Add DebugLog message for bad pattern in rx operator

CHANGES

@@ -1,6 +1,8 @@
 v3.x.y - YYYY-MMM-DD (to be released)
 -------------------------------------
 
+  - Add DebugLog message for bad pattern in rx operator
+    [Issue #2722 - @martinhsv]
   - Support PCRE2
     [Issue #2668 - @martinhsv]
   - Support SecRequestBodyNoFilesLimit

src/operators/rx.cc

@@ -52,6 +52,10 @@ bool Rx::evaluate(Transaction *transaction, RuleWithActions *rule,
     }
 
     std::vector<Utils::SMatchCapture> captures;
+    if (re->hasError()) {
+        ms_dbg_a(transaction, 3, "Error with regular expression: \"" + re->pattern + "\"");
+        return false;
+    }
     re->searchOneMatch(input, captures);
 
     if (rule && rule->hasCaptureAction() && transaction) {

src/utils/regex.cc

@@ -75,6 +75,9 @@ Regex::Regex(const std::string& pattern_, bool ignoreCase)
         pcre2_options, &errornumber, &erroroffset, NULL);
     if (m_pc != NULL) {
         m_match_data = pcre2_match_data_create_from_pattern(m_pc, NULL);
+        if (m_match_data == NULL) {
+            m_pc = NULL;
+        }
     }
 #else
     const char *errptr = NULL;

src/utils/regex.h

@@ -72,6 +72,9 @@ class Regex {
     Regex(const Regex&) = delete;
     Regex& operator=(const Regex&) = delete;
 
+    bool hasError() const {
+        return (m_pc == NULL);
+    }
     std::list<SMatch> searchAll(const std::string& s) const;
     bool searchOneMatch(const std::string& s, std::vector<SMatchCapture>& captures) const;
     bool searchGlobal(const std::string& s, std::vector<SMatchCapture>& captures) const;

test/test-cases/regression/operator-rx.json

@@ -85,5 +85,47 @@
       "SecRuleEngine On",
       "SecRule REQUEST_HEADERS:Content-Length \"!^0$\" \"id:1,phase:2,pass,t:trim,block\""
     ]
+  },
+  {
+    "enabled":1,
+    "version_min":300000,
+    "title":"Testing Operator :: @rx with non-compiling pattern",
+    "client":{
+      "ip":"200.249.12.31",
+      "port":123
+    },
+    "server":{
+      "ip":"200.249.12.31",
+      "port":80
+    },
+    "request":{
+      "headers":{
+        "Host":"localhost",
+        "User-Agent":"curl/7.38.0",
+        "Accept":"*/*",
+        "Content-Length": "27",
+        "Content-Type": "application/x-www-form-urlencoded"
+      },
+      "uri":"/",
+      "method":"HEAD",
+      "body": [ ]
+    },
+    "response":{
+      "headers":{
+        "Date":"Mon, 13 Jul 2015 20:02:41 GMT",
+        "Last-Modified":"Sun, 26 Oct 2014 22:33:37 GMT",
+        "Content-Type":"text/html"
+      },
+      "body":[
+        "no need."
+      ]
+    },
+    "expected":{
+      "debug_log":"Error with regular expression"
+    },
+    "rules":[
+      "SecRuleEngine On",
+      "SecRule REQUEST_HEADERS:Content-Type \"@rx a(b\" \"id:1,phase:2,pass,t:trim,block\""
+    ]
   }
 ]