Adds support for the <keygen> tag for client certificate enrollment under Lin...

net/base/keygen_handler_nss.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"
+
+// Work around https://bugzilla.mozilla.org/show_bug.cgi?id=455424
+// until NSS 3.12.2 comes out and we update to it.
+#define Lock FOO_NSS_Lock
+#include <pk11pub.h>
+#include <secmod.h>
+#include <ssl.h>
+#include <nssb64.h>    // NSSBase64_EncodeItem()
+#include <secder.h>    // DER_Encode()
+#include <cryptohi.h>  // SEC_DerSignData()
+#include <keyhi.h>     // SECKEY_CreateSubjectPublicKeyInfo()
+#undef Lock
+
+#include "base/nss_init.h"
+#include "base/logging.h"
+
+namespace net {
+
+const int64 DEFAULT_RSA_PUBLIC_EXPONENT = 0x10001;
+
+// Template for creating the signed public key structure to be sent to the CA.
+DERTemplate SECAlgorithmIDTemplate[] = {
+  { DER_SEQUENCE,
+    0, NULL, sizeof(SECAlgorithmID) },
+  { DER_OBJECT_ID,
+    offsetof(SECAlgorithmID, algorithm), },
+  { DER_OPTIONAL | DER_ANY,
+    offsetof(SECAlgorithmID, parameters), },
+  { 0, }
+};
+
+DERTemplate CERTSubjectPublicKeyInfoTemplate[] = {
+  { DER_SEQUENCE,
+    0, NULL, sizeof(CERTSubjectPublicKeyInfo) },
+  { DER_INLINE,
+    offsetof(CERTSubjectPublicKeyInfo, algorithm),
+    SECAlgorithmIDTemplate, },
+  { DER_BIT_STRING,
+    offsetof(CERTSubjectPublicKeyInfo, subjectPublicKey), },
+  { 0, }
+};
+
+DERTemplate CERTPublicKeyAndChallengeTemplate[] = {
+  { DER_SEQUENCE,
+    0, NULL, sizeof(CERTPublicKeyAndChallenge) },
+  { DER_ANY,
+    offsetof(CERTPublicKeyAndChallenge, spki), },
+  { DER_IA5_STRING,
+    offsetof(CERTPublicKeyAndChallenge, challenge), },
+  { 0, }
+};
+
+// This maps displayed strings indicating level of keysecurity in the <keygen>
+// menu to the key size in bits.
+// TODO(gauravsh): Should this mapping be moved else where?
+int RSAkeySizeMap[] = {2048, 1024};
+
+KeygenHandler::KeygenHandler(int key_size_index,
+                             const std::string& challenge)
+    : key_size_index_(key_size_index),
+      challenge_(challenge) {
+}
+
+// This function is largely copied from the Firefox's
+// <keygen> implementation in security/manager/ssl/src/nsKeygenHandler.cpp
+// FIXME(gauravsh): Do we need a copy of the Mozilla license here?
+
+std::string KeygenHandler::GenKeyAndSignChallenge() {
+  // Key pair generation mechanism - only RSA is supported at present.
+  PRUint32 keyGenMechanism = CKM_RSA_PKCS_KEY_PAIR_GEN;  // from nss/pkcs11t.h
+  char *keystring = NULL;  // Temporary store for result/
+
+  // Temporary structures used for generating the result
+  // in the right format.
+  PK11SlotInfo *slot = NULL;
+  PK11RSAGenParams rsaKeyGenParams;  // Keygen parameters.
+  SECOidTag algTag;  // used by SEC_DerSignData().
+  SECKEYPrivateKey *privateKey = NULL;
+  SECKEYPublicKey *publicKey = NULL;
+  CERTSubjectPublicKeyInfo *spkInfo = NULL;
+  PRArenaPool *arena = NULL;
+  SECStatus sec_rv =SECFailure;
+  SECItem spkiItem;
+  SECItem pkacItem;
+  SECItem signedItem;
+  CERTPublicKeyAndChallenge pkac;
+  void *keyGenParams;
+  pkac.challenge.data = NULL;
+  bool isSuccess = true;  // Set to false as soon as a step fails.
+
+  std::string result_blob;  // the result.
+
+  // Ensure NSS is initialized.
+  base::EnsureNSSInit();
+
+  slot = PK11_GetInternalKeySlot();
+  if (!slot) {
+    LOG(ERROR) << "Couldn't get Internal key slot!";
+    isSuccess = false;
+    goto failure;
+  }
+
+  switch (keyGenMechanism) {
+    case CKM_RSA_PKCS_KEY_PAIR_GEN:
+      rsaKeyGenParams.keySizeInBits = RSAkeySizeMap[key_size_index_];
+      rsaKeyGenParams.pe = DEFAULT_RSA_PUBLIC_EXPONENT;
+      keyGenParams = &rsaKeyGenParams;
+
+      algTag = SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION;  // from <nss/secoidt.h>.
+      break;
+    default:
+      // TODO(gauravsh): If we ever support other mechanisms,
+      // this can be changed.
+      LOG(ERROR) << "Only RSA keygen mechanism is supported";
+      isSuccess = false;
+      goto failure;
+      break;
+  }
+
+  // Need to make sure that the token was initialized.
+  // Assume a null password.
+  sec_rv = PK11_Authenticate(slot, PR_TRUE, NULL);
+  if (SECSuccess != sec_rv) {
+    LOG(ERROR) << "Couldn't initialze PK11 token!";
+    isSuccess = false;
+    goto failure;
+  }
+
+  LOG(INFO) << "Creating key pair...";
+  privateKey = PK11_GenerateKeyPair(slot,
+                                    keyGenMechanism,
+                                    keyGenParams,
+                                    &publicKey,
+                                    PR_TRUE,  // isPermanent?
+                                    PR_TRUE,  // isSensitive?
+                                    NULL);
+  LOG(INFO) << "done.";
+
+  if (!privateKey) {
+    LOG(INFO) << "Generation of Keypair failed!";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // The CA expects the signed public key in a specific format
+  // Let's create that now.
+
+  // Create a subject public key info from the public key.
+  spkInfo = SECKEY_CreateSubjectPublicKeyInfo(publicKey);
+  if (!spkInfo) {
+    LOG(ERROR) << "Couldn't create SubjectPublicKeyInfo from public key";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // Temporary work store used by NSS.
+  arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
+  if (!arena) {
+    LOG(ERROR) << "PORT_NewArena: Couldn't allocate memory";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // DER encode the whole subjectPublicKeyInfo.
+  sec_rv = DER_Encode(arena, &spkiItem, CERTSubjectPublicKeyInfoTemplate,
+                      spkInfo);
+  if (SECSuccess != sec_rv) {
+    LOG(ERROR) << "Couldn't DER Encode subjectPublicKeyInfo";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // Set up the PublicKeyAndChallenge data structure, then DER encode it.
+  pkac.spki = spkiItem;
+  pkac.challenge.len = challenge_.length();
+  pkac.challenge.data = (unsigned char *)strdup(challenge_.c_str());
+  if (!pkac.challenge.data) {
+    LOG(ERROR) << "Out of memory while making a copy of challenge data";
+    isSuccess = false;
+    goto failure;
+  }
+  sec_rv = DER_Encode(arena, &pkacItem, CERTPublicKeyAndChallengeTemplate,
+                      &pkac);
+  if (SECSuccess != sec_rv) {
+    LOG(ERROR) << "Couldn't DER Encode PublicKeyAndChallenge";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // Sign the DER encoded PublicKeyAndChallenge.
+  sec_rv = SEC_DerSignData(arena, &signedItem, pkacItem.data, pkacItem.len,
+                           privateKey, algTag);
+  if (SECSuccess != sec_rv) {
+    LOG(ERROR) << "Couldn't sign the DER encoded PublicKeyandChallenge";
+    isSuccess = false;
+    goto failure;
+  }
+
+  // Convert the signed public key and challenge into base64/ascii.
+  keystring = NSSBase64_EncodeItem(arena,
+                                   NULL,  // NSS will allocate a buffer for us.
+                                   0,
+                                   &signedItem);
+  if (!keystring) {
+    LOG(ERROR) << "Couldn't convert signed public key into base64";
+    isSuccess = false;
+    goto failure;
+  }
+
+  result_blob = keystring;
+
+ failure:
+  if (!isSuccess) {
+    LOG(ERROR) << "SSL Keygen failed!";
+  } else {
+    LOG(INFO) << "SSl Keygen succeeded!";
+  }
+
+  // Do cleanups
+  if (privateKey) {
+    // TODO(gauravsh): We still need to maintain the private key because it's
+    // used for certificate enrollment checks.
+
+    // PK11_DestroyTokenObject(privateKey->pkcs11Slot,privateKey->pkcs11ID);
+    // SECKEY_DestroyPrivateKey(privateKey);
+  }
+
+  if (publicKey) {
+    PK11_DestroyTokenObject(publicKey->pkcs11Slot, publicKey->pkcs11ID);
+  }
+  if (spkInfo) {
+    SECKEY_DestroySubjectPublicKeyInfo(spkInfo);
+  }
+  if (publicKey) {
+    SECKEY_DestroyPublicKey(publicKey);
+  }
+  if (arena) {
+    PORT_FreeArena(arena, PR_TRUE);
+  }
+  if (slot != NULL) {
+    PK11_FreeSlot(slot);
+  }
+  if (pkac.challenge.data) {
+    free(pkac.challenge.data);
+  }
+
+  return (isSuccess ? result_blob : std::string());
+}
+
+}  // namespace net