diff options
| author | Takashi Iwai <tiwai@suse.de> | 2018-06-25 11:09:11 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-06-25 11:17:01 +0200 |
| commit | b41f794f284966fd6ec634111e3b40d241389f96 (patch) | |
| tree | 036ff9a3465744cf612a7e399d20d3b16823c521 /sound/core/timer.c | |
| parent | e41fc8c5bd41b96bfae5ce4c66bee6edabc932e8 (diff) | |
ALSA: timer: Fix UBSAN warning at SNDRV_TIMER_IOCTL_NEXT_DEVICE ioctl
The kernel may spew a WARNING about UBSAN undefined behavior at
handling ALSA timer ioctl SNDRV_TIMER_IOCTL_NEXT_DEVICE:
UBSAN: Undefined behaviour in sound/core/timer.c:1524:19
signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x122/0x1c8 lib/dump_stack.c:113
ubsan_epilogue+0x12/0x86 lib/ubsan.c:159
handle_overflow+0x1c2/0x21f lib/ubsan.c:190
__ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:198
snd_timer_user_next_device sound/core/timer.c:1524 [inline]
__snd_timer_user_ioctl+0x204d/0x2520 sound/core/timer.c:1939
snd_timer_user_ioctl+0x67/0x95 sound/core/timer.c:1994
....
It happens only when a value with INT_MAX is passed, as we're
incrementing it unconditionally. So the fix is trivial, check the
value with INT_MAX. Although the bug itself is fairly harmless, it's
better to fix it so that fuzzers won't hit this again later.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200213
Reported-and-tested-by: Team OWL337 <icytxw@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core/timer.c')
| -rw-r--r-- | sound/core/timer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/core/timer.c b/sound/core/timer.c index 665089c45560..b6f076bbc72d 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1520,7 +1520,7 @@ static int snd_timer_user_next_device(struct snd_timer_id __user *_tid) } else { if (id.subdevice < 0) id.subdevice = 0; - else + else if (id.subdevice < INT_MAX) id.subdevice++; } } |