[Spice-devel] [PATCH] Don't truncate large 'now' values in _spice_timer_set

[Christophe Fergeau]

From: David Gibson <dgibson at redhat.com>

static void _spice_timer_set(SpiceTimer *timer, uint32_t ms, uint32_t now)

The _spice_timer_set() function takes a 32-bit integer for the "now" value.
The now value passed in however, can exceed 2^32 (it's in ms and derived
from CLOCK_MONOTONIC, which will wrap around a 32-bit integer in around 46
days).

If the now value passed in exceeds 2^32, this will mean timers are inserted
into the active list with expiry values before the current time, they will
immediately trigger, and (if they don't make themselves inactive) be
reinserted still before the current time.

This leads to an infinite loop in spice_timer_queue_cb().

https://bugzilla.redhat.com/show_bug.cgi?id=1072700
---
 server/spice_timer_queue.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/server/spice_timer_queue.c b/server/spice_timer_queue.c
index 8f6e9c8..71de84a 100644
--- a/server/spice_timer_queue.c
+++ b/server/spice_timer_queue.c
@@ -147,7 +147,7 @@ SpiceTimer *spice_timer_queue_add(SpiceTimerFunc func, void *opaque)
     return timer;
 }
 
-static void _spice_timer_set(SpiceTimer *timer, uint32_t ms, uint32_t now)
+static void _spice_timer_set(SpiceTimer *timer, uint32_t ms, uint64_t now)
 {
     RingItem *next_item;
     SpiceTimerQueue *queue;
@@ -183,7 +183,8 @@ void spice_timer_set(SpiceTimer *timer, uint32_t ms)
     spice_assert(pthread_equal(timer->queue->thread, pthread_self()) != 0);
 
     clock_gettime(CLOCK_MONOTONIC, &now);
-    _spice_timer_set(timer, ms, now.tv_sec * 1000 + (now.tv_nsec / 1000 / 1000));
+    _spice_timer_set(timer, ms,
+                     (uint64_t)now.tv_sec * 1000 + (now.tv_nsec / 1000 / 1000));
 }
 
 void spice_timer_cancel(SpiceTimer *timer)
@@ -217,7 +218,7 @@ void spice_timer_remove(SpiceTimer *timer)
 unsigned int spice_timer_queue_get_timeout_ms(void)
 {
     struct timespec now;
-    int now_ms;
+    int64_t now_ms;
     RingItem *head;
     SpiceTimer *head_timer;
     SpiceTimerQueue *queue = spice_timer_queue_find_with_lock();
@@ -232,9 +233,9 @@ unsigned int spice_timer_queue_get_timeout_ms(void)
     head_timer = SPICE_CONTAINEROF(head, SpiceTimer, active_link);
 
     clock_gettime(CLOCK_MONOTONIC, &now);
-    now_ms = (now.tv_sec * 1000) - (now.tv_nsec / 1000 / 1000);
+    now_ms = ((int64_t)now.tv_sec * 1000) - (now.tv_nsec / 1000 / 1000);
 
-    return MAX(0, ((int)head_timer->expiry_time - now_ms));
+    return MAX(0, ((int64_t)head_timer->expiry_time - now_ms));
 }
 
 
@@ -252,7 +253,7 @@ void spice_timer_queue_cb(void)
     }
 
     clock_gettime(CLOCK_MONOTONIC, &now);
-    now_ms = (now.tv_sec * 1000) + (now.tv_nsec / 1000 / 1000);
+    now_ms = ((uint64_t)now.tv_sec * 1000) + (now.tv_nsec / 1000 / 1000);
 
     while ((head = ring_get_head(&queue->active_timers))) {
         SpiceTimer *timer = SPICE_CONTAINEROF(head, SpiceTimer, active_link);
-- 
1.8.5.3