1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (c) 2013, Google Inc.
11 #include <asm/types.h>
12 #include <asm/byteorder.h>
13 #include <linux/errno.h>
14 #include <asm/types.h>
15 #include <asm/unaligned.h>
20 #include <fdt_support.h>
22 #include <linux/kconfig.h>
23 #include <u-boot/rsa-mod-exp.h>
24 #include <u-boot/rsa.h>
29 * Since host tools, like mkimage, make use of openssl library for
30 * RSA encryption, rsa_verify_with_pkey()/rsa_gen_key_prop() are
31 * of no use and should not be compiled in.
32 * So just turn off CONFIG_RSA_VERIFY_WITH_PKEY.
35 #undef CONFIG_RSA_VERIFY_WITH_PKEY
38 /* Default public exponent for backward compatibility */
39 #define RSA_DEFAULT_PUBEXP 65537
42 * rsa_verify_padding() - Verify RSA message padding is valid
44 * Verify a RSA message's padding is consistent with PKCS1.5
45 * padding as described in the RSA PKCS#1 v2.1 standard.
47 * @msg: Padded message
48 * @pad_len: Number of expected padding bytes
49 * @algo: Checksum algo structure having information on DER encoding etc.
50 * @return 0 on success, != 0 on failure
52 static int rsa_verify_padding(const uint8_t *msg, const int pad_len,
53 struct checksum_algo *algo)
58 /* first byte must be 0x00 */
60 /* second byte must be 0x01 */
62 /* next ff_len bytes must be 0xff */
63 ff_len = pad_len - algo->der_len - 3;
65 ret |= memcmp(msg, msg+1, ff_len-1);
67 /* next byte must be 0x00 */
69 /* next der_len bytes must match der_prefix */
70 ret |= memcmp(msg, algo->der_prefix, algo->der_len);
75 int padding_pkcs_15_verify(struct image_sign_info *info,
76 uint8_t *msg, int msg_len,
77 const uint8_t *hash, int hash_len)
79 struct checksum_algo *checksum = info->checksum;
80 int ret, pad_len = msg_len - checksum->checksum_len;
82 /* Check pkcs1.5 padding bytes. */
83 ret = rsa_verify_padding(msg, pad_len, checksum);
85 debug("In RSAVerify(): Padding check failed!\n");
90 if (memcmp((uint8_t *)msg + pad_len, hash, msg_len - pad_len)) {
91 debug("In RSAVerify(): Hash check failed!\n");
98 #ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
99 static void u32_i2osp(uint32_t val, uint8_t *buf)
101 buf[0] = (uint8_t)((val >> 24) & 0xff);
102 buf[1] = (uint8_t)((val >> 16) & 0xff);
103 buf[2] = (uint8_t)((val >> 8) & 0xff);
104 buf[3] = (uint8_t)((val >> 0) & 0xff);
108 * mask_generation_function1() - generate an octet string
110 * Generate an octet string used to check rsa signature.
111 * It use an input octet string and a hash function.
113 * @checksum: A Hash function
114 * @seed: Specifies an input variable octet string
115 * @seed_len: Size of the input octet string
116 * @output: Specifies the output octet string
117 * @output_len: Size of the output octet string
118 * @return 0 if the octet string was correctly generated, others on error
120 static int mask_generation_function1(struct checksum_algo *checksum,
121 uint8_t *seed, int seed_len,
122 uint8_t *output, int output_len)
124 struct image_region region[2];
125 int ret = 0, i, i_output = 0, region_count = 2;
126 uint32_t counter = 0;
127 uint8_t buf_counter[4], *tmp;
128 int hash_len = checksum->checksum_len;
130 memset(output, 0, output_len);
132 region[0].data = seed;
133 region[0].size = seed_len;
134 region[1].data = &buf_counter[0];
137 tmp = malloc(hash_len);
139 debug("%s: can't allocate array tmp\n", __func__);
144 while (i_output < output_len) {
145 u32_i2osp(counter, &buf_counter[0]);
147 ret = checksum->calculate(checksum->name,
148 region, region_count,
151 debug("%s: Error in checksum calculation\n", __func__);
156 while ((i_output < output_len) && (i < hash_len)) {
157 output[i_output] = tmp[i];
171 static int compute_hash_prime(struct checksum_algo *checksum,
172 uint8_t *pad, int pad_len,
173 uint8_t *hash, int hash_len,
174 uint8_t *salt, int salt_len,
177 struct image_region region[3];
178 int ret, region_count = 3;
180 region[0].data = pad;
181 region[0].size = pad_len;
182 region[1].data = hash;
183 region[1].size = hash_len;
184 region[2].data = salt;
185 region[2].size = salt_len;
187 ret = checksum->calculate(checksum->name, region, region_count, hprime);
189 debug("%s: Error in checksum calculation\n", __func__);
197 int padding_pss_verify(struct image_sign_info *info,
198 uint8_t *msg, int msg_len,
199 const uint8_t *hash, int hash_len)
201 uint8_t *masked_db = NULL;
202 int masked_db_len = msg_len - hash_len - 1;
203 uint8_t *h = NULL, *hprime = NULL;
204 int h_len = hash_len;
205 uint8_t *db_mask = NULL;
206 int db_mask_len = masked_db_len;
207 uint8_t *db = NULL, *salt = NULL;
208 int db_len = masked_db_len, salt_len = msg_len - hash_len - 2;
209 uint8_t pad_zero[8] = { 0 };
210 int ret, i, leftmost_bits = 1;
211 uint8_t leftmost_mask;
212 struct checksum_algo *checksum = info->checksum;
214 /* first, allocate everything */
215 masked_db = malloc(masked_db_len);
217 db_mask = malloc(db_mask_len);
219 salt = malloc(salt_len);
220 hprime = malloc(hash_len);
221 if (!masked_db || !h || !db_mask || !db || !salt || !hprime) {
222 printf("%s: can't allocate some buffer\n", __func__);
227 /* step 4: check if the last byte is 0xbc */
228 if (msg[msg_len - 1] != 0xbc) {
229 printf("%s: invalid pss padding (0xbc is missing)\n", __func__);
235 memcpy(masked_db, msg, masked_db_len);
236 memcpy(h, msg + masked_db_len, h_len);
239 leftmost_mask = (0xff >> (8 - leftmost_bits)) << (8 - leftmost_bits);
240 if (masked_db[0] & leftmost_mask) {
241 printf("%s: invalid pss padding ", __func__);
242 printf("(leftmost bit of maskedDB not zero)\n");
248 mask_generation_function1(checksum, h, h_len, db_mask, db_mask_len);
251 for (i = 0; i < db_len; i++)
252 db[i] = masked_db[i] ^ db_mask[i];
255 db[0] &= 0xff >> leftmost_bits;
259 printf("%s: invalid pss padding ", __func__);
260 printf("(leftmost byte of db isn't 0x01)\n");
266 memcpy(salt, &db[1], salt_len);
269 compute_hash_prime(checksum, pad_zero, 8,
270 (uint8_t *)hash, hash_len,
271 salt, salt_len, hprime);
274 ret = memcmp(h, hprime, hash_len);
288 #if CONFIG_IS_ENABLED(FIT_SIGNATURE) || IS_ENABLED(CONFIG_RSA_VERIFY_WITH_PKEY)
290 * rsa_verify_key() - Verify a signature against some data using RSA Key
292 * Verify a RSA PKCS1.5 signature against an expected hash using
293 * the RSA Key properties in prop structure.
295 * @info: Specifies key and FIT information
296 * @prop: Specifies key
298 * @sig_len: Number of bytes in signature
299 * @hash: Pointer to the expected hash
300 * @key_len: Number of bytes in rsa key
301 * @return 0 if verified, -ve on error
303 static int rsa_verify_key(struct image_sign_info *info,
304 struct key_prop *prop, const uint8_t *sig,
305 const uint32_t sig_len, const uint8_t *hash,
306 const uint32_t key_len)
309 #if !defined(USE_HOSTCC)
310 struct udevice *mod_exp_dev;
312 struct checksum_algo *checksum = info->checksum;
313 struct padding_algo *padding = info->padding;
316 if (!prop || !sig || !hash || !checksum)
319 if (sig_len != (prop->num_bits / 8)) {
320 debug("Signature is of incorrect length %d\n", sig_len);
324 debug("Checksum algorithm: %s", checksum->name);
326 /* Sanity check for stack size */
327 if (sig_len > RSA_MAX_SIG_BITS / 8) {
328 debug("Signature length %u exceeds maximum %d\n", sig_len,
329 RSA_MAX_SIG_BITS / 8);
333 uint8_t buf[sig_len];
334 hash_len = checksum->checksum_len;
336 #if !defined(USE_HOSTCC)
337 ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
339 printf("RSA: Can't find Modular Exp implementation\n");
343 ret = rsa_mod_exp(mod_exp_dev, sig, sig_len, prop, buf);
345 ret = rsa_mod_exp_sw(sig, sig_len, prop, buf);
348 debug("Error in Modular exponentation\n");
352 ret = padding->verify(info, buf, key_len, hash, hash_len);
354 debug("In RSAVerify(): padding check failed!\n");
362 #ifdef CONFIG_RSA_VERIFY_WITH_PKEY
364 * rsa_verify_with_pkey() - Verify a signature against some data using
365 * only modulus and exponent as RSA key properties.
366 * @info: Specifies key information
367 * @hash: Pointer to the expected hash
369 * @sig_len: Number of bytes in signature
371 * Parse a RSA public key blob in DER format pointed to in @info and fill
372 * a key_prop structure with properties of the key. Then verify a RSA PKCS1.5
373 * signature against an expected hash using the calculated properties.
375 * Return 0 if verified, -ve on error
377 static int rsa_verify_with_pkey(struct image_sign_info *info,
378 const void *hash, uint8_t *sig, uint sig_len)
380 struct key_prop *prop;
383 /* Public key is self-described to fill key_prop */
384 ret = rsa_gen_key_prop(info->key, info->keylen, &prop);
386 debug("Generating necessary parameter for decoding failed\n");
390 ret = rsa_verify_key(info, prop, sig, sig_len, hash,
391 info->crypto->key_len);
393 rsa_free_key_prop(prop);
398 static int rsa_verify_with_pkey(struct image_sign_info *info,
399 const void *hash, uint8_t *sig, uint sig_len)
405 #if CONFIG_IS_ENABLED(FIT_SIGNATURE)
407 * rsa_verify_with_keynode() - Verify a signature against some data using
408 * information in node with prperties of RSA Key like modulus, exponent etc.
410 * Parse sign-node and fill a key_prop structure with properties of the
411 * key. Verify a RSA PKCS1.5 signature against an expected hash using
412 * the properties parsed
414 * @info: Specifies key and FIT information
415 * @hash: Pointer to the expected hash
417 * @sig_len: Number of bytes in signature
418 * @node: Node having the RSA Key properties
419 * @return 0 if verified, -ve on error
421 static int rsa_verify_with_keynode(struct image_sign_info *info,
422 const void *hash, uint8_t *sig,
423 uint sig_len, int node)
425 const void *blob = info->fdt_blob;
426 struct key_prop prop;
431 debug("%s: Skipping invalid node", __func__);
435 prop.num_bits = fdtdec_get_int(blob, node, "rsa,num-bits", 0);
437 prop.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0);
439 prop.public_exponent = fdt_getprop(blob, node, "rsa,exponent", &length);
440 if (!prop.public_exponent || length < sizeof(uint64_t))
441 prop.public_exponent = NULL;
443 prop.exp_len = sizeof(uint64_t);
445 prop.modulus = fdt_getprop(blob, node, "rsa,modulus", NULL);
447 prop.rr = fdt_getprop(blob, node, "rsa,r-squared", NULL);
449 if (!prop.num_bits || !prop.modulus || !prop.rr) {
450 debug("%s: Missing RSA key info", __func__);
454 ret = rsa_verify_key(info, &prop, sig, sig_len, hash,
455 info->crypto->key_len);
460 static int rsa_verify_with_keynode(struct image_sign_info *info,
461 const void *hash, uint8_t *sig,
462 uint sig_len, int node)
468 int rsa_verify(struct image_sign_info *info,
469 const struct image_region region[], int region_count,
470 uint8_t *sig, uint sig_len)
472 /* Reserve memory for maximum checksum-length */
473 uint8_t hash[info->crypto->key_len];
477 * Verify that the checksum-length does not exceed the
478 * rsa-signature-length
480 if (info->checksum->checksum_len >
481 info->crypto->key_len) {
482 debug("%s: invlaid checksum-algorithm %s for %s\n",
483 __func__, info->checksum->name, info->crypto->name);
487 /* Calculate checksum with checksum-algorithm */
488 ret = info->checksum->calculate(info->checksum->name,
489 region, region_count, hash);
491 debug("%s: Error in checksum calculation\n", __func__);
495 if (IS_ENABLED(CONFIG_RSA_VERIFY_WITH_PKEY) && !info->fdt_blob) {
496 /* don't rely on fdt properties */
497 ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
502 if (CONFIG_IS_ENABLED(FIT_SIGNATURE)) {
503 const void *blob = info->fdt_blob;
508 sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
510 debug("%s: No signature node found\n", __func__);
514 /* See if we must use a particular key */
515 if (info->required_keynode != -1) {
516 ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
517 info->required_keynode);
521 /* Look for a key that matches our hint */
522 snprintf(name, sizeof(name), "key-%s", info->keyname);
523 node = fdt_subnode_offset(blob, sig_node, name);
524 ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
528 /* No luck, so try each of the keys in turn */
529 for (ndepth = 0, noffset = fdt_next_node(info->fit, sig_node,
531 (noffset >= 0) && (ndepth > 0);
532 noffset = fdt_next_node(info->fit, noffset, &ndepth)) {
533 if (ndepth == 1 && noffset != node) {
534 ret = rsa_verify_with_keynode(info, hash,