ALSA: Avoid using timespec for struct snd_pcm_status
The struct snd_pcm_status will use 'timespec' type variables to record
timestamp, which is not year 2038 safe on 32bits system.
Userspace will use SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT
as commands to issue ioctl() to fill the 'snd_pcm_status' structure in
userspace. The command number is always defined through _IOR/_IOW/IORW,
so when userspace changes the definition of 'struct timespec' to use
64-bit types, the command number also changes.
Thus in the kernel, we now need to define two versions of each such ioctl
and corresponding ioctl commands to handle 32bit time_t and 64bit time_t
in native mode:
struct snd_pcm_status32 {
......
s32 trigger_tstamp_sec;
s32 trigger_tstamp_nsec;
......
s32 audio_tstamp_sec;
s32 audio_tstamp_nsec;
......
};
struct snd_pcm_status64 {
......
s32 trigger_tstamp_sec;
s32 trigger_tstamp_nsec;
......
s32 audio_tstamp_sec;
s32 audio_tstamp_nsec;
......
};
Moreover in compat file, we renamed or introduced new structures to handle
32bit/64bit time_t in compatible mode. The 'struct snd_pcm_status32' and
snd_pcm_status_user32() are used to handle 32bit time_t in compat mode.
'struct compat_snd_pcm_status64' and snd_pcm_status_user_compat64() are used
to handle 64bit time_t.
The implicit padding before timespec is made explicit to avoid incompatible
structure layout between 32-bit and 64-bit x86 due to the different
alignment requirements, and the snd_pcm_status structure is now hidden
from the kernel to avoid relying on the timespec definitio definitionn
Finally we can replace SNDRV_PCM_IOCTL_STATUS and SNDRV_PCM_IOCTL_STATUS_EXT
with new commands and introduce new functions to fill new 'struct snd_pcm_status64'
instead of using unsafe 'struct snd_pcm_status'. Then in future, the new
commands can be matched when userspace changes 'timespec' to 64bit type
to make a size change of 'struct snd_pcm_status'. When glibc changes time_t
to 64-bit, any recompiled program will issue ioctl commands that the kernel
does not understand without this patch.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 67fe14b..ad4cf1e 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -891,8 +891,8 @@ snd_pcm_calc_delay(struct snd_pcm_substream *substream)
return delay + substream->runtime->delay;
}
-int snd_pcm_status(struct snd_pcm_substream *substream,
- struct snd_pcm_status *status)
+int snd_pcm_status64(struct snd_pcm_substream *substream,
+ struct snd_pcm_status64 *status)
{
struct snd_pcm_runtime *runtime = substream->runtime;
@@ -918,14 +918,22 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
status->suspended_state = runtime->status->suspended_state;
if (status->state == SNDRV_PCM_STATE_OPEN)
goto _end;
- status->trigger_tstamp = timespec64_to_timespec(runtime->trigger_tstamp);
+ status->trigger_tstamp_sec = runtime->trigger_tstamp.tv_sec;
+ status->trigger_tstamp_nsec = runtime->trigger_tstamp.tv_nsec;
if (snd_pcm_running(substream)) {
snd_pcm_update_hw_ptr(substream);
if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
- status->tstamp = runtime->status->tstamp;
- status->driver_tstamp = timespec64_to_timespec(runtime->driver_tstamp);
- status->audio_tstamp =
- runtime->status->audio_tstamp;
+ status->tstamp_sec = runtime->status->tstamp.tv_sec;
+ status->tstamp_nsec =
+ runtime->status->tstamp.tv_nsec;
+ status->driver_tstamp_sec =
+ runtime->driver_tstamp.tv_sec;
+ status->driver_tstamp_nsec =
+ runtime->driver_tstamp.tv_nsec;
+ status->audio_tstamp_sec =
+ runtime->status->audio_tstamp.tv_sec;
+ status->audio_tstamp_nsec =
+ runtime->status->audio_tstamp.tv_nsec;
if (runtime->audio_tstamp_report.valid == 1)
/* backwards compatibility, no report provided in COMPAT mode */
snd_pcm_pack_audio_tstamp_report(&status->audio_tstamp_data,
@@ -940,7 +948,8 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
struct timespec64 tstamp;
snd_pcm_gettime(runtime, &tstamp);
- status->tstamp = timespec64_to_timespec(tstamp);
+ status->tstamp_sec = tstamp.tv_sec;
+ status->tstamp_nsec = tstamp.tv_nsec;
}
}
_tstamp_end:
@@ -958,11 +967,11 @@ int snd_pcm_status(struct snd_pcm_substream *substream,
return 0;
}
-static int snd_pcm_status_user(struct snd_pcm_substream *substream,
- struct snd_pcm_status __user * _status,
- bool ext)
+static int snd_pcm_status_user64(struct snd_pcm_substream *substream,
+ struct snd_pcm_status64 __user * _status,
+ bool ext)
{
- struct snd_pcm_status status;
+ struct snd_pcm_status64 status;
int res;
memset(&status, 0, sizeof(status));
@@ -974,7 +983,7 @@ static int snd_pcm_status_user(struct snd_pcm_substream *substream,
if (ext && get_user(status.audio_tstamp_data,
(u32 __user *)(&_status->audio_tstamp_data)))
return -EFAULT;
- res = snd_pcm_status(substream, &status);
+ res = snd_pcm_status64(substream, &status);
if (res < 0)
return res;
if (copy_to_user(_status, &status, sizeof(status)))
@@ -982,6 +991,55 @@ static int snd_pcm_status_user(struct snd_pcm_substream *substream,
return 0;
}
+static int snd_pcm_status_user32(struct snd_pcm_substream *substream,
+ struct snd_pcm_status32 __user * _status,
+ bool ext)
+{
+ struct snd_pcm_status64 status64;
+ struct snd_pcm_status32 status32;
+ int res;
+
+ memset(&status64, 0, sizeof(status64));
+ memset(&status32, 0, sizeof(status32));
+ /*
+ * with extension, parameters are read/write,
+ * get audio_tstamp_data from user,
+ * ignore rest of status structure
+ */
+ if (ext && get_user(status64.audio_tstamp_data,
+ (u32 __user *)(&_status->audio_tstamp_data)))
+ return -EFAULT;
+ res = snd_pcm_status64(substream, &status64);
+ if (res < 0)
+ return res;
+
+ status32 = (struct snd_pcm_status32) {
+ .state = status64.state,
+ .trigger_tstamp_sec = status64.trigger_tstamp_sec,
+ .trigger_tstamp_nsec = status64.trigger_tstamp_nsec,
+ .tstamp_sec = status64.tstamp_sec,
+ .tstamp_nsec = status64.tstamp_nsec,
+ .appl_ptr = status64.appl_ptr,
+ .hw_ptr = status64.hw_ptr,
+ .delay = status64.delay,
+ .avail = status64.avail,
+ .avail_max = status64.avail_max,
+ .overrange = status64.overrange,
+ .suspended_state = status64.suspended_state,
+ .audio_tstamp_data = status64.audio_tstamp_data,
+ .audio_tstamp_sec = status64.audio_tstamp_sec,
+ .audio_tstamp_nsec = status64.audio_tstamp_nsec,
+ .driver_tstamp_sec = status64.audio_tstamp_sec,
+ .driver_tstamp_nsec = status64.audio_tstamp_nsec,
+ .audio_tstamp_accuracy = status64.audio_tstamp_accuracy,
+ };
+
+ if (copy_to_user(_status, &status32, sizeof(status32)))
+ return -EFAULT;
+
+ return 0;
+}
+
static int snd_pcm_channel_info(struct snd_pcm_substream *substream,
struct snd_pcm_channel_info * info)
{
@@ -2959,10 +3017,14 @@ static int snd_pcm_common_ioctl(struct file *file,
return snd_pcm_hw_free(substream);
case SNDRV_PCM_IOCTL_SW_PARAMS:
return snd_pcm_sw_params_user(substream, arg);
- case SNDRV_PCM_IOCTL_STATUS:
- return snd_pcm_status_user(substream, arg, false);
- case SNDRV_PCM_IOCTL_STATUS_EXT:
- return snd_pcm_status_user(substream, arg, true);
+ case SNDRV_PCM_IOCTL_STATUS32:
+ return snd_pcm_status_user32(substream, arg, false);
+ case SNDRV_PCM_IOCTL_STATUS_EXT32:
+ return snd_pcm_status_user32(substream, arg, true);
+ case SNDRV_PCM_IOCTL_STATUS64:
+ return snd_pcm_status_user64(substream, arg, false);
+ case SNDRV_PCM_IOCTL_STATUS_EXT64:
+ return snd_pcm_status_user64(substream, arg, true);
case SNDRV_PCM_IOCTL_CHANNEL_INFO:
return snd_pcm_channel_info_user(substream, arg);
case SNDRV_PCM_IOCTL_PREPARE:
