* Re: BUG: bad usercopy in __check_object_size (2)
[not found] <000000000000edab9e0575497f40@google.com>
@ 2018-09-07 15:29 ` syzbot
2018-09-07 16:17 ` Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2018-09-07 15:29 UTC (permalink / raw)
To: crecklin, dvyukov, hpa, keescook, keescook, linux-kernel,
linux-mm, luto, mingo, syzkaller-bugs, tglx, x86
syzbot has found a reproducer for the following crash on:
HEAD commit: 28619527b8a7 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=124e64d1400000
kernel config: https://syzkaller.appspot.com/x/.config?x=62e9b447c16085cf
dashboard link: https://syzkaller.appspot.com/bug?extid=a3c9d2673837ccc0f22b
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=179f9cd1400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b3e8be400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a3c9d2673837ccc0f22b@syzkaller.appspotmail.com
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440479
usercopy: Kernel memory overwrite attempt detected to spans multiple pages
(offset 0, size 64)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5340 Comm: syz-executor610 Not tainted 4.19.0-rc2+ #50
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:90
Code: c0 e8 8a 23 b2 ff 48 8b 55 c0 49 89 d9 4d 89 f0 ff 75 c8 4c 89 e1 4c
89 ee 48 c7 c7 80 48 15 88 ff 75 d0 41 57 e8 5a 38 98 ff <0f> 0b e8 5f 23
b2 ff e8 8a 6e f5 ff 8b 95 5c fe ff ff 4d 89 e0 31
RSP: 0018:ffff8801bbcf6d50 EFLAGS: 00010086
RAX: 000000000000005f RBX: ffffffff881545a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8164f825 RDI: 0000000000000005
RBP: ffff8801bbcf6da8 R08: ffff8801d8f1a500 R09: ffffed003b5c3ee2
R10: ffffed003b5c3ee2 R11: ffff8801dae1f717 R12: ffffffff88154ac0
R13: ffffffff881546e0 R14: ffffffff881545a0 R15: ffffffff881545a0
FS: 000000000225c880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000455350 CR3: 00000001d90eb000 CR4: 00000000001406f0
Call Trace:
check_page_span mm/usercopy.c:212 [inline]
check_heap_object mm/usercopy.c:241 [inline]
__check_object_size.cold.2+0x23/0x134 mm/usercopy.c:266
check_object_size include/linux/thread_info.h:119 [inline]
__copy_from_user_inatomic include/linux/uaccess.h:65 [inline]
__probe_kernel_read+0xda/0x1c0 mm/maccess.c:33
show_opcodes+0x4c/0x70 arch/x86/kernel/dumpstack.c:109
show_ip+0x31/0x36 arch/x86/kernel/dumpstack.c:126
show_iret_regs+0x14/0x38 arch/x86/kernel/dumpstack.c:131
__show_regs+0x1c/0x60 arch/x86/kernel/process_64.c:72
show_regs_if_on_stack.constprop.10+0x36/0x39
arch/x86/kernel/dumpstack.c:149
show_trace_log_lvl+0x25d/0x28c arch/x86/kernel/dumpstack.c:274
show_stack+0x38/0x3a arch/x86/kernel/dumpstack.c:293
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
fail_dump lib/fault-inject.c:51 [inline]
should_fail.cold.4+0xa/0x17 lib/fault-inject.c:149
__should_failslab+0x124/0x180 mm/failslab.c:32
should_failslab+0x9/0x14 mm/slab_common.c:1557
slab_pre_alloc_hook mm/slab.h:423 [inline]
slab_alloc mm/slab.c:3378 [inline]
kmem_cache_alloc_trace+0x2d7/0x750 mm/slab.c:3618
kmalloc include/linux/slab.h:513 [inline]
kzalloc include/linux/slab.h:707 [inline]
aa_alloc_file_ctx security/apparmor/include/file.h:60 [inline]
apparmor_file_alloc_security+0x168/0xaa0 security/apparmor/lsm.c:438
security_file_alloc+0x4c/0xa0 security/security.c:884
__alloc_file+0x12a/0x470 fs/file_table.c:105
alloc_empty_file+0x72/0x170 fs/file_table.c:150
dentry_open+0x71/0x1d0 fs/open.c:894
open_related_ns+0x1b0/0x210 fs/nsfs.c:177
__tun_chr_ioctl+0x48d/0x4690 drivers/net/tun.c:2901
tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3179
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440479
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 5b 14 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe3cf83628 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440479
RDX: 0000000000000000 RSI: 000000000000894c RDI: 0000000000000004
RBP: 00000000006cb018 R08: 0000000000000001 R09: 0000000000000034
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
(ftrace buffer empty)
---[ end trace 125c9e5841391893 ]---
RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:90
Code: c0 e8 8a 23 b2 ff 48 8b 55 c0 49 89 d9 4d 89 f0 ff 75 c8 4c 89 e1 4c
89 ee 48 c7 c7 80 48 15 88 ff 75 d0 41 57 e8 5a 38 98 ff <0f> 0b e8 5f 23
b2 ff e8 8a 6e f5 ff 8b 95 5c fe ff ff 4d 89 e0 31
RSP: 0018:ffff8801bbcf6d50 EFLAGS: 00010086
RAX: 000000000000005f RBX: ffffffff881545a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8164f825 RDI: 0000000000000005
RBP: ffff8801bbcf6da8 R08: ffff8801d8f1a500 R09: ffffed003b5c3ee2
R10: ffffed003b5c3ee2 R11: ffff8801dae1f717 R12: ffffffff88154ac0
R13: ffffffff881546e0 R14: ffffffff881545a0 R15: ffffffff881545a0
FS: 000000000225c880(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000455350 CR3: 00000001d90eb000 CR4: 00000000001406f0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: BUG: bad usercopy in __check_object_size (2)
2018-09-07 15:29 ` BUG: bad usercopy in __check_object_size (2) syzbot
@ 2018-09-07 16:17 ` Tetsuo Handa
2018-09-07 19:57 ` Kees Cook
0 siblings, 1 reply; 4+ messages in thread
From: Tetsuo Handa @ 2018-09-07 16:17 UTC (permalink / raw)
To: keescook, keescook
Cc: syzbot, crecklin, dvyukov, hpa, linux-kernel, linux-mm, luto,
mingo, syzkaller-bugs, tglx, x86
On 2018/09/08 0:29, syzbot wrote:
> syzbot has found a reproducer for the following crash on:
>
> HEAD commit:A A A 28619527b8a7 Merge git://git.kernel.org/pub/scm/linux/kern..
> git tree:A A A A A A bpf
> console output: https://syzkaller.appspot.com/x/log.txt?x=124e64d1400000
> kernel config:A https://syzkaller.appspot.com/x/.config?x=62e9b447c16085cf
> dashboard link: https://syzkaller.appspot.com/bug?extid=a3c9d2673837ccc0f22b
> compiler:A A A A A A gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:A A A A A https://syzkaller.appspot.com/x/repro.syz?x=179f9cd1400000
> C reproducer:A A https://syzkaller.appspot.com/x/repro.c?x=11b3e8be400000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+a3c9d2673837ccc0f22b@syzkaller.appspotmail.com
>
> A entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x440479
> usercopy: Kernel memory overwrite attempt detected to spans multiple pages (offset 0, size 64)!
Kees, is this because check_page_span() is failing to allow on-stack variable
u8 opcodes[OPCODE_BUFSIZE];
which by chance crossed PAGE_SIZE boundary?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: BUG: bad usercopy in __check_object_size (2)
2018-09-07 16:17 ` Tetsuo Handa
@ 2018-09-07 19:57 ` Kees Cook
2018-09-08 15:15 ` Dmitry Vyukov
0 siblings, 1 reply; 4+ messages in thread
From: Kees Cook @ 2018-09-07 19:57 UTC (permalink / raw)
To: Tetsuo Handa
Cc: syzbot, Chris von Recklinghausen, Dmitry Vyukov, H. Peter Anvin,
LKML, Linux-MM, Andy Lutomirski, Ingo Molnar, syzkaller-bugs,
Thomas Gleixner, X86 ML
On Fri, Sep 7, 2018 at 9:17 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
> On 2018/09/08 0:29, syzbot wrote:
>> syzbot has found a reproducer for the following crash on:
>>
>> HEAD commit: 28619527b8a7 Merge git://git.kernel.org/pub/scm/linux/kern..
>> git tree: bpf
>> console output: https://syzkaller.appspot.com/x/log.txt?x=124e64d1400000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=62e9b447c16085cf
>> dashboard link: https://syzkaller.appspot.com/bug?extid=a3c9d2673837ccc0f22b
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=179f9cd1400000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b3e8be400000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+a3c9d2673837ccc0f22b@syzkaller.appspotmail.com
>>
>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x440479
>> usercopy: Kernel memory overwrite attempt detected to spans multiple pages (offset 0, size 64)!
>
> Kees, is this because check_page_span() is failing to allow on-stack variable
>
> u8 opcodes[OPCODE_BUFSIZE];
>
> which by chance crossed PAGE_SIZE boundary?
There are a lot of failure conditions for the PAGESPAN check. This
might be one (and one that I'm hoping to solve separately).
-Kees
--
Kees Cook
Pixel Security
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: BUG: bad usercopy in __check_object_size (2)
2018-09-07 19:57 ` Kees Cook
@ 2018-09-08 15:15 ` Dmitry Vyukov
0 siblings, 0 replies; 4+ messages in thread
From: Dmitry Vyukov @ 2018-09-08 15:15 UTC (permalink / raw)
To: Kees Cook
Cc: Tetsuo Handa, syzbot, Chris von Recklinghausen, H. Peter Anvin,
LKML, Linux-MM, Andy Lutomirski, Ingo Molnar, syzkaller-bugs,
Thomas Gleixner, X86 ML
On Fri, Sep 7, 2018 at 9:57 PM, Kees Cook <keescook@google.com> wrote:
> On Fri, Sep 7, 2018 at 9:17 AM, Tetsuo Handa
> <penguin-kernel@i-love.sakura.ne.jp> wrote:
>> On 2018/09/08 0:29, syzbot wrote:
>>> syzbot has found a reproducer for the following crash on:
>>>
>>> HEAD commit: 28619527b8a7 Merge git://git.kernel.org/pub/scm/linux/kern..
>>> git tree: bpf
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=124e64d1400000
>>> kernel config: https://syzkaller.appspot.com/x/.config?x=62e9b447c16085cf
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=a3c9d2673837ccc0f22b
>>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=179f9cd1400000
>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b3e8be400000
>>>
>>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>> Reported-by: syzbot+a3c9d2673837ccc0f22b@syzkaller.appspotmail.com
>>>
>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>>> RIP: 0033:0x440479
>>> usercopy: Kernel memory overwrite attempt detected to spans multiple pages (offset 0, size 64)!
>>
>> Kees, is this because check_page_span() is failing to allow on-stack variable
>>
>> u8 opcodes[OPCODE_BUFSIZE];
>>
>> which by chance crossed PAGE_SIZE boundary?
>
> There are a lot of failure conditions for the PAGESPAN check. This
> might be one (and one that I'm hoping to solve separately).
Disabled CONFIG_HARDENED_USERCOPY_PAGESPAN on syzbot:
https://github.com/google/syzkaller/commit/be20da425029ecd45b18e99fa5f09691ba0658ea
#syz invalid
^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] <000000000000edab9e0575497f40@google.com>
2018-09-07 15:29 ` BUG: bad usercopy in __check_object_size (2) syzbot
2018-09-07 16:17 ` Tetsuo Handa
2018-09-07 19:57 ` Kees Cook
2018-09-08 15:15 ` Dmitry Vyukov
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