Add support for RFC 7508 (#102)

1 files changed, 90 insertions, 0 deletions

diff --git a/pyasn1_modules/rfc7508.py b/pyasn1_modules/rfc7508.py
new file mode 100644
index 0000000..6646024
--- /dev/null
+++ b/pyasn1_modules/rfc7508.py
@@ -0,0 +1,90 @@
+#
+# This file is part of pyasn1-modules software.
+#
+# Created by Russ Housley with assistance from asn1ate v.0.6.0.
+#
+# Copyright (c) 2019, Vigil Security, LLC
+# License: http://snmplabs.com/pyasn1/license.html
+#
+# Securing Header Fields with S/MIME
+#
+# ASN.1 source from:
+# https://www.rfc-editor.org/rfc/rfc7508.txt
+# https://www.rfc-editor.org/errata/eid5875
+#
+
+from pyasn1.type import char
+from pyasn1.type import constraint
+from pyasn1.type import namedtype
+from pyasn1.type import namedval
+from pyasn1.type import univ
+
+from pyasn1_modules import rfc5652
+
+import string
+
+MAX = float('inf')
+
+
+class Algorithm(univ.Enumerated):
+    namedValues = namedval.NamedValues(
+        ('canonAlgorithmSimple', 0),
+        ('canonAlgorithmRelaxed', 1)
+    )
+
+
+class HeaderFieldStatus(univ.Integer):
+    namedValues = namedval.NamedValues(
+        ('duplicated', 0),
+        ('deleted', 1),
+        ('modified', 2)
+    )
+
+
+class HeaderFieldName(char.VisibleString):
+    subtypeSpec = (
+        constraint.PermittedAlphabetConstraint(*string.printable) -
+        constraint.PermittedAlphabetConstraint(':')
+    )
+
+
+class HeaderFieldValue(char.UTF8String):
+    pass
+
+
+class HeaderField(univ.Sequence):
+    componentType = namedtype.NamedTypes(
+        namedtype.NamedType('field-Name', HeaderFieldName()),
+        namedtype.NamedType('field-Value', HeaderFieldValue()),
+        namedtype.DefaultedNamedType('field-Status',
+            HeaderFieldStatus().subtype(value='duplicated'))
+    )
+
+
+class HeaderFields(univ.SequenceOf):
+    componentType = HeaderField()
+    subtypeSpec = constraint.ValueSizeConstraint(1, MAX)
+
+
+class SecureHeaderFields(univ.Set):
+    componentType = namedtype.NamedTypes(
+        namedtype.NamedType('canonAlgorithm', Algorithm()),
+        namedtype.NamedType('secHeaderFields', HeaderFields())
+    )
+
+
+id_aa = univ.ObjectIdentifier((1, 2, 840, 113549, 1, 9, 16, 2, ))
+
+id_aa_secureHeaderFieldsIdentifier = id_aa + (55, )
+
+
+
+# Map of Attribute Type OIDs to Attributes added to the
+# ones that are in rfc5652.py
+
+_cmsAttributesMapUpdate = {
+    id_aa_secureHeaderFieldsIdentifier: SecureHeaderFields(),
+}
+
+rfc5652.cmsAttributesMap.update(_cmsAttributesMapUpdate)
+