- support signing XML-RPC methodResponses as well (for GetSliceTicket())

- gpg_sign() and gpg_verify() can now sign/verify string blobs
- gpg_sign() and gpg_verify() now support non-detached signatures (for
  GetSliceTicket())
- gpg_verify(): print errors if they happen

diff --git a/PLC/GPG.py b/PLC/GPG.py
index 1652b94..f351f27 100644 (file)
--- a/PLC/GPG.py
+++ b/PLC/GPG.py
@@ -7,11 +7,13 @@
 # Mark Huang <mlhuang@cs.princeton.edu>
 # Copyright (C) 2006 The Trustees of Princeton University
 #
-# $Id: GPG.py,v 1.3 2007/01/08 18:11:54 mlhuang Exp $
+# $Id: GPG.py,v 1.4 2007/01/10 20:18:52 mlhuang Exp $
 #
 
+import os
 import xmlrpclib
 import shutil
+from types import StringTypes
 from StringIO import StringIO
 from xml.dom import minidom
 from xml.dom.ext import Canonicalize
@@ -20,13 +22,14 @@ from tempfile import NamedTemporaryFile, mkdtemp
 
 from PLC.Faults import *
 
-def canonicalize(methodname, args):
+def canonicalize(args, methodname = None, methodresponse = False):
     """
-    Returns a canonicalized XML-RPC representation of the
-    specified method call.
+    Returns a canonicalized XML-RPC representation of the specified
+    method call (methodname != None) or response (methodresponse =
+    True).
     """
 
-    xml = xmlrpclib.dumps(args, methodname, encoding = 'utf-8', allow_none = 1)
+    xml = xmlrpclib.dumps(args, methodname, methodresponse, encoding = 'utf-8', allow_none = 1)
     dom = minidom.parseString(xml)
 
     # Canonicalize(), though it claims to, does not encode unicode
@@ -65,21 +68,40 @@ def gpg_export(keyring, armor = True):
 
     return export
 
-def gpg_sign(methodname, args, secret_keyring, keyring):
+def gpg_sign(args, secret_keyring, keyring, methodname = None, methodresponse = False, detach_sign = True):
     """
-    Signs the specified method call using the specified keyring files.
+    Signs the specified method call (methodname != None) or response
+    (methodresponse == True) using the specified GPG keyring files. If
+    args is not a tuple representing the arguments to the method call
+    or the method response value, then it should be a string
+    representing a generic message to sign (detach_sign == True) or
+    sign/encrypt (detach_sign == False) specified). Returns the
+    detached signature (detach_sign == True) or signed/encrypted
+    message (detach_sign == False).
     """
 
-    message = canonicalize(methodname, args)
+    # Accept either an opaque string blob or a Python tuple
+    if isinstance(args, StringTypes):
+        message = args
+    elif isinstance(args, tuple):
+        message = canonicalize(args, methodname, methodresponse)
 
+    # Use temporary trustdb
     homedir = mkdtemp()
-    p = Popen(["gpg", "--batch", "--no-tty",
-               "--homedir", homedir,
-               "--no-default-keyring",
-               "--secret-keyring", secret_keyring,
-               "--keyring", keyring,
-               "--detach-sign", "--armor"],
-              stdin = PIPE, stdout = PIPE, stderr = PIPE)
+
+    cmd = ["gpg", "--batch", "--no-tty",
+           "--homedir", homedir,
+           "--no-default-keyring",
+           "--secret-keyring", secret_keyring,
+           "--keyring", keyring,
+           "--armor"]
+
+    if detach_sign:
+        cmd.append("--detach-sign")
+    else:
+        cmd.append("--sign")
+
+    p = Popen(cmd, stdin = PIPE, stdout = PIPE, stderr = PIPE)
     p.stdin.write(message)
     p.stdin.close()
     signature = p.stdout.read()
@@ -94,40 +116,68 @@ def gpg_sign(methodname, args, secret_keyring, keyring):
 
     return signature
 
-def gpg_verify(methodname, args, signature, key):
+def gpg_verify(args, key, signature = None, methodname = None, methodresponse = False):
     """
-    Verifys the signature of the method call using the specified public
-    key material.
+    Verifies the signature of the specified method call (methodname !=
+    None) or response (methodresponse = True) using the specified
+    public key material. If args is not a tuple representing the
+    arguments to the method call or the method response value, then it
+    should be a string representing a generic message to verify (if
+    signature is specified) or verify/decrypt (if signature is not
+    specified).
     """
 
-    message = canonicalize(methodname, args)
+    # Accept either an opaque string blob or a Python tuple
+    if isinstance(args, StringTypes):
+        message = args
+    else:
+        message = canonicalize(args, methodname, methodresponse)
 
     # Write public key to temporary file
-    keyfile = NamedTemporaryFile(suffix = '.pub')
-    keyfile.write(key)
-    keyfile.flush()
+    if os.path.exists(key):
+        keyfile = None
+        keyfilename = key
+    else:
+        keyfile = NamedTemporaryFile(suffix = '.pub')
+        keyfile.write(key)
+        keyfile.flush()
+        keyfilename = keyfile.name
 
     # Import public key into temporary keyring
     homedir = mkdtemp()
-    call(["gpg", "--batch", "--no-tty", "--homedir", homedir, "--import", keyfile.name],
+    call(["gpg", "--batch", "--no-tty", "--homedir", homedir, "--import", keyfilename],
          stdin = PIPE, stdout = PIPE, stderr = PIPE)
 
-    # Write detached signature to temporary file
-    sigfile = NamedTemporaryFile()
-    sigfile.write(signature)
-    sigfile.flush()
-
-    # Verify signature
-    p = Popen(["gpg", "--batch", "--no-tty", "--homedir", homedir, "--verify", sigfile.name, "-"],
-              stdin = PIPE, stdout = PIPE, stderr = PIPE)
+    cmd = ["gpg", "--batch", "--no-tty",
+           "--homedir", homedir]
+
+    if signature is not None:
+        # Write detached signature to temporary file
+        sigfile = NamedTemporaryFile()
+        sigfile.write(signature)
+        sigfile.flush()
+        cmd += ["--verify", sigfile.name, "-"]
+    else:
+        # Implicit signature
+        sigfile = None
+        cmd.append("--decrypt")
+
+    p = Popen(cmd, stdin = PIPE, stdout = PIPE, stderr = PIPE)
     p.stdin.write(message)
     p.stdin.close()
+    if signature is None:
+        message = p.stdout.read()
+    err = p.stderr.read()
     rc = p.wait()
 
     # Clean up
-    sigfile.close()
     shutil.rmtree(homedir)
-    keyfile.close()
+    if sigfile:
+        sigfile.close()
+    if keyfile:
+        keyfile.close()
 
     if rc:
-        raise PLCAuthenticationFailure, "GPG verification failed with return code %d" % rc
+        raise PLCAuthenticationFailure, "GPG verification failed with return code %d: %s" % (rc, err)
+
+    return message