[pulseaudio-discuss] [PATCH 3/3] pa_*_volume_change_push: Do not dereference freed memory when freeing the next events

[Felipe Sateler]

Found by coverity
---
 src/pulsecore/sink.c   | 8 ++++++--
 src/pulsecore/source.c | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/pulsecore/sink.c b/src/pulsecore/sink.c
index c2bf0e4..da008dd 100644
--- a/src/pulsecore/sink.c
+++ b/src/pulsecore/sink.c
@@ -3543,6 +3543,7 @@ static void pa_sink_volume_change_free(pa_sink_volume_change *c) {
 void pa_sink_volume_change_push(pa_sink *s) {
     pa_sink_volume_change *c = NULL;
     pa_sink_volume_change *nc = NULL;
+    pa_sink_volume_change *pc = NULL;
     uint32_t safety_margin = s->thread_info.volume_change_safety_margin;
 
     const char *direction = NULL;
@@ -3600,9 +3601,12 @@ void pa_sink_volume_change_push(pa_sink *s) {
     pa_log_debug("Volume going %s to %d at %llu", direction, pa_cvolume_avg(&nc->hw_volume), (long long unsigned) nc->at);
 
     /* We can ignore volume events that came earlier but should happen later than this. */
-    PA_LLIST_FOREACH(c, nc->next) {
+    c = nc->next;
+    while(c) {
         pa_log_debug("Volume change to %d at %llu was dropped", pa_cvolume_avg(&c->hw_volume), (long long unsigned) c->at);
-        pa_sink_volume_change_free(c);
+        pc = c;
+        c = c->next;
+        pa_sink_volume_change_free(pc);
     }
     nc->next = NULL;
     s->thread_info.volume_changes_tail = nc;
diff --git a/src/pulsecore/source.c b/src/pulsecore/source.c
index 2dd7a28..0e304c6 100644
--- a/src/pulsecore/source.c
+++ b/src/pulsecore/source.c
@@ -2654,6 +2654,7 @@ static void pa_source_volume_change_free(pa_source_volume_change *c) {
 void pa_source_volume_change_push(pa_source *s) {
     pa_source_volume_change *c = NULL;
     pa_source_volume_change *nc = NULL;
+    pa_source_volume_change *pc = NULL;
     uint32_t safety_margin = s->thread_info.volume_change_safety_margin;
 
     const char *direction = NULL;
@@ -2711,9 +2712,12 @@ void pa_source_volume_change_push(pa_source *s) {
     pa_log_debug("Volume going %s to %d at %llu", direction, pa_cvolume_avg(&nc->hw_volume), (long long unsigned) nc->at);
 
     /* We can ignore volume events that came earlier but should happen later than this. */
-    PA_LLIST_FOREACH(c, nc->next) {
+    c = nc->next;
+    while(c) {
         pa_log_debug("Volume change to %d at %llu was dropped", pa_cvolume_avg(&c->hw_volume), (long long unsigned) c->at);
-        pa_source_volume_change_free(c);
+        pc = c;
+        c = c->next;
+        pa_source_volume_change_free(pc);
     }
     nc->next = NULL;
     s->thread_info.volume_changes_tail = nc;
-- 
2.5.1