From d02f6fa48457f329bb7066073663112f8c50e325 Mon Sep 17 00:00:00 2001
From: "B. Blechschmidt" <github@blechschmidt.pw>
Date: Wed, 4 Apr 2018 14:28:10 +0200
Subject: [PATCH] Fix termination, use nogroup

---
 flow.h    |  6 +++++-
 main.c    | 11 +++++------
 massdns.h |  1 +
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/flow.h b/flow.h
index 1d3ca02..7659bfc 100644
--- a/flow.h
+++ b/flow.h
@@ -17,6 +17,7 @@ static void kill_process_group(int sig)
     }
     received_termination = 1;
     kill(0, sig);
+    exit(0);
 }
 
 static void handle_termination()
@@ -47,7 +48,10 @@ size_t split_process(size_t times)
                 break;
         }
     }
-    handle_termination();
+    if(times > 1)
+    {
+        handle_termination();
+    }
     return 0;
 }
 
diff --git a/main.c b/main.c
index 214c7b5..fa7798c 100644
--- a/main.c
+++ b/main.c
@@ -37,11 +37,10 @@ void print_help()
                     "Usage: %s [options] [domainlist]\n"
                     "  -b  --bindto           Bind to IP address and port. (Default: 0.0.0.0:0)\n"
 #ifdef HAVE_EPOLL
-                    "      --busy-poll        Increase performance using busy polling instead of epoll.\n"
+                    "      --busy-poll        Use busy-wait polling instead of epoll.\n"
 #endif
                     "  -c  --resolve-count    Number of resolves for a name before giving up. (Default: 50)\n"
-                    "      --drop-group       Group to drop privileges to when running as root. If unspecified,\n"
-                    "                         privileges will be dropped to the group as specified by --drop-user\n"
+                    "      --drop-group       Group to drop privileges to when running as root. (Default: nogroup)\n"
                     "      --drop-user        User to drop privileges to when running as root. (Default: nobody)\n"
                     "      --flush            Flush the output file whenever a response was received.\n"
                     "  -h  --help             Show this help.\n"
@@ -1231,12 +1230,12 @@ void privilege_drop()
         return;
     }
     char *username = context.cmd_args.drop_user ? context.cmd_args.drop_user : COMMON_UNPRIVILEGED_USER;
-    char *groupname = context.cmd_args.drop_group ? context.cmd_args.drop_group : username;
+    char *groupname = context.cmd_args.drop_group ? context.cmd_args.drop_group : COMMON_UNPRIVILEGED_GROUP;
     if(!context.cmd_args.root)
     {
         struct passwd *drop_user = getpwnam(username);
         struct group *drop_group = getgrnam(groupname);
-        if (drop_group && drop_user && setgid(drop_group->gr_gid) && setuid(drop_user->pw_uid) == 0)
+        if (drop_group && drop_user && setgid(drop_group->gr_gid) == 0 && setuid(drop_user->pw_uid) == 0)
         {
             if (!context.cmd_args.quiet)
             {
@@ -1246,7 +1245,7 @@ void privilege_drop()
         else
         {
             log_msg("Privileges could not be dropped to \"%s:%s\".\n"
-                "For security reasons, this program will only run as root user when supplied with --root"
+                "For security reasons, this program will only run as root user when supplied with --root, "
                 "which is not recommended.\n"
                 "It is better practice to run this program as a different user.\n", username, groupname);
             clean_exit(EXIT_FAILURE);
diff --git a/massdns.h b/massdns.h
index 3e8d739..9fbd3d0 100644
--- a/massdns.h
+++ b/massdns.h
@@ -23,6 +23,7 @@
 
 #define MAXIMUM_MODULE_COUNT 0xFF
 #define COMMON_UNPRIVILEGED_USER "nobody"
+#define COMMON_UNPRIVILEGED_GROUP "nogroup"
 
 const uint32_t OUTPUT_BINARY_VERSION = 0x00;