Allow configuration and specification of id attribute name

The id attribute name is used by xmlsec1 to find the correct attribute in the
given element that contains the id of the node that will be signed.

Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com>

2 files changed, 31 insertions, 14 deletions

diff --git a/src/saml2/config.py b/src/saml2/config.py
index 2631d51d..8f90afc8 100644
--- a/src/saml2/config.py
+++ b/src/saml2/config.py
@@ -66,6 +66,7 @@ COMMON_ARGS = [
     "extensions",
     "allow_unknown_attributes",
     "crypto_backend",
+    "id_attr_name",
 ]
 
 SP_ARGS = [
@@ -221,6 +222,7 @@ class Config(object):
         self.name_qualifier = ""
         self.entity_category = ""
         self.crypto_backend = 'xmlsec1'
+        self.id_attr_name = None
         self.scope = ""
         self.allow_unknown_attributes = False
         self.extension_schema = {}
diff --git a/src/saml2/sigver.py b/src/saml2/sigver.py
index 918a23cb..576993be 100644
--- a/src/saml2/sigver.py
+++ b/src/saml2/sigver.py
@@ -205,7 +205,6 @@ def _get_xmlsec_cryptobackend(path=None, search_paths=None):
     return CryptoBackendXmlSec1(path)
 
 
-ID_ATTR = 'ID'
 NODE_NAME = 'urn:oasis:names:tc:SAML:2.0:assertion:Assertion'
 ENC_NODE_NAME = 'urn:oasis:names:tc:SAML:2.0:assertion:EncryptedAssertion'
 ENC_KEY_CLASS = 'EncryptedKey'
@@ -653,7 +652,7 @@ class CryptoBackend(object):
     def encrypt_assertion(self, statement, enc_key, template, key_type, node_xpath):
         raise NotImplementedError()
 
-    def decrypt(self, enctext, key_file):
+    def decrypt(self, enctext, key_file, id_attr):
         raise NotImplementedError()
 
     def sign_statement(self, statement, node_name, key_file, node_id, id_attr):
@@ -779,7 +778,7 @@ class CryptoBackendXmlSec1(CryptoBackend):
 
         return output.decode()
 
-    def decrypt(self, enctext, key_file):
+    def decrypt(self, enctext, key_file, id_attr):
         """
 
         :param enctext: XML document containing an encrypted part
@@ -794,7 +793,7 @@ class CryptoBackendXmlSec1(CryptoBackend):
             self.xmlsec,
             '--decrypt',
             '--privkey-pem', key_file,
-            '--id-attr:{id_attr}'.format(id_attr=ID_ATTR),
+            '--id-attr:{id_attr}'.format(id_attr=id_attr),
             ENC_KEY_CLASS,
         ]
 
@@ -1011,6 +1010,11 @@ def security_context(conf):
     except AttributeError:
         metadata = None
 
+    try:
+        id_attr = conf.id_attr_name
+    except AttributeError:
+        id_attr = None
+
     sec_backend = None
 
     if conf.crypto_backend == 'xmlsec1':
@@ -1069,7 +1073,8 @@ def security_context(conf):
             validate_certificate=conf.validate_certificate,
             enc_key_files=enc_key_files,
             encryption_keypairs=conf.encryption_keypairs,
-            sec_backend=sec_backend)
+            sec_backend=sec_backend,
+            id_attr=id_attr)
 
 
 def encrypt_cert_from_item(item):
@@ -1239,6 +1244,7 @@ class CertHandler(object):
 # openssl x509 -inform pem -noout -in server.crt -pubkey > publickey.pem
 # openssl rsa -inform pem -noout -in publickey.pem -pubin -modulus
 class SecurityContext(object):
+    DEFAULT_ID_ATTR_NAME = 'ID'
     my_cert = None
 
     def __init__(
@@ -1257,7 +1263,10 @@ class SecurityContext(object):
             enc_key_files=None, enc_key_type='pem',
             encryption_keypairs=None,
             enc_cert_type='pem',
-            sec_backend=None):
+            sec_backend=None,
+            id_attr=''):
+
+        self.id_attr = id_attr or SecurityContext.DEFAULT_ID_ATTR_NAME
 
         self.crypto = crypto
         assert (isinstance(self.crypto, CryptoBackend))
@@ -1348,7 +1357,7 @@ class SecurityContext(object):
         return self.crypto.encrypt_assertion(
                 statement, enc_key, template, key_type, node_xpath)
 
-    def decrypt_keys(self, enctext, keys=None):
+    def decrypt_keys(self, enctext, keys=None, id_attr=''):
         """ Decrypting an encrypted text by the use of a private key.
 
         :param enctext: The encrypted text as a string
@@ -1356,12 +1365,15 @@ class SecurityContext(object):
         """
         _enctext = None
 
+        if not id_attr:
+            id_attr = self.id_attr
+
         if not isinstance(keys, list):
             keys = [keys]
 
         if self.enc_key_files is not None:
             for _enc_key_file in self.enc_key_files:
-                _enctext = self.crypto.decrypt(enctext, _enc_key_file)
+                _enctext = self.crypto.decrypt(enctext, _enc_key_file, id_attr)
                 if _enctext is not None and len(_enctext) > 0:
                     return _enctext
 
@@ -1370,13 +1382,13 @@ class SecurityContext(object):
                 if not isinstance(_key, six.binary_type):
                     _key = str(_key).encode('ascii')
                 _, key_file = make_temp(_key, decode=False)
-                _enctext = self.crypto.decrypt(enctext, key_file)
+                _enctext = self.crypto.decrypt(enctext, key_file, id_attr)
                 if _enctext is not None and len(_enctext) > 0:
                     return _enctext
 
         return enctext
 
-    def decrypt(self, enctext, key_file=None):
+    def decrypt(self, enctext, key_file=None, id_attr=''):
         """ Decrypting an encrypted text by the use of a private key.
 
         :param enctext: The encrypted text as a string
@@ -1384,14 +1396,17 @@ class SecurityContext(object):
         """
         _enctext = None
 
+        if not id_attr:
+            id_attr = self.id_attr
+
         if self.enc_key_files is not None:
             for _enc_key_file in self.enc_key_files:
-                _enctext = self.crypto.decrypt(enctext, _enc_key_file)
+                _enctext = self.crypto.decrypt(enctext, _enc_key_file, id_attr)
                 if _enctext is not None and len(_enctext) > 0:
                     return _enctext
 
         if key_file is not None and len(key_file.strip()) > 0:
-            _enctext = self.crypto.decrypt(enctext, key_file)
+            _enctext = self.crypto.decrypt(enctext, key_file, id_attr)
             if _enctext is not None and len(_enctext) > 0:
                 return _enctext
 
@@ -1415,7 +1430,7 @@ class SecurityContext(object):
             cert_type = self.cert_type
 
         if not id_attr:
-            id_attr = ID_ATTR
+            id_attr = self.id_attr
 
         return self.crypto.validate_signature(
                 signedtext,
@@ -1650,7 +1665,7 @@ class SecurityContext(object):
         :return: The signed statement
         """
         if not id_attr:
-            id_attr = ID_ATTR
+            id_attr = self.id_attr
 
         if not key_file and key:
             _, key_file = make_temp(str(key).encode(), '.pem')