Hello,
syzbot found the following issue on:
HEAD commit: 29ad81a1 arch/x86: add missing include to sparsemem.h
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e
dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d
compiler: Debian clang version 11.0.1-2
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
=====================================================
BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x21c/0x280 lib/dump_stack.c:120
kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437
kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
instrument_copy_to_user include/linux/instrumented.h:121 [inline]
_copy_to_user+0x1ac/0x270 lib/usercopy.c:33
copy_to_user include/linux/uaccess.h:209 [inline]
compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866
drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
__do_compat_sys_ioctl fs/ioctl.c:842 [inline]
__se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
__ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
__do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f47549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f55415fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c018643a
RDX: 0000000020000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289
__msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147
compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865
drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
__do_compat_sys_ioctl fs/ioctl.c:842 [inline]
__se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
__ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
__do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
Local variable ----req@compat_drm_wait_vblank created at:
compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
Bytes 12-15 of 16 are uninitialized
Memory access of size 16 starts at ffff88814ffe3c98
Data copied to user address 0000000020000100
=====================================================
---
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On 2021-02-22 10:15 a.m., syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 29ad81a1 arch/x86: add missing include to sparsemem.h
> git tree: https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e
> dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d
> compiler: Debian clang version 11.0.1-2
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> =====================================================
> BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
> CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:79 [inline]
> dump_stack+0x21c/0x280 lib/dump_stack.c:120
> kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
> kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437
> kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
> instrument_copy_to_user include/linux/instrumented.h:121 [inline]
> _copy_to_user+0x1ac/0x270 lib/usercopy.c:33
> copy_to_user include/linux/uaccess.h:209 [inline]
> compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866
> drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
> __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
> __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
> __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
> do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
> __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
> do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
> do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
> entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> RIP: 0023:0xf7f47549
> Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
> RSP: 002b:00000000f55415fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c018643a
> RDX: 0000000020000100 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>
> Uninit was stored to memory at:
> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
> kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289
> __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147
> compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865
> drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
> __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
> __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
> __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
> do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
> __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
> do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
> do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
> entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
>
> Local variable ----req@compat_drm_wait_vblank created at:
> compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
> compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
>
> Bytes 12-15 of 16 are uninitialized
> Memory access of size 16 starts at ffff88814ffe3c98
> Data copied to user address 0000000020000100
> =====================================================
compat_drm_wait_vblank would need to initialize
req.reply.tval_usec = req32.reply.tval_usec;
before calling drm_ioctl_kernel, since it's not aliased by any req.request.* member, and drm_wait_vblank_ioctl doesn't always write to it.
--
Earthling Michel Dänzer | https://redhat.com
Libre software enthusiast | Mesa and X developer
On Wed, Mar 03, 2021 at 04:37:18PM +0100, Michel D?nzer wrote:
> On 2021-02-22 10:15 a.m., syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: 29ad81a1 arch/x86: add missing include to sparsemem.h
> > git tree: https://github.com/google/kmsan.git master
> > console output: https://syzkaller.appspot.com/x/log.txt?x=111e6312d00000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=c8e3b38ca92283e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=620cf21140fc7e772a5d
> > compiler: Debian clang version 11.0.1-2
> > userspace arch: i386
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: [email protected]
> >
> > =====================================================
> > BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
> > CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.11.0-rc7-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> > __dump_stack lib/dump_stack.c:79 [inline]
> > dump_stack+0x21c/0x280 lib/dump_stack.c:120
> > kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:118
> > kmsan_internal_check_memory+0x484/0x520 mm/kmsan/kmsan.c:437
> > kmsan_copy_to_user+0x9c/0xb0 mm/kmsan/kmsan_hooks.c:249
> > instrument_copy_to_user include/linux/instrumented.h:121 [inline]
> > _copy_to_user+0x1ac/0x270 lib/usercopy.c:33
> > copy_to_user include/linux/uaccess.h:209 [inline]
> > compat_drm_wait_vblank+0x36f/0x450 drivers/gpu/drm/drm_ioc32.c:866
> > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
> > __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
> > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
> > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
> > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
> > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
> > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
> > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
> > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> > RIP: 0023:0xf7f47549
> > Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
> > RSP: 002b:00000000f55415fc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
> > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000c018643a
> > RDX: 0000000020000100 RSI: 0000000000000000 RDI: 0000000000000000
> > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> >
> > Uninit was stored to memory at:
> > kmsan_save_stack_with_flags mm/kmsan/kmsan.c:121 [inline]
> > kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:289
> > __msan_chain_origin+0x57/0xa0 mm/kmsan/kmsan_instr.c:147
> > compat_drm_wait_vblank+0x43c/0x450 drivers/gpu/drm/drm_ioc32.c:865
> > drm_compat_ioctl+0x3f6/0x590 drivers/gpu/drm/drm_ioc32.c:995
> > __do_compat_sys_ioctl fs/ioctl.c:842 [inline]
> > __se_compat_sys_ioctl+0x53d/0x1100 fs/ioctl.c:793
> > __ia32_compat_sys_ioctl+0x4a/0x70 fs/ioctl.c:793
> > do_syscall_32_irqs_on arch/x86/entry/common.c:79 [inline]
> > __do_fast_syscall_32+0x102/0x160 arch/x86/entry/common.c:141
> > do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:166
> > do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:209
> > entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> >
> > Local variable ----req@compat_drm_wait_vblank created at:
> > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
> > compat_drm_wait_vblank+0x7b/0x450 drivers/gpu/drm/drm_ioc32.c:849
> >
> > Bytes 12-15 of 16 are uninitialized
> > Memory access of size 16 starts at ffff88814ffe3c98
> > Data copied to user address 0000000020000100
> > =====================================================
>
> compat_drm_wait_vblank would need to initialize
>
> req.reply.tval_usec = req32.reply.tval_usec;
>
> before calling drm_ioctl_kernel, since it's not aliased by any
> req.request.* member, and drm_wait_vblank_ioctl doesn't always write to
> it.
I've fixed this in
commit e926c474ebee404441c838d18224cd6f246a71b7
Author: Daniel Vetter <[email protected]>
Date: Mon Feb 22 11:06:43 2021 +0100
drm/compat: Clear bounce structures
Or at least tried to.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch