From: Philippe Antoine <pantoine@oisf.net>
Date: Sat, 2 May 2020 13:55:23 +0000 (+0200)
Subject: signature: fix linked list for bidirectional signatures
X-Git-Tag: suricata-5.0.4~45
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6db4a37df68ea2051a04c39eac1293ca184ef3a;p=thirdparty%2Fsuricata.git

signature: fix linked list for bidirectional signatures

Bidirectional signatures are really two signatures with one id
This needs to be handled with care when changing a linked list

(cherry picked from commit 5ac8e41a130f7b17678be00a1a5510a85f7baa2e)
---

diff --git a/src/detect-parse.c b/src/detect-parse.c
index 3ea024ad36..f559f826b5 100644
--- a/src/detect-parse.c
+++ b/src/detect-parse.c
@@ -2239,11 +2239,23 @@ static inline int DetectEngineSignatureIsDuplicate(DetectEngineCtx *de_ctx,
         memset(&sw_temp, 0, sizeof(SigDuplWrapper));
         if (sw_dup->s->init_data->init_flags & SIG_FLAG_INIT_BIDIREC) {
             sw_temp.s = sw_dup->s->next->next;
-            sw_dup->s_prev->next = sw_dup->s->next->next;
+            /* If previous signature is bidirectional,
+             * it has 2 items in the linked list.
+             * So we need to change next->next instead of next
+             */
+            if (sw_dup->s_prev->init_data->init_flags & SIG_FLAG_INIT_BIDIREC) {
+                sw_dup->s_prev->next->next = sw_dup->s->next->next;
+            } else {
+                sw_dup->s_prev->next = sw_dup->s->next->next;
+            }
             SigFree(sw_dup->s->next);
         } else {
             sw_temp.s = sw_dup->s->next;
-            sw_dup->s_prev->next = sw_dup->s->next;
+            if (sw_dup->s_prev->init_data->init_flags & SIG_FLAG_INIT_BIDIREC) {
+                sw_dup->s_prev->next->next = sw_dup->s->next;
+            } else {
+                sw_dup->s_prev->next = sw_dup->s->next;
+            }
         }
         SigDuplWrapper *sw_next = NULL;
         if (sw_temp.s != NULL) {