blob: 549130eda1f3a41759522c1e2b84798061fcf08c [file] [log] [blame]
Simon Glass19c402a2013-06-13 15:10:02 -07001/*
2 * Copyright (c) 2013, Google Inc.
3 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02004 * SPDX-License-Identifier: GPL-2.0+
Simon Glass19c402a2013-06-13 15:10:02 -07005 */
6
7#include "mkimage.h"
8#include <stdio.h>
9#include <string.h>
Simon Glass19c402a2013-06-13 15:10:02 -070010#include <image.h>
11#include <time.h>
12#include <openssl/rsa.h>
13#include <openssl/pem.h>
14#include <openssl/err.h>
15#include <openssl/ssl.h>
16#include <openssl/evp.h>
17
18#if OPENSSL_VERSION_NUMBER >= 0x10000000L
19#define HAVE_ERR_REMOVE_THREAD_STATE
20#endif
21
22static int rsa_err(const char *msg)
23{
24 unsigned long sslErr = ERR_get_error();
25
26 fprintf(stderr, "%s", msg);
27 fprintf(stderr, ": %s\n",
28 ERR_error_string(sslErr, 0));
29
30 return -1;
31}
32
33/**
34 * rsa_get_pub_key() - read a public key from a .crt file
35 *
36 * @keydir: Directory containins the key
37 * @name Name of key file (will have a .crt extension)
38 * @rsap Returns RSA object, or NULL on failure
39 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
40 */
41static int rsa_get_pub_key(const char *keydir, const char *name, RSA **rsap)
42{
43 char path[1024];
44 EVP_PKEY *key;
45 X509 *cert;
46 RSA *rsa;
47 FILE *f;
48 int ret;
49
50 *rsap = NULL;
51 snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
52 f = fopen(path, "r");
53 if (!f) {
54 fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
55 path, strerror(errno));
56 return -EACCES;
57 }
58
59 /* Read the certificate */
60 cert = NULL;
61 if (!PEM_read_X509(f, &cert, NULL, NULL)) {
62 rsa_err("Couldn't read certificate");
63 ret = -EINVAL;
64 goto err_cert;
65 }
66
67 /* Get the public key from the certificate. */
68 key = X509_get_pubkey(cert);
69 if (!key) {
70 rsa_err("Couldn't read public key\n");
71 ret = -EINVAL;
72 goto err_pubkey;
73 }
74
75 /* Convert to a RSA_style key. */
76 rsa = EVP_PKEY_get1_RSA(key);
77 if (!rsa) {
78 rsa_err("Couldn't convert to a RSA style key");
79 goto err_rsa;
80 }
81 fclose(f);
82 EVP_PKEY_free(key);
83 X509_free(cert);
84 *rsap = rsa;
85
86 return 0;
87
88err_rsa:
89 EVP_PKEY_free(key);
90err_pubkey:
91 X509_free(cert);
92err_cert:
93 fclose(f);
94 return ret;
95}
96
97/**
98 * rsa_get_priv_key() - read a private key from a .key file
99 *
100 * @keydir: Directory containins the key
101 * @name Name of key file (will have a .key extension)
102 * @rsap Returns RSA object, or NULL on failure
103 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
104 */
105static int rsa_get_priv_key(const char *keydir, const char *name, RSA **rsap)
106{
107 char path[1024];
108 RSA *rsa;
109 FILE *f;
110
111 *rsap = NULL;
112 snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
113 f = fopen(path, "r");
114 if (!f) {
115 fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
116 path, strerror(errno));
117 return -ENOENT;
118 }
119
120 rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
121 if (!rsa) {
122 rsa_err("Failure reading private key");
123 fclose(f);
124 return -EPROTO;
125 }
126 fclose(f);
127 *rsap = rsa;
128
129 return 0;
130}
131
132static int rsa_init(void)
133{
134 int ret;
135
136 ret = SSL_library_init();
137 if (!ret) {
138 fprintf(stderr, "Failure to init SSL library\n");
139 return -1;
140 }
141 SSL_load_error_strings();
142
143 OpenSSL_add_all_algorithms();
144 OpenSSL_add_all_digests();
145 OpenSSL_add_all_ciphers();
146
147 return 0;
148}
149
150static void rsa_remove(void)
151{
152 CRYPTO_cleanup_all_ex_data();
153 ERR_free_strings();
154#ifdef HAVE_ERR_REMOVE_THREAD_STATE
155 ERR_remove_thread_state(NULL);
156#else
157 ERR_remove_state(0);
158#endif
159 EVP_cleanup();
160}
161
162static int rsa_sign_with_key(RSA *rsa, const struct image_region region[],
163 int region_count, uint8_t **sigp, uint *sig_size)
164{
165 EVP_PKEY *key;
166 EVP_MD_CTX *context;
167 int size, ret = 0;
168 uint8_t *sig;
169 int i;
170
171 key = EVP_PKEY_new();
172 if (!key)
173 return rsa_err("EVP_PKEY object creation failed");
174
175 if (!EVP_PKEY_set1_RSA(key, rsa)) {
176 ret = rsa_err("EVP key setup failed");
177 goto err_set;
178 }
179
180 size = EVP_PKEY_size(key);
181 sig = malloc(size);
182 if (!sig) {
183 fprintf(stderr, "Out of memory for signature (%d bytes)\n",
184 size);
185 ret = -ENOMEM;
186 goto err_alloc;
187 }
188
189 context = EVP_MD_CTX_create();
190 if (!context) {
191 ret = rsa_err("EVP context creation failed");
192 goto err_create;
193 }
194 EVP_MD_CTX_init(context);
195 if (!EVP_SignInit(context, EVP_sha1())) {
196 ret = rsa_err("Signer setup failed");
197 goto err_sign;
198 }
199
200 for (i = 0; i < region_count; i++) {
201 if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
202 ret = rsa_err("Signing data failed");
203 goto err_sign;
204 }
205 }
206
207 if (!EVP_SignFinal(context, sig, sig_size, key)) {
208 ret = rsa_err("Could not obtain signature");
209 goto err_sign;
210 }
211 EVP_MD_CTX_cleanup(context);
212 EVP_MD_CTX_destroy(context);
213 EVP_PKEY_free(key);
214
215 debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
216 *sigp = sig;
217 *sig_size = size;
218
219 return 0;
220
221err_sign:
222 EVP_MD_CTX_destroy(context);
223err_create:
224 free(sig);
225err_alloc:
226err_set:
227 EVP_PKEY_free(key);
228 return ret;
229}
230
231int rsa_sign(struct image_sign_info *info,
232 const struct image_region region[], int region_count,
233 uint8_t **sigp, uint *sig_len)
234{
235 RSA *rsa;
236 int ret;
237
238 ret = rsa_init();
239 if (ret)
240 return ret;
241
242 ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
243 if (ret)
244 goto err_priv;
245 ret = rsa_sign_with_key(rsa, region, region_count, sigp, sig_len);
246 if (ret)
247 goto err_sign;
248
249 RSA_free(rsa);
250 rsa_remove();
251
252 return ret;
253
254err_sign:
255 RSA_free(rsa);
256err_priv:
257 rsa_remove();
258 return ret;
259}
260
261/*
262 * rsa_get_params(): - Get the important parameters of an RSA public key
263 */
264int rsa_get_params(RSA *key, uint32_t *n0_invp, BIGNUM **modulusp,
265 BIGNUM **r_squaredp)
266{
267 BIGNUM *big1, *big2, *big32, *big2_32;
268 BIGNUM *n, *r, *r_squared, *tmp;
269 BN_CTX *bn_ctx = BN_CTX_new();
270 int ret = 0;
271
272 /* Initialize BIGNUMs */
273 big1 = BN_new();
274 big2 = BN_new();
275 big32 = BN_new();
276 r = BN_new();
277 r_squared = BN_new();
278 tmp = BN_new();
279 big2_32 = BN_new();
280 n = BN_new();
281 if (!big1 || !big2 || !big32 || !r || !r_squared || !tmp || !big2_32 ||
282 !n) {
283 fprintf(stderr, "Out of memory (bignum)\n");
284 return -ENOMEM;
285 }
286
287 if (!BN_copy(n, key->n) || !BN_set_word(big1, 1L) ||
288 !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L))
289 ret = -1;
290
291 /* big2_32 = 2^32 */
292 if (!BN_exp(big2_32, big2, big32, bn_ctx))
293 ret = -1;
294
295 /* Calculate n0_inv = -1 / n[0] mod 2^32 */
296 if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
297 !BN_sub(tmp, big2_32, tmp))
298 ret = -1;
299 *n0_invp = BN_get_word(tmp);
300
301 /* Calculate R = 2^(# of key bits) */
302 if (!BN_set_word(tmp, BN_num_bits(n)) ||
303 !BN_exp(r, big2, tmp, bn_ctx))
304 ret = -1;
305
306 /* Calculate r_squared = R^2 mod n */
307 if (!BN_copy(r_squared, r) ||
308 !BN_mul(tmp, r_squared, r, bn_ctx) ||
309 !BN_mod(r_squared, tmp, n, bn_ctx))
310 ret = -1;
311
312 *modulusp = n;
313 *r_squaredp = r_squared;
314
315 BN_free(big1);
316 BN_free(big2);
317 BN_free(big32);
318 BN_free(r);
319 BN_free(tmp);
320 BN_free(big2_32);
321 if (ret) {
322 fprintf(stderr, "Bignum operations failed\n");
323 return -ENOMEM;
324 }
325
326 return ret;
327}
328
329static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
330 BIGNUM *num, int num_bits)
331{
332 int nwords = num_bits / 32;
333 int size;
334 uint32_t *buf, *ptr;
335 BIGNUM *tmp, *big2, *big32, *big2_32;
336 BN_CTX *ctx;
337 int ret;
338
339 tmp = BN_new();
340 big2 = BN_new();
341 big32 = BN_new();
342 big2_32 = BN_new();
343 if (!tmp || !big2 || !big32 || !big2_32) {
344 fprintf(stderr, "Out of memory (bignum)\n");
345 return -ENOMEM;
346 }
347 ctx = BN_CTX_new();
348 if (!tmp) {
349 fprintf(stderr, "Out of memory (bignum context)\n");
350 return -ENOMEM;
351 }
352 BN_set_word(big2, 2L);
353 BN_set_word(big32, 32L);
354 BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */
355
356 size = nwords * sizeof(uint32_t);
357 buf = malloc(size);
358 if (!buf) {
359 fprintf(stderr, "Out of memory (%d bytes)\n", size);
360 return -ENOMEM;
361 }
362
363 /* Write out modulus as big endian array of integers */
364 for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
365 BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
366 *ptr = cpu_to_fdt32(BN_get_word(tmp));
367 BN_rshift(num, num, 32); /* N = N/B */
368 }
369
370 ret = fdt_setprop(blob, noffset, prop_name, buf, size);
371 if (ret) {
372 fprintf(stderr, "Failed to write public key to FIT\n");
373 return -ENOSPC;
374 }
375 free(buf);
376 BN_free(tmp);
377 BN_free(big2);
378 BN_free(big32);
379 BN_free(big2_32);
380
381 return ret;
382}
383
384int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
385{
386 BIGNUM *modulus, *r_squared;
387 uint32_t n0_inv;
388 int parent, node;
389 char name[100];
390 int ret;
391 int bits;
392 RSA *rsa;
393
394 debug("%s: Getting verification data\n", __func__);
395 ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
396 if (ret)
397 return ret;
398 ret = rsa_get_params(rsa, &n0_inv, &modulus, &r_squared);
399 if (ret)
400 return ret;
401 bits = BN_num_bits(modulus);
402 parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
403 if (parent == -FDT_ERR_NOTFOUND) {
404 parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
405 if (parent < 0) {
406 fprintf(stderr, "Couldn't create signature node: %s\n",
407 fdt_strerror(parent));
408 return -EINVAL;
409 }
410 }
411
412 /* Either create or overwrite the named key node */
413 snprintf(name, sizeof(name), "key-%s", info->keyname);
414 node = fdt_subnode_offset(keydest, parent, name);
415 if (node == -FDT_ERR_NOTFOUND) {
416 node = fdt_add_subnode(keydest, parent, name);
417 if (node < 0) {
418 fprintf(stderr, "Could not create key subnode: %s\n",
419 fdt_strerror(node));
420 return -EINVAL;
421 }
422 } else if (node < 0) {
423 fprintf(stderr, "Cannot select keys parent: %s\n",
424 fdt_strerror(node));
425 return -ENOSPC;
426 }
427
428 ret = fdt_setprop_string(keydest, node, "key-name-hint",
429 info->keyname);
430 ret |= fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
431 ret |= fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
432 ret |= fdt_add_bignum(keydest, node, "rsa,modulus", modulus, bits);
433 ret |= fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared, bits);
434 ret |= fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
435 info->algo->name);
436 if (info->require_keys) {
437 fdt_setprop_string(keydest, node, "required",
438 info->require_keys);
439 }
440 BN_free(modulus);
441 BN_free(r_squared);
442 if (ret)
443 return -EIO;
444
445 return 0;
446}