Fix msc_who_am_i() to return pointer to a valid C string

Previously this function was unusable as it returned pointer
to some garbage data.

Author: defanator

headers/modsecurity/modsecurity.h

@@ -278,7 +278,7 @@ class ModSecurity {
     ModSecurity();
     ~ModSecurity();
 
-    static const std::string whoAmI();
+    const std::string& whoAmI();
     void setConnectorInformation(std::string connector);
     void setServerLogCb(ModSecLogCb cb);
     /**
@@ -304,6 +304,7 @@ class ModSecurity {
 
  private:
     std::string m_connector;
+    std::string m_whoami;
     ModSecLogCb m_logCb;
     int m_logProperties;
 };

src/modsecurity.cc

@@ -61,6 +61,7 @@ namespace modsecurity {
  */
 ModSecurity::ModSecurity()
     : m_connector(""),
+    m_whoami(""),
 #ifdef WITH_LMDB
     m_global_collection(new collection::backend::LMDB()),
     m_resource_collection(new collection::backend::LMDB()),
@@ -116,7 +117,7 @@ ModSecurity::~ModSecurity() {
  *       update it, make it in a fashion that won't break the existent parsers.
  *       (e.g. adding extra information _only_ to the end of the string)
  */
-const std::string ModSecurity::whoAmI() {
+const std::string& ModSecurity::whoAmI() {
     std::string platform("Unknown platform");
 
 #if AIX
@@ -139,8 +140,11 @@ const std::string ModSecurity::whoAmI() {
     platform = "Windows";
 #endif
 
-    return std::string("ModSecurity v" MODSECURITY_VERSION \
-        " (" + platform + ")");
+    if (m_whoami.empty()) {
+        m_whoami = "ModSecurity v" MODSECURITY_VERSION " (" + platform + ")";
+    }
+
+    return m_whoami;
 }