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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
Doug Zongker54e2e862009-08-17 13:21:04 -070017#include <errno.h>
Elliott Hughes26dbad22015-01-28 12:09:05 -080018#include <malloc.h>
19#include <stdio.h>
20#include <string.h>
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080021
Elliott Hughes8febafa2016-04-13 16:39:56 -070022#include <algorithm>
23#include <memory>
24
David Benjamina86392e2016-04-15 20:22:09 -040025#include <openssl/bn.h>
Elliott Hughes8febafa2016-04-13 16:39:56 -070026#include <openssl/ecdsa.h>
27#include <openssl/obj_mac.h>
28
29#include "asn1_decoder.h"
30#include "common.h"
31#include "ui.h"
32#include "verifier.h"
33
Doug Zongker211aebc2011-10-28 15:13:10 -070034extern RecoveryUI* ui;
35
Elliott Hughes8febafa2016-04-13 16:39:56 -070036static constexpr size_t MiB = 1024 * 1024;
37
Kenny Root7a4adb52013-10-09 10:14:35 -070038/*
39 * Simple version of PKCS#7 SignedData extraction. This extracts the
40 * signature OCTET STRING to be used for signature verification.
41 *
42 * For full details, see http://www.ietf.org/rfc/rfc3852.txt
43 *
44 * The PKCS#7 structure looks like:
45 *
46 * SEQUENCE (ContentInfo)
47 * OID (ContentType)
48 * [0] (content)
49 * SEQUENCE (SignedData)
50 * INTEGER (version CMSVersion)
51 * SET (DigestAlgorithmIdentifiers)
52 * SEQUENCE (EncapsulatedContentInfo)
53 * [0] (CertificateSet OPTIONAL)
54 * [1] (RevocationInfoChoices OPTIONAL)
55 * SET (SignerInfos)
56 * SEQUENCE (SignerInfo)
57 * INTEGER (CMSVersion)
58 * SEQUENCE (SignerIdentifier)
59 * SEQUENCE (DigestAlgorithmIdentifier)
60 * SEQUENCE (SignatureAlgorithmIdentifier)
61 * OCTET STRING (SignatureValue)
62 */
63static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_der,
64 size_t* sig_der_length) {
65 asn1_context_t* ctx = asn1_context_new(pkcs7_der, pkcs7_der_len);
66 if (ctx == NULL) {
67 return false;
68 }
69
70 asn1_context_t* pkcs7_seq = asn1_sequence_get(ctx);
71 if (pkcs7_seq != NULL && asn1_sequence_next(pkcs7_seq)) {
72 asn1_context_t *signed_data_app = asn1_constructed_get(pkcs7_seq);
73 if (signed_data_app != NULL) {
74 asn1_context_t* signed_data_seq = asn1_sequence_get(signed_data_app);
75 if (signed_data_seq != NULL
76 && asn1_sequence_next(signed_data_seq)
77 && asn1_sequence_next(signed_data_seq)
78 && asn1_sequence_next(signed_data_seq)
79 && asn1_constructed_skip_all(signed_data_seq)) {
80 asn1_context_t *sig_set = asn1_set_get(signed_data_seq);
81 if (sig_set != NULL) {
82 asn1_context_t* sig_seq = asn1_sequence_get(sig_set);
83 if (sig_seq != NULL
84 && asn1_sequence_next(sig_seq)
85 && asn1_sequence_next(sig_seq)
86 && asn1_sequence_next(sig_seq)
87 && asn1_sequence_next(sig_seq)) {
88 uint8_t* sig_der_ptr;
89 if (asn1_octet_string_get(sig_seq, &sig_der_ptr, sig_der_length)) {
90 *sig_der = (uint8_t*) malloc(*sig_der_length);
91 if (*sig_der != NULL) {
92 memcpy(*sig_der, sig_der_ptr, *sig_der_length);
93 }
94 }
95 asn1_context_free(sig_seq);
96 }
97 asn1_context_free(sig_set);
98 }
99 asn1_context_free(signed_data_seq);
100 }
101 asn1_context_free(signed_data_app);
102 }
103 asn1_context_free(pkcs7_seq);
104 }
105 asn1_context_free(ctx);
106
107 return *sig_der != NULL;
108}
109
Doug Zongker54e2e862009-08-17 13:21:04 -0700110// Look for an RSA signature embedded in the .ZIP file comment given
111// the path to the zip. Verify it matches one of the given public
112// keys.
113//
114// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
115// or no key matches the signature).
116
Doug Zongker99916f02014-01-13 14:16:58 -0800117int verify_file(unsigned char* addr, size_t length,
Tao Bao71e3e092016-02-02 14:02:27 -0800118 const std::vector<Certificate>& keys) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700119 ui->SetProgress(0.0);
Doug Zongker54e2e862009-08-17 13:21:04 -0700120
Doug Zongker54e2e862009-08-17 13:21:04 -0700121 // An archive with a whole-file signature will end in six bytes:
122 //
Doug Zongker73ae31c2009-12-09 17:01:45 -0800123 // (2-byte signature start) $ff $ff (2-byte comment size)
Doug Zongker54e2e862009-08-17 13:21:04 -0700124 //
125 // (As far as the ZIP format is concerned, these are part of the
126 // archive comment.) We start by reading this footer, this tells
127 // us how far back from the end we have to start reading to find
128 // the whole comment.
129
130#define FOOTER_SIZE 6
131
Doug Zongker99916f02014-01-13 14:16:58 -0800132 if (length < FOOTER_SIZE) {
133 LOGE("not big enough to contain footer\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700134 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800135 }
136
Doug Zongker99916f02014-01-13 14:16:58 -0800137 unsigned char* footer = addr + length - FOOTER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800138
Doug Zongker54e2e862009-08-17 13:21:04 -0700139 if (footer[2] != 0xff || footer[3] != 0xff) {
Doug Zongker30362a62013-04-10 11:32:17 -0700140 LOGE("footer is wrong\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700141 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800142 }
143
Doug Zongker28ce47c2011-10-28 10:33:05 -0700144 size_t comment_size = footer[4] + (footer[5] << 8);
145 size_t signature_start = footer[0] + (footer[1] << 8);
Mark Salyzynf3bb31c2014-03-14 09:39:48 -0700146 LOGI("comment is %zu bytes; signature %zu bytes from end\n",
Doug Zongker54e2e862009-08-17 13:21:04 -0700147 comment_size, signature_start);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800148
Kenny Root7a4adb52013-10-09 10:14:35 -0700149 if (signature_start <= FOOTER_SIZE) {
150 LOGE("Signature start is in the footer");
Doug Zongker54e2e862009-08-17 13:21:04 -0700151 return VERIFY_FAILURE;
152 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800153
Doug Zongker54e2e862009-08-17 13:21:04 -0700154#define EOCD_HEADER_SIZE 22
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800155
Doug Zongker54e2e862009-08-17 13:21:04 -0700156 // The end-of-central-directory record is 22 bytes plus any
157 // comment length.
158 size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800159
Doug Zongker99916f02014-01-13 14:16:58 -0800160 if (length < eocd_size) {
161 LOGE("not big enough to contain EOCD\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700162 return VERIFY_FAILURE;
163 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800164
Doug Zongker54e2e862009-08-17 13:21:04 -0700165 // Determine how much of the file is covered by the signature.
166 // This is everything except the signature data and length, which
167 // includes all of the EOCD except for the comment length field (2
168 // bytes) and the comment data.
Doug Zongker99916f02014-01-13 14:16:58 -0800169 size_t signed_len = length - eocd_size + EOCD_HEADER_SIZE - 2;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800170
Doug Zongker99916f02014-01-13 14:16:58 -0800171 unsigned char* eocd = addr + length - eocd_size;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800172
Doug Zongker54e2e862009-08-17 13:21:04 -0700173 // If this is really is the EOCD record, it will begin with the
174 // magic number $50 $4b $05 $06.
175 if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
176 eocd[2] != 0x05 || eocd[3] != 0x06) {
177 LOGE("signature length doesn't match EOCD marker\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700178 return VERIFY_FAILURE;
179 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800180
Tao Bao71e3e092016-02-02 14:02:27 -0800181 for (size_t i = 4; i < eocd_size-3; ++i) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700182 if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b &&
Doug Zongkerc652e412009-12-08 15:30:09 -0800183 eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700184 // if the sequence $50 $4b $05 $06 appears anywhere after
185 // the real one, minzip will find the later (wrong) one,
186 // which could be exploitable. Fail verification if
187 // this sequence occurs anywhere after the real one.
188 LOGE("EOCD marker occurs after start of EOCD\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700189 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800190 }
191 }
192
Doug Zongker30362a62013-04-10 11:32:17 -0700193 bool need_sha1 = false;
194 bool need_sha256 = false;
Tao Bao71e3e092016-02-02 14:02:27 -0800195 for (const auto& key : keys) {
196 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700197 case SHA_DIGEST_LENGTH: need_sha1 = true; break;
198 case SHA256_DIGEST_LENGTH: need_sha256 = true; break;
Doug Zongker30362a62013-04-10 11:32:17 -0700199 }
200 }
201
202 SHA_CTX sha1_ctx;
203 SHA256_CTX sha256_ctx;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700204 SHA1_Init(&sha1_ctx);
205 SHA256_Init(&sha256_ctx);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800206
Doug Zongker54e2e862009-08-17 13:21:04 -0700207 double frac = -1.0;
208 size_t so_far = 0;
Doug Zongker54e2e862009-08-17 13:21:04 -0700209 while (so_far < signed_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700210 // On a Nexus 9, experiment didn't show any performance improvement with
211 // larger sizes past 1MiB, and they reduce the granularity of the progress
212 // bar. http://b/28135231.
213 size_t size = std::min(signed_len - so_far, 1 * MiB);
Doug Zongker99916f02014-01-13 14:16:58 -0800214
Elliott Hughes8febafa2016-04-13 16:39:56 -0700215 if (need_sha1) SHA1_Update(&sha1_ctx, addr + so_far, size);
216 if (need_sha256) SHA256_Update(&sha256_ctx, addr + so_far, size);
Doug Zongker54e2e862009-08-17 13:21:04 -0700217 so_far += size;
Doug Zongker99916f02014-01-13 14:16:58 -0800218
Doug Zongker54e2e862009-08-17 13:21:04 -0700219 double f = so_far / (double)signed_len;
220 if (f > frac + 0.02 || size == so_far) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700221 ui->SetProgress(f);
Doug Zongker54e2e862009-08-17 13:21:04 -0700222 frac = f;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800223 }
224 }
225
Elliott Hughes8febafa2016-04-13 16:39:56 -0700226 uint8_t sha1[SHA_DIGEST_LENGTH];
227 SHA1_Final(sha1, &sha1_ctx);
228 uint8_t sha256[SHA256_DIGEST_LENGTH];
229 SHA256_Final(sha256, &sha256_ctx);
Doug Zongker30362a62013-04-10 11:32:17 -0700230
Tao Bao71e3e092016-02-02 14:02:27 -0800231 uint8_t* sig_der = nullptr;
Kenny Root7a4adb52013-10-09 10:14:35 -0700232 size_t sig_der_length = 0;
233
234 size_t signature_size = signature_start - FOOTER_SIZE;
235 if (!read_pkcs7(eocd + eocd_size - signature_start, signature_size, &sig_der,
236 &sig_der_length)) {
237 LOGE("Could not find signature DER block\n");
Kenny Root7a4adb52013-10-09 10:14:35 -0700238 return VERIFY_FAILURE;
239 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700240
241 /*
242 * Check to make sure at least one of the keys matches the signature. Since
243 * any key can match, we need to try each before determining a verification
244 * failure has happened.
245 */
Tao Bao71e3e092016-02-02 14:02:27 -0800246 size_t i = 0;
247 for (const auto& key : keys) {
Doug Zongker30362a62013-04-10 11:32:17 -0700248 const uint8_t* hash;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700249 int hash_nid;
Tao Bao71e3e092016-02-02 14:02:27 -0800250 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700251 case SHA_DIGEST_LENGTH:
252 hash = sha1;
253 hash_nid = NID_sha1;
254 break;
255 case SHA256_DIGEST_LENGTH:
256 hash = sha256;
257 hash_nid = NID_sha256;
258 break;
259 default:
260 continue;
Doug Zongker30362a62013-04-10 11:32:17 -0700261 }
262
Doug Zongker73ae31c2009-12-09 17:01:45 -0800263 // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
Doug Zongker54e2e862009-08-17 13:21:04 -0700264 // the signing tool appends after the signature itself.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700265 if (key.key_type == Certificate::KEY_TYPE_RSA) {
266 if (!RSA_verify(hash_nid, hash, key.hash_len, sig_der,
267 sig_der_length, key.rsa.get())) {
Mark Salyzynf3bb31c2014-03-14 09:39:48 -0700268 LOGI("failed to verify against RSA key %zu\n", i);
Kenny Root7a4adb52013-10-09 10:14:35 -0700269 continue;
270 }
271
Mark Salyzynf3bb31c2014-03-14 09:39:48 -0700272 LOGI("whole-file signature verified against RSA key %zu\n", i);
Kenny Root7a4adb52013-10-09 10:14:35 -0700273 free(sig_der);
274 return VERIFY_SUCCESS;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700275 } else if (key.key_type == Certificate::KEY_TYPE_EC
276 && key.hash_len == SHA256_DIGEST_LENGTH) {
277 if (!ECDSA_verify(0, hash, key.hash_len, sig_der,
278 sig_der_length, key.ec.get())) {
Mark Salyzynf3bb31c2014-03-14 09:39:48 -0700279 LOGI("failed to verify against EC key %zu\n", i);
Kenny Root7a4adb52013-10-09 10:14:35 -0700280 continue;
281 }
282
Mark Salyzynf3bb31c2014-03-14 09:39:48 -0700283 LOGI("whole-file signature verified against EC key %zu\n", i);
Kenny Root7a4adb52013-10-09 10:14:35 -0700284 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700285 return VERIFY_SUCCESS;
Doug Zongker6c249f72012-11-02 15:04:05 -0700286 } else {
Tao Bao71e3e092016-02-02 14:02:27 -0800287 LOGI("Unknown key type %d\n", key.key_type);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800288 }
Tao Bao71e3e092016-02-02 14:02:27 -0800289 i++;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800290 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700291 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700292 LOGE("failed to verify whole-file signature\n");
293 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800294}
Doug Zongker6c249f72012-11-02 15:04:05 -0700295
Elliott Hughes8febafa2016-04-13 16:39:56 -0700296std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) {
297 // Read key length in words and n0inv. n0inv is a precomputed montgomery
298 // parameter derived from the modulus and can be used to speed up
299 // verification. n0inv is 32 bits wide here, assuming the verification logic
300 // uses 32 bit arithmetic. However, BoringSSL may use a word size of 64 bits
301 // internally, in which case we don't have a valid n0inv. Thus, we just
302 // ignore the montgomery parameters and have BoringSSL recompute them
303 // internally. If/When the speedup from using the montgomery parameters
304 // becomes relevant, we can add more sophisticated code here to obtain a
305 // 64-bit n0inv and initialize the montgomery parameters in the key object.
306 uint32_t key_len_words = 0;
307 uint32_t n0inv = 0;
308 if (fscanf(file, " %i , 0x%x", &key_len_words, &n0inv) != 2) {
309 return nullptr;
310 }
311
312 if (key_len_words > 8192 / 32) {
313 LOGE("key length (%d) too large\n", key_len_words);
314 return nullptr;
315 }
316
317 // Read the modulus.
318 std::unique_ptr<uint32_t[]> modulus(new uint32_t[key_len_words]);
319 if (fscanf(file, " , { %u", &modulus[0]) != 1) {
320 return nullptr;
321 }
322 for (uint32_t i = 1; i < key_len_words; ++i) {
323 if (fscanf(file, " , %u", &modulus[i]) != 1) {
324 return nullptr;
325 }
326 }
327
328 // Cconvert from little-endian array of little-endian words to big-endian
329 // byte array suitable as input for BN_bin2bn.
330 std::reverse((uint8_t*)modulus.get(),
331 (uint8_t*)(modulus.get() + key_len_words));
332
333 // The next sequence of values is the montgomery parameter R^2. Since we
334 // generally don't have a valid |n0inv|, we ignore this (see comment above).
335 uint32_t rr_value;
336 if (fscanf(file, " } , { %u", &rr_value) != 1) {
337 return nullptr;
338 }
339 for (uint32_t i = 1; i < key_len_words; ++i) {
340 if (fscanf(file, " , %u", &rr_value) != 1) {
341 return nullptr;
342 }
343 }
344 if (fscanf(file, " } } ") != 0) {
345 return nullptr;
346 }
347
348 // Initialize the key.
349 std::unique_ptr<RSA, RSADeleter> key(RSA_new());
350 if (!key) {
351 return nullptr;
352 }
353
354 key->n = BN_bin2bn((uint8_t*)modulus.get(),
355 key_len_words * sizeof(uint32_t), NULL);
356 if (!key->n) {
357 return nullptr;
358 }
359
360 key->e = BN_new();
361 if (!key->e || !BN_set_word(key->e, exponent)) {
362 return nullptr;
363 }
364
365 return key;
366}
367
368struct BNDeleter {
369 void operator()(BIGNUM* bn) {
370 BN_free(bn);
371 }
372};
373
374std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) {
375 uint32_t key_len_bytes = 0;
376 if (fscanf(file, " %i", &key_len_bytes) != 1) {
377 return nullptr;
378 }
379
380 std::unique_ptr<EC_GROUP, void (*)(EC_GROUP*)> group(
381 EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1), EC_GROUP_free);
382 if (!group) {
383 return nullptr;
384 }
385
386 // Verify that |key_len| matches the group order.
387 if (key_len_bytes != BN_num_bytes(EC_GROUP_get0_order(group.get()))) {
388 return nullptr;
389 }
390
391 // Read the public key coordinates. Note that the byte order in the file is
392 // little-endian, so we convert to big-endian here.
393 std::unique_ptr<uint8_t[]> bytes(new uint8_t[key_len_bytes]);
394 std::unique_ptr<BIGNUM, BNDeleter> point[2];
395 for (int i = 0; i < 2; ++i) {
396 unsigned int byte = 0;
397 if (fscanf(file, " , { %u", &byte) != 1) {
398 return nullptr;
399 }
400 bytes[key_len_bytes - 1] = byte;
401
402 for (size_t i = 1; i < key_len_bytes; ++i) {
403 if (fscanf(file, " , %u", &byte) != 1) {
404 return nullptr;
405 }
406 bytes[key_len_bytes - i - 1] = byte;
407 }
408
409 point[i].reset(BN_bin2bn(bytes.get(), key_len_bytes, nullptr));
410 if (!point[i]) {
411 return nullptr;
412 }
413
414 if (fscanf(file, " }") != 0) {
415 return nullptr;
416 }
417 }
418
419 if (fscanf(file, " } ") != 0) {
420 return nullptr;
421 }
422
423 // Create and initialize the key.
424 std::unique_ptr<EC_KEY, ECKEYDeleter> key(EC_KEY_new());
425 if (!key || !EC_KEY_set_group(key.get(), group.get()) ||
426 !EC_KEY_set_public_key_affine_coordinates(key.get(), point[0].get(),
427 point[1].get())) {
428 return nullptr;
429 }
430
431 return key;
432}
433
Doug Zongker6c249f72012-11-02 15:04:05 -0700434// Reads a file containing one or more public keys as produced by
435// DumpPublicKey: this is an RSAPublicKey struct as it would appear
436// as a C source literal, eg:
437//
438// "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
439//
440// For key versions newer than the original 2048-bit e=3 keys
441// supported by Android, the string is preceded by a version
442// identifier, eg:
443//
444// "v2 {64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
445//
446// (Note that the braces and commas in this example are actual
447// characters the parser expects to find in the file; the ellipses
448// indicate more numbers omitted from this example.)
449//
450// The file may contain multiple keys in this format, separated by
451// commas. The last key must not be followed by a comma.
452//
Doug Zongker30362a62013-04-10 11:32:17 -0700453// A Certificate is a pair of an RSAPublicKey and a particular hash
454// (we support SHA-1 and SHA-256; we store the hash length to signify
455// which is being used). The hash used is implied by the version number.
456//
457// 1: 2048-bit RSA key with e=3 and SHA-1 hash
458// 2: 2048-bit RSA key with e=65537 and SHA-1 hash
459// 3: 2048-bit RSA key with e=3 and SHA-256 hash
460// 4: 2048-bit RSA key with e=65537 and SHA-256 hash
Kenny Root7a4adb52013-10-09 10:14:35 -0700461// 5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
Doug Zongker30362a62013-04-10 11:32:17 -0700462//
Tao Bao71e3e092016-02-02 14:02:27 -0800463// Returns true on success, and appends the found keys (at least one) to certs.
464// Otherwise returns false if the file failed to parse, or if it contains zero
465// keys. The contents in certs would be unspecified on failure.
466bool load_keys(const char* filename, std::vector<Certificate>& certs) {
467 std::unique_ptr<FILE, decltype(&fclose)> f(fopen(filename, "r"), fclose);
468 if (!f) {
Doug Zongker6c249f72012-11-02 15:04:05 -0700469 LOGE("opening %s: %s\n", filename, strerror(errno));
Tao Bao71e3e092016-02-02 14:02:27 -0800470 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700471 }
472
Tao Bao71e3e092016-02-02 14:02:27 -0800473 while (true) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700474 certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
Tao Bao71e3e092016-02-02 14:02:27 -0800475 Certificate& cert = certs.back();
Elliott Hughes8febafa2016-04-13 16:39:56 -0700476 uint32_t exponent = 0;
Doug Zongker6c249f72012-11-02 15:04:05 -0700477
Tao Bao71e3e092016-02-02 14:02:27 -0800478 char start_char;
479 if (fscanf(f.get(), " %c", &start_char) != 1) return false;
480 if (start_char == '{') {
481 // a version 1 key has no version specifier.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700482 cert.key_type = Certificate::KEY_TYPE_RSA;
483 exponent = 3;
484 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800485 } else if (start_char == 'v') {
486 int version;
487 if (fscanf(f.get(), "%d {", &version) != 1) return false;
488 switch (version) {
489 case 2:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700490 cert.key_type = Certificate::KEY_TYPE_RSA;
491 exponent = 65537;
492 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800493 break;
494 case 3:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700495 cert.key_type = Certificate::KEY_TYPE_RSA;
496 exponent = 3;
497 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800498 break;
499 case 4:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700500 cert.key_type = Certificate::KEY_TYPE_RSA;
501 exponent = 65537;
502 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800503 break;
504 case 5:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700505 cert.key_type = Certificate::KEY_TYPE_EC;
506 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800507 break;
508 default:
509 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700510 }
Tao Bao71e3e092016-02-02 14:02:27 -0800511 }
Doug Zongker6c249f72012-11-02 15:04:05 -0700512
Elliott Hughes8febafa2016-04-13 16:39:56 -0700513 if (cert.key_type == Certificate::KEY_TYPE_RSA) {
514 cert.rsa = parse_rsa_key(f.get(), exponent);
515 if (!cert.rsa) {
516 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700517 }
Tao Bao71e3e092016-02-02 14:02:27 -0800518
Elliott Hughes8febafa2016-04-13 16:39:56 -0700519 LOGI("read key e=%d hash=%d\n", exponent, cert.hash_len);
520 } else if (cert.key_type == Certificate::KEY_TYPE_EC) {
521 cert.ec = parse_ec_key(f.get());
522 if (!cert.ec) {
523 return false;
Tao Bao71e3e092016-02-02 14:02:27 -0800524 }
Tao Bao71e3e092016-02-02 14:02:27 -0800525 } else {
526 LOGE("Unknown key type %d\n", cert.key_type);
527 return false;
528 }
529
530 // if the line ends in a comma, this file has more keys.
531 int ch = fgetc(f.get());
532 if (ch == ',') {
533 // more keys to come.
534 continue;
535 } else if (ch == EOF) {
536 break;
537 } else {
538 LOGE("unexpected character between keys\n");
539 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700540 }
541 }
542
Tao Bao71e3e092016-02-02 14:02:27 -0800543 return true;
Doug Zongker6c249f72012-11-02 15:04:05 -0700544}