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6780db244d
linux/net/sctp
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Eric Dumazet 6780db244d sctp: do not leak kernel memory to user space 
syzbot produced a nice report [1]

Issue here is that a recvmmsg() managed to leak 8 bytes of kernel memory
to user space, because sin_zero (padding field) was not properly cleared.

[1]
BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline]
BUG: KMSAN: uninit-value in move_addr_to_user+0x32e/0x530 net/socket.c:227
CPU: 1 PID: 3586 Comm: syzkaller481044 Not tainted 4.16.0+ #82
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
 kmsan_internal_check_memory+0x164/0x1d0 mm/kmsan/kmsan.c:1176
 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199
 copy_to_user include/linux/uaccess.h:184 [inline]
 move_addr_to_user+0x32e/0x530 net/socket.c:227
 ___sys_recvmsg+0x4e2/0x810 net/socket.c:2211
 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313
 SYSC_recvmmsg+0x29b/0x3e0 net/socket.c:2394
 SyS_recvmmsg+0x76/0xa0 net/socket.c:2378
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x4401c9
RSP: 002b:00007ffc56f73098 EFLAGS: 00000217 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401c9
RDX: 0000000000000001 RSI: 0000000020003ac0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000020003bc0 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000401af0
R13: 0000000000401b80 R14: 0000000000000000 R15: 0000000000000000

Local variable description: ----addr@___sys_recvmsg
Variable was created at:
 ___sys_recvmsg+0xd5/0x810 net/socket.c:2172
 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313

Bytes 8-15 of 16 are uninitialized

==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3586 Comm: syzkaller481044 Tainted: G    B            4.16.0+ #82
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
 panic+0x39d/0x940 kernel/panic.c:183
 kmsan_report+0x238/0x240 mm/kmsan/kmsan.c:1083
 kmsan_internal_check_memory+0x164/0x1d0 mm/kmsan/kmsan.c:1176
 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199
 copy_to_user include/linux/uaccess.h:184 [inline]
 move_addr_to_user+0x32e/0x530 net/socket.c:227
 ___sys_recvmsg+0x4e2/0x810 net/socket.c:2211
 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313
 SYSC_recvmmsg+0x29b/0x3e0 net/socket.c:2394
 SyS_recvmmsg+0x76/0xa0 net/socket.c:2378
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc:	Vlad Yasevich <vyasevich@gmail.com>
Cc:	Neil Horman <nhorman@tuxdriver.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-08 10:31:51 -04:00
..
associola.c sctp: implement enqueue_event for sctp_stream_interleave 2017-12-11 11:23:05 -05:00
auth.c sctp: add SCTP_AUTH_FREE_KEY type for AUTHENTICATION_EVENT 2018-03-14 13:48:27 -04:00
bind_addr.c sctp: remove the typedef sctp_scope_t 2017-08-06 21:33:41 -07:00
chunk.c sctp: add support for SCTP AUTH Information for sendmsg 2018-03-14 13:48:27 -04:00
debug.c sctp: add SCTP_CID_I_DATA and SCTP_CID_I_FWD_TSN conversion in sctp_cname 2018-02-12 11:40:01 -05:00
diag.c sctp: add file comments in diag.c 2018-02-13 13:56:31 -05:00
endpointola.c sctp: remove unnecessary asoc in sctp_has_association 2018-03-27 10:22:11 -04:00
input.c sctp: remove unnecessary asoc in sctp_has_association 2018-03-27 10:22:11 -04:00
inqueue.c net: use skb_is_gso_sctp() instead of open-coding 2018-03-09 11:41:47 -05:00
ipv6.c sctp: do not leak kernel memory to user space 2018-04-08 10:31:51 -04:00
Kconfig net: sctp: Remove debug SCTP probe module 2018-01-02 14:27:29 -05:00
Makefile sctp: rename sctp_diag.c as diag.c 2018-02-13 13:56:31 -05:00
objcnt.c sctp: use proc_remove_subtree() 2018-03-17 20:11:22 -04:00
offload.c net: use skb_is_gso_sctp() instead of open-coding 2018-03-09 11:41:47 -05:00
output.c sctp: add refcnt support for sh_key 2018-03-14 13:48:27 -04:00
outqueue.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-01-17 00:10:42 -05:00
primitive.c sctp: remove the typedef sctp_subtype_t 2017-08-06 21:33:42 -07:00
proc.c net: Use octal not symbolic permissions 2018-03-26 12:07:48 -04:00
protocol.c sctp: fix unused lable warning 2018-03-29 14:38:27 -04:00
sm_make_chunk.c sctp: add SCTP_AUTH_FREE_KEY type for AUTHENTICATION_EVENT 2018-03-14 13:48:27 -04:00
sm_sideeffect.c sctp: add SCTP_AUTH_NO_AUTH type for AUTHENTICATION_EVENT 2018-03-14 13:48:27 -04:00
sm_statefuns.c sctp: add SCTP_AUTH_NO_AUTH type for AUTHENTICATION_EVENT 2018-03-14 13:48:27 -04:00
sm_statetable.c sctp: implement validate_ftsn for sctp_stream_interleave 2017-12-15 13:52:22 -05:00
socket.c sctp: Fix double free in sctp_sendmsg_to_asoc 2018-03-15 14:32:04 -04:00
stream_interleave.c sctp: remove the left unnecessary check for chunk in sctp_renege_events 2018-02-16 16:32:37 -05:00
stream_sched_prio.c sctp: remove extern from stream sched 2017-11-28 11:00:13 -05:00
stream_sched_rr.c sctp: remove extern from stream sched 2017-11-28 11:00:13 -05:00
stream_sched.c sctp: add stream interleave support in stream scheduler 2017-12-15 13:52:22 -05:00
stream.c sctp: fix some copy-paste errors for file comments 2018-02-14 14:18:32 -05:00
sysctl.c sctp: support sysctl to allow users to use stream interleave 2017-12-15 13:52:22 -05:00
transport.c sctp: fix the handling of ICMP Frag Needed for too small MTUs 2018-01-08 14:19:13 -05:00
tsnmap.c
ulpevent.c sctp: implement abort_pd for sctp_stream_interleave 2017-12-11 11:23:05 -05:00
ulpqueue.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-22 11:16:31 -05:00