detect/prefilter: fix prefilter when setting is 'mpm'

When prefilter is not enabled globally, it is still possible to
enable it per signature. This was broken however, as the setup
code would never be called.

This commit always call the setup code and lets that sort out
which signatures (if any) to enable prefiltering for.

diff --git a/src/detect-engine-prefilter.c b/src/detect-engine-prefilter.c
index f9075ba8d424c76ec93fb82ad35ed6c5087fc2f9..e0b04159b7368f91652c1a87db83a0981fdd225e 100644 (file)
--- a/src/detect-engine-prefilter.c
+++ b/src/detect-engine-prefilter.c
@@ -348,13 +348,12 @@ void PrefilterSetupRuleGroup(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
 {
     BUG_ON(PatternMatchPrepareGroup(de_ctx, sgh) != 0);
 
-    if (de_ctx->prefilter_setting == DETECT_PREFILTER_AUTO) {
-        int i = 0;
-        for (i = 0; i < DETECT_TBLSIZE; i++)
-        {
-            if (sigmatch_table[i].SetupPrefilter != NULL) {
-                sigmatch_table[i].SetupPrefilter(de_ctx, sgh);
-            }
+    /* set up engines if needed - independent of 'detect.prefilter.default'
+     * setting as the prefilter keyword may have enabled individual sigs */
+    for (int i = 0; i < DETECT_TBLSIZE; i++)
+    {
+        if (sigmatch_table[i].SetupPrefilter != NULL) {
+            sigmatch_table[i].SetupPrefilter(de_ctx, sgh);
         }
     }