stateless version

7 files changed, 403 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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index 0000000..02e0d9f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+__pycache__
+*swp
+*~
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,202 @@
+
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diff --git a/README.md b/README.md
new file mode 100644
index 0000000..be8421c
--- /dev/null
+++ b/README.md
@@ -0,0 +1,42 @@
+# apache-auth-xmppmessage
+
+Authenticate users using tokens sent via xmpp.
+
+This script is almost stateless, there is no database required.
+To protect against DoS it uses a lockfile, this way allowing only on
+instance at a time.
+
+## Install requirements
+
+    # pip
+    pip3 install --user -r sleekxmpp==1.3.1
+
+    # FreeBSD:
+    pkg install py34-sleekxmpp
+    pkg install ap24-mod_authnz_external24
+
+
+## Configuration
+
+    DefineExternalAuth xmpp-login pipe /usr/local/etc/apache24/login.py
+    <Location /foo>
+        AuthType Basic
+        AuthName "Login with Jabber ID and empty password to request a token"
+        AuthBasicProvider external
+        AuthExternalContext "validsec=7200;secret=adsasd;users=user1@jabber.org,user2@jabber.org;jid=bot@jabber.org;jid_pw=secret-xmpp-pw"
+        AuthExternal xmpp-login
+        Require valid-user
+    </Location>
+
+### Options
+
+- validsec: timespan in which a token is valid.
+  There are always 2 valid tokens, the current and the previous.
+  The current is `token(now % validsec)`. The previous is `token(now % validsec - validsec)`.
+  A token valid-range is determined by `% validsec` and NOT by the time the token was requested.
+- secret: random secret data. Used as a salt for the token.
+- users: comma separated list of JIDs that are allowed to receive tokens.
+  Tokens are user-specific. User `A` cannot use the token from user `B`.
+- jid: JID of the bot who sends the tokens to the users.
+- jid\_pw: password of the bot.
+
diff --git a/demo.sh b/demo.sh
new file mode 100755
index 0000000..67cb4dc
--- /dev/null
+++ b/demo.sh
@@ -0,0 +1,22 @@
+#!/bin/sh
+# Usage:
+# - No arguments: Request a token
+# - With arguments: Verify a token
+export IP=1.2.3.4
+export URI=/test
+export HTTP_HOST=www.example.com;
+export CONTEXT="validsec=60;secret=asdsad;users=yvesf@xapek.org,marc@xapek.org;jid=___;jid_pw=___"
+export SKIP_XMPP=1
+
+if [ -z "$1" ]; then # request token
+    (
+        echo "yvesf@xapek.org"
+        echo ""
+    ) | ./login.py
+else # verify token
+    (
+        echo "yvesf@xapek.org"
+        echo "$1"
+    ) | ./login.py
+    echo "Result $?"
+fi
diff --git a/login-freebsd.sh b/login-freebsd.sh
new file mode 100755
index 0000000..f943eec
--- /dev/null
+++ b/login-freebsd.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+dir="`dirname \"$0\"`"
+/usr/local/bin/python3.4 "$dir/"login.py $*
diff --git a/login.py b/login.py
new file mode 100755
index 0000000..584398c
--- /dev/null
+++ b/login.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python3.4
+import os
+import re
+import sys
+import time
+import struct
+import hashlib
+
+# To speed up start time load some modules only as needed
+
+if sys.version_info < (3, 0):
+    raise Exception("Require python3+")
+
+
+def file_lock(lock_file):
+    from contextlib import contextmanager
+
+    @contextmanager
+    def file_lock():
+        try:
+            with open(lock_file, "x") as fh:
+                try:
+                    yield
+                except:
+                    raise
+                finally:
+                    fh.close()
+                    os.remove(lock_file)
+        except FileExistsError:
+            raise Exception("Locking failed on {}".format(lock_file))
+    return file_lock()
+
+
+def send_message(jid, password, recipient, message):
+    import sleekxmpp
+
+    def start(event):
+        cl.send_message(mto=recipient, mtype='chat', mbody=message)
+        cl.disconnect(wait=True)
+
+    cl = sleekxmpp.ClientXMPP(jid, password)
+    cl.add_event_handler("session_start", start, threaded=True)
+    if cl.connect():
+        cl.process(block=True)
+    else:
+        raise Exception("Unable to connect to xmpp server")
+
+
+def generate_token(username, secret, time):
+    input = "{}{}{}".format(secret, username, time).encode('utf-8')
+    output = struct.unpack(b"<L", hashlib.md5(input).digest()[:4])[0]
+    token = "{:02X}-{:02X}-{:02X}".format(
+            (output >> 16) & 0xff, (output >> 8) & 0xff, output & 0xff)
+    return token
+
+
+def token_message(username, secret, validsec):
+    time_now = int(time.time())
+    time_now_start = int(time_now - time_now % validsec)
+    time_next_end = time_now_start + 2 * validsec
+    token = generate_token(username, secret, time_now_start)
+    message = "Username: {} Token: {}".format(username, token)
+    message += "\nValid from: {} to: {}".format(
+        time.strftime("%c %Z(%z)", time.gmtime(time_now_start)),
+        time.strftime("%c %Z(%z)", time.gmtime(time_next_end)))
+    message += "\nRequested by: {} for: {} on: {}".format(
+        os.getenv("IP"), ascii(os.getenv("URI")), os.getenv("HTTP_HOST"))
+    return message
+
+
+def normalize_token(token):
+    return re.sub(r"[^A-F0-9]", "", token.upper())
+
+
+def run(config):
+    conf_users = config['users'].split(',')
+    conf_secret = config['secret']
+    conf_validsec = int(config['validsec'])
+    conf_jid = config['jid']
+    conf_jid_pw = config['jid_pw']
+
+    # reading the credential supplied in a pipe from apache
+    username = sys.stdin.readline().strip()
+    password = sys.stdin.readline().strip()
+
+    if password == "" and username in conf_users:
+        # avoid spamming by allowing only one message sent at a time
+        lockfile = os.path.basename(__file__)
+        with file_lock("/tmp/lock." + lockfile):
+            message = token_message(username, conf_secret, conf_validsec)
+            if os.getenv("SKIP_XMPP"):  # used for testing
+                print(message)
+            else:
+                send_message(conf_jid, conf_jid_pw, username, message)
+    elif username in conf_users:
+        time_now = int(time.time())
+        time_now_start = int(time_now - time_now % conf_validsec)
+        time_prev_start = time_now_start - conf_validsec
+        valid_tokens = list(map(normalize_token, (
+            generate_token(username, conf_secret, time_now_start),
+            generate_token(username, conf_secret, time_prev_start)
+        )))
+        if normalize_token(password) in valid_tokens:
+            return os.EX_OK  # grant access
+
+    return os.EX_NOPERM  # fail by default
+
+if __name__ == "__main__":
+    config = dict(map(lambda kv: kv.split("="),
+                      os.getenv("CONTEXT").split(";")))
+    sys.exit(run(config))
diff --git a/login_test.py b/login_test.py
new file mode 100755
index 0000000..4557de8
--- /dev/null
+++ b/login_test.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+import unittest
+import login
+
+
+class TestStringMethods(unittest.TestCase):
+    def test_normalize(self):
+        self.assertEqual(login.normalize_token("A4-B4-C5"),
+            "A4B4C5")
+        self.assertEqual(login.normalize_token("a4-b4-c5"),
+            "A4B4C5")
+        self.assertEqual(login.normalize_token("a4b4c5"),
+            "A4B4C5")
+        self.assertEqual(login.normalize_token("A4B4C5"),
+            "A4B4C5")
+
+
+if __name__ == '__main__':
+    unittest.main()
+