1// Copyright (c) 2009 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "net/base/keygen_handler.h"
6
7#include <pk11pub.h>
8#include <secmod.h>
9#include <ssl.h>
10#include <nssb64.h>    // NSSBase64_EncodeItem()
11#include <secder.h>    // DER_Encode()
12#include <cryptohi.h>  // SEC_DerSignData()
13#include <keyhi.h>     // SECKEY_CreateSubjectPublicKeyInfo()
14
15#include "base/nss_util.h"
16#include "base/logging.h"
17
18namespace net {
19
20const int64 DEFAULT_RSA_PUBLIC_EXPONENT = 0x10001;
21
22// Template for creating the signed public key structure to be sent to the CA.
23DERTemplate SECAlgorithmIDTemplate[] = {
24  { DER_SEQUENCE,
25    0, NULL, sizeof(SECAlgorithmID) },
26  { DER_OBJECT_ID,
27    offsetof(SECAlgorithmID, algorithm), },
28  { DER_OPTIONAL | DER_ANY,
29    offsetof(SECAlgorithmID, parameters), },
30  { 0, }
31};
32
33DERTemplate CERTSubjectPublicKeyInfoTemplate[] = {
34  { DER_SEQUENCE,
35    0, NULL, sizeof(CERTSubjectPublicKeyInfo) },
36  { DER_INLINE,
37    offsetof(CERTSubjectPublicKeyInfo, algorithm),
38    SECAlgorithmIDTemplate, },
39  { DER_BIT_STRING,
40    offsetof(CERTSubjectPublicKeyInfo, subjectPublicKey), },
41  { 0, }
42};
43
44DERTemplate CERTPublicKeyAndChallengeTemplate[] = {
45  { DER_SEQUENCE,
46    0, NULL, sizeof(CERTPublicKeyAndChallenge) },
47  { DER_ANY,
48    offsetof(CERTPublicKeyAndChallenge, spki), },
49  { DER_IA5_STRING,
50    offsetof(CERTPublicKeyAndChallenge, challenge), },
51  { 0, }
52};
53
54// This maps displayed strings indicating level of keysecurity in the <keygen>
55// menu to the key size in bits.
56// TODO(gauravsh): Should this mapping be moved else where?
57int RSAkeySizeMap[] = {2048, 1024};
58
59KeygenHandler::KeygenHandler(int key_size_index,
60                             const std::string& challenge)
61    : key_size_index_(key_size_index),
62      challenge_(challenge) {
63  if (key_size_index_ < 0 ||
64      key_size_index_ >=
65          static_cast<int>(sizeof(RSAkeySizeMap) / sizeof(RSAkeySizeMap[0])))
66    key_size_index_ = 0;
67}
68
69// This function is largely copied from the Firefox's
70// <keygen> implementation in security/manager/ssl/src/nsKeygenHandler.cpp
71// FIXME(gauravsh): Do we need a copy of the Mozilla license here?
72
73std::string KeygenHandler::GenKeyAndSignChallenge() {
74  // Key pair generation mechanism - only RSA is supported at present.
75  PRUint32 keyGenMechanism = CKM_RSA_PKCS_KEY_PAIR_GEN;  // from nss/pkcs11t.h
76  char *keystring = NULL;  // Temporary store for result/
77
78  // Temporary structures used for generating the result
79  // in the right format.
80  PK11SlotInfo *slot = NULL;
81  PK11RSAGenParams rsaKeyGenParams;  // Keygen parameters.
82  SECOidTag algTag;  // used by SEC_DerSignData().
83  SECKEYPrivateKey *privateKey = NULL;
84  SECKEYPublicKey *publicKey = NULL;
85  CERTSubjectPublicKeyInfo *spkInfo = NULL;
86  PRArenaPool *arena = NULL;
87  SECStatus sec_rv =SECFailure;
88  SECItem spkiItem;
89  SECItem pkacItem;
90  SECItem signedItem;
91  CERTPublicKeyAndChallenge pkac;
92  void *keyGenParams;
93  pkac.challenge.data = NULL;
94  bool isSuccess = true;  // Set to false as soon as a step fails.
95
96  std::string result_blob;  // the result.
97
98  // Ensure NSS is initialized.
99  base::EnsureNSSInit();
100
101  slot = PK11_GetInternalKeySlot();
102  if (!slot) {
103    LOG(ERROR) << "Couldn't get Internal key slot!";
104    isSuccess = false;
105    goto failure;
106  }
107
108  switch (keyGenMechanism) {
109    case CKM_RSA_PKCS_KEY_PAIR_GEN:
110      rsaKeyGenParams.keySizeInBits = RSAkeySizeMap[key_size_index_];
111      rsaKeyGenParams.pe = DEFAULT_RSA_PUBLIC_EXPONENT;
112      keyGenParams = &rsaKeyGenParams;
113
114      algTag = SEC_OID_PKCS1_MD5_WITH_RSA_ENCRYPTION;  // from <nss/secoidt.h>.
115      break;
116    default:
117      // TODO(gauravsh): If we ever support other mechanisms,
118      // this can be changed.
119      LOG(ERROR) << "Only RSA keygen mechanism is supported";
120      isSuccess = false;
121      goto failure;
122      break;
123  }
124
125  // Need to make sure that the token was initialized.
126  // Assume a null password.
127  sec_rv = PK11_Authenticate(slot, PR_TRUE, NULL);
128  if (SECSuccess != sec_rv) {
129    LOG(ERROR) << "Couldn't initialze PK11 token!";
130    isSuccess = false;
131    goto failure;
132  }
133
134  LOG(INFO) << "Creating key pair...";
135  privateKey = PK11_GenerateKeyPair(slot,
136                                    keyGenMechanism,
137                                    keyGenParams,
138                                    &publicKey,
139                                    PR_TRUE,  // isPermanent?
140                                    PR_TRUE,  // isSensitive?
141                                    NULL);
142  LOG(INFO) << "done.";
143
144  if (!privateKey) {
145    LOG(INFO) << "Generation of Keypair failed!";
146    isSuccess = false;
147    goto failure;
148  }
149
150  // The CA expects the signed public key in a specific format
151  // Let's create that now.
152
153  // Create a subject public key info from the public key.
154  spkInfo = SECKEY_CreateSubjectPublicKeyInfo(publicKey);
155  if (!spkInfo) {
156    LOG(ERROR) << "Couldn't create SubjectPublicKeyInfo from public key";
157    isSuccess = false;
158    goto failure;
159  }
160
161  // Temporary work store used by NSS.
162  arena = PORT_NewArena(DER_DEFAULT_CHUNKSIZE);
163  if (!arena) {
164    LOG(ERROR) << "PORT_NewArena: Couldn't allocate memory";
165    isSuccess = false;
166    goto failure;
167  }
168
169  // DER encode the whole subjectPublicKeyInfo.
170  sec_rv = DER_Encode(arena, &spkiItem, CERTSubjectPublicKeyInfoTemplate,
171                      spkInfo);
172  if (SECSuccess != sec_rv) {
173    LOG(ERROR) << "Couldn't DER Encode subjectPublicKeyInfo";
174    isSuccess = false;
175    goto failure;
176  }
177
178  // Set up the PublicKeyAndChallenge data structure, then DER encode it.
179  pkac.spki = spkiItem;
180  pkac.challenge.len = challenge_.length();
181  pkac.challenge.data = (unsigned char *)strdup(challenge_.c_str());
182  if (!pkac.challenge.data) {
183    LOG(ERROR) << "Out of memory while making a copy of challenge data";
184    isSuccess = false;
185    goto failure;
186  }
187  sec_rv = DER_Encode(arena, &pkacItem, CERTPublicKeyAndChallengeTemplate,
188                      &pkac);
189  if (SECSuccess != sec_rv) {
190    LOG(ERROR) << "Couldn't DER Encode PublicKeyAndChallenge";
191    isSuccess = false;
192    goto failure;
193  }
194
195  // Sign the DER encoded PublicKeyAndChallenge.
196  sec_rv = SEC_DerSignData(arena, &signedItem, pkacItem.data, pkacItem.len,
197                           privateKey, algTag);
198  if (SECSuccess != sec_rv) {
199    LOG(ERROR) << "Couldn't sign the DER encoded PublicKeyandChallenge";
200    isSuccess = false;
201    goto failure;
202  }
203
204  // Convert the signed public key and challenge into base64/ascii.
205  keystring = NSSBase64_EncodeItem(arena,
206                                   NULL,  // NSS will allocate a buffer for us.
207                                   0,
208                                   &signedItem);
209  if (!keystring) {
210    LOG(ERROR) << "Couldn't convert signed public key into base64";
211    isSuccess = false;
212    goto failure;
213  }
214
215  result_blob = keystring;
216
217 failure:
218  if (!isSuccess) {
219    LOG(ERROR) << "SSL Keygen failed!";
220  } else {
221    LOG(INFO) << "SSl Keygen succeeded!";
222  }
223
224  // Do cleanups
225  if (privateKey) {
226    // TODO(gauravsh): We still need to maintain the private key because it's
227    // used for certificate enrollment checks.
228
229    // PK11_DestroyTokenObject(privateKey->pkcs11Slot,privateKey->pkcs11ID);
230    // SECKEY_DestroyPrivateKey(privateKey);
231  }
232
233  if (publicKey) {
234    PK11_DestroyTokenObject(publicKey->pkcs11Slot, publicKey->pkcs11ID);
235  }
236  if (spkInfo) {
237    SECKEY_DestroySubjectPublicKeyInfo(spkInfo);
238  }
239  if (publicKey) {
240    SECKEY_DestroyPublicKey(publicKey);
241  }
242  if (arena) {
243    PORT_FreeArena(arena, PR_TRUE);
244  }
245  if (slot != NULL) {
246    PK11_FreeSlot(slot);
247  }
248  if (pkac.challenge.data) {
249    free(pkac.challenge.data);
250  }
251
252  return (isSuccess ? result_blob : std::string());
253}
254
255}  // namespace net
256