Merge GH #591

Change behavior of default key usage encoding, default now omits
the key usage unless the user set a value.

Fix allowed_usage which could produce incorrect results.

More X.509 tests

6 files changed, 83 insertions, 80 deletions

diff --git a/src/lib/cert/x509/key_constraint.cpp b/src/lib/cert/x509/key_constraint.cpp
index 24791b34a..a90af013c 100644
--- a/src/lib/cert/x509/key_constraint.cpp
+++ b/src/lib/cert/x509/key_constraint.cpp
@@ -1,69 +1,46 @@
 /*
 * KeyUsage
 * (C) 1999-2007 Jack Lloyd
+* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
 #include <botan/key_constraint.h>
 #include <botan/x509_key.h>
-#include <botan/ber_dec.h>
 
 namespace Botan {
 
-namespace BER {
-
-/*
-* Decode a BER encoded KeyUsage
-*/
-void decode(BER_Decoder& source, Key_Constraints& key_usage)
-   {
-   BER_Object obj = source.get_next_object();
-
-   if(obj.type_tag != BIT_STRING || obj.class_tag != UNIVERSAL)
-      throw BER_Bad_Tag("Bad tag for usage constraint",
-                        obj.type_tag, obj.class_tag);
-   if(obj.value.size() != 2 && obj.value.size() != 3)
-      throw BER_Decoding_Error("Bad size for BITSTRING in usage constraint");
-   if(obj.value[0] >= 8)
-      throw BER_Decoding_Error("Invalid unused bits in usage constraint");
-
-   const byte mask = (0xFF << obj.value[0]);
-   obj.value[obj.value.size()-1] &= mask;
-
-   u16bit usage = 0;
-   for(size_t j = 1; j != obj.value.size(); ++j)
-      usage = (obj.value[j] << 8) | usage;
-
-   key_usage = Key_Constraints(usage);
-   }
-
-}
-
 /*
-* Find the allowable key constraints
+* Make sure the given key constraints are permitted for the given key type
 */
-Key_Constraints find_constraints(const Public_Key& pub_key,
-                                 Key_Constraints limits)
+void verify_cert_constraints_valid_for_key_type(const Public_Key& pub_key,
+                                                      Key_Constraints constraints)
    {
    const std::string name = pub_key.algo_name();
 
-   size_t constraints = 0;
+   size_t permitted = 0;
 
    if(name == "DH" || name == "ECDH")
-      constraints |= KEY_AGREEMENT;
+      {
+      permitted |= KEY_AGREEMENT | ENCIPHER_ONLY | DECIPHER_ONLY;
+      }
 
    if(name == "RSA" || name == "ElGamal")
-      constraints |= KEY_ENCIPHERMENT | DATA_ENCIPHERMENT;
+      {
+      permitted |= KEY_ENCIPHERMENT | DATA_ENCIPHERMENT;
+      }
 
    if(name == "RSA" || name == "RW" || name == "NR" ||
-      name == "DSA" || name == "ECDSA")
-      constraints |= DIGITAL_SIGNATURE | NON_REPUDIATION;
-
-   if(limits)
-      constraints &= limits;
-
-   return Key_Constraints(constraints);
+      name == "DSA" || name == "ECDSA" || name == "ECGDSA" || name == "ECKCDSA")
+      {
+      permitted |= DIGITAL_SIGNATURE | NON_REPUDIATION | KEY_CERT_SIGN | CRL_SIGN;
+      }
+
+   if ( ( constraints & permitted ) != constraints )
+      {
+      throw Exception("Constraint not permitted for key type " + name);
+      }
    }
 
 }
diff --git a/src/lib/cert/x509/key_constraint.h b/src/lib/cert/x509/key_constraint.h
index 179e413b5..b67eb7010 100644
--- a/src/lib/cert/x509/key_constraint.h
+++ b/src/lib/cert/x509/key_constraint.h
@@ -1,6 +1,7 @@
 /*
 * Enumerations
 * (C) 1999-2007 Jack Lloyd
+* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -8,7 +9,7 @@
 #ifndef BOTAN_ENUMS_H__
 #define BOTAN_ENUMS_H__
 
-#include <botan/ber_dec.h>
+#include <botan/build.h>
 
 namespace Botan {
 
@@ -32,26 +33,13 @@ enum Key_Constraints {
 class Public_Key;
 
 /**
-* Create the key constraints for a specific public key.
-* @param pub_key the public key from which the basic set of
-* constraints to be placed in the return value is derived
-* @param limits additional limits that will be incorporated into the
-* return value
-* @return combination of key type specific constraints and
-* additional limits
+* Check that key constraints are permitted for a specific public key.
+* @param pub_key the public key on which the constraints shall be enforced on
+* @param constrains the constraints that shall be enforced on the key
+* @throw Exception if the given constraints are not permitted for this key
 */
-
-BOTAN_DLL Key_Constraints find_constraints(const Public_Key& pub_key,
-                                           Key_Constraints limits);
-
-/**
-* BER Decoding Function for key constraints
-*/
-namespace BER {
-
-void BOTAN_DLL decode(BER_Decoder&, Key_Constraints&);
-
-}
+BOTAN_DLL void verify_cert_constraints_valid_for_key_type(const Public_Key& pub_key,
+                                                                Key_Constraints constraints);
 
 }
 
diff --git a/src/lib/cert/x509/x509_ca.cpp b/src/lib/cert/x509/x509_ca.cpp
index 147fdd6ad..58c6676f4 100644
--- a/src/lib/cert/x509/x509_ca.cpp
+++ b/src/lib/cert/x509/x509_ca.cpp
@@ -52,11 +52,14 @@ X509_Certificate X509_CA::sign_request(const PKCS10_Request& req,
    {
    Key_Constraints constraints;
    if(req.is_CA())
+      {
       constraints = Key_Constraints(KEY_CERT_SIGN | CRL_SIGN);
+      }
    else
       {
       std::unique_ptr<Public_Key> key(req.subject_public_key());
-      constraints = find_constraints(*key, req.constraints());
+      verify_cert_constraints_valid_for_key_type(*key, req.constraints());
+      constraints = req.constraints();
       }
 
    Extensions extensions;
@@ -65,7 +68,10 @@ X509_Certificate X509_CA::sign_request(const PKCS10_Request& req,
       new Cert_Extension::Basic_Constraints(req.is_CA(), req.path_limit()),
       true);
 
-   extensions.add(new Cert_Extension::Key_Usage(constraints), true);
+   if(constraints != NO_CONSTRAINTS)
+      {
+      extensions.add(new Cert_Extension::Key_Usage(constraints), true);
+      }
 
    extensions.add(new Cert_Extension::Authority_Key_ID(m_cert.subject_key_id()));
    extensions.add(new Cert_Extension::Subject_Key_ID(req.raw_public_key()));
@@ -233,11 +239,17 @@ PK_Signer* choose_sig_format(const Private_Key& key,
 
    std::string padding;
    if(algo_name == "RSA")
+      {
       padding = "EMSA3";
-   else if(algo_name == "DSA" || algo_name == "ECDSA" )
+      }
+   else if(algo_name == "DSA" || algo_name == "ECDSA" || algo_name == "ECGDSA" || algo_name == "ECKCDSA")
+      {
       padding = "EMSA1";
+      }
    else
+      {
       throw Invalid_Argument("Unknown X.509 signing key type: " + algo_name);
+      }
 
    const Signature_Format format = (key.message_parts() > 1) ? DER_SEQUENCE : IEEE_1363;
 
diff --git a/src/lib/cert/x509/x509_ext.cpp b/src/lib/cert/x509/x509_ext.cpp
index 986254bc9..650c20d53 100644
--- a/src/lib/cert/x509/x509_ext.cpp
+++ b/src/lib/cert/x509/x509_ext.cpp
@@ -1,6 +1,7 @@
 /*
 * X.509 Certificate Extensions
 * (C) 1999-2010,2012 Jack Lloyd
+* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -293,7 +294,9 @@ void Key_Usage::decode_inner(const std::vector<byte>& in)
 
    u16bit usage = 0;
    for(size_t i = 1; i != obj.value.size(); ++i)
-      usage = (obj.value[i] << 8) | usage;
+      {
+      usage = (obj.value[i] << 8*(sizeof(usage)-i)) | usage;
+      }
 
    m_constraints = Key_Constraints(usage);
    }
@@ -818,13 +821,12 @@ std::vector<byte> Unknown_Critical_Extension::encode_inner() const
    throw Not_Implemented("Unknown_Critical_Extension encoding");
    }
 
-void Unknown_Critical_Extension::decode_inner(const std::vector<byte>& buf)
+void Unknown_Critical_Extension::decode_inner(const std::vector<byte>&)
    {
    }
 
-void Unknown_Critical_Extension::contents_to(Data_Store& info, Data_Store&) const
+void Unknown_Critical_Extension::contents_to(Data_Store&, Data_Store&) const
    {
-   // TODO: textual representation?
    }
 
 }
diff --git a/src/lib/cert/x509/x509cert.cpp b/src/lib/cert/x509/x509cert.cpp
index bd3aff6d5..20a4bca25 100644
--- a/src/lib/cert/x509/x509cert.cpp
+++ b/src/lib/cert/x509/x509cert.cpp
@@ -1,6 +1,7 @@
 /*
 * X.509 Certificates
 * (C) 1999-2010,2015 Jack Lloyd
+* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -257,7 +258,7 @@ bool X509_Certificate::allowed_usage(Key_Constraints usage) const
    {
    if(constraints() == NO_CONSTRAINTS)
       return true;
-   return ((constraints() & usage) != 0);
+   return ((constraints() & usage) == usage);
    }
 
 bool X509_Certificate::allowed_extended_usage(const std::string& usage) const
@@ -565,7 +566,7 @@ std::string X509_Certificate::to_string() const
       if(constraints & DIGITAL_SIGNATURE)
          out << "   Digital Signature\n";
       if(constraints & NON_REPUDIATION)
-         out << "   Non-Repuidation\n";
+         out << "   Non-Repudiation\n";
       if(constraints & KEY_ENCIPHERMENT)
          out << "   Key Encipherment\n";
       if(constraints & DATA_ENCIPHERMENT)
@@ -576,6 +577,10 @@ std::string X509_Certificate::to_string() const
          out << "   Cert Sign\n";
       if(constraints & CRL_SIGN)
          out << "   CRL Sign\n";
+      if(constraints & ENCIPHER_ONLY)
+         out << "   Encipher Only\n";
+      if(constraints & DECIPHER_ONLY)
+         out << "   Decipher Only\n";
       }
 
    std::vector<std::string> policies = this->policies();
diff --git a/src/lib/cert/x509/x509self.cpp b/src/lib/cert/x509/x509self.cpp
index 8b9aeda09..102e24f77 100644
--- a/src/lib/cert/x509/x509self.cpp
+++ b/src/lib/cert/x509/x509self.cpp
@@ -55,9 +55,14 @@ X509_Certificate create_self_signed_cert(const X509_Cert_Options& opts,
 
    Key_Constraints constraints;
    if(opts.is_CA)
+      {
       constraints = Key_Constraints(KEY_CERT_SIGN | CRL_SIGN);
+      }
    else
-      constraints = find_constraints(key, opts.constraints);
+      {
+      verify_cert_constraints_valid_for_key_type(key, opts.constraints);
+      constraints = opts.constraints;
+      }
 
    Extensions extensions;
 
@@ -65,7 +70,10 @@ X509_Certificate create_self_signed_cert(const X509_Cert_Options& opts,
       new Cert_Extension::Basic_Constraints(opts.is_CA, opts.path_limit),
       true);
 
-   extensions.add(new Cert_Extension::Key_Usage(constraints), true);
+   if(constraints != NO_CONSTRAINTS)
+      {
+      extensions.add(new Cert_Extension::Key_Usage(constraints), true);
+      }
 
    extensions.add(new Cert_Extension::Subject_Key_ID(pub_key));
 
@@ -99,16 +107,27 @@ PKCS10_Request create_cert_req(const X509_Cert_Options& opts,
 
    const size_t PKCS10_VERSION = 0;
 
+   Key_Constraints constraints;
+   if(opts.is_CA)
+      {
+      constraints = Key_Constraints(KEY_CERT_SIGN | CRL_SIGN);
+      }
+   else
+      {
+      verify_cert_constraints_valid_for_key_type(key, opts.constraints);
+      constraints = opts.constraints;
+      }
+
    Extensions extensions;
 
    extensions.add(
       new Cert_Extension::Basic_Constraints(opts.is_CA, opts.path_limit));
-   extensions.add(
-      new Cert_Extension::Key_Usage(
-         opts.is_CA ? Key_Constraints(KEY_CERT_SIGN | CRL_SIGN) :
-                      find_constraints(key, opts.constraints)
-         )
-      );
+
+   if(constraints != NO_CONSTRAINTS)
+      {
+      extensions.add(
+         new Cert_Extension::Key_Usage(constraints));
+      }
    extensions.add(
       new Cert_Extension::Extended_Key_Usage(opts.ex_constraints));
    extensions.add(