Auto sudoers file (#269)

* added sudoers options to command line arguments

* added sudoers options to command line arguments

* template for sudoers file

* Added option for GUI sudo

* added support for GUI sudo

* script for auto adding sudo file

* sudoers auto add works and validates

* small change

* Clean up for CI

* removed code that belongs in another PR

* added path for package bins

* added sudoers bin

* added sudoers-add to setup file

* fixed issue with sudoers bash script

* auto sudoers now works

* added --sudoers-no-modify option

* bin now works with ./run

* removed debug print

* Updated sudoers-add script

* Fixed error passing sudoers config to script

* more dynamic building of sudoers file

* added option to specify sudoers.d file name

* fixed indent issue

* fixed indent issue

* indent issue

* clean up

* formating

* docs

* fix for flags

* Update usage.rst

* removed shell=true

* cleared CI errors

* cleared CI errors

* removed random

* cleared linter issue

* cleared linter issue

* cleared linter issue

* updated sudoers-add script

* safer temp file

* moved bin directory

* moved bin directory

* removed print

* fixed spacing issue

* sudoers commands must only containe upper case latters

9 files changed, 266 insertions, 0 deletions

diff --git a/bin/sudoers-add b/bin/sudoers-add
new file mode 100755
index 0000000..5bec3d1
--- /dev/null
+++ b/bin/sudoers-add
@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+# William Mantly <wmantly@gmail.com>
+# MIT License
+# https://github.com/wmantly/sudoers-add
+
+NEWLINE=$'\n'
+CONTENT=""
+ME="$(basename "$(test -L "$0" && readlink "$0" || echo "$0")")"
+
+if [ "$1" == "--help" ] || [ "$1" == "-h" ]; then
+	echo "Usage: $ME [file_path] [sudoers-file-name]"
+	echo "Usage: [content] | $ME sudoers-file-name"
+	echo "This will take a sudoers config validate it and add it to /etc/sudoers.d/{sudoers-file-name}"
+	echo "The config can come from a file, first usage example or piped in second example."
+
+	exit 0
+fi
+
+if [ "$1" == "" ]; then
+	(>&2 echo "This command take at lest one argument. See $ME --help")
+
+	exit 1	
+fi
+
+if [ "$2" == "" ]; then
+	FILE_NAME=$1
+	shift
+else
+	FILE_NAME=$2
+fi
+
+if [[ $EUID -ne 0 ]]; then
+	echo "This script must be run as root"
+
+	exit 1
+fi
+
+while read -r line
+do
+	CONTENT+="${line}${NEWLINE}"
+done < "${1:-/dev/stdin}"
+
+if [ "$CONTENT" == "" ]; then
+	(>&2 echo "No config content specified. See $ME --help")
+	exit 1
+fi
+
+if [ "$FILE_NAME" == "" ]; then
+	(>&2 echo "No sudoers file name specified. See $ME --help")
+	exit 1
+fi
+
+# Make a temp file to hold the sudoers config
+umask 077
+TEMP_FILE=$(mktemp)
+echo "$CONTENT" > "$TEMP_FILE"
+
+# Make sure the content is valid
+visudo_STDOUT=$(visudo -c -f "$TEMP_FILE" 2>&1)
+visudo_code=$?
+# The temp file is no longer needed
+rm "$TEMP_FILE"
+
+if [ $visudo_code -eq 0 ]; then
+	echo "$CONTENT" > "/etc/sudoers.d/$FILE_NAME"
+	chmod 0440 "/etc/sudoers.d/$FILE_NAME"
+	echo "The sudoers file /etc/sudoers.d/$FILE_NAME has been successfully created!"
+
+	exit 0
+else
+	echo "Invalid sudoers config!"
+	echo "$visudo_STDOUT"
+
+	exit 1
+fi
+
diff --git a/docs/installation.rst b/docs/installation.rst
index 5a28f6a..2adddf6 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -5,8 +5,18 @@ Installation
 
       pip install sshuttle
 
+- Debain package manager::
+		sudo apt install sshuttle
+
 - Clone::
 
       git clone https://github.com/sshuttle/sshuttle.git
       cd sshuttle
       ./setup.py install
+
+
+Optionally after installation
+-----------------------------
+
+- Add to sudoers file
+		sshuttle --sudoers
diff --git a/docs/manpage.rst b/docs/manpage.rst
index 5d09c25..34516ed 100644
--- a/docs/manpage.rst
+++ b/docs/manpage.rst
@@ -234,6 +234,29 @@ Options
     makes it a lot easier to debug and test the :option:`--auto-hosts`
     feature.
 
+.. option:: --sudoers
+
+    sshuttle will auto generate the proper sudoers.d config file and add it.
+    Once this is completed, sshuttle will exit and tell the user if
+    it succeed or not. Do not call this options with sudo, it may generate a
+    incorrect config file.
+
+.. option:: --sudoers-no-modify
+
+    sshuttle will auto generate the proper sudoers.d config and print it to
+    stdout. The option will not modify the system at all.
+
+.. option:: --sudoers-user
+
+    Set the user name or group with %group_name for passwordless operation.
+    Default is the current user.set ALL for all users. Only works with
+    --sudoers or --sudoers-no-modify option.
+
+--option:: --sudoers-filename
+
+    Set the file name for the sudoers.d file to be added. Default is
+    "sshuttle_auto". Only works with --sudoers.
+
 .. option:: --version
 
     Print program version.
diff --git a/docs/usage.rst b/docs/usage.rst
index d782a95..d1960c1 100644
--- a/docs/usage.rst
+++ b/docs/usage.rst
@@ -60,3 +60,46 @@ the data back and forth through ssh.
 Fun, right?  A poor man's instant VPN, and you don't even have to have
 admin access on the server.
 
+Sudoers File
+------------
+sshuttle can auto-generate the proper sudoers.d file using the current user 
+for Linux and OSX. Doing this will allow sshuttle to run without asking for
+the local sudo password and to give users who do not have sudo access
+ability to run sshuttle.
+
+  sshuttle --sudoers
+
+DO NOT run this command with sudo, it will ask for your sudo password when
+it is needed.
+
+A costume user or group can be set with the :
+option:`sshuttle --sudoers --sudoers-username {user_descriptor}` option. Valid
+values for this vary based on how your system is configured. Values such as 
+usernames, groups pre-pended with `%` and sudoers user aliases will work. See
+the sudoers manual for more information on valid user specif actions.
+The options must be used with `--sudoers`
+
+  sshuttle --sudoers --sudoers-user mike
+  sshuttle --sudoers --sudoers-user %sudo
+
+The name of the file to be added to sudoers.d can be configured as well. This
+is mostly not necessary but can be useful for giving more than one user
+access to sshuttle. The default is `sshuttle_auto`
+
+  sshuttle --sudoer --sudoers-filename sshuttle_auto_mike
+  sshuttle --sudoer --sudoers-filename sshuttle_auto_tommy
+
+You can also see what configuration will be added to your system without
+modifying anything. This can be helpfull is the auto feature does not work, or
+you want more control. This option also works with `--sudoers-username`.
+`--sudoers-filename` has no effect with this option.
+
+  sshuttle --sudoers-no-modify
+
+This will simply sprint the generated configuration to STDOUT. Example
+
+  08:40 PM william$ sshuttle --sudoers-no-modify
+
+  Cmnd_Alias SSHUTTLE304 = /usr/bin/env PYTHONPATH=/usr/local/lib/python2.7/dist-packages/sshuttle-0.78.5.dev30+gba5e6b5.d20180909-py2.7.egg /usr/bin/python /usr/local/bin/sshuttle --method auto --firewall
+
+  william ALL=NOPASSWD: SSHUTTLE304
diff --git a/run b/run
index c52932a..c2c1a33 100755
--- a/run
+++ b/run
@@ -1,6 +1,7 @@
 #!/usr/bin/env sh
 set -e
 export PYTHONPATH="$(dirname $0):$PYTHONPATH"
+export PATH="$(dirname $0)/bin:$PATH"
 
 python_best_version() {
   if [ -x "$(command -v python3)" ] &&
diff --git a/setup.py b/setup.py
index d5f3c7e..5d71237 100755
--- a/setup.py
+++ b/setup.py
@@ -52,6 +52,7 @@ setup(
         "Programming Language :: Python :: 3.5",
         "Topic :: System :: Networking",
     ],
+    scripts=['bin/sudoers-add'],
     entry_points={
         'console_scripts': [
             'sshuttle = sshuttle.cmdline:main',
diff --git a/sshuttle/cmdline.py b/sshuttle/cmdline.py
index 31a57bf..5f1ba10 100644
--- a/sshuttle/cmdline.py
+++ b/sshuttle/cmdline.py
@@ -1,5 +1,6 @@
 import re
 import socket
+import platform
 import sshuttle.helpers as helpers
 import sshuttle.client as client
 import sshuttle.firewall as firewall
@@ -7,11 +8,27 @@ import sshuttle.hostwatch as hostwatch
 import sshuttle.ssyslog as ssyslog
 from sshuttle.options import parser, parse_ipport
 from sshuttle.helpers import family_ip_tuple, log, Fatal
+from sshuttle.sudoers import sudoers
 
 
 def main():
     opt = parser.parse_args()
 
+    if opt.sudoers or opt.sudoers_no_modify:
+        if platform.platform().startswith('OpenBSD'):
+            log('Automatic sudoers does not work on BSD')
+            exit(1)
+
+        if not opt.sudoers_filename:
+            log('--sudoers-file must be set or omited.')
+            exit(1)
+
+        sudoers(
+            user_name=opt.sudoers_user,
+            no_modify=opt.sudoers_no_modify,
+            file_name=opt.sudoers_filename
+        )
+
     if opt.daemon:
         opt.syslog = 1
     if opt.wrap:
diff --git a/sshuttle/options.py b/sshuttle/options.py
index 62f3510..79c404b 100644
--- a/sshuttle/options.py
+++ b/sshuttle/options.py
@@ -322,6 +322,37 @@ parser.add_argument(
     """
 )
 parser.add_argument(
+    "--sudoers",
+    action="store_true",
+    help="""
+    Add sshuttle to the sudoers for this user
+    """
+)
+parser.add_argument(
+    "--sudoers-no-modify",
+    action="store_true",
+    help="""
+    Prints the sudoers config to STDOUT and DOES NOT modify anything.
+    """
+)
+parser.add_argument(
+    "--sudoers-user",
+    default="",
+    help="""
+    Set the user name or group with %%group_name for passwordless operation.
+    Default is the current user.set ALL for all users. Only works with
+    --sudoers or --sudoers-no-modify option.
+    """
+)
+parser.add_argument(
+    "--sudoers-filename",
+    default="sshuttle_auto",
+    help="""
+    Set the file name for the sudoers.d file to be added. Default is
+    "sshuttle_auto". Only works with --sudoers or --sudoers-no-modify option.
+    """
+)
+parser.add_argument(
     "--no-sudo-pythonpath",
     action="store_false",
     dest="sudo_pythonpath",
diff --git a/sshuttle/sudoers.py b/sshuttle/sudoers.py
new file mode 100644
index 0000000..3f01e8e
--- /dev/null
+++ b/sshuttle/sudoers.py
@@ -0,0 +1,64 @@
+import os
+import sys
+import getpass
+from uuid import uuid4
+from subprocess import Popen, PIPE
+from sshuttle.helpers import log, debug1
+from distutils import spawn
+
+path_to_sshuttle = sys.argv[0]
+path_to_dist_packages = os.path.dirname(os.path.abspath(__file__))[:-9]
+
+# randomize command alias to avoid collisions
+command_alias = 'SSHUTTLE%(num)s' % {'num': uuid4().hex[-3:].upper()}
+
+# Template for the sudoers file
+template = '''
+Cmnd_Alias %(ca)s = /usr/bin/env PYTHONPATH=%(dist_packages)s %(py)s %(path)s *
+
+%(user_name)s ALL=NOPASSWD: %(ca)s
+'''
+
+
+def build_config(user_name):
+    content = template % {
+        'ca': command_alias,
+        'dist_packages': path_to_dist_packages,
+        'py': sys.executable,
+        'path': path_to_sshuttle,
+        'user_name': user_name,
+    }
+
+    return content
+
+
+def save_config(content, file_name):
+    process = Popen([
+        '/usr/bin/sudo',
+        spawn.find_executable('sudoers-add'),
+        file_name,
+    ], stdout=PIPE, stdin=PIPE)
+
+    process.stdin.write(content.encode())
+
+    streamdata = process.communicate()[0]
+    returncode = process.returncode
+
+    if returncode:
+        log('Failed updating sudoers file.\n')
+        debug1(streamdata)
+        exit(returncode)
+    else:
+        log('Success, sudoers file update.\n')
+        exit(0)
+
+
+def sudoers(user_name=None, no_modify=None, file_name=None):
+    user_name = user_name or getpass.getuser()
+    content = build_config(user_name)
+
+    if no_modify:
+        sys.stdout.write(content)
+        exit(0)
+    else:
+        save_config(content, file_name)