More changes to swich from regexes to patterns.

Change falco_engine::enable_rule to use substring matches instead of
regex pattern matches. Only substrings were actually used in practice
outside of tests and regex matches weren't even working, due to
regex_match() not working properly with the default compiler we
use. This is noted on the c++11 compatibility notes for gcc 4.8.2:
https://gcc.gnu.org/onlinedocs/gcc-4.8.2/libstdc++/manual/manual/status.html#status.iso.2011.

test/falco_test.py

@@ -268,7 +268,7 @@ class FalcoTest(Test):
         triggered_rules = match.group(1)
 
         for rule, count in self.detect_counts.iteritems():
-            expected = '\s{}: (\d+)'.format(rule)
+            expected = '\s{}: (\d+)'.format(re.sub(r'([$\.*+?()[\]{}|^])', r'\\\1', rule))
             match = re.search(expected, triggered_rules)
 
             if match is None:

test/falco_tests.yaml

@@ -86,6 +86,15 @@ trace_files: !mux
       - rules/rule_names_with_spaces.yaml
     trace_file: trace_files/cat_write.scap
 
+  rule_names_with_regex_chars:
+    detect: True
+    detect_level: WARNING
+    rules_file:
+      - rules/rule_names_with_regex_chars.yaml
+    detect_counts:
+      - 'Open From Cat ($\.*+?()[]{}|^)': 8
+    trace_file: trace_files/cat_write.scap
+
   multiple_rules_first_empty:
     detect: True
     detect_level: WARNING
@@ -447,13 +456,13 @@ trace_files: !mux
       - open_from_cat
     trace_file: trace_files/cat_write.scap
 
-  disabled_rules_using_regex:
+  disabled_rules_using_substring:
     detect: False
     rules_file:
       - rules/empty_rules.yaml
       - rules/single_rule.yaml
     disabled_rules:
-      - "open.*"
+      - "open_from"
     trace_file: trace_files/cat_write.scap
 
   disabled_rules_using_enabled_flag:

test/rules/rule_names_with_regex_chars.yaml

@@ -0,0 +1,25 @@
+#
+# Copyright (C) 2016-2018 Draios Inc dba Sysdig.
+#
+# This file is part of falco.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+- macro: is_cat
+  condition: proc.name=cat
+
+- rule: Open From Cat ($\.*+?()[]{}|^)
+  desc: A process named cat does an open
+  condition: evt.type=open and is_cat
+  output: "An open was seen (command=%proc.cmdline)"
+  priority: WARNING

userspace/engine/falco_engine.cpp

@@ -206,17 +206,17 @@ void falco_engine::load_rules_file(const string &rules_filename, bool verbose, b
 	load_rules(rules_content, verbose, all_events, required_engine_version);
 }
 
-void falco_engine::enable_rule(const string &pattern, bool enabled, const string &ruleset)
+void falco_engine::enable_rule(const string &substring, bool enabled, const string &ruleset)
 {
 	uint16_t ruleset_id = find_ruleset_id(ruleset);
 
-	m_sinsp_rules->enable(pattern, enabled, ruleset_id);
+	m_sinsp_rules->enable(substring, enabled, ruleset_id);
-	m_k8s_audit_rules->enable(pattern, enabled, ruleset_id);
+	m_k8s_audit_rules->enable(substring, enabled, ruleset_id);
 }
 
-void falco_engine::enable_rule(const string &pattern, bool enabled)
+void falco_engine::enable_rule(const string &substring, bool enabled)
 {
-	enable_rule(pattern, enabled, m_default_ruleset);
+	enable_rule(substring, enabled, m_default_ruleset);
 }
 
 void falco_engine::enable_rule_by_tag(const set<string> &tags, bool enabled, const string &ruleset)

userspace/engine/falco_engine.h

@@ -76,16 +76,17 @@ public:
 	void load_rules(const std::string &rules_content, bool verbose, bool all_events, uint64_t &required_engine_version);
 
 	//
-	// Enable/Disable any rules matching the provided pattern
+	// Enable/Disable any rules matching the provided substring.
-	// (regex). When provided, enable/disable these rules in the
+	// If the substring is "", all rules are enabled/disabled.
+	// When provided, enable/disable these rules in the
 	// context of the provided ruleset. The ruleset (id) can later
 	// be passed as an argument to process_event(). This allows
 	// for different sets of rules being active at once.
 	//
-	void enable_rule(const std::string &pattern, bool enabled, const std::string &ruleset);
+	void enable_rule(const std::string &substring, bool enabled, const std::string &ruleset);
 
 	// Wrapper that assumes the default ruleset
-	void enable_rule(const std::string &pattern, bool enabled);
+	void enable_rule(const std::string &substring, bool enabled);
 
 	//
 	// Enable/Disable any rules with any of the provided tags (set, exact matches only)

userspace/engine/rules.cpp

@@ -17,6 +17,7 @@ limitations under the License.
 
 */
 
+
 #include "rules.h"
 #include "logger.h"
 

userspace/engine/ruleset.cpp

@@ -202,19 +202,8 @@ void falco_ruleset::add(string &name,
 	}
 }
 
-void falco_ruleset::enable(const string &pattern, bool enabled, uint16_t ruleset)
+void falco_ruleset::enable(const string &substring, bool enabled, uint16_t ruleset)
 {
-	regex re;
-	bool match_using_regex = true;
-
-	try {
-		re.assign(pattern);
-	}
-	catch (std::regex_error e)
-	{
-		match_using_regex = false;
-	}
-
 	while (m_rulesets.size() < (size_t) ruleset + 1)
 	{
 		m_rulesets.push_back(new ruleset_filters());
@@ -223,14 +212,9 @@ void falco_ruleset::enable(const string &pattern, bool enabled, uint16_t ruleset
 	for(const auto &val : m_filters)
 	{
 		bool matches;
-		if(match_using_regex)
+
-		{
+		matches = (substring == "" || (val.first.find(substring) != string::npos));
-			matches = regex_match(val.first, re);
+
-		}
-		else
-		{
-			matches = (val.first.find(pattern) != string::npos);
-		}
 		if (matches)
 		{
 			if(enabled)

userspace/engine/ruleset.h

@@ -24,7 +24,6 @@ limitations under the License.
 #include <vector>
 #include <list>
 #include <map>
-#include <regex>
 
 #include "sinsp.h"
 #include "filter.h"
@@ -48,9 +47,9 @@ public:
         // specifying unnecessarily large rulesets will result in
         // unnecessarily large vectors.
 
-	// Find those rules matching the provided pattern and set
+	// Find those rules matching the provided substring and set
 	// their enabled status to enabled.
-	void enable(const std::string &pattern, bool enabled, uint16_t ruleset = 0);
+	void enable(const std::string &substring, bool enabled, uint16_t ruleset = 0);
 
 	// Find those rules that have a tag in the set of tags and set
 	// their enabled status to enabled. Note that the enabled

userspace/falco/falco.cpp

@@ -87,7 +87,7 @@ static void usage()
 	   " --cri <path>                  Path to CRI socket for container metadata\n"
 	   "                               Use the specified socket to fetch data from a CRI-compatible runtime\n"
 	   " -d, --daemon                  Run as a daemon\n"
-	   " -D <pattern>                  Disable any rules matching the regex <pattern>. Can be specified multiple times.\n"
+	   " -D <substring>                Disable any rules with names having the substring <substring>. Can be specified multiple times.\n"
 	   "                               Can not be specified with -t.\n"
 	   " -e <events_file>              Read the events from <events_file> (in .scap format for sinsp events, or jsonl for\n"
 	   "                               k8s audit events) instead of tapping into live.\n"
@@ -471,9 +471,9 @@ int falco_init(int argc, char **argv)
 
 	try
 	{
-		set<string> disabled_rule_patterns;
+		set<string> disabled_rule_substrings;
-		string pattern;
+		string substring;
-		string all_rules = ".*";
+		string all_rules = "";
 		set<string> disabled_rule_tags;
 		set<string> enabled_rule_tags;
 
@@ -502,8 +502,8 @@ int falco_init(int argc, char **argv)
 				daemon = true;
 				break;
 			case 'D':
-				pattern = optarg;
+				substring = optarg;
-				disabled_rule_patterns.insert(pattern);
+				disabled_rule_substrings.insert(substring);
 				break;
 			case 'e':
 				trace_filename = optarg;
@@ -781,15 +781,15 @@ int falco_init(int argc, char **argv)
 		}
 
 		// You can't both disable and enable rules
-		if((disabled_rule_patterns.size() + disabled_rule_tags.size() > 0) &&
+		if((disabled_rule_substrings.size() + disabled_rule_tags.size() > 0) &&
 		    enabled_rule_tags.size() > 0) {
 			throw std::invalid_argument("You can not specify both disabled (-D/-T) and enabled (-t) rules");
 		}
 
-		for (auto pattern : disabled_rule_patterns)
+		for (auto substring : disabled_rule_substrings)
 		{
-			falco_logger::log(LOG_INFO, "Disabling rules matching pattern: " + pattern + "\n");
+			falco_logger::log(LOG_INFO, "Disabling rules matching substring: " + substring + "\n");
-			engine->enable_rule(pattern, false);
+			engine->enable_rule(substring, false);
 		}
 
 		if(disabled_rule_tags.size() > 0)