1 files changed, 46 insertions, 2 deletions

diff --git a/src/blocks.c b/src/blocks.c
index 1c1d160..c680535 100644
--- a/src/blocks.c
+++ b/src/blocks.c
@@ -96,6 +96,8 @@ cmark_parser *cmark_parser_new_with_mem(int options, cmark_mem *mem) {
   parser->refmap = cmark_reference_map_new(mem);
   parser->root = document;
   parser->current = document;
+  parser->error_code = CMARK_ERR_NONE;
+  parser->total_bytes = 0;
   parser->line_number = 0;
   parser->line_offset = 0;
   parser->offset = 0;
@@ -550,6 +552,20 @@ static void S_parser_feed(cmark_parser *parser, const unsigned char *buffer,
   const unsigned char *skipped;
   static const uint8_t repl[] = {239, 191, 189};
 
+  if (parser->error_code) {
+    return;
+  }
+
+  // Limit maximum document size to BUFSIZE_MAX. This makes sure that we
+  // never create strbufs larger than BUFSIZE_MAX. Unfortunately, the
+  // public API doesn't have an error reporting mechanism, so all we can
+  // do is to abort.
+  if (len > (size_t)(BUFSIZE_MAX - parser->total_bytes)) {
+    parser->error_code = CMARK_ERR_INPUT_TOO_LARGE;
+    return;
+  }
+  parser->total_bytes += (bufsize_t)len;
+
   if (parser->last_buffer_ended_with_cr && *buffer == '\n') {
     // skip NL if last buffer ended with CR ; see #117
     buffer++;
@@ -1266,14 +1282,19 @@ cmark_node *cmark_parser_finish(cmark_parser *parser) {
     cmark_strbuf_clear(&parser->linebuf);
   }
 
+  cmark_strbuf_clear(&parser->curline);
+
+  if (parser->error_code) {
+    cmark_node_free(parser->root);
+    return NULL;
+  }
+
   finalize_document(parser);
 
   if (parser->options & CMARK_OPT_NORMALIZE) {
     cmark_consolidate_text_nodes(parser->root);
   }
 
-  cmark_strbuf_free(&parser->curline);
-
 #if CMARK_DEBUG_NODES
   if (cmark_node_check(parser->root, stderr)) {
     abort();
@@ -1287,3 +1308,26 @@ cmark_parser_get_first_source_extent(cmark_parser *parser)
 {
   return parser->source_map->head;
 }
+
+cmark_err_type cmark_parser_get_error(cmark_parser *parser) {
+  return parser->error_code;
+}
+
+const char *cmark_parser_get_error_message(cmark_parser *parser) {
+  const char *str = NULL;
+
+  switch (parser->error_code) {
+    case CMARK_ERR_OUT_OF_MEMORY:
+      str = "Out of memory";
+      break;
+    case CMARK_ERR_INPUT_TOO_LARGE:
+      str = "Input too large";
+      break;
+    default:
+      str = "Unknown error";
+      break;
+  }
+
+  return str;
+}
+