On Wed, Nov 25, 2015 at 4:12 PM, Vlad Yasevich <vyasevich@xxxxxxxxx> wrote: > On 11/24/2015 03:45 PM, Neil Horman wrote: >> On Tue, Nov 24, 2015 at 11:10:32AM +0100, Dmitry Vyukov wrote: >>> On Tue, Nov 24, 2015 at 10:31 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>>> On Tue, Nov 24, 2015 at 10:15 AM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: >>>>> Hello, >>>>> >>>>> The following program triggers use-after-free in sctp_do_sm: >>>>> >>>>> // autogenerated by syzkaller (http://github.com/google/syzkaller) >>>>> #include <syscall.h> >>>>> #include <string.h> >>>>> #include <stdint.h> >>>>> >>>>> int main() >>>>> { >>>>> long r0 = syscall(SYS_socket, 0xaul, 0x80805ul, 0x0ul, 0, 0, 0); >>>>> long r1 = syscall(SYS_mmap, 0x20000000ul, 0x10000ul, 0x3ul, >>>>> 0x32ul, 0xfffffffffffffffful, 0x0ul); >>>>> memcpy((void*)0x20002fe4, >>>>> "\x0a\x00\x33\xe7\xeb\x9d\xcf\x61\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xc5\xc8\x88\x64", >>>>> 28); >>>>> long r3 = syscall(SYS_bind, r0, 0x20002fe4ul, 0x1cul, 0, 0, 0); >>>>> memcpy((void*)0x20000faa, >>>>> "\x9b\x01\x7d\xcd\xb8\x6a\xc7\x3d\x09\x3a\x07\x00\xa7\xc4\xe9\xee\x0a\xd6\xec\xde\x26\x75\x5f\x22\xae\x4e\x33\x00\xb0\x76\x10\x70\xd6\xca\x19\xbc\x15\x83\xcf\x2e\xbc\x99\x0c\x5e\x83\x89\xc1\x44\x9c\x6e\x74\xd8\x5d\x5d\xd0\xf0\xdf\x47\xc0\x00\x71\x0b\x55\x4c\xab\xf0\xd8\x90\xd5\x92\x8c\x6e\x33\x22\x15\x5b\x19\xfb\xed\xdd\xa6\xac\xcb\x60\xcf\xe2\xde\xed\xdb\x95\x5c\xaa\x20\xa3", >>>>> 94); >>>>> memcpy((void*)0x2000033a, >>>>> "\x02\x00\x33\xe2\x7f\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", >>>>> 128); >>>>> long r6 = syscall(SYS_sendto, r0, 0x20000faaul, 0x5eul, >>>>> 0x81ul, 0x2000033aul, 0x80ul); >>>>> return 0; >>>>> } >>>>> >>>>> >>>>> ================================================================== >>>>> BUG: KASAN: use-after-free in sctp_do_sm+0x42f6/0x4f60 at addr ffff880036fa80a8 >>>>> Read of size 4 by task a.out/5664 >>>>> ============================================================================= >>>>> BUG kmalloc-4096 (Tainted: G B ): kasan: bad access detected >>>>> ----------------------------------------------------------------------------- >>>>> >>>>> INFO: Allocated in sctp_association_new+0x6f/0x1ea0 age=8 cpu=1 pid=5664 >>>>> [< none >] kmem_cache_alloc_trace+0x1cf/0x220 ./mm/slab.c:3707 >>>>> [< none >] sctp_association_new+0x6f/0x1ea0 >>>>> [< none >] sctp_sendmsg+0x1954/0x28e0 >>>>> [< none >] inet_sendmsg+0x316/0x4f0 ./net/ipv4/af_inet.c:802 >>>>> [< inline >] __sock_sendmsg_nosec ./net/socket.c:641 >>>>> [< inline >] __sock_sendmsg ./net/socket.c:651 >>>>> [< none >] sock_sendmsg+0xca/0x110 ./net/socket.c:662 >>>>> [< none >] SYSC_sendto+0x208/0x350 ./net/socket.c:1841 >>>>> [< none >] SyS_sendto+0x40/0x50 ./net/socket.c:1862 >>>>> [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a >>>>> >>>>> INFO: Freed in sctp_association_put+0x150/0x250 age=14 cpu=1 pid=5664 >>>>> [< none >] kfree+0x199/0x1b0 ./mm/slab.c:1211 >>>>> [< none >] sctp_association_put+0x150/0x250 >>>>> [< none >] sctp_association_free+0x498/0x630 >>>>> [< none >] sctp_do_sm+0xd8b/0x4f60 >>>>> [< none >] sctp_primitive_SHUTDOWN+0xa9/0xd0 >>>>> [< none >] sctp_close+0x616/0x790 >>>>> [< none >] inet_release+0xed/0x1c0 ./net/ipv4/af_inet.c:471 >>>>> [< none >] inet6_release+0x50/0x70 ./net/ipv6/af_inet6.c:416 >>>>> [< inline >] constant_test_bit ././arch/x86/include/asm/bitops.h:321 >>>>> [< none >] sock_release+0x8d/0x200 ./net/socket.c:601 >>>>> [< none >] sock_close+0x16/0x20 ./net/socket.c:1188 >>>>> [< none >] __fput+0x21d/0x6e0 ./fs/file_table.c:265 >>>>> [< none >] ____fput+0x15/0x20 ./fs/file_table.c:84 >>>>> [< none >] task_work_run+0x163/0x1f0 ./include/trace/events/rcu.h:20 >>>>> [< inline >] __list_add ./include/linux/list.h:42 >>>>> [< inline >] list_add_tail ./include/linux/list.h:76 >>>>> [< inline >] list_move_tail ./include/linux/list.h:168 >>>>> [< inline >] reparent_leader ./kernel/exit.c:618 >>>>> [< inline >] forget_original_parent ./kernel/exit.c:669 >>>>> [< inline >] exit_notify ./kernel/exit.c:697 >>>>> [< none >] do_exit+0x809/0x2b90 ./kernel/exit.c:878 >>>>> [< none >] do_group_exit+0x108/0x320 ./kernel/exit.c:985 >>>>> >>>>> INFO: Slab 0xffffea0000dbea00 objects=7 used=1 fp=0xffff880036fa8000 >>>>> flags=0x100000000004080 >>>>> INFO: Object 0xffff880036fa8000 @offset=0 fp=0xffff880036fad668 >>>>> CPU: 1 PID: 5664 Comm: a.out Tainted: G B 4.4.0-rc1+ #81 >>>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 >>>>> 00000000ffffffff ffff880061d6f700 ffffffff825d3336 ffff88003e806d00 >>>>> ffff880036fa8000 ffff880036fa8000 ffff880061d6f730 ffffffff81618784 >>>>> ffff88003e806d00 ffffea0000dbea00 ffff880036fa8000 0000000000000000 >>>>> >>>>> Call Trace: >>>>> [<ffffffff8162131e>] __asan_report_load4_noabort+0x3e/0x40 >>>>> [<ffffffff8475ac76>] sctp_do_sm+0x42f6/0x4f60 >>>>> [<ffffffff847b50e9>] sctp_primitive_SHUTDOWN+0xa9/0xd0 >>>>> [<ffffffff847a1426>] sctp_close+0x616/0x790 >>>>> [<ffffffff8409bb0d>] inet_release+0xed/0x1c0 ./net/ipv4/af_inet.c:471 >>>>> [<ffffffff84192cc0>] inet6_release+0x50/0x70 ./net/ipv6/af_inet6.c:416 >>>>> [< inline >] constant_test_bit ././arch/x86/include/asm/bitops.h:321 >>>>> [<ffffffff83dc78cd>] sock_release+0x8d/0x200 ./net/socket.c:601 >>>>> [<ffffffff83dc7a56>] sock_close+0x16/0x20 ./net/socket.c:1188 >>>>> [<ffffffff81662f5d>] __fput+0x21d/0x6e0 ./fs/file_table.c:265 >>>>> [<ffffffff816634a5>] ____fput+0x15/0x20 ./fs/file_table.c:84 >>>>> [<ffffffff812a33d3>] task_work_run+0x163/0x1f0 ./include/trace/events/rcu.h:20 >>>>> [< inline >] __list_add ./include/linux/list.h:42 >>>>> [< inline >] list_add_tail ./include/linux/list.h:76 >>>>> [< inline >] list_move_tail ./include/linux/list.h:168 >>>>> [< inline >] reparent_leader ./kernel/exit.c:618 >>>>> [< inline >] forget_original_parent ./kernel/exit.c:669 >>>>> [< inline >] exit_notify ./kernel/exit.c:697 >>>>> [<ffffffff812505d9>] do_exit+0x809/0x2b90 ./kernel/exit.c:878 >>>>> [<ffffffff81252ad8>] do_group_exit+0x108/0x320 ./kernel/exit.c:985 >>>>> [<ffffffff81252d0d>] SyS_exit_group+0x1d/0x20 ./kernel/exit.c:1002 >>>>> [<ffffffff84bf0c36>] entry_SYSCALL_64_fastpath+0x16/0x7a >>>>> ================================================================== >>>>> >>>>> >>>>> I am on commit 90b55590c43258a157a2a143748455dcc50fbb53 of net-next (Nov 22). >>> >>> The right commit is: >>> >>> commit 7d267278a9ece963d77eefec61630223fce08c6c >>> Author: Rainer Weikusat >>> Date: Fri Nov 20 22:07:23 2015 +0000 >>> unix: avoid use-after-free in ep_remove_wait_queue >> This commit doesn't seem to exist > > I don't think this matters... I think what's happening is that a close is happening on a > socket still in connection initialization phase and we've never handled that particularly > well... > > Net-next kernel with mem debugging hangs on boot for me with a ton of printks suppressed. > Will try the net kernel to see if that's better This also seems to lead the the following WARNINGS: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 21734 at kernel/jump_label.c:77 __static_key_slow_dec+0xfb/0x120() jump label: negative count! Modules linked in: CPU: 3 PID: 21734 Comm: executor Tainted: G B W 4.4.0-rc2+ #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 00000000ffffffff ffff88006083f660 ffffffff82719fc6 ffff88006083f6d0 ffff88003bbf8000 ffffffff85a612e0 ffff88006083f6a0 ffffffff81244ec9 ffffffff8152c54b ffffed000c107ed6 ffffffff85a612e0 000000000000004d Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82719fc6>] dump_stack+0x68/0x92 lib/dump_stack.c:50 [<ffffffff81244ec9>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:460 [<ffffffff81244fd9>] warn_slowpath_fmt+0xa9/0xd0 kernel/panic.c:472 [<ffffffff8152c54b>] __static_key_slow_dec+0xfb/0x120 kernel/jump_label.c:76 [<ffffffff8152c5c1>] static_key_slow_dec+0x51/0x90 kernel/jump_label.c:100 [<ffffffff84962d9b>] net_disable_timestamp+0x3b/0x50 net/core/dev.c:1709 [<ffffffff84914d43>] sock_disable_timestamp+0x93/0xb0 net/core/sock.c:444 [<ffffffff8491f82c>] sk_destruct+0xec/0x440 net/core/sock.c:1457 [<ffffffff8491fbd7>] __sk_free+0x57/0x200 net/core/sock.c:1476 [<ffffffff8491fdb0>] sk_free+0x30/0x40 net/core/sock.c:1487 [< inline >] sock_put include/net/sock.h:1623 [<ffffffff854c8a18>] sctp_close+0x628/0x790 net/sctp/socket.c:1546 [<ffffffff84d4b3ed>] inet_release+0xed/0x1c0 net/ipv4/af_inet.c:413 [<ffffffff84e70240>] inet6_release+0x50/0x70 net/ipv6/af_inet6.c:406 [<ffffffff84909bbd>] sock_release+0x8d/0x1d0 net/socket.c:571 [<ffffffff84909d16>] sock_close+0x16/0x20 net/socket.c:1022 [<ffffffff81663a00>] __fput+0x220/0x770 fs/file_table.c:208 [<ffffffff81663fd5>] ____fput+0x15/0x20 fs/file_table.c:244 [<ffffffff8129f673>] task_work_run+0x163/0x1f0 kernel/task_work.c:115 [< inline >] exit_task_work include/linux/task_work.h:21 [<ffffffff8124d9e9>] do_exit+0x809/0x2ae0 kernel/exit.c:750 [<ffffffff8124fe38>] do_group_exit+0x108/0x320 kernel/exit.c:880 [<ffffffff81271df7>] get_signal+0x597/0x1630 kernel/signal.c:2307 [<ffffffff8114c77f>] do_signal+0x7f/0x18e0 arch/x86/kernel/signal.c:709 [<ffffffff81003901>] exit_to_usermode_loop+0xf1/0x1a0 arch/x86/entry/common.c:247 [< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:282 [<ffffffff8100616f>] syscall_return_slowpath+0x19f/0x210 arch/x86/entry/common.c:344 [<ffffffff85955362>] int_ret_from_sys_call+0x25/0x9f arch/x86/entry/entry_64.S:281 ---[ end trace 3e42717665ff2020 ]--- These WARNINGS always go with the original use-after-free reports. And I was not able to reproduce this WARNING with commented out sctp_association_destroy. For the reference here is syzkaller program that triggers the WARNING. r0 = socket(0xa, 0x1, 0x84) mmap(&(0x7f0000000000)=nil, (0x10000), 0x3, 0x32, 0xffffffffffffffff, 0x0) bind(r0, &(0x7f0000000000)="0a0033e049d02e70000000000000000000000000000000014c37ffc4", 0x1c) connect(r0, &(0x7f0000001000)="020033d97f000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", 0x80) setsockopt$sock_int(r0, 0x1, 0x1d, &(0x7f0000001000+0x336)=0x1, 0x4) listen(r0, 0xbb3) r1 = accept(r0, &(0x7f0000003000+0xfd6)=nil, &(0x7f0000004000-0x2)=nil) -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
