2 * Copyright (c) 2013, Google Inc.
4 * SPDX-License-Identifier: GPL-2.0+
12 #include <openssl/bn.h>
13 #include <openssl/rsa.h>
14 #include <openssl/pem.h>
15 #include <openssl/err.h>
16 #include <openssl/ssl.h>
17 #include <openssl/evp.h>
18 #include <openssl/engine.h>
20 #if OPENSSL_VERSION_NUMBER >= 0x10000000L
21 #define HAVE_ERR_REMOVE_THREAD_STATE
24 #if OPENSSL_VERSION_NUMBER < 0x10100000L
25 static void RSA_get0_key(const RSA *r,
26 const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
37 static int rsa_err(const char *msg)
39 unsigned long sslErr = ERR_get_error();
41 fprintf(stderr, "%s", msg);
42 fprintf(stderr, ": %s\n",
43 ERR_error_string(sslErr, 0));
49 * rsa_pem_get_pub_key() - read a public key from a .crt file
51 * @keydir: Directory containins the key
52 * @name Name of key file (will have a .crt extension)
53 * @rsap Returns RSA object, or NULL on failure
54 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
56 static int rsa_pem_get_pub_key(const char *keydir, const char *name, RSA **rsap)
66 snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
69 fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
70 path, strerror(errno));
74 /* Read the certificate */
76 if (!PEM_read_X509(f, &cert, NULL, NULL)) {
77 rsa_err("Couldn't read certificate");
82 /* Get the public key from the certificate. */
83 key = X509_get_pubkey(cert);
85 rsa_err("Couldn't read public key\n");
90 /* Convert to a RSA_style key. */
91 rsa = EVP_PKEY_get1_RSA(key);
93 rsa_err("Couldn't convert to a RSA style key");
114 * rsa_engine_get_pub_key() - read a public key from given engine
116 * @keydir: Key prefix
118 * @engine Engine to use
119 * @rsap Returns RSA object, or NULL on failure
120 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
122 static int rsa_engine_get_pub_key(const char *keydir, const char *name,
123 ENGINE *engine, RSA **rsap)
125 const char *engine_id;
133 engine_id = ENGINE_get_id(engine);
135 if (engine_id && !strcmp(engine_id, "pkcs11")) {
137 snprintf(key_id, sizeof(key_id),
138 "pkcs11:%s;object=%s;type=public",
141 snprintf(key_id, sizeof(key_id),
142 "pkcs11:object=%s;type=public",
145 fprintf(stderr, "Engine not supported\n");
149 key = ENGINE_load_public_key(engine, key_id, NULL, NULL);
151 return rsa_err("Failure loading public key from engine");
153 /* Convert to a RSA_style key. */
154 rsa = EVP_PKEY_get1_RSA(key);
156 rsa_err("Couldn't convert to a RSA style key");
172 * rsa_get_pub_key() - read a public key
174 * @keydir: Directory containing the key (PEM file) or key prefix (engine)
175 * @name Name of key file (will have a .crt extension)
176 * @engine Engine to use
177 * @rsap Returns RSA object, or NULL on failure
178 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
180 static int rsa_get_pub_key(const char *keydir, const char *name,
181 ENGINE *engine, RSA **rsap)
184 return rsa_engine_get_pub_key(keydir, name, engine, rsap);
185 return rsa_pem_get_pub_key(keydir, name, rsap);
189 * rsa_pem_get_priv_key() - read a private key from a .key file
191 * @keydir: Directory containing the key
192 * @name Name of key file (will have a .key extension)
193 * @rsap Returns RSA object, or NULL on failure
194 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
196 static int rsa_pem_get_priv_key(const char *keydir, const char *name,
204 snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
205 f = fopen(path, "r");
207 fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
208 path, strerror(errno));
212 rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
214 rsa_err("Failure reading private key");
225 * rsa_engine_get_priv_key() - read a private key from given engine
227 * @keydir: Key prefix
229 * @engine Engine to use
230 * @rsap Returns RSA object, or NULL on failure
231 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
233 static int rsa_engine_get_priv_key(const char *keydir, const char *name,
234 ENGINE *engine, RSA **rsap)
236 const char *engine_id;
244 engine_id = ENGINE_get_id(engine);
246 if (engine_id && !strcmp(engine_id, "pkcs11")) {
248 snprintf(key_id, sizeof(key_id),
249 "pkcs11:%s;object=%s;type=private",
252 snprintf(key_id, sizeof(key_id),
253 "pkcs11:object=%s;type=private",
256 fprintf(stderr, "Engine not supported\n");
260 key = ENGINE_load_private_key(engine, key_id, NULL, NULL);
262 return rsa_err("Failure loading private key from engine");
264 /* Convert to a RSA_style key. */
265 rsa = EVP_PKEY_get1_RSA(key);
267 rsa_err("Couldn't convert to a RSA style key");
283 * rsa_get_priv_key() - read a private key
285 * @keydir: Directory containing the key (PEM file) or key prefix (engine)
287 * @engine Engine to use for signing
288 * @rsap Returns RSA object, or NULL on failure
289 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
291 static int rsa_get_priv_key(const char *keydir, const char *name,
292 ENGINE *engine, RSA **rsap)
295 return rsa_engine_get_priv_key(keydir, name, engine, rsap);
296 return rsa_pem_get_priv_key(keydir, name, rsap);
299 static int rsa_init(void)
303 #if OPENSSL_VERSION_NUMBER < 0x10100000L
304 ret = SSL_library_init();
306 ret = OPENSSL_init_ssl(0, NULL);
309 fprintf(stderr, "Failure to init SSL library\n");
312 #if OPENSSL_VERSION_NUMBER < 0x10100000L
313 SSL_load_error_strings();
315 OpenSSL_add_all_algorithms();
316 OpenSSL_add_all_digests();
317 OpenSSL_add_all_ciphers();
323 static int rsa_engine_init(const char *engine_id, ENGINE **pe)
328 ENGINE_load_builtin_engines();
330 e = ENGINE_by_id(engine_id);
332 fprintf(stderr, "Engine isn't available\n");
334 goto err_engine_by_id;
337 if (!ENGINE_init(e)) {
338 fprintf(stderr, "Couldn't initialize engine\n");
340 goto err_engine_init;
343 if (!ENGINE_set_default_RSA(e)) {
344 fprintf(stderr, "Couldn't set engine as default for RSA\n");
358 #if OPENSSL_VERSION_NUMBER < 0x10100000L
364 static void rsa_remove(void)
366 #if OPENSSL_VERSION_NUMBER < 0x10100000L
367 CRYPTO_cleanup_all_ex_data();
369 #ifdef HAVE_ERR_REMOVE_THREAD_STATE
370 ERR_remove_thread_state(NULL);
378 static void rsa_engine_remove(ENGINE *e)
386 static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
387 const struct image_region region[], int region_count,
388 uint8_t **sigp, uint *sig_size)
396 key = EVP_PKEY_new();
398 return rsa_err("EVP_PKEY object creation failed");
400 if (!EVP_PKEY_set1_RSA(key, rsa)) {
401 ret = rsa_err("EVP key setup failed");
405 size = EVP_PKEY_size(key);
408 fprintf(stderr, "Out of memory for signature (%d bytes)\n",
414 context = EVP_MD_CTX_create();
416 ret = rsa_err("EVP context creation failed");
419 EVP_MD_CTX_init(context);
420 if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
421 ret = rsa_err("Signer setup failed");
425 for (i = 0; i < region_count; i++) {
426 if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
427 ret = rsa_err("Signing data failed");
432 if (!EVP_SignFinal(context, sig, sig_size, key)) {
433 ret = rsa_err("Could not obtain signature");
436 #if OPENSSL_VERSION_NUMBER < 0x10100000L
437 EVP_MD_CTX_cleanup(context);
439 EVP_MD_CTX_reset(context);
441 EVP_MD_CTX_destroy(context);
444 debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
451 EVP_MD_CTX_destroy(context);
460 int rsa_sign(struct image_sign_info *info,
461 const struct image_region region[], int region_count,
462 uint8_t **sigp, uint *sig_len)
472 if (info->engine_id) {
473 ret = rsa_engine_init(info->engine_id, &e);
478 ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
481 ret = rsa_sign_with_key(rsa, info->checksum, region,
482 region_count, sigp, sig_len);
488 rsa_engine_remove(e);
497 rsa_engine_remove(e);
504 * rsa_get_exponent(): - Get the public exponent from an RSA key
506 static int rsa_get_exponent(RSA *key, uint64_t *e)
519 RSA_get0_key(key, NULL, &key_e, NULL);
520 if (BN_num_bits(key_e) > 64)
523 *e = BN_get_word(key_e);
525 if (BN_num_bits(key_e) < 33) {
530 bn_te = BN_dup(key_e);
534 if (!BN_rshift(bn_te, bn_te, 32))
537 if (!BN_mask_bits(bn_te, 32))
540 te = BN_get_word(bn_te);
553 * rsa_get_params(): - Get the important parameters of an RSA public key
555 int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
556 BIGNUM **modulusp, BIGNUM **r_squaredp)
558 BIGNUM *big1, *big2, *big32, *big2_32;
559 BIGNUM *n, *r, *r_squared, *tmp;
561 BN_CTX *bn_ctx = BN_CTX_new();
564 /* Initialize BIGNUMs */
569 r_squared = BN_new();
573 if (!big1 || !big2 || !big32 || !r || !r_squared || !tmp || !big2_32 ||
575 fprintf(stderr, "Out of memory (bignum)\n");
579 if (0 != rsa_get_exponent(key, exponent))
582 RSA_get0_key(key, &key_n, NULL, NULL);
583 if (!BN_copy(n, key_n) || !BN_set_word(big1, 1L) ||
584 !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L))
588 if (!BN_exp(big2_32, big2, big32, bn_ctx))
591 /* Calculate n0_inv = -1 / n[0] mod 2^32 */
592 if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
593 !BN_sub(tmp, big2_32, tmp))
595 *n0_invp = BN_get_word(tmp);
597 /* Calculate R = 2^(# of key bits) */
598 if (!BN_set_word(tmp, BN_num_bits(n)) ||
599 !BN_exp(r, big2, tmp, bn_ctx))
602 /* Calculate r_squared = R^2 mod n */
603 if (!BN_copy(r_squared, r) ||
604 !BN_mul(tmp, r_squared, r, bn_ctx) ||
605 !BN_mod(r_squared, tmp, n, bn_ctx))
609 *r_squaredp = r_squared;
618 fprintf(stderr, "Bignum operations failed\n");
625 static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
626 BIGNUM *num, int num_bits)
628 int nwords = num_bits / 32;
631 BIGNUM *tmp, *big2, *big32, *big2_32;
639 if (!tmp || !big2 || !big32 || !big2_32) {
640 fprintf(stderr, "Out of memory (bignum)\n");
645 fprintf(stderr, "Out of memory (bignum context)\n");
648 BN_set_word(big2, 2L);
649 BN_set_word(big32, 32L);
650 BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */
652 size = nwords * sizeof(uint32_t);
655 fprintf(stderr, "Out of memory (%d bytes)\n", size);
659 /* Write out modulus as big endian array of integers */
660 for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
661 BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
662 *ptr = cpu_to_fdt32(BN_get_word(tmp));
663 BN_rshift(num, num, 32); /* N = N/B */
667 * We try signing with successively increasing size values, so this
668 * might fail several times
670 ret = fdt_setprop(blob, noffset, prop_name, buf, size);
672 return -FDT_ERR_NOSPACE;
682 int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
684 BIGNUM *modulus, *r_squared;
694 debug("%s: Getting verification data\n", __func__);
695 if (info->engine_id) {
696 ret = rsa_engine_init(info->engine_id, &e);
700 ret = rsa_get_pub_key(info->keydir, info->keyname, e, &rsa);
702 goto err_get_pub_key;
703 ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
706 bits = BN_num_bits(modulus);
707 parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
708 if (parent == -FDT_ERR_NOTFOUND) {
709 parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
712 if (ret != -FDT_ERR_NOSPACE) {
713 fprintf(stderr, "Couldn't create signature node: %s\n",
714 fdt_strerror(parent));
721 /* Either create or overwrite the named key node */
722 snprintf(name, sizeof(name), "key-%s", info->keyname);
723 node = fdt_subnode_offset(keydest, parent, name);
724 if (node == -FDT_ERR_NOTFOUND) {
725 node = fdt_add_subnode(keydest, parent, name);
728 if (ret != -FDT_ERR_NOSPACE) {
729 fprintf(stderr, "Could not create key subnode: %s\n",
733 } else if (node < 0) {
734 fprintf(stderr, "Cannot select keys parent: %s\n",
740 ret = fdt_setprop_string(keydest, node, "key-name-hint",
744 ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
746 ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
748 ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
751 ret = fdt_add_bignum(keydest, node, "rsa,modulus", modulus,
755 ret = fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared,
759 ret = fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
762 if (!ret && info->require_keys) {
763 ret = fdt_setprop_string(keydest, node, "required",
770 ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
775 rsa_engine_remove(e);