From 07d2b1a005b7875b268af736349246b9d6421059 Mon Sep 17 00:00:00 2001
From: Rayson Zhu <vfreex+github@gmail.com>
Date: Sun, 13 Nov 2016 23:32:43 -0600
Subject: [PATCH] exit when running as a nonexistent user and warn when running
 as root

---
 src/local.c   | 7 +++++--
 src/manager.c | 9 ++++++---
 src/redir.c   | 7 +++++--
 src/server.c  | 7 +++++--
 src/tunnel.c  | 7 +++++--
 5 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/src/local.c b/src/local.c
index 8066d47f..e8faceac 100644
--- a/src/local.c
+++ b/src/local.c
@@ -1440,8 +1440,11 @@ main(int argc, char **argv)
         LOGI("listening at %s:%s", local_addr, local_port);
 
     // setuid
-    if (user != NULL) {
-        run_as(user);
+    if (user != NULL && ! run_as(user)) {
+        FATAL("failed to switch user");
+    }
+    if (geteuid() == 0){
+        LOGI("You are running this process as the root user!");
     }
 
     // Init connections
diff --git a/src/manager.c b/src/manager.c
index 7ef7459c..78bca1f4 100644
--- a/src/manager.c
+++ b/src/manager.c
@@ -845,11 +845,14 @@ main(int argc, char **argv)
     struct ev_loop *loop = EV_DEFAULT;
 
     // setuid
-    if (user != NULL) {
-        run_as(user);
+    if (user != NULL && ! run_as(user)) {
+        FATAL("failed to switch user");
+    }
+    if (geteuid() == 0){
+        LOGI("You are running this process as the root user!");
     }
 
-    struct passwd *pw   = getpwuid(getuid());
+    struct passwd *pw   = getpwuid(geteuid());
     const char *homedir = pw->pw_dir;
     working_dir_size = strlen(homedir) + 15;
     working_dir      = malloc(working_dir_size);
diff --git a/src/redir.c b/src/redir.c
index 8daeb2f2..5880c936 100644
--- a/src/redir.c
+++ b/src/redir.c
@@ -1021,8 +1021,11 @@ main(int argc, char **argv)
     LOGI("listening at %s:%s", local_addr, local_port);
 
     // setuid
-    if (user != NULL) {
-        run_as(user);
+    if (user != NULL && ! run_as(user)) {
+        FATAL("failed to switch user");
+    }
+    if (geteuid() == 0){
+        LOGI("You are running this process as the root user!");
     }
 
     ev_run(loop, 0);
diff --git a/src/server.c b/src/server.c
index 0569d68a..3f1b4e1a 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1871,8 +1871,11 @@ main(int argc, char **argv)
     ev_timer_start(EV_DEFAULT, &block_list_watcher);
 
     // setuid
-    if (user != NULL) {
-        run_as(user);
+    if (user != NULL && ! run_as(user)) {
+        FATAL("failed to switch user");
+    }
+    if (geteuid() == 0){
+        LOGI("You are running this process as the root user!");
     }
 
     // init block list
diff --git a/src/tunnel.c b/src/tunnel.c
index 4ddfe0b6..0bfe2ec0 100644
--- a/src/tunnel.c
+++ b/src/tunnel.c
@@ -1028,8 +1028,11 @@ main(int argc, char **argv)
     LOGI("listening at %s:%s", local_addr, local_port);
 
     // setuid
-    if (user != NULL) {
-        run_as(user);
+    if (user != NULL && ! run_as(user)) {
+        FATAL("failed to switch user");
+    }
+    if (geteuid() == 0){
+        LOGI("You are running this process as the root user!");
     }
 
     ev_run(loop, 0);