[Feature] Add heuristic to detect broken messages

diff --git a/src/libmime/mime_parser.c b/src/libmime/mime_parser.c
index c409e404d8af5120e5f56e89a37dade996cb62f9..ac0e90b0573cfcfb9e3ce0d2820bd766933fdbe3 100644 (file)
--- a/src/libmime/mime_parser.c
+++ b/src/libmime/mime_parser.c
@@ -753,6 +753,72 @@ rspamd_mime_preprocess_cb (struct rspamd_multipattern *mp,
        return 0;
 }
 
+static goffset
+rspamd_mime_parser_headers_heuristic (GString *input, goffset *body_start)
+{
+       const gsize default_max_len = 76;
+       gsize max_len = MIN (input->len, default_max_len);
+       const gchar *p, *end;
+       enum {
+               st_before_colon = 0,
+               st_colon,
+               st_spaces_after_colon,
+               st_value,
+               st_error
+       } state = st_before_colon;
+
+       p = input->str;
+       end = p + max_len;
+
+       while (p < end) {
+               switch (state) {
+               case st_before_colon:
+                       if (G_UNLIKELY (*p == ':')) {
+                               state = st_colon;
+                       }
+                       else if (G_UNLIKELY (!g_ascii_isgraph (*p))) {
+                               state = st_error;
+                       }
+
+                       p ++;
+                       break;
+               case st_colon:
+                       if (g_ascii_isspace (*p)) {
+                               state = st_spaces_after_colon;
+                       }
+                       else {
+                               state = st_value;
+                       }
+                       p ++;
+                       break;
+               case st_spaces_after_colon:
+                       if (!g_ascii_isspace (*p)) {
+                               state = st_value;
+                       }
+                       p ++;
+                       break;
+               case st_value:
+                       /* We accept any value */
+                       goto end;
+                       break;
+               case st_error:
+                       return (-1);
+                       break;
+               }
+       }
+
+end:
+       if (state == st_value) {
+               if (body_start) {
+                       *body_start = input->len;
+               }
+
+               return input->len;
+       }
+
+       return (-1);
+}
+
 static void
 rspamd_mime_preprocess_message (struct rspamd_task *task,
                struct rspamd_mime_part *top,
@@ -844,6 +910,7 @@ rspamd_mime_parse_message (struct rspamd_task *task,
                hdr_pos = rspamd_string_find_eoh (&str, &body_pos);
 
                if (hdr_pos > 0 && hdr_pos < str.len) {
+
                        task->raw_headers_content.begin = (gchar *) (str.str);
                        task->raw_headers_content.len = hdr_pos;
                        task->raw_headers_content.body_start = str.str + body_pos;
@@ -860,7 +927,29 @@ rspamd_mime_parse_message (struct rspamd_task *task,
                                        "Content-Type", FALSE);
                }
                else {
-                       body_pos = 0;
+                       /* First apply heuristic, maybe we have just headers */
+                       hdr_pos = rspamd_mime_parser_headers_heuristic (&str, &body_pos);
+
+                       if (hdr_pos > 0 && hdr_pos <= str.len) {
+                               task->raw_headers_content.begin = (gchar *) (str.str);
+                               task->raw_headers_content.len = hdr_pos;
+                               task->raw_headers_content.body_start = str.str + body_pos;
+
+                               if (task->raw_headers_content.len > 0) {
+                                       rspamd_mime_headers_process (task, task->raw_headers,
+                                                       task->raw_headers_content.begin,
+                                                       task->raw_headers_content.len,
+                                                       TRUE);
+                               }
+
+                               hdrs = rspamd_message_get_header_from_hash (task->raw_headers,
+                                               task->task_pool,
+                                               "Content-Type", FALSE);
+                               task->flags |= RSPAMD_TASK_FLAG_BROKEN_HEADERS|RSPAMD_TASK_FLAG_EMPTY;
+                       }
+                       else {
+                               body_pos = 0;
+                       }
                }
 
                pbegin = st->start + body_pos;