Mac: implement <keygen> support, including adding generated cert to the Keychain.

net/base/keygen_handler_mac.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/keygen_handler.h"
 
+#include <Security/SecAsn1Coder.h>
+#include <Security/SecAsn1Templates.h>
+#include <Security/Security.h>
+
+#include "base/base64.h"
 #include "base/logging.h"
+#include "base/scoped_cftyperef.h"
+
+// These are in Security.framework but not declared in a public header.
+extern const SecAsn1Template kSecAsn1AlgorithmIDTemplate[];
+extern const SecAsn1Template kSecAsn1SubjectPublicKeyInfoTemplate[];
 
 namespace net {
 
-KeygenHandler::KeygenHandler(int key_size_index,
-                             const std::string& challenge)
-    : key_size_index_(key_size_index),
-      challenge_(challenge) {
-  NOTIMPLEMENTED();
-}
+// Declarations of Netscape keygen cert structures for ASN.1 encoding:
+
+struct PublicKeyAndChallenge {
+  CSSM_X509_SUBJECT_PUBLIC_KEY_INFO spki;
+  CSSM_DATA challenge_string;
+};
+
+static const SecAsn1Template kPublicKeyAndChallengeTemplate[] = {
+  {
+    SEC_ASN1_SEQUENCE,
+    0,
+    NULL,
+    sizeof(PublicKeyAndChallenge)
+  },
+  {
+    SEC_ASN1_INLINE,
+    offsetof(PublicKeyAndChallenge, spki),
+    kSecAsn1SubjectPublicKeyInfoTemplate
+  },
+  {
+    SEC_ASN1_INLINE,
+    offsetof(PublicKeyAndChallenge, challenge_string),
+    kSecAsn1IA5StringTemplate
+  },
+  {
+    0
+  }
+};
+
+struct SignedPublicKeyAndChallenge {
+  PublicKeyAndChallenge pkac;
+  CSSM_X509_ALGORITHM_IDENTIFIER signature_algorithm;
+  CSSM_DATA signature;
+};
+
+static const SecAsn1Template kSignedPublicKeyAndChallengeTemplate[] = {
+  {
+    SEC_ASN1_SEQUENCE,
+    0,
+    NULL,
+    sizeof(SignedPublicKeyAndChallenge)
+  },
+  {
+    SEC_ASN1_INLINE,
+    offsetof(SignedPublicKeyAndChallenge, pkac),
+    kPublicKeyAndChallengeTemplate
+  },
+  {
+    SEC_ASN1_INLINE,
+    offsetof(SignedPublicKeyAndChallenge, signature_algorithm),
+    kSecAsn1AlgorithmIDTemplate
+  },
+  {
+    SEC_ASN1_BIT_STRING,
+    offsetof(SignedPublicKeyAndChallenge, signature)
+  },
+  {
+    0
+  }
+};
+
+
+static OSStatus CreateRSAKeyPair(int size_in_bits,
+                                 SecKeyRef* out_pub_key,
+                                 SecKeyRef* out_priv_key);
+static OSStatus SignData(CSSM_DATA data,
+                         SecKeyRef private_key,
+                         CSSM_DATA* signature);
+
 
 std::string KeygenHandler::GenKeyAndSignChallenge() {
-  NOTIMPLEMENTED();
-  return std::string();
+  std::string result;
+  OSStatus err;
+  SecKeyRef public_key = NULL;
+  SecKeyRef private_key = NULL;
+  SecAsn1CoderRef coder = NULL;
+  CSSM_DATA signature = {0, NULL};
+
+  {
+    // Create the key-pair.
+    err = CreateRSAKeyPair(key_size_in_bits_, &public_key, &private_key);
+    if (err)
+      goto failure;
+
+    // Get the public key data (DER sequence of modulus, exponent).
+    CFDataRef key_data = NULL;
+    err = SecKeychainItemExport(public_key, kSecFormatBSAFE, 0, NULL,
+                                &key_data);
+    if (err)
+      goto failure;
+    scoped_cftyperef<CFDataRef> scoped_key_data(key_data);
+
+    // Create an ASN.1 encoder.
+    err = SecAsn1CoderCreate(&coder);
+    if (err)
+      goto failure;
+
+    // Fill in and DER-encode the PublicKeyAndChallenge:
+    SignedPublicKeyAndChallenge spkac;
+    memset(&spkac, 0, sizeof(spkac));
+    spkac.pkac.spki.algorithm.algorithm = CSSMOID_RSA;
+    spkac.pkac.spki.subjectPublicKey.Length =
+        CFDataGetLength(key_data) * 8;  // interpreted as a _bit_ count
+    spkac.pkac.spki.subjectPublicKey.Data =
+        const_cast<uint8_t*>(CFDataGetBytePtr(key_data));
+    spkac.pkac.challenge_string.Length = challenge_.length();
+    spkac.pkac.challenge_string.Data =
+        reinterpret_cast<uint8_t*>(const_cast<char*>(challenge_.data()));
+
+    CSSM_DATA encoded;
+    err = SecAsn1EncodeItem(coder, &spkac.pkac,
+                            kPublicKeyAndChallengeTemplate, &encoded);
+    if (err)
+      goto failure;
+
+    // Compute a signature of the result:
+    err = SignData(encoded, private_key, &signature);
+    if (err)
+      goto failure;
+    spkac.signature.Data = signature.Data;
+    spkac.signature.Length = signature.Length * 8;  // a _bit_ count
+    spkac.signature_algorithm.algorithm = CSSMOID_MD5WithRSA;

[wtc, 2010/03/01 23:05:40]

Can we use SHA1WithRSA instead of MD5WithRSA?  (This needs to
match what you specify on line 241 below.)

I know this comes from the NSS-based implementation and is
specified in http://dev.w3.org/html5/spec/Overview.html#the-keygen-element
but not in https://developer.mozilla.org/En/HTML/HTML_Extensions/KEYGEN_Tag

For now, let's just add a TODO comment and link to the
Mozilla bug I just filed:
https://bugzilla.mozilla.org/show_bug.cgi?id=549460

+
+    // DER-encode the entire SignedPublicKeyAndChallenge:
+    err = SecAsn1EncodeItem(coder, &spkac,
+                            kSignedPublicKeyAndChallengeTemplate, &encoded);
+    if (err)
+      goto failure;
+
+    // Base64 encode the result.
+    std::string input(reinterpret_cast<char*>(encoded.Data), encoded.Length);
+    base::Base64Encode(input, &result);
+  }
+
+failure:
+  if (err) {
+    LOG(ERROR) << "SSL Keygen failed! OSStatus = " << err;
+  } else {
+    LOG(INFO) << "SSL Keygen succeeded! Output is: " << result;
+  }
+
+  // Remove keys from keychain if asked to during unit testing:
+  if (!stores_key_) {
+    if (public_key)
+      SecKeychainItemDelete(reinterpret_cast<SecKeychainItemRef>(public_key));
+    if (private_key)
+      SecKeychainItemDelete(reinterpret_cast<SecKeychainItemRef>(private_key));
+  }
+
+  // Clean up:
+  free(signature.Data);
+  if (coder)
+    SecAsn1CoderRelease(coder);
+  if (public_key)
+    CFRelease(public_key);
+  if (private_key)
+    CFRelease(private_key);
+  return result;
+}
+
+
+static OSStatus CreateRSAKeyPair(int size_in_bits,
+                                 SecKeyRef* out_pub_key,
+                                 SecKeyRef* out_priv_key) {
+  OSStatus err;
+  SecKeychainRef keychain;
+  err = SecKeychainCopyDefault(&keychain);
+  if (err)
+    return err;
+  scoped_cftyperef<SecKeychainRef> scoped_keychain(keychain);
+  return SecKeyCreatePair(
+      keychain,
+      CSSM_ALGID_RSA,
+      size_in_bits,
+      0LL,
+      // public key usage and attributes:
+      CSSM_KEYUSE_ENCRYPT | CSSM_KEYUSE_VERIFY | CSSM_KEYUSE_WRAP,
+      CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_PERMANENT,
+      // private key usage and attributes:
+      CSSM_KEYUSE_DECRYPT | CSSM_KEYUSE_SIGN | CSSM_KEYUSE_UNWRAP,                               // private key
+      CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_PERMANENT |
+          CSSM_KEYATTR_SENSITIVE,
+      NULL,
+      out_pub_key, out_priv_key);
+}
+
+static OSStatus CreateSignatureContext(SecKeyRef key,
+                                       CSSM_ALGORITHMS algorithm,
+                                       CSSM_CC_HANDLE* out_cc_handle) {
+  OSStatus err;
+  const CSSM_ACCESS_CREDENTIALS* credentials = NULL;
+  err = SecKeyGetCredentials(key,
+                             CSSM_ACL_AUTHORIZATION_SIGN,
+                             kSecCredentialTypeDefault,
+                             &credentials);
+  if (err)
+      return err;
+
+  CSSM_CSP_HANDLE csp_handle = 0;
+  err = SecKeyGetCSPHandle(key, &csp_handle);
+  if (err)
+    return err;
+
+  const CSSM_KEY* cssm_key = NULL;
+  err = SecKeyGetCSSMKey(key, &cssm_key);
+  if (err)
+    return err;
+
+  return CSSM_CSP_CreateSignatureContext(csp_handle,
+                                         algorithm,
+                                         credentials,
+                                         cssm_key,
+                                         out_cc_handle);
+}
+
+static OSStatus SignData(CSSM_DATA data,
+                         SecKeyRef private_key,
+                         CSSM_DATA* signature) {
+  CSSM_CC_HANDLE cc_handle;
+  OSStatus err = CreateSignatureContext(private_key,
+                                        CSSM_ALGID_MD5WithRSA,
+                                        &cc_handle);
+  if (err)
+    return err;
+  err = CSSM_SignData(cc_handle, &data, 1, CSSM_ALGID_NONE, signature);
+  CSSM_DeleteContext(cc_handle);
+  return err;
 }
 
 }  // namespace net