> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 5ff2756a Merge tag 'nfs-for-5.13-2' of git://git.linux-nfs..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17872d5bd00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=770708ea7cfd4916
> dashboard link: https://syzkaller.appspot.com/bug?extid=d102fa5b35335a7e544e
>
> 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]
>
> ================================================================================
> UBSAN: shift-out-of-bounds in sound/core/timer.c:1376:23
> shift exponent 105 is too large for 32-bit type 'int'
> CPU: 1 PID: 10368 Comm: syz-executor.1 Not tainted 5.13.0-rc3-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+0x141/0x1d7 lib/dump_stack.c:120
> ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
> __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
> snd_timer_user_ccallback.cold+0x19/0x1e sound/core/timer.c:1376
>
> snd_timer_notify1+0x243/0x3b0 sound/core/timer.c:525
The root cause of this bug is in the snd_timer_notify1 [1]. At the end
of this function, it calls "ts->ccallback(ts, event + 100, &tstamp,
resolution)".
Here the variable event is 5. It adds 100 and is passed as 2nd
argument of snd_timer_user_ccallback.
From the variable naming, the 2nd argument should an event, and in the
range of event enumeration. In fact, 105 (event + 100) is out of this
range. I don't quite understand the meaning of adding 100. Any thought
here?
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/core/timer.c?id=5ff2756afde08b266fbb673849899fec694f39f1#n497
--
My best regards to you.
No System Is Safe!
Dongliang Mu
On 02. 06. 21 15:18, Dongliang Mu wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 5ff2756a Merge tag 'nfs-for-5.13-2' of git://git.linux-nfs..
>> git tree: upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=17872d5bd00000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=770708ea7cfd4916
>> dashboard link: https://syzkaller.appspot.com/bug?extid=d102fa5b35335a7e544e
>>
>> 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]
>>
>> ================================================================================
>> UBSAN: shift-out-of-bounds in sound/core/timer.c:1376:23
>> shift exponent 105 is too large for 32-bit type 'int'
>> CPU: 1 PID: 10368 Comm: syz-executor.1 Not tainted 5.13.0-rc3-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+0x141/0x1d7 lib/dump_stack.c:120
>> ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
>> __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
>> snd_timer_user_ccallback.cold+0x19/0x1e sound/core/timer.c:1376
>>
>> snd_timer_notify1+0x243/0x3b0 sound/core/timer.c:525
>
> The root cause of this bug is in the snd_timer_notify1 [1]. At the end
> of this function, it calls "ts->ccallback(ts, event + 100, &tstamp,
> resolution)".
>
> Here the variable event is 5. It adds 100 and is passed as 2nd
> argument of snd_timer_user_ccallback.
>
>>From the variable naming, the 2nd argument should an event, and in the
> range of event enumeration. In fact, 105 (event + 100) is out of this
> range. I don't quite understand the meaning of adding 100. Any thought
> here?
It seems that the original intent was to move the event to the M... events:
SNDRV_TIMER_EVENT_MSTART = SNDRV_TIMER_EVENT_START + 10,
So the added value should be 10 which should not break the shift range (8
/resume/ + 10 = 18).
Jaroslav
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/core/timer.c?id=5ff2756afde08b266fbb673849899fec694f39f1#n497
>
> --
> My best regards to you.
>
> No System Is Safe!
> Dongliang Mu
>
--
Jaroslav Kysela <[email protected]>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
On Wed, Jun 2, 2021 at 10:19 PM Jaroslav Kysela <[email protected]> wrote:
>
> On 02. 06. 21 15:18, Dongliang Mu wrote:
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: 5ff2756a Merge tag 'nfs-for-5.13-2' of git://git.linux-nfs..
> >> git tree: upstream
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=17872d5bd00000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=770708ea7cfd4916
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=d102fa5b35335a7e544e
> >>
> >> 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]
> >>
> >> ================================================================================
> >> UBSAN: shift-out-of-bounds in sound/core/timer.c:1376:23
> >> shift exponent 105 is too large for 32-bit type 'int'
> >> CPU: 1 PID: 10368 Comm: syz-executor.1 Not tainted 5.13.0-rc3-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+0x141/0x1d7 lib/dump_stack.c:120
> >> ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
> >> __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
> >> snd_timer_user_ccallback.cold+0x19/0x1e sound/core/timer.c:1376
> >>
> >> snd_timer_notify1+0x243/0x3b0 sound/core/timer.c:525
> >
> > The root cause of this bug is in the snd_timer_notify1 [1]. At the end
> > of this function, it calls "ts->ccallback(ts, event + 100, &tstamp,
> > resolution)".
> >
> > Here the variable event is 5. It adds 100 and is passed as 2nd
> > argument of snd_timer_user_ccallback.
> >
> >>From the variable naming, the 2nd argument should an event, and in the
> > range of event enumeration. In fact, 105 (event + 100) is out of this
> > range. I don't quite understand the meaning of adding 100. Any thought
> > here?
>
> It seems that the original intent was to move the event to the M... events:
>
> SNDRV_TIMER_EVENT_MSTART = SNDRV_TIMER_EVENT_START + 10,
>
> So the added value should be 10 which should not break the shift range (8
> /resume/ + 10 = 18).
It seems you are right. Then event should be between
SNDRV_TIMER_EVENT_MSTART and SNDRV_TIMER_EVENT_MPAUSE.
I double check all the ccallback site, only snd_timer_notify1 invokes
ccallback with event + 100, others seem ok.
1 timer.c snd_timer_notify1 515 if (ti->ccallback)
2 timer.c snd_timer_notify1 516 ti->ccallback(ti, event,
&tstamp, resolution);
3 timer.c snd_timer_notify1 524 if (ts->ccallback)
4 timer.c snd_timer_notify1 525 ts->ccallback(ts, event + 100,
&tstamp, resolution);
5 timer.c snd_timer_notify 1092 if (ti->ccallback)
6 timer.c snd_timer_notify 1093 ti->ccallback(ti, event,
tstamp, resolution);
7 timer.c snd_timer_notify 1095 if (ts->ccallback)
8 timer.c snd_timer_notify 1096 ts->ccallback(ts, event,
tstamp, resolution);
9 timer.c snd_timer_user_tselect 1782 tu->timeri->ccallback =
snd_timer_user_ccallback;
a aloop.c loopback_snd_timer_open 1137 timeri->ccallback =
loopback_snd_timer_event;
>
> Jaroslav
>
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/core/timer.c?id=5ff2756afde08b266fbb673849899fec694f39f1#n497
> >
> > --
> > My best regards to you.
> >
> > No System Is Safe!
> > Dongliang Mu
> >
>
>
> --
> Jaroslav Kysela <[email protected]>
> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
On Wed, 02 Jun 2021 16:19:13 +0200,
Jaroslav Kysela wrote:
>
> On 02. 06. 21 15:18, Dongliang Mu wrote:
> >> Hello,
> >>
> >> syzbot found the following issue on:
> >>
> >> HEAD commit: 5ff2756a Merge tag 'nfs-for-5.13-2' of git://git.linux-nfs..
> >> git tree: upstream
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=17872d5bd00000
> >> kernel config: https://syzkaller.appspot.com/x/.config?x=770708ea7cfd4916
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=d102fa5b35335a7e544e
> >>
> >> 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]
> >>
> >> ================================================================================
> >> UBSAN: shift-out-of-bounds in sound/core/timer.c:1376:23
> >> shift exponent 105 is too large for 32-bit type 'int'
> >> CPU: 1 PID: 10368 Comm: syz-executor.1 Not tainted 5.13.0-rc3-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+0x141/0x1d7 lib/dump_stack.c:120
> >> ubsan_epilogue+0xb/0x5a lib/ubsan.c:148
> >> __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:327
> >> snd_timer_user_ccallback.cold+0x19/0x1e sound/core/timer.c:1376
> >>
> >> snd_timer_notify1+0x243/0x3b0 sound/core/timer.c:525
> >
> > The root cause of this bug is in the snd_timer_notify1 [1]. At the end
> > of this function, it calls "ts->ccallback(ts, event + 100, &tstamp,
> > resolution)".
> >
> > Here the variable event is 5. It adds 100 and is passed as 2nd
> > argument of snd_timer_user_ccallback.
> >
> >>From the variable naming, the 2nd argument should an event, and in the
> > range of event enumeration. In fact, 105 (event + 100) is out of this
> > range. I don't quite understand the meaning of adding 100. Any thought
> > here?
>
> It seems that the original intent was to move the event to the M... events:
>
> SNDRV_TIMER_EVENT_MSTART = SNDRV_TIMER_EVENT_START + 10,
>
> So the added value should be 10 which should not break the shift range (8
> /resume/ + 10 = 18).
I've already submitted the fix patch, but it doesn't seem reaching
properly to ML. Hmm. Will resend.
Takashi