File atftp-drop_privileges_non-daemon.patch of Package atftp

Index: atftp-0.7/tftpd.c
===================================================================
--- atftp-0.7.orig/tftpd.c	2016-12-06 13:41:15.955496990 +0100
+++ atftp-0.7/tftpd.c	2016-12-06 14:55:23.573139906 +0100
@@ -95,8 +95,8 @@ int deny_severity = LOG_NOTICE;
 #endif
 
 /* user ID and group ID when running as a daemon */
-char user_name[MAXLEN] = "nobody";
-char group_name[MAXLEN] = "nogroup";
+char user_name[MAXLEN] = "tftp";
+char group_name[MAXLEN] = "tftp";
 
 /* For special uses, disable source port checking */
 int source_port_checking = 1;
@@ -274,33 +274,47 @@ int main(int argc, char **argv)
           dup2(sockfd, 0);
           close(sockfd);
 
-          /* release priviliedge */
-          user = getpwnam(user_name);
-          group = getgrnam(group_name);
-          if (!user || !group)
-          {
-               logger(LOG_ERR,
-                      "atftpd: can't change identity to %s.%s, exiting.",
-                      user_name, group_name);
-               exit(1);
-          }
+     }
 
-          /* write our pid in the specified file before changing user*/
-          if (pidfile)
-          {
-               if (tftpd_pid_file(pidfile, 1) != OK)
-                    exit(1);
-               /* to be able to remove it later */
-               chown(pidfile, user->pw_uid, group->gr_gid);
-          }
+     /* release privilege */
+     user = getpwnam(user_name);
+     group = getgrnam(group_name);
+     if (!user || !group)
+     {
+          logger(LOG_ERR,
+                 "atftpd: can't change identity to %s.%s, exiting.",
+                 user_name, group_name);
+          exit(1);
+     }
 
-          setgid(group->gr_gid);
-          setuid(user->pw_uid);
+     /* write our pid in the specified file before changing user*/
+     if (pidfile)
+     {
+          if (tftpd_pid_file(pidfile, 1) != OK)
+               exit(1);
+          /* to be able to remove it later */
+          chown(pidfile, user->pw_uid, group->gr_gid);
+     }
 
-          /* Reopen log file now that we changed user, and that we've
-           * open and dup2 the socket. */
-          open_logger("atftpd", log_file, logging_level);
+     if(setgid(group->gr_gid))
+     {
+          logger(LOG_ERR, "atftpd: can't switch group to %s, exiting.", group_name);
+          exit(1);
+     }
+     if (setgroups(0, NULL))
+     {
+          logger(LOG_ERR, "atftpd: can't clear supplementary group list");
+          exit(1);
      }
+     if(setuid(user->pw_uid))
+     {
+          logger(LOG_ERR, "atftpd: can't switch user to %s, exiting.", user_name);
+          exit(1);
+     }
+
+     /* Reopen log file now that we changed user, and that we've
+      * open and dup2 the socket. */
+     open_logger("atftpd", log_file, logging_level);
 
      /* We need to retieve some information from incomming packets */
      if (setsockopt(0, SOL_IP, IP_PKTINFO, &one, sizeof(one)) != 0)