libvncserver: add missing NULL pointer checks

LibVNC · May 28, 2020 · 38e98ee · 38e98ee
1 parent 74e8a70
commit 38e98ee
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Showing 2 changed files with 19 additions and 11 deletions.
diff --git a/libvncserver/rfbregion.c b/libvncserver/rfbregion.c
@@ -51,24 +51,30 @@ sraSpanDup(const sraSpan *src) {
 
 static void
 sraSpanInsertAfter(sraSpan *newspan, sraSpan *after) {
-  newspan->_next = after->_next;
-  newspan->_prev = after;
-  after->_next->_prev = newspan;
-  after->_next = newspan;
+  if(newspan && after) {
+    newspan->_next = after->_next;
+    newspan->_prev = after;
+    after->_next->_prev = newspan;
+    after->_next = newspan;
+  }
 }
 
 static void
 sraSpanInsertBefore(sraSpan *newspan, sraSpan *before) {
-  newspan->_next = before;
-  newspan->_prev = before->_prev;
-  before->_prev->_next = newspan;
-  before->_prev = newspan;
+  if(newspan && before) {
+    newspan->_next = before;
+    newspan->_prev = before->_prev;
+    before->_prev->_next = newspan;
+    before->_prev = newspan;
+  }
 }
 
 static void
 sraSpanRemove(sraSpan *span) {
-  span->_prev->_next = span->_next;
-  span->_next->_prev = span->_prev;
+  if(span) {
+    span->_prev->_next = span->_next;
+    span->_next->_prev = span->_prev;
+  }
 }
 
 static void

diff --git a/libvncserver/rfbserver.c b/libvncserver/rfbserver.c
@@ -207,6 +207,8 @@ rfbClientIteratorHead(rfbClientIteratorPtr i)
 rfbClientPtr
 rfbClientIteratorNext(rfbClientIteratorPtr i)
 {
+  if (!i)
+    return NULL;
   if(i->next == 0) {
     LOCK(rfbClientListMutex);
     i->next = i->screen->clientHead;
@@ -231,7 +233,7 @@ rfbClientIteratorNext(rfbClientIteratorPtr i)
 void
 rfbReleaseClientIterator(rfbClientIteratorPtr iterator)
 {
-  if(iterator->next) rfbDecrClientRef(iterator->next);
+  if(iterator && iterator->next) rfbDecrClientRef(iterator->next);
   free(iterator);
 }