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. Also add one struct compat_snd_timer_tread64_x86_32 to
handle 64bit time_t with 32bit alignment. That means we will set
tu->tread = 2 when user space has a 64bit time_t, then we will copy
to user with struct snd_timer_tread64. For x86_32 mode, we will set
tu->tread = 3 to copy struct compat_snd_timer_tread64_x86_32 for user.
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.w...@linaro.org>
---
 include/uapi/sound/asound.h |   11 ++-
 sound/core/timer.c          |  163 +++++++++++++++++++++++++++++++++++--------
 2 files changed, 142 insertions(+), 32 deletions(-)

diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h
index 71bce52..ef738bf 100644
--- a/include/uapi/sound/asound.h
+++ b/include/uapi/sound/asound.h
@@ -760,7 +760,7 @@ 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)
@@ -773,6 +773,15 @@ 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;
diff --git a/sound/core/timer.c b/sound/core/timer.c
index 376b7e6..c33a1be 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -58,6 +58,22 @@
 MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
 MODULE_ALIAS("devname:snd/timer");
 
+struct snd_timer_tread64 {
+       int event;
+       u32 pad1;
+       struct { s64 tv_sec; s64 tv_nsec; } tstamp;
+       unsigned int val;
+       u32 pad2;
+};
+
+#ifdef IA32_EMULATION
+struct compat_snd_timer_tread64_x86_32 {
+       int event;
+       struct { s64 tv_sec; s64 tv_nsec; } tstamp;
+       unsigned int val;
+} __packed;
+#endif
+
 struct snd_timer_user {
        struct snd_timer_instance *timeri;
        int tread;              /* enhanced read with timestamps and events */
@@ -69,7 +85,7 @@ 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;
@@ -1262,7 +1278,7 @@ 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++;
@@ -1279,7 +1295,7 @@ 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 &&
@@ -1289,7 +1305,8 @@ 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.tv_sec = tstamp->tv_sec;
+       r1.tstamp.tv_nsec = tstamp->tv_nsec;
        r1.val = resolution;
        spin_lock_irqsave(&tu->qlock, flags);
        snd_timer_user_append_to_tqueue(tu, &r1);
@@ -1311,7 +1328,7 @@ 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;
 
@@ -1332,7 +1349,8 @@ 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.tv_sec = tstamp.tv_sec;
+               r1.tstamp.tv_nsec = tstamp.tv_nsec;
                r1.val = resolution;
                snd_timer_user_append_to_tqueue(tu, &r1);
                tu->last_resolution = resolution;
@@ -1346,14 +1364,16 @@ 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.tv_sec = tstamp.tv_sec;
+                       r->tstamp.tv_nsec = tstamp.tv_nsec;
                        r->val += ticks;
                        append++;
                        goto __wake;
                }
        }
        r1.event = SNDRV_TIMER_EVENT_TICK;
-       r1.tstamp = timespec64_to_timespec(tstamp);
+       r1.tstamp.tv_sec = tstamp.tv_sec;
+       r1.tstamp.tv_nsec = tstamp.tv_nsec;
        r1.val = ticks;
        snd_timer_user_append_to_tqueue(tu, &r1);
        append++;
@@ -1368,7 +1388,7 @@ 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);
@@ -1797,7 +1817,7 @@ 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;
@@ -1921,6 +1941,39 @@ static int snd_timer_user_pause(struct file *file)
        return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
 }
 
+static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
+                               unsigned int cmd)
+{
+       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 __BITS_PER_LONG == 64
+       tu->tread = xarg ? 2 : 0;
+#ifdef IA32_EMULATION
+       tu->tread = xarg ? 3 : 0;
+#endif
+#else
+       if (cmd == SNDRV_TIMER_IOCTL_TREAD64)
+               tu->tread = xarg ? 2 : 0;
+       else
+               tu->tread = xarg ? 1 : 0;
+#endif
+
+       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),
@@ -1941,23 +1994,9 @@ 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);
        case SNDRV_TIMER_IOCTL_GINFO:
                return snd_timer_user_ginfo(file, argp);
        case SNDRV_TIMER_IOCTL_GPARAMS:
@@ -2021,7 +2060,25 @@ static ssize_t snd_timer_user_read(struct file *file, 
char __user *buffer,
        int err = 0;
 
        tu = file->private_data;
-       unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct 
snd_timer_read);
+       switch (tu->tread) {
+#ifdef IA32_EMULATION
+       case 3:
+               unit = sizeof(struct compat_snd_timer_tread64_x86_32);
+               break;
+#endif
+       case 2:
+               unit = sizeof(struct snd_timer_tread64);
+               break;
+       case 1:
+               unit = sizeof(struct snd_timer_tread);
+               break;
+       case 0:
+               unit = sizeof(struct snd_timer_read);
+               break;
+       default:
+               return -ENOTSUPP;
+       }
+
        mutex_lock(&tu->ioctl_lock);
        spin_lock_irq(&tu->qlock);
        while ((long)count - result >= unit) {
@@ -2061,9 +2118,53 @@ static ssize_t snd_timer_user_read(struct file *file, 
char __user *buffer,
                spin_unlock_irq(&tu->qlock);
 
                if (tu->tread) {
-                       if (copy_to_user(buffer, &tu->tqueue[qhead],
-                                        sizeof(struct snd_timer_tread)))
-                               err = -EFAULT;
+                       struct snd_timer_tread64 *tread = &tu->tqueue[qhead];
+                       struct snd_timer_tread tread32;
+#ifdef IA32_EMULATION
+                       struct compat_snd_timer_tread64_x86_32 compat_tread64;
+#endif
+
+                       switch (tu->tread) {
+#ifdef IA32_EMULATION
+                       case 3:
+                               memset(&compat_tread64, 0, 
sizeof(compat_tread64));
+                               compat_tread64 = (struct 
compat_snd_timer_tread64_x86_32) {
+                                       .event = tread->event,
+                                       .tstamp = {
+                                               .tv_sec = tread->tstamp.tv_sec,
+                                               .tv_nsec = 
tread->tstamp.tv_nsec,
+                                       },
+                                       .val = tread->val,
+                               };
+
+                               if (copy_to_user(buffer, &compat_tread64,
+                                                sizeof(compat_tread64)))
+                                       err = -EFAULT;
+                               break;
+#endif
+                       case 2:
+                               if (copy_to_user(buffer, tread,
+                                                sizeof(struct 
snd_timer_tread64)))
+                                       err = -EFAULT;
+                               break;
+                       case 1:
+                               memset(&tread32, 0, sizeof(tread32));
+                               tread32 = (struct snd_timer_tread) {
+                                       .event = tread->event,
+                                       .tstamp = {
+                                               .tv_sec = tread->tstamp.tv_sec,
+                                               .tv_nsec = 
tread->tstamp.tv_nsec,
+                                       },
+                                       .val = tread->val,
+                               };
+
+                               if (copy_to_user(buffer, &tread32, 
sizeof(tread32)))
+                                       err = -EFAULT;
+                               break;
+                       default:
+                               err = -ENOTSUPP;
+                               break;
+                       }
                } else {
                        if (copy_to_user(buffer, &tu->queue[qhead],
                                         sizeof(struct snd_timer_read)))
-- 
1.7.9.5

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