Eliminate non-thread-safe calls to localtime

localtime uses an internal static storage to which a pointer is given as return value.
Due to this it is not safe to call localtime from multiple threads since the same static storage is used.

Use localtime_r instead which allows to pass in a tm struct.

Fixes:
https://github.com/ZoneMinder/zoneminder/security/code-scanning/24
https://github.com/ZoneMinder/zoneminder/security/code-scanning/25
https://github.com/ZoneMinder/zoneminder/security/code-scanning/26
https://github.com/ZoneMinder/zoneminder/security/code-scanning/27
https://github.com/ZoneMinder/zoneminder/security/code-scanning/28
https://github.com/ZoneMinder/zoneminder/security/code-scanning/30
https://github.com/ZoneMinder/zoneminder/security/code-scanning/31
https://github.com/ZoneMinder/zoneminder/security/code-scanning/33
https://github.com/ZoneMinder/zoneminder/security/code-scanning/58
https://github.com/ZoneMinder/zoneminder/security/code-scanning/59
https://github.com/ZoneMinder/zoneminder/security/code-scanning/63
https://github.com/ZoneMinder/zoneminder/security/code-scanning/64
https://github.com/ZoneMinder/zoneminder/security/code-scanning/65

src/zm_event.cpp

@@ -71,8 +71,8 @@ Event::Event(
   std::string notes;
   createNotes(notes);
 
-  struct timeval now;
+  timeval now = {};
-  gettimeofday(&now, 0);
+  gettimeofday(&now, nullptr);
 
   if ( !start_time.tv_sec ) {
     Warning("Event has zero time, setting to now");
@@ -80,12 +80,12 @@ Event::Event(
   } else if ( start_time.tv_sec > now.tv_sec ) {
     char buffer[26];
     char buffer_now[26];
-    struct tm* tm_info;
+    tm tm_info = {};
 
-    tm_info = localtime(&start_time.tv_sec);
+    localtime_r(&start_time.tv_sec, &tm_info);
-    strftime(buffer, 26, "%Y:%m:%d %H:%M:%S", tm_info);
+    strftime(buffer, 26, "%Y:%m:%d %H:%M:%S", &tm_info);
-    tm_info = localtime(&now.tv_sec);
+    localtime_r(&now.tv_sec, &tm_info);
-    strftime(buffer_now, 26, "%Y:%m:%d %H:%M:%S", tm_info);
+    strftime(buffer_now, 26, "%Y:%m:%d %H:%M:%S", &tm_info);
 
     Error(
         "StartDateTime in the future starttime %u.%u >? now %u.%u difference %d\n%s\n%s",
@@ -661,16 +661,17 @@ bool Event::SetPath(Storage *storage) {
     return false;
   }
 
-  struct tm *stime = localtime(&start_time.tv_sec);
+  tm stime = {};
+  localtime_r(&start_time.tv_sec, &stime);
   if ( scheme == Storage::DEEP ) {
 
     int dt_parts[6];
-    dt_parts[0] = stime->tm_year-100;
+    dt_parts[0] = stime.tm_year-100;
-    dt_parts[1] = stime->tm_mon+1;
+    dt_parts[1] = stime.tm_mon+1;
-    dt_parts[2] = stime->tm_mday;
+    dt_parts[2] = stime.tm_mday;
-    dt_parts[3] = stime->tm_hour;
+    dt_parts[3] = stime.tm_hour;
-    dt_parts[4] = stime->tm_min;
+    dt_parts[4] = stime.tm_min;
-    dt_parts[5] = stime->tm_sec;
+    dt_parts[5] = stime.tm_sec;
 
     std::string date_path;
     std::string time_path;
@@ -685,7 +686,7 @@ bool Event::SetPath(Storage *storage) {
       if ( i == 2 )
 				date_path = path;
     }
-		time_path = stringtf("%02d/%02d/%02d", stime->tm_hour, stime->tm_min, stime->tm_sec);
+		time_path = stringtf("%02d/%02d/%02d", stime.tm_hour, stime.tm_min, stime.tm_sec);
 
     // Create event id symlink
     std::string id_file = stringtf("%s/.%" PRIu64, date_path.c_str(), id);
@@ -695,7 +696,7 @@ bool Event::SetPath(Storage *storage) {
     }
   } else if ( scheme == Storage::MEDIUM ) {
     path += stringtf("/%04d-%02d-%02d",
-        stime->tm_year+1900, stime->tm_mon+1, stime->tm_mday
+        stime.tm_year+1900, stime.tm_mon+1, stime.tm_mday
         );
     if ( mkdir(path.c_str(), 0755) and ( errno != EEXIST ) ) {
       Error("Can't mkdir %s: %s", path.c_str(), strerror(errno));

src/zm_event.h

@@ -138,18 +138,20 @@ class Event {
     bool SetPath(Storage *storage);
 
  public:
-    static const char *getSubPath(struct tm *time) {
+    static const char *getSubPath(tm time) {
       static char subpath[PATH_MAX] = "";
       snprintf(subpath, sizeof(subpath), "%02d/%02d/%02d/%02d/%02d/%02d",
-          time->tm_year-100, time->tm_mon+1, time->tm_mday,
+          time.tm_year-100, time.tm_mon+1, time.tm_mday,
-          time->tm_hour, time->tm_min, time->tm_sec);
+          time.tm_hour, time.tm_min, time.tm_sec);
       return subpath;
     }
     static const char *getSubPath(time_t *time) {
-      return Event::getSubPath(localtime(time));
+      tm time_tm = {};
+      localtime_r(time, &time_tm);
+      return Event::getSubPath(time_tm);
     }
 
-    const char* getEventFile(void) const {
+    const char* getEventFile() const {
       return video_file.c_str();
     }
 

src/zm_eventstream.cpp

@@ -171,33 +171,35 @@ bool EventStream::loadEventData(uint64_t event_id) {
   const char *storage_path = storage->Path();
 
   if ( event_data->scheme == Storage::DEEP ) {
-    struct tm *event_time = localtime(&event_data->start_time);
+    tm event_time = {};
+    localtime_r(&event_data->start_time, &event_time);
 
     if ( storage_path[0] == '/' )
       snprintf(event_data->path, sizeof(event_data->path),
           "%s/%u/%02d/%02d/%02d/%02d/%02d/%02d",
           storage_path, event_data->monitor_id,
-          event_time->tm_year-100, event_time->tm_mon+1, event_time->tm_mday,
+          event_time.tm_year-100, event_time.tm_mon+1, event_time.tm_mday,
-          event_time->tm_hour, event_time->tm_min, event_time->tm_sec);
+          event_time.tm_hour, event_time.tm_min, event_time.tm_sec);
     else
       snprintf(event_data->path, sizeof(event_data->path),
           "%s/%s/%u/%02d/%02d/%02d/%02d/%02d/%02d",
           staticConfig.PATH_WEB.c_str(), storage_path, event_data->monitor_id,
-          event_time->tm_year-100, event_time->tm_mon+1, event_time->tm_mday,
+          event_time.tm_year-100, event_time.tm_mon+1, event_time.tm_mday,
-          event_time->tm_hour, event_time->tm_min, event_time->tm_sec);
+          event_time.tm_hour, event_time.tm_min, event_time.tm_sec);
   } else if ( event_data->scheme == Storage::MEDIUM ) {
-    struct tm *event_time = localtime(&event_data->start_time);
+    tm event_time = {};
+    localtime_r(&event_data->start_time, &event_time);
     if ( storage_path[0] == '/' )
       snprintf(event_data->path, sizeof(event_data->path),
           "%s/%u/%04d-%02d-%02d/%" PRIu64,
           storage_path, event_data->monitor_id,
-          event_time->tm_year+1900, event_time->tm_mon+1, event_time->tm_mday,
+          event_time.tm_year+1900, event_time.tm_mon+1, event_time.tm_mday,
           event_data->event_id);
     else
       snprintf(event_data->path, sizeof(event_data->path),
           "%s/%s/%u/%04d-%02d-%02d/%" PRIu64,
           staticConfig.PATH_WEB.c_str(), storage_path, event_data->monitor_id,
-          event_time->tm_year+1900, event_time->tm_mon+1, event_time->tm_mday,
+          event_time.tm_year+1900, event_time.tm_mon+1, event_time.tm_mday,
           event_data->event_id);
 
   } else {

src/zm_image.cpp

@@ -1186,7 +1186,8 @@ cinfo->out_color_space = JCS_RGB;
 
     // This is a lot of stuff to allocate on the stack.  Recommend char *timebuf[64];
     char timebuf[64], msbuf[64];
-    strftime(timebuf, sizeof timebuf, "%Y:%m:%d %H:%M:%S", localtime(&(timestamp.tv_sec)));
+    tm timestamp_tm = {};
+    strftime(timebuf, sizeof timebuf, "%Y:%m:%d %H:%M:%S", localtime_r(&timestamp.tv_sec, &timestamp_tm));
     snprintf(msbuf, sizeof msbuf, "%06d",(int)(timestamp.tv_usec));  // we only use milliseconds because that's all defined in exif, but this is the whole microseconds because we have it
     unsigned char exiftimes[82] = {
       0x45, 0x78, 0x69, 0x66, 0x00, 0x00, 0x49, 0x49, 0x2A, 0x00, 0x08, 0x00, 0x00, 0x00, 0x01, 0x00,
@@ -2132,7 +2133,8 @@ void Image::Annotate(
 
 void Image::Timestamp( const char *label, const time_t when, const Coord &coord, const int size ) {
   char time_text[64];
-  strftime(time_text, sizeof(time_text), "%y/%m/%d %H:%M:%S", localtime(&when));
+  tm when_tm = {};
+  strftime(time_text, sizeof(time_text), "%y/%m/%d %H:%M:%S", localtime_r(&when, &when_tm));
   if ( label ) {
     // Assume label is max 64, + ' - ' + 64 chars of time_text
     char text[132];

src/zm_logger.cpp

@@ -447,7 +447,8 @@ void Logger::logPrint(bool hex, const char * const filepath, const int line, con
   } else {
 #endif
     char *timePtr = timeString;
-    timePtr += strftime(timePtr, sizeof(timeString), "%x %H:%M:%S", localtime(&timeVal.tv_sec));
+    tm now_tm = {};
+    timePtr += strftime(timePtr, sizeof(timeString), "%x %H:%M:%S", localtime_r(&timeVal.tv_sec, &now_tm));
     snprintf(timePtr, sizeof(timeString)-(timePtr-timeString), ".%06ld", timeVal.tv_usec);
 #if 0
   }

src/zm_monitor.cpp

@@ -2842,7 +2842,8 @@ void Monitor::TimestampImage(Image *ts_image, const struct timeval *ts_time) con
 
   // Expand the strftime macros first
   char label_time_text[256];
-  strftime(label_time_text, sizeof(label_time_text), label_format, localtime(&ts_time->tv_sec));
+  tm ts_tm = {};
+  strftime(label_time_text, sizeof(label_time_text), label_format, localtime_r(&ts_time->tv_sec, &ts_tm));
   char label_text[1024];
   const char *s_ptr = label_time_text;
   char *d_ptr = label_text;

src/zm_user.cpp

@@ -245,18 +245,19 @@ User *zmLoadAuthUser(const char *auth, bool use_remote_addr) {
     const char *pass = dbrow[2];
 
     time_t our_now = now;
+    tm now_tm = {};
     for ( unsigned int i = 0; i < hours; i++, our_now -= 3600 ) {
-      struct tm *now_tm = localtime(&our_now);
+      localtime_r(&our_now, &now_tm);
 
       snprintf(auth_key, sizeof(auth_key)-1, "%s%s%s%s%d%d%d%d",
         config.auth_hash_secret,
         user,
         pass,
         remote_addr,
-        now_tm->tm_hour,
+        now_tm.tm_hour,
-        now_tm->tm_mday,
+        now_tm.tm_mday,
-        now_tm->tm_mon,
+        now_tm.tm_mon,
-        now_tm->tm_year);
+        now_tm.tm_year);
 
 #if HAVE_DECL_MD5
       MD5((unsigned char *)auth_key, strlen(auth_key), md5sum);

src/zmu.cpp

@@ -506,8 +506,10 @@ int main(int argc, char *argv[]) {
       struct timeval timestamp = monitor->GetTimestamp(image_idx);
       if ( verbose ) {
         char timestamp_str[64] = "None";
-        if ( timestamp.tv_sec )
+        if ( timestamp.tv_sec ) {
-          strftime(timestamp_str, sizeof(timestamp_str), "%Y-%m-%d %H:%M:%S", localtime(&timestamp.tv_sec));
+          tm tm_info = {};
+          strftime(timestamp_str, sizeof(timestamp_str), "%Y-%m-%d %H:%M:%S", localtime_r(&timestamp.tv_sec, &tm_info));
+        }
         if ( image_idx == -1 )
           printf("Time of last image capture: %s.%02ld\n", timestamp_str, timestamp.tv_usec/10000);
         else