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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 Baoc0319b62016-10-13 15:17:04 -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 Baoc0319b62016-10-13 15:17:04 -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
Kenny Root7a4adb52013-10-09 10:14:35 -0700150 if (signature_start <= FOOTER_SIZE) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700151 LOG(ERROR) << "Signature start is in the footer";
Doug Zongker54e2e862009-08-17 13:21:04 -0700152 return VERIFY_FAILURE;
153 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800154
Doug Zongker54e2e862009-08-17 13:21:04 -0700155#define EOCD_HEADER_SIZE 22
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800156
Doug Zongker54e2e862009-08-17 13:21:04 -0700157 // The end-of-central-directory record is 22 bytes plus any
158 // comment length.
159 size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800160
Doug Zongker99916f02014-01-13 14:16:58 -0800161 if (length < eocd_size) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700162 LOG(ERROR) << "not big enough to contain EOCD";
Doug Zongker54e2e862009-08-17 13:21:04 -0700163 return VERIFY_FAILURE;
164 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800165
Doug Zongker54e2e862009-08-17 13:21:04 -0700166 // Determine how much of the file is covered by the signature.
167 // This is everything except the signature data and length, which
168 // includes all of the EOCD except for the comment length field (2
169 // bytes) and the comment data.
Doug Zongker99916f02014-01-13 14:16:58 -0800170 size_t signed_len = length - eocd_size + EOCD_HEADER_SIZE - 2;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800171
Doug Zongker99916f02014-01-13 14:16:58 -0800172 unsigned char* eocd = addr + length - eocd_size;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800173
Doug Zongker54e2e862009-08-17 13:21:04 -0700174 // If this is really is the EOCD record, it will begin with the
175 // magic number $50 $4b $05 $06.
176 if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
177 eocd[2] != 0x05 || eocd[3] != 0x06) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700178 LOG(ERROR) << "signature length doesn't match EOCD marker";
Doug Zongker54e2e862009-08-17 13:21:04 -0700179 return VERIFY_FAILURE;
180 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800181
Tao Bao71e3e092016-02-02 14:02:27 -0800182 for (size_t i = 4; i < eocd_size-3; ++i) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700183 if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b &&
Doug Zongkerc652e412009-12-08 15:30:09 -0800184 eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700185 // if the sequence $50 $4b $05 $06 appears anywhere after
Tianjie Xu8cf5c8f2016-09-08 20:10:11 -0700186 // the real one, libziparchive will find the later (wrong) one,
Doug Zongker54e2e862009-08-17 13:21:04 -0700187 // which could be exploitable. Fail verification if
188 // this sequence occurs anywhere after the real one.
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700189 LOG(ERROR) << "EOCD marker occurs after start of EOCD";
Doug Zongker54e2e862009-08-17 13:21:04 -0700190 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800191 }
192 }
193
Doug Zongker30362a62013-04-10 11:32:17 -0700194 bool need_sha1 = false;
195 bool need_sha256 = false;
Tao Bao71e3e092016-02-02 14:02:27 -0800196 for (const auto& key : keys) {
197 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700198 case SHA_DIGEST_LENGTH: need_sha1 = true; break;
199 case SHA256_DIGEST_LENGTH: need_sha256 = true; break;
Doug Zongker30362a62013-04-10 11:32:17 -0700200 }
201 }
202
203 SHA_CTX sha1_ctx;
204 SHA256_CTX sha256_ctx;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700205 SHA1_Init(&sha1_ctx);
206 SHA256_Init(&sha256_ctx);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800207
Doug Zongker54e2e862009-08-17 13:21:04 -0700208 double frac = -1.0;
209 size_t so_far = 0;
Doug Zongker54e2e862009-08-17 13:21:04 -0700210 while (so_far < signed_len) {
Elliott Hughesdd895d02016-04-19 15:24:38 -0700211 // On a Nexus 5X, experiment showed 16MiB beat 1MiB by 6% faster for a
212 // 1196MiB full OTA and 60% for an 89MiB incremental OTA.
213 // http://b/28135231.
214 size_t size = std::min(signed_len - so_far, 16 * MiB);
Doug Zongker99916f02014-01-13 14:16:58 -0800215
Elliott Hughes8febafa2016-04-13 16:39:56 -0700216 if (need_sha1) SHA1_Update(&sha1_ctx, addr + so_far, size);
217 if (need_sha256) SHA256_Update(&sha256_ctx, addr + so_far, size);
Doug Zongker54e2e862009-08-17 13:21:04 -0700218 so_far += size;
Doug Zongker99916f02014-01-13 14:16:58 -0800219
Doug Zongker54e2e862009-08-17 13:21:04 -0700220 double f = so_far / (double)signed_len;
221 if (f > frac + 0.02 || size == so_far) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700222 ui->SetProgress(f);
Doug Zongker54e2e862009-08-17 13:21:04 -0700223 frac = f;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800224 }
225 }
226
Elliott Hughes8febafa2016-04-13 16:39:56 -0700227 uint8_t sha1[SHA_DIGEST_LENGTH];
228 SHA1_Final(sha1, &sha1_ctx);
229 uint8_t sha256[SHA256_DIGEST_LENGTH];
230 SHA256_Final(sha256, &sha256_ctx);
Doug Zongker30362a62013-04-10 11:32:17 -0700231
Tao Bao71e3e092016-02-02 14:02:27 -0800232 uint8_t* sig_der = nullptr;
Kenny Root7a4adb52013-10-09 10:14:35 -0700233 size_t sig_der_length = 0;
234
Tao Baoe1792762016-04-19 22:31:01 -0700235 uint8_t* signature = eocd + eocd_size - signature_start;
Kenny Root7a4adb52013-10-09 10:14:35 -0700236 size_t signature_size = signature_start - FOOTER_SIZE;
Tao Baoe1792762016-04-19 22:31:01 -0700237
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700238 LOG(INFO) << "signature (offset: " << std::hex << (length - signature_start) << ", length: "
239 << signature_size << "): " << print_hex(signature, signature_size);
Tao Baoe1792762016-04-19 22:31:01 -0700240
241 if (!read_pkcs7(signature, signature_size, &sig_der, &sig_der_length)) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700242 LOG(ERROR) << "Could not find signature DER block";
Kenny Root7a4adb52013-10-09 10:14:35 -0700243 return VERIFY_FAILURE;
244 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700245
246 /*
247 * Check to make sure at least one of the keys matches the signature. Since
248 * any key can match, we need to try each before determining a verification
249 * failure has happened.
250 */
Tao Bao71e3e092016-02-02 14:02:27 -0800251 size_t i = 0;
252 for (const auto& key : keys) {
Doug Zongker30362a62013-04-10 11:32:17 -0700253 const uint8_t* hash;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700254 int hash_nid;
Tao Bao71e3e092016-02-02 14:02:27 -0800255 switch (key.hash_len) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700256 case SHA_DIGEST_LENGTH:
257 hash = sha1;
258 hash_nid = NID_sha1;
259 break;
260 case SHA256_DIGEST_LENGTH:
261 hash = sha256;
262 hash_nid = NID_sha256;
263 break;
264 default:
265 continue;
Doug Zongker30362a62013-04-10 11:32:17 -0700266 }
267
Doug Zongker73ae31c2009-12-09 17:01:45 -0800268 // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
Doug Zongker54e2e862009-08-17 13:21:04 -0700269 // the signing tool appends after the signature itself.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700270 if (key.key_type == Certificate::KEY_TYPE_RSA) {
271 if (!RSA_verify(hash_nid, hash, key.hash_len, sig_der,
272 sig_der_length, key.rsa.get())) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700273 LOG(INFO) << "failed to verify against RSA key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700274 continue;
275 }
276
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700277 LOG(INFO) << "whole-file signature verified against RSA key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700278 free(sig_der);
279 return VERIFY_SUCCESS;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700280 } else if (key.key_type == Certificate::KEY_TYPE_EC
281 && key.hash_len == SHA256_DIGEST_LENGTH) {
282 if (!ECDSA_verify(0, hash, key.hash_len, sig_der,
283 sig_der_length, key.ec.get())) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700284 LOG(INFO) << "failed to verify against EC key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700285 continue;
286 }
287
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700288 LOG(INFO) << "whole-file signature verified against EC key " << i;
Kenny Root7a4adb52013-10-09 10:14:35 -0700289 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700290 return VERIFY_SUCCESS;
Doug Zongker6c249f72012-11-02 15:04:05 -0700291 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700292 LOG(INFO) << "Unknown key type " << key.key_type;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800293 }
Tao Bao71e3e092016-02-02 14:02:27 -0800294 i++;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800295 }
Tao Baoe1792762016-04-19 22:31:01 -0700296
297 if (need_sha1) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700298 LOG(INFO) << "SHA-1 digest: " << print_hex(sha1, SHA_DIGEST_LENGTH);
Tao Baoe1792762016-04-19 22:31:01 -0700299 }
300 if (need_sha256) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700301 LOG(INFO) << "SHA-256 digest: " << print_hex(sha256, SHA256_DIGEST_LENGTH);
Tao Baoe1792762016-04-19 22:31:01 -0700302 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700303 free(sig_der);
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700304 LOG(ERROR) << "failed to verify whole-file signature";
Doug Zongker54e2e862009-08-17 13:21:04 -0700305 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800306}
Doug Zongker6c249f72012-11-02 15:04:05 -0700307
Elliott Hughes8febafa2016-04-13 16:39:56 -0700308std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) {
309 // Read key length in words and n0inv. n0inv is a precomputed montgomery
310 // parameter derived from the modulus and can be used to speed up
311 // verification. n0inv is 32 bits wide here, assuming the verification logic
312 // uses 32 bit arithmetic. However, BoringSSL may use a word size of 64 bits
313 // internally, in which case we don't have a valid n0inv. Thus, we just
314 // ignore the montgomery parameters and have BoringSSL recompute them
315 // internally. If/When the speedup from using the montgomery parameters
316 // becomes relevant, we can add more sophisticated code here to obtain a
317 // 64-bit n0inv and initialize the montgomery parameters in the key object.
318 uint32_t key_len_words = 0;
319 uint32_t n0inv = 0;
320 if (fscanf(file, " %i , 0x%x", &key_len_words, &n0inv) != 2) {
321 return nullptr;
322 }
323
324 if (key_len_words > 8192 / 32) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700325 LOG(ERROR) << "key length (" << key_len_words << ") too large";
Elliott Hughes8febafa2016-04-13 16:39:56 -0700326 return nullptr;
327 }
328
329 // Read the modulus.
330 std::unique_ptr<uint32_t[]> modulus(new uint32_t[key_len_words]);
331 if (fscanf(file, " , { %u", &modulus[0]) != 1) {
332 return nullptr;
333 }
334 for (uint32_t i = 1; i < key_len_words; ++i) {
335 if (fscanf(file, " , %u", &modulus[i]) != 1) {
336 return nullptr;
337 }
338 }
339
340 // Cconvert from little-endian array of little-endian words to big-endian
341 // byte array suitable as input for BN_bin2bn.
342 std::reverse((uint8_t*)modulus.get(),
343 (uint8_t*)(modulus.get() + key_len_words));
344
345 // The next sequence of values is the montgomery parameter R^2. Since we
346 // generally don't have a valid |n0inv|, we ignore this (see comment above).
347 uint32_t rr_value;
348 if (fscanf(file, " } , { %u", &rr_value) != 1) {
349 return nullptr;
350 }
351 for (uint32_t i = 1; i < key_len_words; ++i) {
352 if (fscanf(file, " , %u", &rr_value) != 1) {
353 return nullptr;
354 }
355 }
356 if (fscanf(file, " } } ") != 0) {
357 return nullptr;
358 }
359
360 // Initialize the key.
361 std::unique_ptr<RSA, RSADeleter> key(RSA_new());
362 if (!key) {
363 return nullptr;
364 }
365
366 key->n = BN_bin2bn((uint8_t*)modulus.get(),
367 key_len_words * sizeof(uint32_t), NULL);
368 if (!key->n) {
369 return nullptr;
370 }
371
372 key->e = BN_new();
373 if (!key->e || !BN_set_word(key->e, exponent)) {
374 return nullptr;
375 }
376
377 return key;
378}
379
380struct BNDeleter {
381 void operator()(BIGNUM* bn) {
382 BN_free(bn);
383 }
384};
385
386std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) {
387 uint32_t key_len_bytes = 0;
388 if (fscanf(file, " %i", &key_len_bytes) != 1) {
389 return nullptr;
390 }
391
392 std::unique_ptr<EC_GROUP, void (*)(EC_GROUP*)> group(
393 EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1), EC_GROUP_free);
394 if (!group) {
395 return nullptr;
396 }
397
398 // Verify that |key_len| matches the group order.
399 if (key_len_bytes != BN_num_bytes(EC_GROUP_get0_order(group.get()))) {
400 return nullptr;
401 }
402
403 // Read the public key coordinates. Note that the byte order in the file is
404 // little-endian, so we convert to big-endian here.
405 std::unique_ptr<uint8_t[]> bytes(new uint8_t[key_len_bytes]);
406 std::unique_ptr<BIGNUM, BNDeleter> point[2];
407 for (int i = 0; i < 2; ++i) {
408 unsigned int byte = 0;
409 if (fscanf(file, " , { %u", &byte) != 1) {
410 return nullptr;
411 }
412 bytes[key_len_bytes - 1] = byte;
413
414 for (size_t i = 1; i < key_len_bytes; ++i) {
415 if (fscanf(file, " , %u", &byte) != 1) {
416 return nullptr;
417 }
418 bytes[key_len_bytes - i - 1] = byte;
419 }
420
421 point[i].reset(BN_bin2bn(bytes.get(), key_len_bytes, nullptr));
422 if (!point[i]) {
423 return nullptr;
424 }
425
426 if (fscanf(file, " }") != 0) {
427 return nullptr;
428 }
429 }
430
431 if (fscanf(file, " } ") != 0) {
432 return nullptr;
433 }
434
435 // Create and initialize the key.
436 std::unique_ptr<EC_KEY, ECKEYDeleter> key(EC_KEY_new());
437 if (!key || !EC_KEY_set_group(key.get(), group.get()) ||
438 !EC_KEY_set_public_key_affine_coordinates(key.get(), point[0].get(),
439 point[1].get())) {
440 return nullptr;
441 }
442
443 return key;
444}
445
Doug Zongker6c249f72012-11-02 15:04:05 -0700446// Reads a file containing one or more public keys as produced by
447// DumpPublicKey: this is an RSAPublicKey struct as it would appear
448// as a C source literal, eg:
449//
450// "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
451//
452// For key versions newer than the original 2048-bit e=3 keys
453// supported by Android, the string is preceded by a version
454// identifier, eg:
455//
456// "v2 {64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
457//
458// (Note that the braces and commas in this example are actual
459// characters the parser expects to find in the file; the ellipses
460// indicate more numbers omitted from this example.)
461//
462// The file may contain multiple keys in this format, separated by
463// commas. The last key must not be followed by a comma.
464//
Doug Zongker30362a62013-04-10 11:32:17 -0700465// A Certificate is a pair of an RSAPublicKey and a particular hash
466// (we support SHA-1 and SHA-256; we store the hash length to signify
467// which is being used). The hash used is implied by the version number.
468//
469// 1: 2048-bit RSA key with e=3 and SHA-1 hash
470// 2: 2048-bit RSA key with e=65537 and SHA-1 hash
471// 3: 2048-bit RSA key with e=3 and SHA-256 hash
472// 4: 2048-bit RSA key with e=65537 and SHA-256 hash
Kenny Root7a4adb52013-10-09 10:14:35 -0700473// 5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
Doug Zongker30362a62013-04-10 11:32:17 -0700474//
Tao Bao71e3e092016-02-02 14:02:27 -0800475// Returns true on success, and appends the found keys (at least one) to certs.
476// Otherwise returns false if the file failed to parse, or if it contains zero
477// keys. The contents in certs would be unspecified on failure.
478bool load_keys(const char* filename, std::vector<Certificate>& certs) {
479 std::unique_ptr<FILE, decltype(&fclose)> f(fopen(filename, "r"), fclose);
480 if (!f) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700481 PLOG(ERROR) << "error opening " << filename;
Tao Bao71e3e092016-02-02 14:02:27 -0800482 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700483 }
484
Tao Bao71e3e092016-02-02 14:02:27 -0800485 while (true) {
Elliott Hughes8febafa2016-04-13 16:39:56 -0700486 certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
Tao Bao71e3e092016-02-02 14:02:27 -0800487 Certificate& cert = certs.back();
Elliott Hughes8febafa2016-04-13 16:39:56 -0700488 uint32_t exponent = 0;
Doug Zongker6c249f72012-11-02 15:04:05 -0700489
Tao Bao71e3e092016-02-02 14:02:27 -0800490 char start_char;
491 if (fscanf(f.get(), " %c", &start_char) != 1) return false;
492 if (start_char == '{') {
493 // a version 1 key has no version specifier.
Elliott Hughes8febafa2016-04-13 16:39:56 -0700494 cert.key_type = Certificate::KEY_TYPE_RSA;
495 exponent = 3;
496 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800497 } else if (start_char == 'v') {
498 int version;
499 if (fscanf(f.get(), "%d {", &version) != 1) return false;
500 switch (version) {
501 case 2:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700502 cert.key_type = Certificate::KEY_TYPE_RSA;
503 exponent = 65537;
504 cert.hash_len = SHA_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800505 break;
506 case 3:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700507 cert.key_type = Certificate::KEY_TYPE_RSA;
508 exponent = 3;
509 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800510 break;
511 case 4:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700512 cert.key_type = Certificate::KEY_TYPE_RSA;
513 exponent = 65537;
514 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800515 break;
516 case 5:
Elliott Hughes8febafa2016-04-13 16:39:56 -0700517 cert.key_type = Certificate::KEY_TYPE_EC;
518 cert.hash_len = SHA256_DIGEST_LENGTH;
Tao Bao71e3e092016-02-02 14:02:27 -0800519 break;
520 default:
521 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700522 }
Tao Bao71e3e092016-02-02 14:02:27 -0800523 }
Doug Zongker6c249f72012-11-02 15:04:05 -0700524
Elliott Hughes8febafa2016-04-13 16:39:56 -0700525 if (cert.key_type == Certificate::KEY_TYPE_RSA) {
526 cert.rsa = parse_rsa_key(f.get(), exponent);
527 if (!cert.rsa) {
528 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700529 }
Tao Bao71e3e092016-02-02 14:02:27 -0800530
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700531 LOG(INFO) << "read key e=" << exponent << " hash=" << cert.hash_len;
Elliott Hughes8febafa2016-04-13 16:39:56 -0700532 } else if (cert.key_type == Certificate::KEY_TYPE_EC) {
533 cert.ec = parse_ec_key(f.get());
534 if (!cert.ec) {
535 return false;
Tao Bao71e3e092016-02-02 14:02:27 -0800536 }
Tao Bao71e3e092016-02-02 14:02:27 -0800537 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700538 LOG(ERROR) << "Unknown key type " << cert.key_type;
Tao Bao71e3e092016-02-02 14:02:27 -0800539 return false;
540 }
541
542 // if the line ends in a comma, this file has more keys.
543 int ch = fgetc(f.get());
544 if (ch == ',') {
545 // more keys to come.
546 continue;
547 } else if (ch == EOF) {
548 break;
549 } else {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700550 LOG(ERROR) << "unexpected character between keys";
Tao Bao71e3e092016-02-02 14:02:27 -0800551 return false;
Doug Zongker6c249f72012-11-02 15:04:05 -0700552 }
553 }
554
Tao Bao71e3e092016-02-02 14:02:27 -0800555 return true;
Doug Zongker6c249f72012-11-02 15:04:05 -0700556}