1 files changed, 5 insertions, 2 deletions
diff --git a/libs/libcurl/src/strdup.c b/libs/libcurl/src/strdup.c
index f3d8ed3846..94caa05fb8 100644
--- a/libs/libcurl/src/strdup.c
+++ b/libs/libcurl/src/strdup.c
@@ -104,7 +104,7 @@ void *Curl_memdup(const void *src, size_t length)
  * Curl_memdup0(source, length)
  *
  * Copies the 'source' string to a newly allocated buffer (that is returned).
- * Copies 'length' bytes then adds a null terminator.
+ * Copies 'length' bytes then adds a null-terminator.
  *
  * Returns the new pointer or NULL on failure.
  *
@@ -114,7 +114,10 @@ void *Curl_memdup0(const char *src, size_t length)
   char *buf = malloc(length + 1);
   if(!buf)
     return NULL;
-  memcpy(buf, src, length);
+  if(length) {
+    DEBUGASSERT(src); /* must never be NULL */
+    memcpy(buf, src, length);
+  }
   buf[length] = 0;
   return buf;
 }