[Fix] Fix fuzzy image score calculation #2962

diff --git a/src/plugins/fuzzy_check.c b/src/plugins/fuzzy_check.c
index 566c8e93d06aae70524ab5116a39b925d2207105..8d1c630100a00a377e68b8a0013d9ec06ceae3da 100644 (file)
--- a/src/plugins/fuzzy_check.c
+++ b/src/plugins/fuzzy_check.c
@@ -2121,16 +2121,37 @@ fuzzy_insert_metric_results (struct rspamd_task *task, GPtrArray *results)
 {
        struct fuzzy_client_result *res;
        guint i;
-       gboolean seen_text = FALSE, seen_img = FALSE;
+       gboolean seen_text_hash = FALSE, seen_img_hash = FALSE, seen_text = FALSE,
+                       seen_long_text = FALSE;
        gdouble prob_txt = 0.0, mult;
+       struct rspamd_mime_text_part *tp;
+
+       /* About 5 words */
+       static const text_length_cutoff = 25;
 
        PTR_ARRAY_FOREACH (results, i, res) {
                if (res->type == FUZZY_RESULT_TXT) {
-                       seen_text = TRUE;
+                       seen_text_hash = TRUE;
                        prob_txt = MAX (prob_txt, res->prob);
                }
                else if (res->type == FUZZY_RESULT_IMG) {
-                       seen_img = TRUE;
+                       seen_img_hash = TRUE;
+               }
+       }
+
+       PTR_ARRAY_FOREACH (task->text_parts, i, tp) {
+               if (!IS_PART_EMPTY (tp)) {
+                       seen_text = TRUE;
+               }
+               else if (tp->utf_stripped_text.magic == UTEXT_MAGIC) {
+                       if (utext_isLengthExpensive (&tp->utf_stripped_text)) {
+                               seen_long_text =
+                                               utext_nativeLength (&tp->utf_stripped_text) > text_length_cutoff;
+                       }
+                       else {
+                               /* Cannot directly calculate length */
+                               seen_long_text = tp->utf_stripped_content->len / 2 > text_length_cutoff;
+                       }
                }
        }
 
@@ -2138,16 +2159,28 @@ fuzzy_insert_metric_results (struct rspamd_task *task, GPtrArray *results)
                mult = 1.0;
 
                if (res->type == FUZZY_RESULT_IMG) {
-                       if (!seen_text) {
-                               mult *= 0.25;
+                       if (!seen_text_hash) {
+                               if (seen_long_text) {
+                                       mult *= 0.25;
+                               }
+                               else if (seen_text) {
+                                       /* We have some short text + image */
+                                       mult *= 0.9;
+                               }
+                               /* Otherwise apply full score */
                        }
                        else if (prob_txt < 0.75) {
                                /* Penalize sole image without matching text */
-                               mult *= prob_txt;
+                               if (prob_txt > 0.5) {
+                                       mult *= prob_txt;
+                               }
+                               else {
+                                       mult *= 0.5; /* cutoff */
+                               }
                        }
                }
                else if (res->type == FUZZY_RESULT_TXT) {
-                       if (seen_img) {
+                       if (seen_img_hash) {
                                /* Slightly increase score */
                                mult = 1.1;
                        }