[Mesa-dev] [PATCH] mesa: Check for valid debug label before memcpy.

[Vinson Lee]

Fixes "Dereference after null check" reported by Coverity.

Signed-off-by: Vinson Lee <vlee at freedesktop.org>
---
 src/mesa/main/objectlabel.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/mesa/main/objectlabel.c b/src/mesa/main/objectlabel.c
index 90d9e09..79fd8c7 100644
--- a/src/mesa/main/objectlabel.c
+++ b/src/mesa/main/objectlabel.c
@@ -90,16 +90,28 @@ set_label(struct gl_context *ctx, char **labelPtr, const char *label,
 static void
 copy_label(char **labelPtr, char *label, int *length, int bufSize)
 {
+   /* From http://www.opengl.org/registry/specs/KHR/debug.txt:
+    * "If <length> is NULL, no length is returned. The maximum number of
+    * characters that may be written into <label>, including the null
+    * terminator, is specified by <bufSize>. If no debug label was specified
+    * for the object then <label> will contain a null-terminated empty string,
+    * and zero will be returned in <length>. If <label> is NULL and <length>
+    * is non-NULL then no string will be returned and the length of the label
+    * will be returned in <length>."
+    */
+
    int labelLen = 0;
 
    if (*labelPtr)
       labelLen = strlen(*labelPtr);
 
    if (label) {
-      if (bufSize <= labelLen)
-         labelLen =  bufSize-1;
+      if (*labelPtr) {
+         if (bufSize <= labelLen)
+            labelLen =  bufSize-1;
 
-      memcpy(label, *labelPtr, labelLen);
+         memcpy(label, *labelPtr, labelLen);
+      }
       label[labelLen] = '\0';
    }
 
-- 
1.8.1.2