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The Android Open Source Projectc24a8e62009-03-03 19:28:42 -08001/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
Tao Baoac9d94d2016-11-03 11:37:15 -070017#include "verifier.h"
18
Doug Zongker54e2e862009-08-17 13:21:04 -070019#include <errno.h>
Elliott Hughes26dbad22015-01-28 12:09:05 -080020#include <stdio.h>
Tao Baoac9d94d2016-11-03 11:37:15 -070021#include <stdlib.h>
Elliott Hughes26dbad22015-01-28 12:09:05 -080022#include <string.h>
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080023
Elliott Hughes8febafa2016-04-13 16:39:56 -070024#include <algorithm>
25#include <memory>
26
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -070027#include <android-base/logging.h>
David Benjamina86392e2016-04-15 20:22:09 -040028#include <openssl/bn.h>
Elliott Hughes8febafa2016-04-13 16:39:56 -070029#include <openssl/ecdsa.h>
30#include <openssl/obj_mac.h>
31
32#include "asn1_decoder.h"
33#include "common.h"
Tao Baoe1792762016-04-19 22:31:01 -070034#include "print_sha1.h"
Elliott Hughes8febafa2016-04-13 16:39:56 -070035#include "ui.h"
Doug Zongker211aebc2011-10-28 15:13:10 -070036
Elliott Hughes8febafa2016-04-13 16:39:56 -070037static constexpr size_t MiB = 1024 * 1024;
38
Kenny Root7a4adb52013-10-09 10:14:35 -070039/*
40 * Simple version of PKCS#7 SignedData extraction. This extracts the
41 * signature OCTET STRING to be used for signature verification.
42 *
43 * For full details, see http://www.ietf.org/rfc/rfc3852.txt
44 *
45 * The PKCS#7 structure looks like:
46 *
47 * SEQUENCE (ContentInfo)
48 * OID (ContentType)
49 * [0] (content)
50 * SEQUENCE (SignedData)
51 * INTEGER (version CMSVersion)
52 * SET (DigestAlgorithmIdentifiers)
53 * SEQUENCE (EncapsulatedContentInfo)
54 * [0] (CertificateSet OPTIONAL)
55 * [1] (RevocationInfoChoices OPTIONAL)
56 * SET (SignerInfos)
57 * SEQUENCE (SignerInfo)
58 * INTEGER (CMSVersion)
59 * SEQUENCE (SignerIdentifier)
60 * SEQUENCE (DigestAlgorithmIdentifier)
61 * SEQUENCE (SignatureAlgorithmIdentifier)
62 * OCTET STRING (SignatureValue)
63 */
64static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_der,
65 size_t* sig_der_length) {
66 asn1_context_t* ctx = asn1_context_new(pkcs7_der, pkcs7_der_len);
67 if (ctx == NULL) {
68 return false;
69 }
70
71 asn1_context_t* pkcs7_seq = asn1_sequence_get(ctx);
72 if (pkcs7_seq != NULL && asn1_sequence_next(pkcs7_seq)) {
73 asn1_context_t *signed_data_app = asn1_constructed_get(pkcs7_seq);
74 if (signed_data_app != NULL) {
75 asn1_context_t* signed_data_seq = asn1_sequence_get(signed_data_app);
76 if (signed_data_seq != NULL
77 && asn1_sequence_next(signed_data_seq)
78 && asn1_sequence_next(signed_data_seq)
79 && asn1_sequence_next(signed_data_seq)
80 && asn1_constructed_skip_all(signed_data_seq)) {
81 asn1_context_t *sig_set = asn1_set_get(signed_data_seq);
82 if (sig_set != NULL) {
83 asn1_context_t* sig_seq = asn1_sequence_get(sig_set);
84 if (sig_seq != NULL
85 && asn1_sequence_next(sig_seq)
86 && asn1_sequence_next(sig_seq)
87 && asn1_sequence_next(sig_seq)
88 && asn1_sequence_next(sig_seq)) {
89 uint8_t* sig_der_ptr;
90 if (asn1_octet_string_get(sig_seq, &sig_der_ptr, sig_der_length)) {
91 *sig_der = (uint8_t*) malloc(*sig_der_length);
92 if (*sig_der != NULL) {
93 memcpy(*sig_der, sig_der_ptr, *sig_der_length);
94 }
95 }
96 asn1_context_free(sig_seq);
97 }
98 asn1_context_free(sig_set);
99 }
100 asn1_context_free(signed_data_seq);
101 }
102 asn1_context_free(signed_data_app);
103 }
104 asn1_context_free(pkcs7_seq);
105 }
106 asn1_context_free(ctx);
107
108 return *sig_der != NULL;
109}
110
Doug Zongker54e2e862009-08-17 13:21:04 -0700111// Look for an RSA signature embedded in the .ZIP file comment given
112// the path to the zip. Verify it matches one of the given public
113// keys.
114//
115// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
116// or no key matches the signature).
117
Doug Zongker99916f02014-01-13 14:16:58 -0800118int verify_file(unsigned char* addr, size_t length,
Tao Bao71e3e092016-02-02 14:02:27 -0800119 const std::vector<Certificate>& keys) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700120 ui->SetProgress(0.0);
Doug Zongker54e2e862009-08-17 13:21:04 -0700121
Doug Zongker54e2e862009-08-17 13:21:04 -0700122 // An archive with a whole-file signature will end in six bytes:
123 //
Doug Zongker73ae31c2009-12-09 17:01:45 -0800124 // (2-byte signature start) $ff $ff (2-byte comment size)
Doug Zongker54e2e862009-08-17 13:21:04 -0700125 //
126 // (As far as the ZIP format is concerned, these are part of the
127 // archive comment.) We start by reading this footer, this tells
128 // us how far back from the end we have to start reading to find
129 // the whole comment.
130
131#define FOOTER_SIZE 6
132
Doug Zongker99916f02014-01-13 14:16:58 -0800133 if (length < FOOTER_SIZE) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700134 LOG(ERROR) << "not big enough to contain footer";
Doug Zongker54e2e862009-08-17 13:21:04 -0700135 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800136 }
137
Doug Zongker99916f02014-01-13 14:16:58 -0800138 unsigned char* footer = addr + length - FOOTER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800139
Doug Zongker54e2e862009-08-17 13:21:04 -0700140 if (footer[2] != 0xff || footer[3] != 0xff) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700141 LOG(ERROR) << "footer is wrong";
Doug Zongker54e2e862009-08-17 13:21:04 -0700142 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800143 }
144
Doug Zongker28ce47c2011-10-28 10:33:05 -0700145 size_t comment_size = footer[4] + (footer[5] << 8);
146 size_t signature_start = footer[0] + (footer[1] << 8);
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700147 LOG(INFO) << "comment is " << comment_size << " bytes; signature is " << signature_start
148 << " bytes from end";
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800149
Tianjie Xu54ea1362016-12-16 16:24:09 -0800150 if (signature_start > comment_size) {
Tianjie Xu97ea8442017-01-18 15:12:54 -0800151 LOG(ERROR) << "signature start: " << signature_start << " is larger than comment size: "
152 << comment_size;
Tianjie Xu54ea1362016-12-16 16:24:09 -0800153 return VERIFY_FAILURE;
154 }
155
Kenny Root7a4adb52013-10-09 10:14:35 -0700156 if (signature_start <= FOOTER_SIZE) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700157 LOG(ERROR) << "Signature start is in the footer";
Doug Zongker54e2e862009-08-17 13:21:04 -0700158 return VERIFY_FAILURE;
159 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800160
Doug Zongker54e2e862009-08-17 13:21:04 -0700161#define EOCD_HEADER_SIZE 22
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800162
Doug Zongker54e2e862009-08-17 13:21:04 -0700163 // The end-of-central-directory record is 22 bytes plus any
164 // comment length.
165 size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800166
Doug Zongker99916f02014-01-13 14:16:58 -0800167 if (length < eocd_size) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700168 LOG(ERROR) << "not big enough to contain EOCD";
Doug Zongker54e2e862009-08-17 13:21:04 -0700169 return VERIFY_FAILURE;
170 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800171
Doug Zongker54e2e862009-08-17 13:21:04 -0700172 // Determine how much of the file is covered by the signature.
173 // This is everything except the signature data and length, which
174 // includes all of the EOCD except for the comment length field (2
175 // bytes) and the comment data.
Doug Zongker99916f02014-01-13 14:16:58 -0800176 size_t signed_len = length - eocd_size + EOCD_HEADER_SIZE - 2;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800177
Doug Zongker99916f02014-01-13 14:16:58 -0800178 unsigned char* eocd = addr + length - eocd_size;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800179
Doug Zongker54e2e862009-08-17 13:21:04 -0700180 // If this is really is the EOCD record, it will begin with the
181 // magic number $50 $4b $05 $06.
182 if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
183 eocd[2] != 0x05 || eocd[3] != 0x06) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700184 LOG(ERROR) << "signature length doesn't match EOCD marker";
Doug Zongker54e2e862009-08-17 13:21:04 -0700185 return VERIFY_FAILURE;
186 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800187
Tao Bao71e3e092016-02-02 14:02:27 -0800188 for (size_t i = 4; i < eocd_size-3; ++i) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700189 if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b &&
Doug Zongkerc652e412009-12-08 15:30:09 -0800190 eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700191 // if the sequence $50 $4b $05 $06 appears anywhere after
Tianjie Xu8cf5c8f2016-09-08 20:10:11 -0700192 // the real one, libziparchive will find the later (wrong) one,
Doug Zongker54e2e862009-08-17 13:21:04 -0700193 // which could be exploitable. Fail verification if
194 // this sequence occurs anywhere after the real one.
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700195 LOG(ERROR) << "EOCD marker occurs after start of EOCD";
Doug Zongker54e2e862009-08-17 13:21:04 -0700196 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800197 }
198 }
199
Doug Zongker30362a62013-04-10 11:32:17 -0700200 bool need_sha1 = false;
201 bool need_sha256 = false;
Tao Bao71e3e092016-02-02 14:02:27 -0800202 for (const auto& key : keys) {
203 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700204 case SHA_DIGEST_LENGTH: need_sha1 = true; break;
205 case SHA256_DIGEST_LENGTH: need_sha256 = true; break;
Doug Zongker30362a62013-04-10 11:32:17 -0700206 }
207 }
208
209 SHA_CTX sha1_ctx;
210 SHA256_CTX sha256_ctx;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700211 SHA1_Init(&sha1_ctx);
212 SHA256_Init(&sha256_ctx);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800213
Doug Zongker54e2e862009-08-17 13:21:04 -0700214 double frac = -1.0;
215 size_t so_far = 0;
Doug Zongker54e2e862009-08-17 13:21:04 -0700216 while (so_far < signed_len) {
Elliott Hughesdd895d02016-04-19 15:24:38 -0700217 // On a Nexus 5X, experiment showed 16MiB beat 1MiB by 6% faster for a
218 // 1196MiB full OTA and 60% for an 89MiB incremental OTA.
219 // http://b/28135231.
220 size_t size = std::min(signed_len - so_far, 16 * MiB);
Doug Zongker99916f02014-01-13 14:16:58 -0800221
Elliott Hughes8febafa2016-04-13 16:39:56 -0700222 if (need_sha1) SHA1_Update(&sha1_ctx, addr + so_far, size);
223 if (need_sha256) SHA256_Update(&sha256_ctx, addr + so_far, size);
Doug Zongker54e2e862009-08-17 13:21:04 -0700224 so_far += size;
Doug Zongker99916f02014-01-13 14:16:58 -0800225
Doug Zongker54e2e862009-08-17 13:21:04 -0700226 double f = so_far / (double)signed_len;
227 if (f > frac + 0.02 || size == so_far) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700228 ui->SetProgress(f);
Doug Zongker54e2e862009-08-17 13:21:04 -0700229 frac = f;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800230 }
231 }
232
Elliott Hughes8febafa2016-04-13 16:39:56 -0700233 uint8_t sha1[SHA_DIGEST_LENGTH];
234 SHA1_Final(sha1, &sha1_ctx);
235 uint8_t sha256[SHA256_DIGEST_LENGTH];
236 SHA256_Final(sha256, &sha256_ctx);
Doug Zongker30362a62013-04-10 11:32:17 -0700237
Tao Bao71e3e092016-02-02 14:02:27 -0800238 uint8_t* sig_der = nullptr;
Kenny Root7a4adb52013-10-09 10:14:35 -0700239 size_t sig_der_length = 0;
240
Tao Baoe1792762016-04-19 22:31:01 -0700241 uint8_t* signature = eocd + eocd_size - signature_start;
Kenny Root7a4adb52013-10-09 10:14:35 -0700242 size_t signature_size = signature_start - FOOTER_SIZE;
Tao Baoe1792762016-04-19 22:31:01 -0700243
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700244 LOG(INFO) << "signature (offset: " << std::hex << (length - signature_start) << ", length: "
245 << signature_size << "): " << print_hex(signature, signature_size);
Tao Baoe1792762016-04-19 22:31:01 -0700246
247 if (!read_pkcs7(signature, signature_size, &sig_der, &sig_der_length)) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700248 LOG(ERROR) << "Could not find signature DER block";
Kenny Root7a4adb52013-10-09 10:14:35 -0700249 return VERIFY_FAILURE;
250 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700251
252 /*
253 * Check to make sure at least one of the keys matches the signature. Since
254 * any key can match, we need to try each before determining a verification
255 * failure has happened.
256 */
Tao Bao71e3e092016-02-02 14:02:27 -0800257 size_t i = 0;
258 for (const auto& key : keys) {
Doug Zongker30362a62013-04-10 11:32:17 -0700259 const uint8_t* hash;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700260 int hash_nid;
Tao Bao71e3e092016-02-02 14:02:27 -0800261 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700262 case SHA_DIGEST_LENGTH:
263 hash = sha1;
264 hash_nid = NID_sha1;
265 break;
266 case SHA256_DIGEST_LENGTH:
267 hash = sha256;
268 hash_nid = NID_sha256;
269 break;
270 default:
271 continue;
Doug Zongker30362a62013-04-10 11:32:17 -0700272 }
273
Doug Zongker73ae31c2009-12-09 17:01:45 -0800274 // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
Doug Zongker54e2e862009-08-17 13:21:04 -0700275 // the signing tool appends after the signature itself.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700276 if (key.key_type == Certificate::KEY_TYPE_RSA) {
277 if (!RSA_verify(hash_nid, hash, key.hash_len, sig_der,
278 sig_der_length, key.rsa.get())) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700279 LOG(INFO) << "failed to verify against RSA key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700280 continue;
281 }
282
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700283 LOG(INFO) << "whole-file signature verified against RSA key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700284 free(sig_der);
285 return VERIFY_SUCCESS;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700286 } else if (key.key_type == Certificate::KEY_TYPE_EC
287 && key.hash_len == SHA256_DIGEST_LENGTH) {
288 if (!ECDSA_verify(0, hash, key.hash_len, sig_der,
289 sig_der_length, key.ec.get())) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700290 LOG(INFO) << "failed to verify against EC key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700291 continue;
292 }
293
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700294 LOG(INFO) << "whole-file signature verified against EC key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700295 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700296 return VERIFY_SUCCESS;
Doug Zongker6c249f72012-11-02 15:04:05 -0700297 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700298 LOG(INFO) << "Unknown key type " << key.key_type;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800299 }
Tao Bao71e3e092016-02-02 14:02:27 -0800300 i++;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800301 }
Tao Baoe1792762016-04-19 22:31:01 -0700302
303 if (need_sha1) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700304 LOG(INFO) << "SHA-1 digest: " << print_hex(sha1, SHA_DIGEST_LENGTH);
Tao Baoe1792762016-04-19 22:31:01 -0700305 }
306 if (need_sha256) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700307 LOG(INFO) << "SHA-256 digest: " << print_hex(sha256, SHA256_DIGEST_LENGTH);
Tao Baoe1792762016-04-19 22:31:01 -0700308 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700309 free(sig_der);
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700310 LOG(ERROR) << "failed to verify whole-file signature";
Doug Zongker54e2e862009-08-17 13:21:04 -0700311 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800312}
Doug Zongker6c249f72012-11-02 15:04:05 -0700313
Elliott Hughes8febafa2016-04-13 16:39:56 -0700314std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) {
315 // Read key length in words and n0inv. n0inv is a precomputed montgomery
316 // parameter derived from the modulus and can be used to speed up
317 // verification. n0inv is 32 bits wide here, assuming the verification logic
318 // uses 32 bit arithmetic. However, BoringSSL may use a word size of 64 bits
319 // internally, in which case we don't have a valid n0inv. Thus, we just
320 // ignore the montgomery parameters and have BoringSSL recompute them
321 // internally. If/When the speedup from using the montgomery parameters
322 // becomes relevant, we can add more sophisticated code here to obtain a
323 // 64-bit n0inv and initialize the montgomery parameters in the key object.
324 uint32_t key_len_words = 0;
325 uint32_t n0inv = 0;
326 if (fscanf(file, " %i , 0x%x", &key_len_words, &n0inv) != 2) {
327 return nullptr;
328 }
329
330 if (key_len_words > 8192 / 32) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700331 LOG(ERROR) << "key length (" << key_len_words << ") too large";
Elliott Hughes8febafa2016-04-13 16:39:56 -0700332 return nullptr;
333 }
334
335 // Read the modulus.
336 std::unique_ptr<uint32_t[]> modulus(new uint32_t[key_len_words]);
337 if (fscanf(file, " , { %u", &modulus[0]) != 1) {
338 return nullptr;
339 }
340 for (uint32_t i = 1; i < key_len_words; ++i) {
341 if (fscanf(file, " , %u", &modulus[i]) != 1) {
342 return nullptr;
343 }
344 }
345
346 // Cconvert from little-endian array of little-endian words to big-endian
347 // byte array suitable as input for BN_bin2bn.
348 std::reverse((uint8_t*)modulus.get(),
349 (uint8_t*)(modulus.get() + key_len_words));
350
351 // The next sequence of values is the montgomery parameter R^2. Since we
352 // generally don't have a valid |n0inv|, we ignore this (see comment above).
353 uint32_t rr_value;
354 if (fscanf(file, " } , { %u", &rr_value) != 1) {
355 return nullptr;
356 }
357 for (uint32_t i = 1; i < key_len_words; ++i) {
358 if (fscanf(file, " , %u", &rr_value) != 1) {
359 return nullptr;
360 }
361 }
362 if (fscanf(file, " } } ") != 0) {
363 return nullptr;
364 }
365
366 // Initialize the key.
367 std::unique_ptr<RSA, RSADeleter> key(RSA_new());
368 if (!key) {
369 return nullptr;
370 }
371
372 key->n = BN_bin2bn((uint8_t*)modulus.get(),
373 key_len_words * sizeof(uint32_t), NULL);
374 if (!key->n) {
375 return nullptr;
376 }
377
378 key->e = BN_new();
379 if (!key->e || !BN_set_word(key->e, exponent)) {
380 return nullptr;
381 }
382
383 return key;
384}
385
386struct BNDeleter {
387 void operator()(BIGNUM* bn) {
388 BN_free(bn);
389 }
390};
391
392std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) {
393 uint32_t key_len_bytes = 0;
394 if (fscanf(file, " %i", &key_len_bytes) != 1) {
395 return nullptr;
396 }
397
398 std::unique_ptr<EC_GROUP, void (*)(EC_GROUP*)> group(
399 EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1), EC_GROUP_free);
400 if (!group) {
401 return nullptr;
402 }
403
404 // Verify that |key_len| matches the group order.
405 if (key_len_bytes != BN_num_bytes(EC_GROUP_get0_order(group.get()))) {
406 return nullptr;
407 }
408
409 // Read the public key coordinates. Note that the byte order in the file is
410 // little-endian, so we convert to big-endian here.
411 std::unique_ptr<uint8_t[]> bytes(new uint8_t[key_len_bytes]);
412 std::unique_ptr<BIGNUM, BNDeleter> point[2];
413 for (int i = 0; i < 2; ++i) {
414 unsigned int byte = 0;
415 if (fscanf(file, " , { %u", &byte) != 1) {
416 return nullptr;
417 }
418 bytes[key_len_bytes - 1] = byte;
419
420 for (size_t i = 1; i < key_len_bytes; ++i) {
421 if (fscanf(file, " , %u", &byte) != 1) {
422 return nullptr;
423 }
424 bytes[key_len_bytes - i - 1] = byte;
425 }
426
427 point[i].reset(BN_bin2bn(bytes.get(), key_len_bytes, nullptr));
428 if (!point[i]) {
429 return nullptr;
430 }
431
432 if (fscanf(file, " }") != 0) {
433 return nullptr;
434 }
435 }
436
437 if (fscanf(file, " } ") != 0) {
438 return nullptr;
439 }
440
441 // Create and initialize the key.
442 std::unique_ptr<EC_KEY, ECKEYDeleter> key(EC_KEY_new());
443 if (!key || !EC_KEY_set_group(key.get(), group.get()) ||
444 !EC_KEY_set_public_key_affine_coordinates(key.get(), point[0].get(),
445 point[1].get())) {
446 return nullptr;
447 }
448
449 return key;
450}
451
Doug Zongker6c249f72012-11-02 15:04:05 -0700452// Reads a file containing one or more public keys as produced by
453// DumpPublicKey: this is an RSAPublicKey struct as it would appear
454// as a C source literal, eg:
455//
456// "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
457//
458// For key versions newer than the original 2048-bit e=3 keys
459// supported by Android, the string is preceded by a version
460// identifier, eg:
461//
462// "v2 {64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
463//
464// (Note that the braces and commas in this example are actual
465// characters the parser expects to find in the file; the ellipses
466// indicate more numbers omitted from this example.)
467//
468// The file may contain multiple keys in this format, separated by
469// commas. The last key must not be followed by a comma.
470//
Doug Zongker30362a62013-04-10 11:32:17 -0700471// A Certificate is a pair of an RSAPublicKey and a particular hash
472// (we support SHA-1 and SHA-256; we store the hash length to signify
473// which is being used). The hash used is implied by the version number.
474//
475// 1: 2048-bit RSA key with e=3 and SHA-1 hash
476// 2: 2048-bit RSA key with e=65537 and SHA-1 hash
477// 3: 2048-bit RSA key with e=3 and SHA-256 hash
478// 4: 2048-bit RSA key with e=65537 and SHA-256 hash
Kenny Root7a4adb52013-10-09 10:14:35 -0700479// 5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
Doug Zongker30362a62013-04-10 11:32:17 -0700480//
Tao Bao71e3e092016-02-02 14:02:27 -0800481// Returns true on success, and appends the found keys (at least one) to certs.
482// Otherwise returns false if the file failed to parse, or if it contains zero
483// keys. The contents in certs would be unspecified on failure.
484bool load_keys(const char* filename, std::vector<Certificate>& certs) {
485 std::unique_ptr<FILE, decltype(&fclose)> f(fopen(filename, "r"), fclose);
486 if (!f) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700487 PLOG(ERROR) << "error opening " << filename;
Tao Bao71e3e092016-02-02 14:02:27 -0800488 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700489 }
490
Tao Bao71e3e092016-02-02 14:02:27 -0800491 while (true) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700492 certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
Tao Bao71e3e092016-02-02 14:02:27 -0800493 Certificate& cert = certs.back();
Elliott Hughes8febafa2016-04-13 16:39:56 -0700494 uint32_t exponent = 0;
Doug Zongker6c249f72012-11-02 15:04:05 -0700495
Tao Bao71e3e092016-02-02 14:02:27 -0800496 char start_char;
497 if (fscanf(f.get(), " %c", &start_char) != 1) return false;
498 if (start_char == '{') {
499 // a version 1 key has no version specifier.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700500 cert.key_type = Certificate::KEY_TYPE_RSA;
501 exponent = 3;
502 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800503 } else if (start_char == 'v') {
504 int version;
505 if (fscanf(f.get(), "%d {", &version) != 1) return false;
506 switch (version) {
507 case 2:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700508 cert.key_type = Certificate::KEY_TYPE_RSA;
509 exponent = 65537;
510 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800511 break;
512 case 3:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700513 cert.key_type = Certificate::KEY_TYPE_RSA;
514 exponent = 3;
515 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800516 break;
517 case 4:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700518 cert.key_type = Certificate::KEY_TYPE_RSA;
519 exponent = 65537;
520 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800521 break;
522 case 5:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700523 cert.key_type = Certificate::KEY_TYPE_EC;
524 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800525 break;
526 default:
527 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700528 }
Tao Bao71e3e092016-02-02 14:02:27 -0800529 }
Doug Zongker6c249f72012-11-02 15:04:05 -0700530
Elliott Hughes8febafa2016-04-13 16:39:56 -0700531 if (cert.key_type == Certificate::KEY_TYPE_RSA) {
532 cert.rsa = parse_rsa_key(f.get(), exponent);
533 if (!cert.rsa) {
534 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700535 }
Tao Bao71e3e092016-02-02 14:02:27 -0800536
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700537 LOG(INFO) << "read key e=" << exponent << " hash=" << cert.hash_len;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700538 } else if (cert.key_type == Certificate::KEY_TYPE_EC) {
539 cert.ec = parse_ec_key(f.get());
540 if (!cert.ec) {
541 return false;
Tao Bao71e3e092016-02-02 14:02:27 -0800542 }
Tao Bao71e3e092016-02-02 14:02:27 -0800543 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700544 LOG(ERROR) << "Unknown key type " << cert.key_type;
Tao Bao71e3e092016-02-02 14:02:27 -0800545 return false;
546 }
547
548 // if the line ends in a comma, this file has more keys.
549 int ch = fgetc(f.get());
550 if (ch == ',') {
551 // more keys to come.
552 continue;
553 } else if (ch == EOF) {
554 break;
555 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700556 LOG(ERROR) << "unexpected character between keys";
Tao Bao71e3e092016-02-02 14:02:27 -0800557 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700558 }
559 }
560
Tao Bao71e3e092016-02-02 14:02:27 -0800561 return true;
Doug Zongker6c249f72012-11-02 15:04:05 -0700562}