dccp: initialize ireq->ir_mark
syzbot reported an uninit-value read of skb->mark in iptable_mangle_hook()

Thanks to the nice report, I tracked the problem to dccp not caring
of ireq->ir_mark for passive sessions.

BUG: KMSAN: uninit-value in ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:66 [inline]
BUG: KMSAN: uninit-value in iptable_mangle_hook+0x5e5/0x720 net/ipv4/netfilter/iptable_mangle.c:84
CPU: 0 PID: 5300 Comm: syz-executor3 Not tainted 4.16.0+ #81
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:66 [inline]
 iptable_mangle_hook+0x5e5/0x720 net/ipv4/netfilter/iptable_mangle.c:84
 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline]
 nf_hook_slow+0x158/0x3d0 net/netfilter/core.c:483
 nf_hook include/linux/netfilter.h:243 [inline]
 __ip_local_out net/ipv4/ip_output.c:113 [inline]
 ip_local_out net/ipv4/ip_output.c:122 [inline]
 ip_queue_xmit+0x1d21/0x21c0 net/ipv4/ip_output.c:504
 dccp_transmit_skb+0x15eb/0x1900 net/dccp/output.c:142
 dccp_xmit_packet+0x814/0x9e0 net/dccp/output.c:281
 dccp_write_xmit+0x20f/0x480 net/dccp/output.c:363
 dccp_sendmsg+0x12ca/0x12d0 net/dccp/proto.c:818
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455259
RSP: 002b:00007f1a4473dc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f1a4473e6d4 RCX: 0000000000455259
RDX: 0000000000000000 RSI: 0000000020b76fc8 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004f0 R14: 00000000006fa720 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
 ip_queue_xmit+0x1e35/0x21c0 net/ipv4/ip_output.c:502
 dccp_transmit_skb+0x15eb/0x1900 net/dccp/output.c:142
 dccp_xmit_packet+0x814/0x9e0 net/dccp/output.c:281
 dccp_write_xmit+0x20f/0x480 net/dccp/output.c:363
 dccp_sendmsg+0x12ca/0x12d0 net/dccp/proto.c:818
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
 inet_csk_clone_lock+0x503/0x580 net/ipv4/inet_connection_sock.c:797
 dccp_create_openreq_child+0x7f/0x890 net/dccp/minisocks.c:92
 dccp_v4_request_recv_sock+0x22c/0xe90 net/dccp/ipv4.c:408
 dccp_v6_request_recv_sock+0x290/0x2000 net/dccp/ipv6.c:414
 dccp_check_req+0x7b9/0x8f0 net/dccp/minisocks.c:197
 dccp_v4_rcv+0x12e4/0x2630 net/dccp/ipv4.c:840
 ip_local_deliver_finish+0x6ed/0xd40 net/ipv4/ip_input.c:216
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:257
 dst_input include/net/dst.h:449 [inline]
 ip_rcv_finish+0x1253/0x16d0 net/ipv4/ip_input.c:397
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_rcv+0x119d/0x16f0 net/ipv4/ip_input.c:493
 __netif_receive_skb_core+0x47cf/0x4a80 net/core/dev.c:4562
 __netif_receive_skb net/core/dev.c:4627 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5307
 napi_poll net/core/dev.c:5705 [inline]
 net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
 __do_softirq+0x56d/0x93d kernel/softirq.c:285
Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmem_cache_alloc+0xaab/0xb90 mm/slub.c:2756
 reqsk_alloc include/net/request_sock.h:88 [inline]
 inet_reqsk_alloc+0xc4/0x7f0 net/ipv4/tcp_input.c:6145
 dccp_v4_conn_request+0x5cc/0x1770 net/dccp/ipv4.c:600
 dccp_v6_conn_request+0x299/0x1880 net/dccp/ipv6.c:317
 dccp_rcv_state_process+0x2ea/0x2410 net/dccp/input.c:612
 dccp_v4_do_rcv+0x229/0x340 net/dccp/ipv4.c:682
 dccp_v6_do_rcv+0x16d/0x1220 net/dccp/ipv6.c:578
 sk_backlog_rcv include/net/sock.h:908 [inline]
 __sk_receive_skb+0x60e/0xf20 net/core/sock.c:513
 dccp_v4_rcv+0x24d4/0x2630 net/dccp/ipv4.c:874
 ip_local_deliver_finish+0x6ed/0xd40 net/ipv4/ip_input.c:216
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_local_deliver+0x43c/0x4e0 net/ipv4/ip_input.c:257
 dst_input include/net/dst.h:449 [inline]
 ip_rcv_finish+0x1253/0x16d0 net/ipv4/ip_input.c:397
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_rcv+0x119d/0x16f0 net/ipv4/ip_input.c:493
 __netif_receive_skb_core+0x47cf/0x4a80 net/core/dev.c:4562
 __netif_receive_skb net/core/dev.c:4627 [inline]
 process_backlog+0x62d/0xe20 net/core/dev.c:5307
 napi_poll net/core/dev.c:5705 [inline]
 net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
 __do_softirq+0x56d/0x93d kernel/softirq.c:285

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-07 22:32:31 -04:00
arch Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
block Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: af_alg - fix possible uninit-value in alg_bind() 2018-04-07 22:32:31 -04:00
Documentation Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
drivers net: phy: marvell: Enable interrupt function on LED2 pin 2018-04-06 13:36:57 -04:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
include net: fix rtnh_ok() 2018-04-07 22:32:31 -04:00
init Merge branch 'syscalls-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux 2018-04-02 21:22:12 -07:00
ipc Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-03 19:15:32 -07:00
kernel Driver core patches for 4.17-rc1 2018-04-04 19:41:45 -07:00
lib Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next 2018-04-03 14:08:58 -07:00
net dccp: initialize ireq->ir_mark 2018-04-07 22:32:31 -04:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-04-03 14:04:18 -07:00
scripts RISC-V changes for 4.17 2018-04-04 16:43:47 -07:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-03 19:15:32 -07:00
sound Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-04-03 14:04:18 -07:00
tools Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt kvm/arm fixes for 4.16, take 2 2018-03-15 21:45:37 +01:00
.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: move include/config/ksym/* to include/ksym/* 2018-03-26 02:01:23 +09:00
.mailmap Merge remote-tracking branch 'spi/topic/samsung' into spi-next 2018-04-02 15:56:32 +01:00
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 Char/Misc patches for 4.17-rc1 2018-04-04 20:07:20 -07:00
Makefile Kconfig updates for v4.17 2018-04-03 16:28:01 -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.