mime-decode: don't scan attachment's data for URLs.

move event pointer lookup inside extract_urls and protect pointer walk.

src/mime-decode.c

@@ -164,26 +164,58 @@ MimeDecConfig * MimeDecGetConfig(void) {
 }
 
 /**
- * \brief Recursively frees a mime entity tree
+ * \brief Follow the 'next' pointers to the leaf
+ *
+ * \param node The root entity
+ *
+ * \return Pointer to leaf on 'next' side
+ *
+ */
+static MimeDecEntity *findLastSibling(MimeDecEntity *node)
+{
+    if (node == NULL)
+        return NULL;
+    while(node->next != NULL)
+        node = node->next;
+    return node;
+}
+
+/**
+ * \brief Frees a mime entity tree
  *
  * \param entity The root entity
  *
  * \return none
  *
  */
-void MimeDecFreeEntity (MimeDecEntity *entity) {
-
-    if (entity != NULL) {
+void MimeDecFreeEntity (MimeDecEntity *entity)
+{
+    if (entity == NULL)
+        return;
+    MimeDecEntity *lastSibling = findLastSibling(entity);
+    while (entity != NULL)
+    {
+        /**
+         * Move child to next
+         * Transform tree into list
+         */
+        if (entity->child != NULL)
+        {
+            lastSibling->next = entity->child;
+            lastSibling = findLastSibling(lastSibling);
+        }
 
-        MimeDecFreeField(entity->field_list);
-        MimeDecFreeUrl(entity->url_list);
-        SCFree(entity->filename);
+        /**
+         * Move to next element
+         */
+        MimeDecEntity *old = entity;
+        entity = entity->next;
 
-        /* Use recursion */
-        MimeDecFreeEntity(entity->child);
-        MimeDecFreeEntity(entity->next);
+        MimeDecFreeField(old->field_list);
+        MimeDecFreeUrl(old->url_list);
+        SCFree(old->filename);
 
-        SCFree(entity);
+        SCFree(old);
     }
 }
 
@@ -1085,15 +1117,17 @@ static int ProcessDecodedDataChunk(const uint8_t *chunk, uint32_t len,
         MimeDecParseState *state) {
 
     int ret = MIME_DEC_OK;
-    MimeDecEntity *entity = (MimeDecEntity *) state->stack->top->data;
     char *remainPtr, *tok;
     uint32_t tokLen;
 
     MimeDecConfig *mdcfg = MimeDecGetConfig();
     if (mdcfg != NULL && mdcfg->extract_urls) {
+        if ((state->stack != NULL) && (state->stack->top != NULL)) {
+            MimeDecEntity *entity = (MimeDecEntity *) state->stack->top->data;
             /* If plain text or html, then look for URLs */
-        if ((entity->ctnt_flags & CTNT_IS_TEXT) ||
-                (entity->ctnt_flags & CTNT_IS_HTML)) {
+            if (((entity->ctnt_flags & CTNT_IS_TEXT) ||
+                (entity->ctnt_flags & CTNT_IS_HTML)) &&
+                ((entity->ctnt_flags & CTNT_IS_ATTACHMENT) == 0)) {
 
                 /* Remainder from previous line */
                 if (state->linerem_len > 0) {
@@ -1127,6 +1161,9 @@ static int ProcessDecodedDataChunk(const uint8_t *chunk, uint32_t len,
                     } while (tok != remainPtr && remainPtr - (char *) chunk < len);
                 }
             }
+        } else {
+            SCLogDebug("Error: Stack pointer missing");
+        }
     }
 
     /* Now invoke callback */