In snd_timer_proc_read(), there is an if statement on line 1204 to check whether timer->card is NULL: if (timer->card && timer->card->shutdown)
When timer->card is NULL, it is used on lines 1212 and 1215: timer->card->number
Thus, possible null-pointer dereferences may occur.
To fix these bugs, timer->card is checked before being used.
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai baijiaju1990@gmail.com --- sound/core/timer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/core/timer.c b/sound/core/timer.c index 5c9fbf3f4340..967d06a3cdec 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1208,11 +1208,13 @@ static void snd_timer_proc_read(struct snd_info_entry *entry, snd_iprintf(buffer, "G%i: ", timer->tmr_device); break; case SNDRV_TIMER_CLASS_CARD: - snd_iprintf(buffer, "C%i-%i: ", - timer->card->number, timer->tmr_device); + snd_iprintf(buffer, "C%i-%i: ", + timer->card ? timer->card->number : -1, + timer->tmr_device); break; case SNDRV_TIMER_CLASS_PCM: - snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number, + snd_iprintf(buffer, "P%i-%i-%i: ", + timer->card ? timer->card->number : -1, timer->tmr_device, timer->tmr_subdevice); break; default: