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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
Kenny Root7a4adb52013-10-09 10:14:35 -070017#include "asn1_decoder.h"
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080018#include "common.h"
Doug Zongker28ce47c2011-10-28 10:33:05 -070019#include "ui.h"
Kenny Root7a4adb52013-10-09 10:14:35 -070020#include "verifier.h"
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080021
Kenny Root7a4adb52013-10-09 10:14:35 -070022#include "mincrypt/dsa_sig.h"
23#include "mincrypt/p256.h"
24#include "mincrypt/p256_ecdsa.h"
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080025#include "mincrypt/rsa.h"
26#include "mincrypt/sha.h"
Doug Zongker30362a62013-04-10 11:32:17 -070027#include "mincrypt/sha256.h"
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080028
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080029#include <string.h>
Doug Zongker54e2e862009-08-17 13:21:04 -070030#include <stdio.h>
31#include <errno.h>
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -080032
Doug Zongker211aebc2011-10-28 15:13:10 -070033extern RecoveryUI* ui;
34
Kenny Root7a4adb52013-10-09 10:14:35 -070035/*
36 * Simple version of PKCS#7 SignedData extraction. This extracts the
37 * signature OCTET STRING to be used for signature verification.
38 *
39 * For full details, see http://www.ietf.org/rfc/rfc3852.txt
40 *
41 * The PKCS#7 structure looks like:
42 *
43 * SEQUENCE (ContentInfo)
44 * OID (ContentType)
45 * [0] (content)
46 * SEQUENCE (SignedData)
47 * INTEGER (version CMSVersion)
48 * SET (DigestAlgorithmIdentifiers)
49 * SEQUENCE (EncapsulatedContentInfo)
50 * [0] (CertificateSet OPTIONAL)
51 * [1] (RevocationInfoChoices OPTIONAL)
52 * SET (SignerInfos)
53 * SEQUENCE (SignerInfo)
54 * INTEGER (CMSVersion)
55 * SEQUENCE (SignerIdentifier)
56 * SEQUENCE (DigestAlgorithmIdentifier)
57 * SEQUENCE (SignatureAlgorithmIdentifier)
58 * OCTET STRING (SignatureValue)
59 */
60static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_der,
61 size_t* sig_der_length) {
62 asn1_context_t* ctx = asn1_context_new(pkcs7_der, pkcs7_der_len);
63 if (ctx == NULL) {
64 return false;
65 }
66
67 asn1_context_t* pkcs7_seq = asn1_sequence_get(ctx);
68 if (pkcs7_seq != NULL && asn1_sequence_next(pkcs7_seq)) {
69 asn1_context_t *signed_data_app = asn1_constructed_get(pkcs7_seq);
70 if (signed_data_app != NULL) {
71 asn1_context_t* signed_data_seq = asn1_sequence_get(signed_data_app);
72 if (signed_data_seq != NULL
73 && asn1_sequence_next(signed_data_seq)
74 && asn1_sequence_next(signed_data_seq)
75 && asn1_sequence_next(signed_data_seq)
76 && asn1_constructed_skip_all(signed_data_seq)) {
77 asn1_context_t *sig_set = asn1_set_get(signed_data_seq);
78 if (sig_set != NULL) {
79 asn1_context_t* sig_seq = asn1_sequence_get(sig_set);
80 if (sig_seq != NULL
81 && asn1_sequence_next(sig_seq)
82 && asn1_sequence_next(sig_seq)
83 && asn1_sequence_next(sig_seq)
84 && asn1_sequence_next(sig_seq)) {
85 uint8_t* sig_der_ptr;
86 if (asn1_octet_string_get(sig_seq, &sig_der_ptr, sig_der_length)) {
87 *sig_der = (uint8_t*) malloc(*sig_der_length);
88 if (*sig_der != NULL) {
89 memcpy(*sig_der, sig_der_ptr, *sig_der_length);
90 }
91 }
92 asn1_context_free(sig_seq);
93 }
94 asn1_context_free(sig_set);
95 }
96 asn1_context_free(signed_data_seq);
97 }
98 asn1_context_free(signed_data_app);
99 }
100 asn1_context_free(pkcs7_seq);
101 }
102 asn1_context_free(ctx);
103
104 return *sig_der != NULL;
105}
106
Doug Zongker54e2e862009-08-17 13:21:04 -0700107// Look for an RSA signature embedded in the .ZIP file comment given
108// the path to the zip. Verify it matches one of the given public
109// keys.
110//
111// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
112// or no key matches the signature).
113
Doug Zongker30362a62013-04-10 11:32:17 -0700114int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700115 ui->SetProgress(0.0);
Doug Zongker54e2e862009-08-17 13:21:04 -0700116
117 FILE* f = fopen(path, "rb");
118 if (f == NULL) {
119 LOGE("failed to open %s (%s)\n", path, strerror(errno));
120 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800121 }
122
Doug Zongker54e2e862009-08-17 13:21:04 -0700123 // An archive with a whole-file signature will end in six bytes:
124 //
Doug Zongker73ae31c2009-12-09 17:01:45 -0800125 // (2-byte signature start) $ff $ff (2-byte comment size)
Doug Zongker54e2e862009-08-17 13:21:04 -0700126 //
127 // (As far as the ZIP format is concerned, these are part of the
128 // archive comment.) We start by reading this footer, this tells
129 // us how far back from the end we have to start reading to find
130 // the whole comment.
131
132#define FOOTER_SIZE 6
133
134 if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) {
135 LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
136 fclose(f);
137 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800138 }
139
Doug Zongker54e2e862009-08-17 13:21:04 -0700140 unsigned char footer[FOOTER_SIZE];
141 if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) {
142 LOGE("failed to read footer from %s (%s)\n", path, strerror(errno));
143 fclose(f);
144 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800145 }
146
Doug Zongker54e2e862009-08-17 13:21:04 -0700147 if (footer[2] != 0xff || footer[3] != 0xff) {
Doug Zongker30362a62013-04-10 11:32:17 -0700148 LOGE("footer is wrong\n");
Doug Zongker54e2e862009-08-17 13:21:04 -0700149 fclose(f);
150 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800151 }
152
Doug Zongker28ce47c2011-10-28 10:33:05 -0700153 size_t comment_size = footer[4] + (footer[5] << 8);
154 size_t signature_start = footer[0] + (footer[1] << 8);
Doug Zongker54e2e862009-08-17 13:21:04 -0700155 LOGI("comment is %d bytes; signature %d bytes from end\n",
156 comment_size, signature_start);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800157
Kenny Root7a4adb52013-10-09 10:14:35 -0700158 if (signature_start <= FOOTER_SIZE) {
159 LOGE("Signature start is in the footer");
Doug Zongker54e2e862009-08-17 13:21:04 -0700160 fclose(f);
161 return VERIFY_FAILURE;
162 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800163
Doug Zongker54e2e862009-08-17 13:21:04 -0700164#define EOCD_HEADER_SIZE 22
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800165
Doug Zongker54e2e862009-08-17 13:21:04 -0700166 // The end-of-central-directory record is 22 bytes plus any
167 // comment length.
168 size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800169
Doug Zongker54e2e862009-08-17 13:21:04 -0700170 if (fseek(f, -eocd_size, SEEK_END) != 0) {
171 LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
172 fclose(f);
173 return VERIFY_FAILURE;
174 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800175
Doug Zongker54e2e862009-08-17 13:21:04 -0700176 // Determine how much of the file is covered by the signature.
177 // This is everything except the signature data and length, which
178 // includes all of the EOCD except for the comment length field (2
179 // bytes) and the comment data.
180 size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800181
Doug Zongker28ce47c2011-10-28 10:33:05 -0700182 unsigned char* eocd = (unsigned char*)malloc(eocd_size);
Doug Zongker54e2e862009-08-17 13:21:04 -0700183 if (eocd == NULL) {
184 LOGE("malloc for EOCD record failed\n");
185 fclose(f);
186 return VERIFY_FAILURE;
187 }
188 if (fread(eocd, 1, eocd_size, f) != eocd_size) {
189 LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno));
190 fclose(f);
191 return VERIFY_FAILURE;
192 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800193
Doug Zongker54e2e862009-08-17 13:21:04 -0700194 // If this is really is the EOCD record, it will begin with the
195 // magic number $50 $4b $05 $06.
196 if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
197 eocd[2] != 0x05 || eocd[3] != 0x06) {
198 LOGE("signature length doesn't match EOCD marker\n");
199 fclose(f);
200 return VERIFY_FAILURE;
201 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800202
Doug Zongker28ce47c2011-10-28 10:33:05 -0700203 size_t i;
Doug Zongker54e2e862009-08-17 13:21:04 -0700204 for (i = 4; i < eocd_size-3; ++i) {
205 if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b &&
Doug Zongkerc652e412009-12-08 15:30:09 -0800206 eocd[i+2] == 0x05 && eocd[i+3] == 0x06) {
Doug Zongker54e2e862009-08-17 13:21:04 -0700207 // if the sequence $50 $4b $05 $06 appears anywhere after
208 // the real one, minzip will find the later (wrong) one,
209 // which could be exploitable. Fail verification if
210 // this sequence occurs anywhere after the real one.
211 LOGE("EOCD marker occurs after start of EOCD\n");
212 fclose(f);
213 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800214 }
215 }
216
Doug Zongker54e2e862009-08-17 13:21:04 -0700217#define BUFFER_SIZE 4096
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800218
Doug Zongker30362a62013-04-10 11:32:17 -0700219 bool need_sha1 = false;
220 bool need_sha256 = false;
221 for (i = 0; i < numKeys; ++i) {
222 switch (pKeys[i].hash_len) {
223 case SHA_DIGEST_SIZE: need_sha1 = true; break;
224 case SHA256_DIGEST_SIZE: need_sha256 = true; break;
225 }
226 }
227
228 SHA_CTX sha1_ctx;
229 SHA256_CTX sha256_ctx;
230 SHA_init(&sha1_ctx);
231 SHA256_init(&sha256_ctx);
Doug Zongker28ce47c2011-10-28 10:33:05 -0700232 unsigned char* buffer = (unsigned char*)malloc(BUFFER_SIZE);
Doug Zongker54e2e862009-08-17 13:21:04 -0700233 if (buffer == NULL) {
234 LOGE("failed to alloc memory for sha1 buffer\n");
235 fclose(f);
236 return VERIFY_FAILURE;
237 }
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800238
Doug Zongker54e2e862009-08-17 13:21:04 -0700239 double frac = -1.0;
240 size_t so_far = 0;
241 fseek(f, 0, SEEK_SET);
242 while (so_far < signed_len) {
Doug Zongker28ce47c2011-10-28 10:33:05 -0700243 size_t size = BUFFER_SIZE;
Doug Zongker54e2e862009-08-17 13:21:04 -0700244 if (signed_len - so_far < size) size = signed_len - so_far;
245 if (fread(buffer, 1, size, f) != size) {
246 LOGE("failed to read data from %s (%s)\n", path, strerror(errno));
247 fclose(f);
248 return VERIFY_FAILURE;
249 }
Doug Zongker30362a62013-04-10 11:32:17 -0700250 if (need_sha1) SHA_update(&sha1_ctx, buffer, size);
251 if (need_sha256) SHA256_update(&sha256_ctx, buffer, size);
Doug Zongker54e2e862009-08-17 13:21:04 -0700252 so_far += size;
253 double f = so_far / (double)signed_len;
254 if (f > frac + 0.02 || size == so_far) {
Doug Zongker211aebc2011-10-28 15:13:10 -0700255 ui->SetProgress(f);
Doug Zongker54e2e862009-08-17 13:21:04 -0700256 frac = f;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800257 }
258 }
Doug Zongker54e2e862009-08-17 13:21:04 -0700259 fclose(f);
260 free(buffer);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800261
Doug Zongker30362a62013-04-10 11:32:17 -0700262 const uint8_t* sha1 = SHA_final(&sha1_ctx);
263 const uint8_t* sha256 = SHA256_final(&sha256_ctx);
264
Kenny Root7a4adb52013-10-09 10:14:35 -0700265 uint8_t* sig_der = NULL;
266 size_t sig_der_length = 0;
267
268 size_t signature_size = signature_start - FOOTER_SIZE;
269 if (!read_pkcs7(eocd + eocd_size - signature_start, signature_size, &sig_der,
270 &sig_der_length)) {
271 LOGE("Could not find signature DER block\n");
272 free(eocd);
273 return VERIFY_FAILURE;
274 }
275 free(eocd);
276
277 /*
278 * Check to make sure at least one of the keys matches the signature. Since
279 * any key can match, we need to try each before determining a verification
280 * failure has happened.
281 */
Doug Zongker54e2e862009-08-17 13:21:04 -0700282 for (i = 0; i < numKeys; ++i) {
Doug Zongker30362a62013-04-10 11:32:17 -0700283 const uint8_t* hash;
284 switch (pKeys[i].hash_len) {
285 case SHA_DIGEST_SIZE: hash = sha1; break;
286 case SHA256_DIGEST_SIZE: hash = sha256; break;
287 default: continue;
288 }
289
Doug Zongker73ae31c2009-12-09 17:01:45 -0800290 // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that
Doug Zongker54e2e862009-08-17 13:21:04 -0700291 // the signing tool appends after the signature itself.
Kenny Root7a4adb52013-10-09 10:14:35 -0700292 if (pKeys[i].key_type == Certificate::RSA) {
293 if (sig_der_length < RSANUMBYTES) {
294 // "signature" block isn't big enough to contain an RSA block.
295 LOGI("signature is too short for RSA key %d\n", i);
296 continue;
297 }
298
299 if (!RSA_verify(pKeys[i].rsa, sig_der, RSANUMBYTES,
300 hash, pKeys[i].hash_len)) {
301 LOGI("failed to verify against RSA key %d\n", i);
302 continue;
303 }
304
305 LOGI("whole-file signature verified against RSA key %d\n", i);
306 free(sig_der);
307 return VERIFY_SUCCESS;
308 } else if (pKeys[i].key_type == Certificate::EC
309 && pKeys[i].hash_len == SHA256_DIGEST_SIZE) {
310 p256_int r, s;
311 if (!dsa_sig_unpack(sig_der, sig_der_length, &r, &s)) {
312 LOGI("Not a DSA signature block for EC key %d\n", i);
313 continue;
314 }
315
316 p256_int p256_hash;
317 p256_from_bin(hash, &p256_hash);
318 if (!p256_ecdsa_verify(&(pKeys[i].ec->x), &(pKeys[i].ec->y),
319 &p256_hash, &r, &s)) {
320 LOGI("failed to verify against EC key %d\n", i);
321 continue;
322 }
323
324 LOGI("whole-file signature verified against EC key %d\n", i);
325 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700326 return VERIFY_SUCCESS;
Doug Zongker6c249f72012-11-02 15:04:05 -0700327 } else {
Kenny Root7a4adb52013-10-09 10:14:35 -0700328 LOGI("Unknown key type %d\n", pKeys[i].key_type);
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800329 }
330 }
Kenny Root7a4adb52013-10-09 10:14:35 -0700331 free(sig_der);
Doug Zongker54e2e862009-08-17 13:21:04 -0700332 LOGE("failed to verify whole-file signature\n");
333 return VERIFY_FAILURE;
The Android Open Source Projectc24a8e62009-03-03 19:28:42 -0800334}
Doug Zongker6c249f72012-11-02 15:04:05 -0700335
336// Reads a file containing one or more public keys as produced by
337// DumpPublicKey: this is an RSAPublicKey struct as it would appear
338// as a C source literal, eg:
339//
340// "{64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
341//
342// For key versions newer than the original 2048-bit e=3 keys
343// supported by Android, the string is preceded by a version
344// identifier, eg:
345//
346// "v2 {64,0xc926ad21,{1795090719,...,-695002876},{-857949815,...,1175080310}}"
347//
348// (Note that the braces and commas in this example are actual
349// characters the parser expects to find in the file; the ellipses
350// indicate more numbers omitted from this example.)
351//
352// The file may contain multiple keys in this format, separated by
353// commas. The last key must not be followed by a comma.
354//
Doug Zongker30362a62013-04-10 11:32:17 -0700355// A Certificate is a pair of an RSAPublicKey and a particular hash
356// (we support SHA-1 and SHA-256; we store the hash length to signify
357// which is being used). The hash used is implied by the version number.
358//
359// 1: 2048-bit RSA key with e=3 and SHA-1 hash
360// 2: 2048-bit RSA key with e=65537 and SHA-1 hash
361// 3: 2048-bit RSA key with e=3 and SHA-256 hash
362// 4: 2048-bit RSA key with e=65537 and SHA-256 hash
Kenny Root7a4adb52013-10-09 10:14:35 -0700363// 5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
Doug Zongker30362a62013-04-10 11:32:17 -0700364//
Doug Zongker6c249f72012-11-02 15:04:05 -0700365// Returns NULL if the file failed to parse, or if it contain zero keys.
Doug Zongker30362a62013-04-10 11:32:17 -0700366Certificate*
Doug Zongker6c249f72012-11-02 15:04:05 -0700367load_keys(const char* filename, int* numKeys) {
Doug Zongker30362a62013-04-10 11:32:17 -0700368 Certificate* out = NULL;
Doug Zongker6c249f72012-11-02 15:04:05 -0700369 *numKeys = 0;
370
371 FILE* f = fopen(filename, "r");
372 if (f == NULL) {
373 LOGE("opening %s: %s\n", filename, strerror(errno));
374 goto exit;
375 }
376
377 {
378 int i;
379 bool done = false;
380 while (!done) {
381 ++*numKeys;
Doug Zongker30362a62013-04-10 11:32:17 -0700382 out = (Certificate*)realloc(out, *numKeys * sizeof(Certificate));
383 Certificate* cert = out + (*numKeys - 1);
Kenny Root7a4adb52013-10-09 10:14:35 -0700384 memset(cert, '\0', sizeof(Certificate));
Doug Zongker6c249f72012-11-02 15:04:05 -0700385
386 char start_char;
387 if (fscanf(f, " %c", &start_char) != 1) goto exit;
388 if (start_char == '{') {
389 // a version 1 key has no version specifier.
Kenny Root7a4adb52013-10-09 10:14:35 -0700390 cert->key_type = Certificate::RSA;
391 cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
392 cert->rsa->exponent = 3;
Doug Zongker30362a62013-04-10 11:32:17 -0700393 cert->hash_len = SHA_DIGEST_SIZE;
Doug Zongker6c249f72012-11-02 15:04:05 -0700394 } else if (start_char == 'v') {
395 int version;
396 if (fscanf(f, "%d {", &version) != 1) goto exit;
Doug Zongker30362a62013-04-10 11:32:17 -0700397 switch (version) {
398 case 2:
Kenny Root7a4adb52013-10-09 10:14:35 -0700399 cert->key_type = Certificate::RSA;
400 cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
401 cert->rsa->exponent = 65537;
Doug Zongker30362a62013-04-10 11:32:17 -0700402 cert->hash_len = SHA_DIGEST_SIZE;
403 break;
404 case 3:
Kenny Root7a4adb52013-10-09 10:14:35 -0700405 cert->key_type = Certificate::RSA;
406 cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
407 cert->rsa->exponent = 3;
Doug Zongker30362a62013-04-10 11:32:17 -0700408 cert->hash_len = SHA256_DIGEST_SIZE;
409 break;
410 case 4:
Kenny Root7a4adb52013-10-09 10:14:35 -0700411 cert->key_type = Certificate::RSA;
412 cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
413 cert->rsa->exponent = 65537;
414 cert->hash_len = SHA256_DIGEST_SIZE;
415 break;
416 case 5:
417 cert->key_type = Certificate::EC;
418 cert->ec = (ECPublicKey*)calloc(1, sizeof(ECPublicKey));
Doug Zongker30362a62013-04-10 11:32:17 -0700419 cert->hash_len = SHA256_DIGEST_SIZE;
420 break;
421 default:
422 goto exit;
Doug Zongker6c249f72012-11-02 15:04:05 -0700423 }
424 }
425
Kenny Root7a4adb52013-10-09 10:14:35 -0700426 if (cert->key_type == Certificate::RSA) {
427 RSAPublicKey* key = cert->rsa;
428 if (fscanf(f, " %i , 0x%x , { %u",
429 &(key->len), &(key->n0inv), &(key->n[0])) != 3) {
430 goto exit;
431 }
432 if (key->len != RSANUMWORDS) {
433 LOGE("key length (%d) does not match expected size\n", key->len);
434 goto exit;
435 }
436 for (i = 1; i < key->len; ++i) {
437 if (fscanf(f, " , %u", &(key->n[i])) != 1) goto exit;
438 }
439 if (fscanf(f, " } , { %u", &(key->rr[0])) != 1) goto exit;
440 for (i = 1; i < key->len; ++i) {
441 if (fscanf(f, " , %u", &(key->rr[i])) != 1) goto exit;
442 }
443 fscanf(f, " } } ");
444
445 LOGI("read key e=%d hash=%d\n", key->exponent, cert->hash_len);
446 } else if (cert->key_type == Certificate::EC) {
447 ECPublicKey* key = cert->ec;
448 int key_len;
449 unsigned int byte;
450 uint8_t x_bytes[P256_NBYTES];
451 uint8_t y_bytes[P256_NBYTES];
452 if (fscanf(f, " %i , { %u", &key_len, &byte) != 2) goto exit;
453 if (key_len != P256_NBYTES) {
454 LOGE("Key length (%d) does not match expected size %d\n", key_len, P256_NBYTES);
455 goto exit;
456 }
457 x_bytes[P256_NBYTES - 1] = byte;
458 for (i = P256_NBYTES - 2; i >= 0; --i) {
459 if (fscanf(f, " , %u", &byte) != 1) goto exit;
460 x_bytes[i] = byte;
461 }
462 if (fscanf(f, " } , { %u", &byte) != 1) goto exit;
463 y_bytes[P256_NBYTES - 1] = byte;
464 for (i = P256_NBYTES - 2; i >= 0; --i) {
465 if (fscanf(f, " , %u", &byte) != 1) goto exit;
466 y_bytes[i] = byte;
467 }
468 fscanf(f, " } } ");
469 p256_from_bin(x_bytes, &key->x);
470 p256_from_bin(y_bytes, &key->y);
471 } else {
472 LOGE("Unknown key type %d\n", cert->key_type);
Doug Zongker6c249f72012-11-02 15:04:05 -0700473 goto exit;
474 }
Doug Zongker6c249f72012-11-02 15:04:05 -0700475
476 // if the line ends in a comma, this file has more keys.
477 switch (fgetc(f)) {
478 case ',':
479 // more keys to come.
480 break;
481
482 case EOF:
483 done = true;
484 break;
485
486 default:
487 LOGE("unexpected character between keys\n");
488 goto exit;
489 }
Doug Zongker6c249f72012-11-02 15:04:05 -0700490 }
491 }
492
493 fclose(f);
494 return out;
495
496exit:
497 if (f) fclose(f);
498 free(out);
499 *numKeys = 0;
500 return NULL;
501}