Hello,
syzbot found the following crash on:
HEAD commit: 8ada228a Add linux-next specific files for 20191011
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1423a87f600000
kernel config: https://syzkaller.appspot.com/x/.config?x=7cf4eed5fe42c31a
dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
------------[ cut here ]------------
WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
check_copy_size include/linux/thread_info.h:150 [inline]
WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
copy_from_user include/linux/uaccess.h:143 [inline]
WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
drm_mode_createblob_ioctl+0x398/0x490 drivers/gpu/drm/drm_property.c:800
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 30449 Comm: syz-executor.5 Not tainted 5.4.0-rc2-next-20191011
#0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
panic+0x2e3/0x75c kernel/panic.c:221
__warn.cold+0x2f/0x35 kernel/panic.c:582
report_bug+0x289/0x300 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:174 [inline]
fixup_bug arch/x86/kernel/traps.c:169 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:check_copy_size include/linux/thread_info.h:150 [inline]
RIP: 0010:copy_from_user include/linux/uaccess.h:143 [inline]
RIP: 0010:drm_mode_createblob_ioctl+0x398/0x490
drivers/gpu/drm/drm_property.c:800
Code: c1 ea 03 80 3c 02 00 0f 85 ed 00 00 00 49 89 5d 00 e8 3c 28 cb fd 4c
89 f7 e8 64 92 9e 03 31 c0 e9 75 fd ff ff e8 28 28 cb fd <0f> 0b e8 21 28
cb fd 4d 85 e4 b8 f2 ff ff ff 0f 84 5b fd ff ff 89
RSP: 0018:ffff8880584efaa8 EFLAGS: 00010246
RAX: 0000000000040000 RBX: ffff8880a3a90000 RCX: ffffc900109da000
RDX: 0000000000040000 RSI: ffffffff83a7eaf8 RDI: 0000000000000007
RBP: ffff8880584efae8 R08: ffff888096c40080 R09: ffffed1014752110
R10: ffffed101475210f R11: ffff8880a3a9087f R12: ffffc90014907000
R13: ffff888028aa0000 R14: 000000009a6c7969 R15: ffffc90014907058
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
On Sun, Oct 13, 2019 at 11:09:09PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 8ada228a Add linux-next specific files for 20191011
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1423a87f600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=7cf4eed5fe42c31a
> dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
Hm only thing that could go wrong is how we allocate the target for the
user_copy, which is an argument directly from the ioctl parameter struct.
Does syzbot not track that? We use the standard linux ioctl struct
encoding in drm.
Otherwise I have no idea why it can't create a reliable reproducer for
this ... I'm also not seeing the bug, all the input validation we have
seems correct :-/
-Daniel
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: [email protected]
>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
> check_copy_size include/linux/thread_info.h:150 [inline]
> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150 copy_from_user
> include/linux/uaccess.h:143 [inline]
> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
> drm_mode_createblob_ioctl+0x398/0x490 drivers/gpu/drm/drm_property.c:800
> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 1 PID: 30449 Comm: syz-executor.5 Not tainted 5.4.0-rc2-next-20191011
> #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x172/0x1f0 lib/dump_stack.c:113
> panic+0x2e3/0x75c kernel/panic.c:221
> __warn.cold+0x2f/0x35 kernel/panic.c:582
> report_bug+0x289/0x300 lib/bug.c:195
> fixup_bug arch/x86/kernel/traps.c:174 [inline]
> fixup_bug arch/x86/kernel/traps.c:169 [inline]
> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
> RIP: 0010:check_copy_size include/linux/thread_info.h:150 [inline]
> RIP: 0010:copy_from_user include/linux/uaccess.h:143 [inline]
> RIP: 0010:drm_mode_createblob_ioctl+0x398/0x490
> drivers/gpu/drm/drm_property.c:800
> Code: c1 ea 03 80 3c 02 00 0f 85 ed 00 00 00 49 89 5d 00 e8 3c 28 cb fd 4c
> 89 f7 e8 64 92 9e 03 31 c0 e9 75 fd ff ff e8 28 28 cb fd <0f> 0b e8 21 28 cb
> fd 4d 85 e4 b8 f2 ff ff ff 0f 84 5b fd ff ff 89
> RSP: 0018:ffff8880584efaa8 EFLAGS: 00010246
> RAX: 0000000000040000 RBX: ffff8880a3a90000 RCX: ffffc900109da000
> RDX: 0000000000040000 RSI: ffffffff83a7eaf8 RDI: 0000000000000007
> RBP: ffff8880584efae8 R08: ffff888096c40080 R09: ffffed1014752110
> R10: ffffed101475210f R11: ffff8880a3a9087f R12: ffffc90014907000
> R13: ffff888028aa0000 R14: 000000009a6c7969 R15: ffffc90014907058
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Op 14-10-2019 om 11:16 schreef Daniel Vetter:
> On Sun, Oct 13, 2019 at 11:09:09PM -0700, syzbot wrote:
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit: 8ada228a Add linux-next specific files for 20191011
>> git tree: linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1423a87f600000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=7cf4eed5fe42c31a
>> dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
>> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
>>
>> Unfortunately, I don't have any reproducer for this crash yet.
> Hm only thing that could go wrong is how we allocate the target for the
> user_copy, which is an argument directly from the ioctl parameter struct.
> Does syzbot not track that? We use the standard linux ioctl struct
> encoding in drm.
>
> Otherwise I have no idea why it can't create a reliable reproducer for
> this ... I'm also not seeing the bug, all the input validation we have
> seems correct :-/
I would like to see the entire dmesg?
in particular because it's likely WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count),
so I'd like to see the size it thinks for both..
> -Daniel
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> ------------[ cut here ]------------
>> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
>> check_copy_size include/linux/thread_info.h:150 [inline]
>> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150 copy_from_user
>> include/linux/uaccess.h:143 [inline]
>> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
>> drm_mode_createblob_ioctl+0x398/0x490 drivers/gpu/drm/drm_property.c:800
>> Kernel panic - not syncing: panic_on_warn set ...
>> CPU: 1 PID: 30449 Comm: syz-executor.5 Not tainted 5.4.0-rc2-next-20191011
>> #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Call Trace:
>> __dump_stack lib/dump_stack.c:77 [inline]
>> dump_stack+0x172/0x1f0 lib/dump_stack.c:113
>> panic+0x2e3/0x75c kernel/panic.c:221
>> __warn.cold+0x2f/0x35 kernel/panic.c:582
>> report_bug+0x289/0x300 lib/bug.c:195
>> fixup_bug arch/x86/kernel/traps.c:174 [inline]
>> fixup_bug arch/x86/kernel/traps.c:169 [inline]
>> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
>> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
>> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
>> RIP: 0010:check_copy_size include/linux/thread_info.h:150 [inline]
>> RIP: 0010:copy_from_user include/linux/uaccess.h:143 [inline]
>> RIP: 0010:drm_mode_createblob_ioctl+0x398/0x490
>> drivers/gpu/drm/drm_property.c:800
>> Code: c1 ea 03 80 3c 02 00 0f 85 ed 00 00 00 49 89 5d 00 e8 3c 28 cb fd 4c
>> 89 f7 e8 64 92 9e 03 31 c0 e9 75 fd ff ff e8 28 28 cb fd <0f> 0b e8 21 28 cb
>> fd 4d 85 e4 b8 f2 ff ff ff 0f 84 5b fd ff ff 89
>> RSP: 0018:ffff8880584efaa8 EFLAGS: 00010246
>> RAX: 0000000000040000 RBX: ffff8880a3a90000 RCX: ffffc900109da000
>> RDX: 0000000000040000 RSI: ffffffff83a7eaf8 RDI: 0000000000000007
>> RBP: ffff8880584efae8 R08: ffff888096c40080 R09: ffffed1014752110
>> R10: ffffed101475210f R11: ffff8880a3a9087f R12: ffffc90014907000
>> R13: ffff888028aa0000 R14: 000000009a6c7969 R15: ffffc90014907058
>>
>>
>> ---
>> This bug is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at [email protected].
>>
>> syzbot will keep track of this bug report. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
On Mon, Oct 14, 2019 at 11:39 AM syzbot
<[email protected]> wrote:
>
> Op 14-10-2019 om 11:16 schreef Daniel Vetter:
> > On Sun, Oct 13, 2019 at 11:09:09PM -0700, syzbot wrote:
> >> Hello,
> >>
> >> syzbot found the following crash on:
> >>
> >> HEAD commit: 8ada228a Add linux-next specific files for 20191011
> >> git tree: linux-next
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=1423a87f600000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=7cf4eed5fe42c31a
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> >> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> >>
> >> Unfortunately, I don't have any reproducer for this crash yet.
> > Hm only thing that could go wrong is how we allocate the target for the
> > user_copy, which is an argument directly from the ioctl parameter struct.
> > Does syzbot not track that? We use the standard linux ioctl struct
> > encoding in drm.
> >
> > Otherwise I have no idea why it can't create a reliable reproducer for
> > this ... I'm also not seeing the bug, all the input validation we have
> > seems correct :-/
>
> I would like to see the entire dmesg?
>
> in particular because it's likely WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count),
>
> so I'd like to see the size it thinks for both..
And who are "you"? :) The email as if comes from syzbot:
From: syzbot <[email protected]>
But it is clearly not generated by syzbot code. Or is it some kind of
a glitch?...
Anyway, full console output is always referenced on every syzbot bug
report as "console output:" link.
> > -Daniel
> >> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> >> Reported-by: [email protected]
> >>
> >> ------------[ cut here ]------------
> >> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
> >> check_copy_size include/linux/thread_info.h:150 [inline]
> >> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150 copy_from_user
> >> include/linux/uaccess.h:143 [inline]
> >> WARNING: CPU: 1 PID: 30449 at include/linux/thread_info.h:150
> >> drm_mode_createblob_ioctl+0x398/0x490 drivers/gpu/drm/drm_property.c:800
> >> Kernel panic - not syncing: panic_on_warn set ...
> >> CPU: 1 PID: 30449 Comm: syz-executor.5 Not tainted 5.4.0-rc2-next-20191011
> >> #0
> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> >> Google 01/01/2011
> >> Call Trace:
> >> __dump_stack lib/dump_stack.c:77 [inline]
> >> dump_stack+0x172/0x1f0 lib/dump_stack.c:113
> >> panic+0x2e3/0x75c kernel/panic.c:221
> >> __warn.cold+0x2f/0x35 kernel/panic.c:582
> >> report_bug+0x289/0x300 lib/bug.c:195
> >> fixup_bug arch/x86/kernel/traps.c:174 [inline]
> >> fixup_bug arch/x86/kernel/traps.c:169 [inline]
> >> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
> >> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
> >> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
> >> RIP: 0010:check_copy_size include/linux/thread_info.h:150 [inline]
> >> RIP: 0010:copy_from_user include/linux/uaccess.h:143 [inline]
> >> RIP: 0010:drm_mode_createblob_ioctl+0x398/0x490
> >> drivers/gpu/drm/drm_property.c:800
> >> Code: c1 ea 03 80 3c 02 00 0f 85 ed 00 00 00 49 89 5d 00 e8 3c 28 cb fd 4c
> >> 89 f7 e8 64 92 9e 03 31 c0 e9 75 fd ff ff e8 28 28 cb fd <0f> 0b e8 21 28 cb
> >> fd 4d 85 e4 b8 f2 ff ff ff 0f 84 5b fd ff ff 89
> >> RSP: 0018:ffff8880584efaa8 EFLAGS: 00010246
> >> RAX: 0000000000040000 RBX: ffff8880a3a90000 RCX: ffffc900109da000
> >> RDX: 0000000000040000 RSI: ffffffff83a7eaf8 RDI: 0000000000000007
> >> RBP: ffff8880584efae8 R08: ffff888096c40080 R09: ffffed1014752110
> >> R10: ffffed101475210f R11: ffff8880a3a9087f R12: ffffc90014907000
> >> R13: ffff888028aa0000 R14: 000000009a6c7969 R15: ffffc90014907058
> >>
> >>
> >> ---
> >> This bug is generated by a bot. It may contain errors.
> >> See https://goo.gl/tpsmEJ for more information about syzbot.
> >> syzbot engineers can be reached at [email protected].
> >>
> >> syzbot will keep track of this bug report. See:
> >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/67fb1a91-7ef3-9036-2d1b-877e394bcab2%40linux.intel.com.
syzbot has found a reproducer for the following crash on:
HEAD commit: 51309b9d Add linux-next specific files for 20191105
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13f5c078e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
------------[ cut here ]------------
WARNING: CPU: 0 PID: 8842 at include/linux/thread_info.h:150
check_copy_size include/linux/thread_info.h:150 [inline]
WARNING: CPU: 0 PID: 8842 at include/linux/thread_info.h:150 copy_from_user
include/linux/uaccess.h:143 [inline]
WARNING: CPU: 0 PID: 8842 at include/linux/thread_info.h:150
drm_mode_createblob_ioctl+0x398/0x490 drivers/gpu/drm/drm_property.c:800
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 8842 Comm: syz-executor938 Not tainted 5.4.0-rc6-next-20191105
#0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
panic+0x2e3/0x75c kernel/panic.c:221
__warn.cold+0x2f/0x35 kernel/panic.c:582
report_bug+0x289/0x300 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:174 [inline]
fixup_bug arch/x86/kernel/traps.c:169 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:check_copy_size include/linux/thread_info.h:150 [inline]
RIP: 0010:copy_from_user include/linux/uaccess.h:143 [inline]
RIP: 0010:drm_mode_createblob_ioctl+0x398/0x490
drivers/gpu/drm/drm_property.c:800
Code: c1 ea 03 80 3c 02 00 0f 85 ed 00 00 00 49 89 5d 00 e8 0c f2 c6 fd 4c
89 f7 e8 24 af aa 03 31 c0 e9 75 fd ff ff e8 f8 f1 c6 fd <0f> 0b e8 f1 f1
c6 fd 4d 85 e4 b8 f2 ff ff ff 0f 84 5b fd ff ff 89
RSP: 0018:ffff8880a5e07aa8 EFLAGS: 00010293
RAX: ffff88809f3a0440 RBX: ffff8880a387c000 RCX: ffffffff83ac75e2
RDX: 0000000000000000 RSI: ffffffff83ac77a8 RDI: 0000000000000007
RBP: ffff8880a5e07ae8 R08: ffff88809f3a0440 R09: ffffed101470f910
R10: ffffed101470f90f R11: ffff8880a387c87f R12: ffffc90005f5d000
R13: ffff8880a4d78000 R14: 0000000096e170d0 R15: ffffc90005f5d058
drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786
drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886
vfs_ioctl fs/ioctl.c:47 [inline]
file_ioctl fs/ioctl.c:545 [inline]
do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x449659
Code: e8 fc b8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 ab d6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6951f91db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000449659
RDX: 0000000020000000 RSI: ffffffffffffffbd RDI: 0000000000000004
RBP: 00000000006dac30 R08: 00007f6951f92700 R09: 0000000000000000
R10: 00007f6951f92700 R11: 0000000000000246 R12: 00000000006dac3c
R13: 00007ffeae0e7e9f R14: 00007f6951f929c0 R15: 20c49ba5e353f7cf
Kernel Offset: disabled
Rebooting in 86400 seconds..
syzbot has bisected this bug to:
commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
Author: Kees Cook <[email protected]>
Date: Mon Nov 4 22:57:23 2019 +0000
uaccess: disallow > INT_MAX copy sizes
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
start commit: 51309b9d Add linux-next specific files for 20191105
git tree: linux-next
final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
Reported-by: [email protected]
Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
On Wed, Nov 6, 2019 at 4:23 PM Daniel Vetter <[email protected]> wrote:
>
> On Wed, Nov 6, 2019 at 4:20 PM syzbot
> <[email protected]> wrote:
> >
> > syzbot has bisected this bug to:
> >
> > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> > Author: Kees Cook <[email protected]>
> > Date: Mon Nov 4 22:57:23 2019 +0000
> >
> > uaccess: disallow > INT_MAX copy sizes
>
> Ah cool, this explains it.
>
> fwiw I never managed to get the WARNING in the backtrace to lign up
> with any code. No idea what's been going on.
Ok I think I have an idea, the above commit isn't in the linux-next I
have here. Where is this from?
-Daniel
>
> I'll type a patch to paper over this.
> -Daniel
>
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
> > start commit: 51309b9d Add linux-next specific files for 20191105
> > git tree: linux-next
> > final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
> > dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
> >
> > Reported-by: [email protected]
> > Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Nov 6, 2019 at 4:20 PM syzbot
<[email protected]> wrote:
>
> syzbot has bisected this bug to:
>
> commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> Author: Kees Cook <[email protected]>
> Date: Mon Nov 4 22:57:23 2019 +0000
>
> uaccess: disallow > INT_MAX copy sizes
Ah cool, this explains it.
fwiw I never managed to get the WARNING in the backtrace to lign up
with any code. No idea what's been going on.
I'll type a patch to paper over this.
-Daniel
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
> start commit: 51309b9d Add linux-next specific files for 20191105
> git tree: linux-next
> final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
> dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
>
> Reported-by: [email protected]
> Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Nov 6, 2019 at 4:28 PM Daniel Vetter <[email protected]> wrote:
>
> On Wed, Nov 6, 2019 at 4:23 PM Daniel Vetter <[email protected]> wrote:
> >
> > On Wed, Nov 6, 2019 at 4:20 PM syzbot
> > <[email protected]> wrote:
> > >
> > > syzbot has bisected this bug to:
> > >
> > > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> > > Author: Kees Cook <[email protected]>
> > > Date: Mon Nov 4 22:57:23 2019 +0000
> > >
> > > uaccess: disallow > INT_MAX copy sizes
> >
> > Ah cool, this explains it.
> >
> > fwiw I never managed to get the WARNING in the backtrace to lign up
> > with any code. No idea what's been going on.
>
> Ok I think I have an idea, the above commit isn't in the linux-next I
> have here. Where is this from?
> -Daniel
You need to fetch tags to linux-next. syzbot started bisecting from
the commit where the crash happened, and it is now probably not the
current tag.
linux$ git show 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
Author: Kees Cook <[email protected]>
Date: Tue Nov 5 09:57:23 2019 +1100
uaccess: disallow > INT_MAX copy sizes
As we've done with VFS, string operations, etc, reject usercopy sizes
larger than INT_MAX, which would be nice to have for catching bugs related
to size calculation overflows[1].
This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data
section:
text data bss dec hex filename
19691167 5134320 1646664 26472151 193eed7 vmlinux.before
19691177 5136300 1646664 26474141 193f69d vmlinux.after
[1] https://marc.info/?l=linux-s390&m=156631939010493&w=2
Link: http://lkml.kernel.org/r/201908251612.F9902D7A@keescook
Signed-off-by: Kees Cook <[email protected]>
Suggested-by: Dan Carpenter <[email protected]>
Cc: Alexander Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 659a4400517b2..e93e249a4e9bf 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -147,6 +147,8 @@ check_copy_size(const void *addr, size_t bytes,
bool is_source)
__bad_copy_to();
return false;
}
+ if (WARN_ON_ONCE(bytes > INT_MAX))
+ return false;
check_object_size(addr, bytes, is_source);
return true;
}
> > I'll type a patch to paper over this.
> > -Daniel
> >
> > >
> > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
> > > start commit: 51309b9d Add linux-next specific files for 20191105
> > > git tree: linux-next
> > > final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
> > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
> > >
> > > Reported-by: [email protected]
> > > Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
> > >
> > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> >
> >
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
On Wed, Nov 6, 2019 at 4:30 PM Daniel Vetter <[email protected]> wrote:
>
> On Wed, Nov 6, 2019 at 4:20 PM syzbot
> <[email protected]> wrote:
> >
> > syzbot has bisected this bug to:
> >
> > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> > Author: Kees Cook <[email protected]>
> > Date: Mon Nov 4 22:57:23 2019 +0000
> >
> > uaccess: disallow > INT_MAX copy sizes
>
> Ah cool, this explains it.
>
> fwiw I never managed to get the WARNING in the backtrace to lign up
> with any code. No idea what's been going on.
>
> I'll type a patch to paper over this.
> -Daniel
If I get:
git checkout 8ada228a
then include/linux/thread_info.h:150
points right to:
if (WARN_ON_ONCE(bytes > INT_MAX))
Is the size user-controllable here?
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
> > start commit: 51309b9d Add linux-next specific files for 20191105
> > git tree: linux-next
> > final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
> > dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
> >
> > Reported-by: [email protected]
> > Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/CAKMK7uFQt%2B%3D7XMo9jvz77QvDWLAAU_V7-_qZ%3DiKe-GXG7cqeJg%40mail.gmail.com.
On Wed, Nov 6, 2019 at 4:33 PM Dmitry Vyukov <[email protected]> wrote:
>
> On Wed, Nov 6, 2019 at 4:28 PM Daniel Vetter <[email protected]> wrote:
> >
> > On Wed, Nov 6, 2019 at 4:23 PM Daniel Vetter <[email protected]> wrote:
> > >
> > > On Wed, Nov 6, 2019 at 4:20 PM syzbot
> > > <[email protected]> wrote:
> > > >
> > > > syzbot has bisected this bug to:
> > > >
> > > > commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> > > > Author: Kees Cook <[email protected]>
> > > > Date: Mon Nov 4 22:57:23 2019 +0000
> > > >
> > > > uaccess: disallow > INT_MAX copy sizes
> > >
> > > Ah cool, this explains it.
> > >
> > > fwiw I never managed to get the WARNING in the backtrace to lign up
> > > with any code. No idea what's been going on.
> >
> > Ok I think I have an idea, the above commit isn't in the linux-next I
> > have here. Where is this from?
> > -Daniel
>
> You need to fetch tags to linux-next. syzbot started bisecting from
> the commit where the crash happened, and it is now probably not the
> current tag.
Indeed it's an -mm patch so rebases every day. I tried looking for it,
but found nothing, not sure what exactly I screwed up. Patch on the
way.
-Daniel
>
> linux$ git show 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> commit 9e5a64c71b2f70ba530f8156046dd7dfb8a7a0ba
> Author: Kees Cook <[email protected]>
> Date: Tue Nov 5 09:57:23 2019 +1100
>
> uaccess: disallow > INT_MAX copy sizes
>
> As we've done with VFS, string operations, etc, reject usercopy sizes
> larger than INT_MAX, which would be nice to have for catching bugs related
> to size calculation overflows[1].
>
> This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data
> section:
>
> text data bss dec hex filename
> 19691167 5134320 1646664 26472151 193eed7 vmlinux.before
> 19691177 5136300 1646664 26474141 193f69d vmlinux.after
>
> [1] https://marc.info/?l=linux-s390&m=156631939010493&w=2
>
> Link: http://lkml.kernel.org/r/201908251612.F9902D7A@keescook
> Signed-off-by: Kees Cook <[email protected]>
> Suggested-by: Dan Carpenter <[email protected]>
> Cc: Alexander Viro <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> Signed-off-by: Stephen Rothwell <[email protected]>
>
> diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
> index 659a4400517b2..e93e249a4e9bf 100644
> --- a/include/linux/thread_info.h
> +++ b/include/linux/thread_info.h
> @@ -147,6 +147,8 @@ check_copy_size(const void *addr, size_t bytes,
> bool is_source)
> __bad_copy_to();
> return false;
> }
> + if (WARN_ON_ONCE(bytes > INT_MAX))
> + return false;
> check_object_size(addr, bytes, is_source);
> return true;
> }
>
>
> > > I'll type a patch to paper over this.
> > > -Daniel
> > >
> > > >
> > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=125fe6dce00000
> > > > start commit: 51309b9d Add linux-next specific files for 20191105
> > > > git tree: linux-next
> > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=115fe6dce00000
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=165fe6dce00000
> > > > kernel config: https://syzkaller.appspot.com/x/.config?x=a9b1a641c1f1fc52
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=fb77e97ebf0612ee6914
> > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1212dc3ae00000
> > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145f604ae00000
> > > >
> > > > Reported-by: [email protected]
> > > > Fixes: 9e5a64c71b2f ("uaccess: disallow > INT_MAX copy sizes")
> > > >
> > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > >
> > >
> > >
> > > --
> > > Daniel Vetter
> > > Software Engineer, Intel Corporation
> > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
> >
> >
> >
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch