• Takashi Iwai's avatar
    ALSA: timer: Fix UBSAN warning at SNDRV_TIMER_IOCTL_NEXT_DEVICE ioctl · b41f794f
    Takashi Iwai authored
    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=200213Reported-and-tested-by: default avatarTeam OWL337 <icytxw@gmail.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    b41f794f
timer.c 54.6 KB