From a18444813b076433258b7e5598765a5b8c91f590 Mon Sep 17 00:00:00 2001
From: Teddy Reed <teddy@prosauce.org>
Date: Sat, 26 Mar 2016 21:52:22 -0700
Subject: [PATCH] [Fix #1971] Use recursive locks for config data predicates

---
 osquery/config/config.cpp | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/osquery/config/config.cpp b/osquery/config/config.cpp
index b9e52b46..8affe424 100644
--- a/osquery/config/config.cpp
+++ b/osquery/config/config.cpp
@@ -56,12 +56,17 @@ const std::string kExecutingQuery = "executing_query";
 const std::string kFailedQueries = "failed_queries";
 
 // The config may be accessed and updated asynchronously; use mutexes.
-Mutex config_schedule_mutex_;
-Mutex config_performance_mutex_;
-Mutex config_files_mutex_;
 Mutex config_hash_mutex_;
 Mutex config_valid_mutex_;
 
+using RecursiveMutex = std::recursive_mutex;
+using RecursiveLock = std::lock_guard<std::recursive_mutex>;
+
+/// Several config methods require enumeration via predicate lambdas.
+RecursiveMutex config_schedule_mutex_;
+RecursiveMutex config_files_mutex_;
+RecursiveMutex config_performance_mutex_;
+
 using PackRef = std::shared_ptr<Pack>;
 
 /**
@@ -218,7 +223,7 @@ Config::Config()
 void Config::addPack(const std::string& name,
                      const std::string& source,
                      const pt::ptree& tree) {
-  WriteLock wlock(config_schedule_mutex_);
+  RecursiveLock wlock(config_schedule_mutex_);
   try {
     schedule_->add(std::make_shared<Pack>(name, source, tree));
     if (schedule_->last()->shouldPackExecute()) {
@@ -230,19 +235,19 @@ void Config::addPack(const std::string& name,
 }
 
 void Config::removePack(const std::string& pack) {
-  WriteLock wlock(config_schedule_mutex_);
+  RecursiveLock wlock(config_schedule_mutex_);
   return schedule_->remove(pack);
 }
 
 void Config::addFile(const std::string& source,
                      const std::string& category,
                      const std::string& path) {
-  WriteLock wlock(config_files_mutex_);
+  RecursiveLock wlock(config_files_mutex_);
   files_[source][category].push_back(path);
 }
 
 void Config::removeFiles(const std::string& source) {
-  WriteLock wlock(config_files_mutex_);
+  RecursiveLock wlock(config_files_mutex_);
   if (files_.count(source)) {
     FileCategories().swap(files_[source]);
   }
@@ -251,7 +256,7 @@ void Config::removeFiles(const std::string& source) {
 void Config::scheduledQueries(
     std::function<void(const std::string& name, const ScheduledQuery& query)>
         predicate) {
-  WriteLock lock(config_schedule_mutex_);
+  RecursiveLock lock(config_schedule_mutex_);
   for (const PackRef& pack : *schedule_) {
     for (const auto& it : pack->getSchedule()) {
       std::string name = it.first;
@@ -279,7 +284,7 @@ void Config::scheduledQueries(
 }
 
 void Config::packs(std::function<void(PackRef& pack)> predicate) {
-  WriteLock lock(config_schedule_mutex_);
+  RecursiveLock lock(config_schedule_mutex_);
   for (PackRef& pack : schedule_->packs_) {
     predicate(pack);
   }
@@ -532,7 +537,7 @@ void Config::purge() {
     return false;
   };
 
-  WriteLock lock(config_schedule_mutex_);
+  RecursiveLock lock(config_schedule_mutex_);
   // Iterate over each result set in the database.
   for (const auto& saved_query : saved_queries) {
     if (queryExists(saved_query)) {
@@ -585,7 +590,7 @@ void Config::recordQueryPerformance(const std::string& name,
                                     size_t size,
                                     const Row& r0,
                                     const Row& r1) {
-  WriteLock lock(config_performance_mutex_);
+  RecursiveLock lock(config_performance_mutex_);
   if (performance_.count(name) == 0) {
     performance_[name] = QueryPerformance();
   }
@@ -643,7 +648,7 @@ void Config::getPerformanceStats(
     const std::string& name,
     std::function<void(const QueryPerformance& query)> predicate) {
   if (performance_.count(name) > 0) {
-    WriteLock lock(config_performance_mutex_);
+    RecursiveLock lock(config_performance_mutex_);
     predicate(performance_.at(name));
   }
 }
@@ -688,7 +693,7 @@ const std::shared_ptr<ConfigParserPlugin> Config::getParser(
 void Config::files(
     std::function<void(const std::string& category,
                        const std::vector<std::string>& files)> predicate) {
-  WriteLock lock(config_files_mutex_);
+  RecursiveLock lock(config_files_mutex_);
   for (const auto& it : files_) {
     for (const auto& category : it.second) {
       predicate(category.first, category.second);