ALSA firewire-motu driver recently got support for event notification via ALSA HwDep interface for register DSP models. However, when polling ALSA HwDep cdev, the driver can cause null pointer dereference for the other models due to accessing to unallocated memory or uninitialized memory.
This commit fixes the bug by check the type of model before accessing to the memory.
Reported-by: kernel test robot lkp@intel.com Suggested-by: Takashi Iwai tiwai@suse.de Fixes: 634ec0b2906e ("ALSA: firewire-motu: notify event for parameter change in register DSP model") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/motu/motu-hwdep.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c index 9c2e457ce692..a900fc0e7644 100644 --- a/sound/firewire/motu/motu-hwdep.c +++ b/sound/firewire/motu/motu-hwdep.c @@ -16,6 +16,14 @@
#include "motu.h"
+static bool has_dsp_event(struct snd_motu *motu) +{ + if (motu->spec->flags & SND_MOTU_SPEC_REGISTER_DSP) + return (snd_motu_register_dsp_message_parser_count_event(motu) > 0); + else + return false; +} + static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, loff_t *offset) { @@ -25,8 +33,7 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
spin_lock_irq(&motu->lock);
- while (!motu->dev_lock_changed && motu->msg == 0 && - snd_motu_register_dsp_message_parser_count_event(motu) == 0) { + while (!motu->dev_lock_changed && motu->msg == 0 && !has_dsp_event(motu)) { prepare_to_wait(&motu->hwdep_wait, &wait, TASK_INTERRUPTIBLE); spin_unlock_irq(&motu->lock); schedule(); @@ -55,7 +62,7 @@ static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, count = min_t(long, count, sizeof(event)); if (copy_to_user(buf, &event, count)) return -EFAULT; - } else if (snd_motu_register_dsp_message_parser_count_event(motu) > 0) { + } else if (has_dsp_event(motu)) { size_t consumed = 0; u32 __user *ptr; u32 ev; @@ -94,8 +101,7 @@ static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_wait(file, &motu->hwdep_wait, wait);
spin_lock_irq(&motu->lock); - if (motu->dev_lock_changed || motu->msg || - snd_motu_register_dsp_message_parser_count_event(motu) > 0) + if (motu->dev_lock_changed || motu->msg || has_dsp_event(motu)) events = EPOLLIN | EPOLLRDNORM; else events = 0;