[PATCH v8 6/9] ALSA: Avoid using timespec for struct snd_timer_tread

From: Arnd Bergmann
Date: Tue Dec 17 2019 - 16:20:12 EST

From: Baolin Wang <baolin.wang@xxxxxxxxxx>

The struct snd_timer_tread will use 'timespec' type variables to record
timestamp, which is not year 2038 safe on 32bits system.

Since the struct snd_timer_tread is passed through read() rather than
ioctl(), and the read syscall has no command number that lets us pick
between the 32-bit or 64-bit version of this structure.

Thus we introduced one new command SNDRV_TIMER_IOCTL_TREAD64 and new
struct snd_timer_tread64 replacing timespec with s64 type to handle
64bit time_t. That means we will set tu->tread = TREAD_FORMAT_64BIT
when user space has a 64bit time_t, then we will copy to user with
struct snd_timer_tread64. Otherwise we will use 32bit time_t variables
when copying to user.

Moreover this patch replaces timespec type with timespec64 type and
related y2038 safe APIs.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
This v8 is what is in the pull request "[GIT PULL, v8] Fix year 2038
issue for sound subsystem", posted here for reference

include/uapi/sound/asound.h | 15 +++-
sound/core/timer.c | 150 +++++++++++++++++++++++++++---------
sound/core/timer_compat.c | 5 +-
3 files changed, 131 insertions(+), 39 deletions(-)

diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index e0ada33afa1e..ad86c5a7a1e2 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -783,7 +783,7 @@ struct snd_timer_status {

#define SNDRV_TIMER_IOCTL_PVERSION _IOR('T', 0x00, int)
#define SNDRV_TIMER_IOCTL_NEXT_DEVICE _IOWR('T', 0x01, struct snd_timer_id)
-#define SNDRV_TIMER_IOCTL_TREAD _IOW('T', 0x02, int)
+#define SNDRV_TIMER_IOCTL_TREAD_OLD _IOW('T', 0x02, int)
#define SNDRV_TIMER_IOCTL_GINFO _IOWR('T', 0x03, struct snd_timer_ginfo)
#define SNDRV_TIMER_IOCTL_GPARAMS _IOW('T', 0x04, struct snd_timer_gparams)
#define SNDRV_TIMER_IOCTL_GSTATUS _IOWR('T', 0x05, struct snd_timer_gstatus)
@@ -796,6 +796,15 @@ struct snd_timer_status {
#define SNDRV_TIMER_IOCTL_STOP _IO('T', 0xa1)
#define SNDRV_TIMER_IOCTL_CONTINUE _IO('T', 0xa2)
#define SNDRV_TIMER_IOCTL_PAUSE _IO('T', 0xa3)
+#define SNDRV_TIMER_IOCTL_TREAD64 _IOW('T', 0xa4, int)
+
+#if __BITS_PER_LONG == 64
+#define SNDRV_TIMER_IOCTL_TREAD SNDRV_TIMER_IOCTL_TREAD_OLD
+#else
+#define SNDRV_TIMER_IOCTL_TREAD ((sizeof(__kernel_long_t) >= sizeof(time_t)) ? \
+ SNDRV_TIMER_IOCTL_TREAD_OLD : \
+ SNDRV_TIMER_IOCTL_TREAD64)
+#endif

struct snd_timer_read {
unsigned int resolution;
@@ -821,11 +830,15 @@ enum {
SNDRV_TIMER_EVENT_MRESUME = SNDRV_TIMER_EVENT_RESUME + 10,
};

+#ifndef __KERNEL__
struct snd_timer_tread {
int event;
+ __time_pad pad1;
struct timespec tstamp;
unsigned int val;
+ __time_pad pad2;
};
+#endif

/****************************************************************************
* *
diff --git a/sound/core/timer.c b/sound/core/timer.c
index d2f69039f941..4cfd8e691903 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -44,6 +44,28 @@ MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for t
MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
MODULE_ALIAS("devname:snd/timer");

+enum timer_tread_format {
+ TREAD_FORMAT_NONE = 0,
+ TREAD_FORMAT_TIME64,
+ TREAD_FORMAT_TIME32,
+};
+
+struct snd_timer_tread32 {
+ int event;
+ s32 tstamp_sec;
+ s32 tstamp_nsec;
+ unsigned int val;
+};
+
+struct snd_timer_tread64 {
+ int event;
+ u8 pad1[4];
+ s64 tstamp_sec;
+ s64 tstamp_nsec;
+ unsigned int val;
+ u8 pad2[4];
+};
+
struct snd_timer_user {
struct snd_timer_instance *timeri;
int tread; /* enhanced read with timestamps and events */
@@ -55,7 +77,7 @@ struct snd_timer_user {
int queue_size;
bool disconnected;
struct snd_timer_read *queue;
- struct snd_timer_tread *tqueue;
+ struct snd_timer_tread64 *tqueue;
spinlock_t qlock;
unsigned long last_resolution;
unsigned int filter;
@@ -1329,7 +1351,7 @@ static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
}

static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
- struct snd_timer_tread *tread)
+ struct snd_timer_tread64 *tread)
{
if (tu->qused >= tu->queue_size) {
tu->overrun++;
@@ -1346,7 +1368,7 @@ static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
unsigned long resolution)
{
struct snd_timer_user *tu = timeri->callback_data;
- struct snd_timer_tread r1;
+ struct snd_timer_tread64 r1;
unsigned long flags;

if (event >= SNDRV_TIMER_EVENT_START &&
@@ -1356,7 +1378,8 @@ static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
return;
memset(&r1, 0, sizeof(r1));
r1.event = event;
- r1.tstamp = timespec64_to_timespec(*tstamp);
+ r1.tstamp_sec = tstamp->tv_sec;
+ r1.tstamp_nsec = tstamp->tv_nsec;
r1.val = resolution;
spin_lock_irqsave(&tu->qlock, flags);
snd_timer_user_append_to_tqueue(tu, &r1);
@@ -1378,7 +1401,7 @@ static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
unsigned long ticks)
{
struct snd_timer_user *tu = timeri->callback_data;
- struct snd_timer_tread *r, r1;
+ struct snd_timer_tread64 *r, r1;
struct timespec64 tstamp;
int prev, append = 0;

@@ -1399,7 +1422,8 @@ static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
tu->last_resolution != resolution) {
r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
- r1.tstamp = timespec64_to_timespec(tstamp);
+ r1.tstamp_sec = tstamp.tv_sec;
+ r1.tstamp_nsec = tstamp.tv_nsec;
r1.val = resolution;
snd_timer_user_append_to_tqueue(tu, &r1);
tu->last_resolution = resolution;
@@ -1413,14 +1437,16 @@ static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
r = &tu->tqueue[prev];
if (r->event == SNDRV_TIMER_EVENT_TICK) {
- r->tstamp = timespec64_to_timespec(tstamp);
+ r->tstamp_sec = tstamp.tv_sec;
+ r->tstamp_nsec = tstamp.tv_nsec;
r->val += ticks;
append++;
goto __wake;
}
}
r1.event = SNDRV_TIMER_EVENT_TICK;
- r1.tstamp = timespec64_to_timespec(tstamp);
+ r1.tstamp_sec = tstamp.tv_sec;
+ r1.tstamp_nsec = tstamp.tv_nsec;
r1.val = ticks;
snd_timer_user_append_to_tqueue(tu, &r1);
append++;
@@ -1435,7 +1461,7 @@ static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
static int realloc_user_queue(struct snd_timer_user *tu, int size)
{
struct snd_timer_read *queue = NULL;
- struct snd_timer_tread *tqueue = NULL;
+ struct snd_timer_tread64 *tqueue = NULL;

if (tu->tread) {
tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
@@ -1874,11 +1900,11 @@ static int snd_timer_user_params(struct file *file,
tu->qhead = tu->qtail = tu->qused = 0;
if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
if (tu->tread) {
- struct snd_timer_tread tread;
+ struct snd_timer_tread64 tread;
memset(&tread, 0, sizeof(tread));
tread.event = SNDRV_TIMER_EVENT_EARLY;
- tread.tstamp.tv_sec = 0;
- tread.tstamp.tv_nsec = 0;
+ tread.tstamp_sec = 0;
+ tread.tstamp_nsec = 0;
tread.val = 0;
snd_timer_user_append_to_tqueue(tu, &tread);
} else {
@@ -2008,6 +2034,36 @@ static int snd_timer_user_pause(struct file *file)
return 0;
}

+static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
+ unsigned int cmd, bool compat)
+{
+ int __user *p = argp;
+ int xarg, old_tread;
+
+ if (tu->timeri) /* too late */
+ return -EBUSY;
+ if (get_user(xarg, p))
+ return -EFAULT;
+
+ old_tread = tu->tread;
+
+ if (!xarg)
+ tu->tread = TREAD_FORMAT_NONE;
+ else if (cmd == SNDRV_TIMER_IOCTL_TREAD64 ||
+ (IS_ENABLED(CONFIG_64BIT) && !compat))
+ tu->tread = TREAD_FORMAT_TIME64;
+ else
+ tu->tread = TREAD_FORMAT_TIME32;
+
+ if (tu->tread != old_tread &&
+ realloc_user_queue(tu, tu->queue_size) < 0) {
+ tu->tread = old_tread;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
enum {
SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
@@ -2016,7 +2072,7 @@ enum {
};

static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
- unsigned long arg)
+ unsigned long arg, bool compat)
{
struct snd_timer_user *tu;
void __user *argp = (void __user *)arg;
@@ -2028,23 +2084,9 @@ static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
return snd_timer_user_next_device(argp);
- case SNDRV_TIMER_IOCTL_TREAD:
- {
- int xarg, old_tread;
-
- if (tu->timeri) /* too late */
- return -EBUSY;
- if (get_user(xarg, p))
- return -EFAULT;
- old_tread = tu->tread;
- tu->tread = xarg ? 1 : 0;
- if (tu->tread != old_tread &&
- realloc_user_queue(tu, tu->queue_size) < 0) {
- tu->tread = old_tread;
- return -ENOMEM;
- }
- return 0;
- }
+ case SNDRV_TIMER_IOCTL_TREAD_OLD:
+ case SNDRV_TIMER_IOCTL_TREAD64:
+ return snd_timer_user_tread(argp, tu, cmd, compat);
case SNDRV_TIMER_IOCTL_GINFO:
return snd_timer_user_ginfo(file, argp);
case SNDRV_TIMER_IOCTL_GPARAMS:
@@ -2084,7 +2126,7 @@ static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
long ret;

mutex_lock(&tu->ioctl_lock);
- ret = __snd_timer_user_ioctl(file, cmd, arg);
+ ret = __snd_timer_user_ioctl(file, cmd, arg, false);
mutex_unlock(&tu->ioctl_lock);
return ret;
}
@@ -2100,13 +2142,29 @@ static int snd_timer_user_fasync(int fd, struct file * file, int on)
static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
size_t count, loff_t *offset)
{
+ struct snd_timer_tread64 *tread;
+ struct snd_timer_tread32 tread32;
struct snd_timer_user *tu;
long result = 0, unit;
int qhead;
int err = 0;

tu = file->private_data;
- unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
+ switch (tu->tread) {
+ case TREAD_FORMAT_TIME64:
+ unit = sizeof(struct snd_timer_tread64);
+ break;
+ case TREAD_FORMAT_TIME32:
+ unit = sizeof(struct snd_timer_tread32);
+ break;
+ case TREAD_FORMAT_NONE:
+ unit = sizeof(struct snd_timer_read);
+ break;
+ default:
+ WARN_ONCE(1, "Corrupt snd_timer_user\n");
+ return -ENOTSUPP;
+ }
+
mutex_lock(&tu->ioctl_lock);
spin_lock_irq(&tu->qlock);
while ((long)count - result >= unit) {
@@ -2145,14 +2203,34 @@ static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
tu->qused--;
spin_unlock_irq(&tu->qlock);

- if (tu->tread) {
- if (copy_to_user(buffer, &tu->tqueue[qhead],
- sizeof(struct snd_timer_tread)))
+ tread = &tu->tqueue[qhead];
+
+ switch (tu->tread) {
+ case TREAD_FORMAT_TIME64:
+ if (copy_to_user(buffer, tread,
+ sizeof(struct snd_timer_tread64)))
err = -EFAULT;
- } else {
+ break;
+ case TREAD_FORMAT_TIME32:
+ memset(&tread32, 0, sizeof(tread32));
+ tread32 = (struct snd_timer_tread32) {
+ .event = tread->event,
+ .tstamp_sec = tread->tstamp_sec,
+ .tstamp_sec = tread->tstamp_nsec,
+ .val = tread->val,
+ };
+
+ if (copy_to_user(buffer, &tread32, sizeof(tread32)))
+ err = -EFAULT;
+ break;
+ case TREAD_FORMAT_NONE:
if (copy_to_user(buffer, &tu->queue[qhead],
sizeof(struct snd_timer_read)))
err = -EFAULT;
+ break;
+ default:
+ err = -ENOTSUPP;
+ break;
}

spin_lock_irq(&tu->qlock);
diff --git a/sound/core/timer_compat.c b/sound/core/timer_compat.c
index 20eef5bc304b..0103d16f6f9f 100644
--- a/sound/core/timer_compat.c
+++ b/sound/core/timer_compat.c
@@ -83,7 +83,8 @@ static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,

switch (cmd) {
case SNDRV_TIMER_IOCTL_PVERSION:
- case SNDRV_TIMER_IOCTL_TREAD:
+ case SNDRV_TIMER_IOCTL_TREAD_OLD:
+ case SNDRV_TIMER_IOCTL_TREAD64:
case SNDRV_TIMER_IOCTL_GINFO:
case SNDRV_TIMER_IOCTL_GSTATUS:
case SNDRV_TIMER_IOCTL_SELECT:
@@ -97,7 +98,7 @@ static long __snd_timer_user_ioctl_compat(struct file *file, unsigned int cmd,
case SNDRV_TIMER_IOCTL_PAUSE:
case SNDRV_TIMER_IOCTL_PAUSE_OLD:
case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
- return __snd_timer_user_ioctl(file, cmd, (unsigned long)argp);
+ return __snd_timer_user_ioctl(file, cmd, (unsigned long)argp, true);
case SNDRV_TIMER_IOCTL_GPARAMS32:
return snd_timer_user_gparams_compat(file, argp);
case SNDRV_TIMER_IOCTL_INFO32:
--
2.20.0