droping privileges is now possible without chroot

added groupname command line option

6 files changed, 106 insertions, 62 deletions

diff --git a/cmd-option-letters b/cmd-option-letters
index e9ad440..841a06d 100644
--- a/cmd-option-letters
+++ b/cmd-option-letters
@@ -4,7 +4,7 @@ c: cipher
 d: device name
 e:
 f: input file
-g:
+g: unix group
 h: print help text
 i: local interface
 j:
@@ -18,7 +18,7 @@ q:
 r: remote host
 s: sender id
 t: device type
-u: username when chroot
+u: unix username
 v:
 w: window size
 x: post up script
@@ -27,18 +27,18 @@ z:
 
 A: master salt
 B:
-C: run in chroot
+C: chroot directory
 D: do not daemonize
 E: passphrase
 F:
 G:
-H: chroot direcotry
+H: 
 I: local sync interface
 J:
 K: master key
 L:
 M: remote sync hosts
-N:
+N: 
 O:
 P: write pid file
 Q:
diff --git a/src/anytun-controld.cpp b/src/anytun-controld.cpp
index c73abbd..cff0932 100644
--- a/src/anytun-controld.cpp
+++ b/src/anytun-controld.cpp
@@ -120,12 +120,13 @@ int main(int argc, char* argv[])
     std::ifstream file( gOpt.getFileName().c_str() );
     if( file.is_open() )
       file.close();
-    else
-    {
+    else {
       std::cout << "ERROR: unable to open file!" << std::endl;
       exit(-1);
     }
     
+    PrivInfo privs(gOpt.getUsername(), gOpt.getGroupname());
+
     std::ofstream pidFile;
     if(gOpt.getPidFile() != "") {
       pidFile.open(gOpt.getPidFile().c_str());
@@ -134,10 +135,12 @@ int main(int argc, char* argv[])
       }
     }
     
-    if(gOpt.getChroot())
-      chrootAndDrop(gOpt.getChrootDir(), gOpt.getUsername());
-    if(gOpt.getDaemonize())
-    {
+    if(gOpt.getChrootDir() != "")
+      do_chroot(gOpt.getChrootDir());
+    
+    privs.drop();
+
+    if(gOpt.getDaemonize()) {
       daemonize();
       daemonized = true;
     }
diff --git a/src/anytun.cpp b/src/anytun.cpp
index 19c4587..8f6a0c9 100644
--- a/src/anytun.cpp
+++ b/src/anytun.cpp
@@ -346,6 +346,8 @@ int main(int argc, char* argv[])
     }
 
 #ifndef NO_DAEMON
+    PrivInfo privs(gOpt.getUsername(), gOpt.getGroupname());
+
     std::ofstream pidFile;
     if(gOpt.getPidFile() != "") {
       pidFile.open(gOpt.getPidFile().c_str());
@@ -412,10 +414,12 @@ int main(int argc, char* argv[])
 		}
 #endif
 #ifndef NO_DAEMON
-    if(gOpt.getChroot())
-      chrootAndDrop(gOpt.getChrootDir(), gOpt.getUsername());
-    if(gOpt.getDaemonize())
-    {
+    if(gOpt.getChrootDir() != "")
+      do_chroot(gOpt.getChrootDir());
+
+    privs.drop();
+
+    if(gOpt.getDaemonize()) {
       daemonize();
       daemonized = true;
     }
diff --git a/src/daemon.hpp b/src/daemon.hpp
index 0bcd7f3..cc95337 100644
--- a/src/daemon.hpp
+++ b/src/daemon.hpp
@@ -33,6 +33,8 @@
 #define _DAEMON_HPP
 #ifndef NO_DAEMON
 
+#include <sstream>
+
 #include <poll.h>
 #include <fcntl.h>
 #include <pwd.h>
@@ -41,39 +43,76 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-void chrootAndDrop(std::string const& chrootdir, std::string const& username)
+#include "log.h"
+
+class PrivInfo
 {
-  if (getuid() != 0)
+public:
+  PrivInfo(std::string const& username, std::string const& groupname)
   {
-    std::cerr << "this programm has to be run as root in order to run in a chroot" << std::endl;
-    exit(-1);
+    pw_ = NULL;
+    gr_ = NULL;
+    
+    if(username == "")
+      return;
+
+    pw_ = getpwnam(username.c_str());
+    if(!pw_)
+      throw std::runtime_error("unkown user " + username);
+    
+    if(groupname != "")
+      gr_ = getgrnam(groupname.c_str());
+    else
+      gr_ = getgrgid(pw_->pw_gid);
+    
+    if(!gr_)
+      throw std::runtime_error("unkown group " + groupname);
   }
 
-  struct passwd *pw = getpwnam(username.c_str());
-  if(pw) {
-    if(chroot(chrootdir.c_str()))
-    {
-      std::cerr << "can't chroot to " << chrootdir << std::endl;
-      exit(-1);
+  void drop()
+  {
+    if(!pw_ || !gr_)
+      return;
+
+    if(setgid(gr_->gr_gid)) {
+      std::stringstream msg;
+      msg << "setgid('" << gr_->gr_name << "') failed: " << LogErrno(errno);
+      throw std::runtime_error(msg.str());
     }
-    cLog.msg(Log::PRIO_NOTICE) << "we are in chroot jail (" << chrootdir << ") now" << std::endl;
-    if(chdir("/"))
-    {
-      std::cerr << "can't change to /" << std::endl;
-      exit(-1);
+    
+    gid_t gr_list[1];
+    gr_list[0] = gr_->gr_gid;
+    if(setgroups (1, gr_list)) {
+      std::stringstream msg;
+      msg << "setgroups(['" << gr_->gr_name << "']) failed: " << LogErrno(errno);
+      throw std::runtime_error(msg.str());
     }
-    if (initgroups(pw->pw_name, pw->pw_gid) || setgid(pw->pw_gid) || setuid(pw->pw_uid))
-    {
-      std::cerr << "can't drop to user " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
-      exit(-1);
+    
+    if(setuid(pw_->pw_uid)) {
+      std::stringstream msg;
+      msg << "setuid('" << pw_->pw_name << "') failed: " << LogErrno(errno);
+      throw std::runtime_error(msg.str());
     }
-    cLog.msg(Log::PRIO_NOTICE) << "dropped user to " << username << " " << pw->pw_uid << ":" << pw->pw_gid << std::endl;
-  }
-  else
-  {
-    std::cerr << "unknown user " << username << std::endl;
-    exit(-1);
+    
+    cLog.msg(Log::PRIO_NOTICE) << "dropped privileges to " << pw_->pw_name << ":" << gr_->gr_name;
   }
+
+private:
+  struct passwd* pw_;
+  struct group* gr_;
+};
+
+void do_chroot(std::string const& chrootdir)
+{
+  if (getuid() != 0)
+    throw std::runtime_error("this programm has to be run as root in order to run in a chroot");
+
+  if(chroot(chrootdir.c_str()))
+    throw std::runtime_error("can't chroot to " + chrootdir);
+
+  cLog.msg(Log::PRIO_NOTICE) << "we are in chroot jail (" << chrootdir << ") now" << std::endl;
+  if(chdir("/"))
+    throw std::runtime_error("can't change to /");
 }
 
 void daemonize()
diff --git a/src/options.cpp b/src/options.cpp
index ba49711..690630b 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -142,18 +142,16 @@ Options::Options() : key_(u_int32_t(0)), salt_(u_int32_t(0))
 {
 #if defined(ANYCTR_OPTIONS)
   progname_ = "anytun-controld";
-  chroot_dir_ = "/var/run/anytun-controld";
 #elif defined(ANYCONF_OPTIONS)
   progname_ = "anytun-config";
-  chroot_dir_ = "/var/run/anytun-config";
 #else
   progname_ = "anytun";
-  chroot_dir_ = "/var/run/anytun";
 #endif
 
   daemonize_ = true;
-  chroot_ = false;
-  username_ = "nobody";
+  username_ = "";
+  groupname_ = "";
+  chroot_dir_ = "";
   pid_file_ = "";
 
   file_name_ = "";
@@ -324,9 +322,9 @@ bool Options::parse(int argc, char* argv[])
 
   #ifndef NO_DAEMON
     PARSE_INVERSE_BOOL_PARAM("-D","--nodaemonize", daemonize_)
-    PARSE_BOOL_PARAM("-C","--chroot", chroot_)
     PARSE_SCALAR_PARAM("-u","--username", username_)
-    PARSE_SCALAR_PARAM("-H","--chroot-dir", chroot_dir_)
+    PARSE_SCALAR_PARAM("-g","--groupname", groupname_)
+    PARSE_SCALAR_PARAM("-C","--chroot-dir", chroot_dir_)
     PARSE_SCALAR_PARAM("-P","--write-pid", pid_file_)
   #endif
 
@@ -427,9 +425,9 @@ void Options::printUsage()
 
  #ifndef NO_DAEMON
   std::cout << "   [-D|--nodaemonize]                  don't run in background" << std::endl;
-  std::cout << "   [-C|--chroot]                       chroot and drop privileges" << std::endl;
-  std::cout << "   [-u|--username] <username>          if chroot change to this user" << std::endl;
-  std::cout << "   [-H|--chroot-dir] <path>            chroot to this directory" << std::endl;
+  std::cout << "   [-u|--username] <username>          change to this user" << std::endl;
+  std::cout << "   [-g|--groupname] <groupname>        change to this group" << std::endl;
+  std::cout << "   [-C|--chroot-dir] <path>            chroot to this directory" << std::endl;
   std::cout << "   [-P|--write-pid] <path>             write pid to this file" << std::endl;
  #endif
 
@@ -509,8 +507,8 @@ void Options::printOptions()
   std::cout << "Options:" << std::endl;
   std::cout << std::endl;
   std::cout << "daemonize = " << daemonize_ << std::endl;
-  std::cout << "chroot = " << chroot_ << std::endl;
   std::cout << "username = '" << username_ << "'" << std::endl;
+  std::cout << "groupname = '" << groupname_ << "'" << std::endl;
   std::cout << "chroot_dir = '" << chroot_dir_ << "'" << std::endl;
   std::cout << "pid_file = '" << pid_file_ << "'" << std::endl;
   std::cout << std::endl;
@@ -580,29 +578,29 @@ Options& Options::setDaemonize(bool d)
   return *this;
 }
 
-bool Options::getChroot()
+std::string Options::getUsername()
 {
   ReadersLock lock(mutex);
-  return chroot_;
+  return username_;
 }
 
-Options& Options::setChroot(bool c)
+Options& Options::setUsername(std::string u)
 {
   WritersLock lock(mutex);
-  chroot_ = c;
+  username_ = u;
   return *this;
 }
 
-std::string Options::getUsername()
+std::string Options::getGroupname()
 {
   ReadersLock lock(mutex);
-  return username_;
+  return groupname_;
 }
 
-Options& Options::setUsername(std::string u)
+Options& Options::setGroupname(std::string g)
 {
   WritersLock lock(mutex);
-  username_ = u;
+  groupname_ = g;
   return *this;
 }
 
diff --git a/src/options.h b/src/options.h
index 694526e..e24655f 100644
--- a/src/options.h
+++ b/src/options.h
@@ -88,10 +88,10 @@ public:
   Options& setProgname(std::string p);
   bool getDaemonize();
   Options& setDaemonize(bool d);
-  bool getChroot();
-  Options& setChroot(bool b);
   std::string getUsername();
   Options& setUsername(std::string u);
+  std::string getGroupname();
+  Options& setGroupname(std::string g);
   std::string getChrootDir();
   Options& setChrootDir(std::string c);
   std::string getPidFile();
@@ -174,8 +174,8 @@ private:
 
   std::string progname_;
   bool daemonize_;
-  bool chroot_;
   std::string username_;
+  std::string groupname_;
   std::string chroot_dir_;
   std::string pid_file_;