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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (c) 2013, Google Inc.
- */
- #ifndef USE_HOSTCC
- #include <common.h>
- #include <fdtdec.h>
- #include <log.h>
- #include <malloc.h>
- #include <asm/types.h>
- #include <asm/byteorder.h>
- #include <linux/errno.h>
- #include <asm/types.h>
- #include <asm/unaligned.h>
- #include <dm.h>
- #else
- #include "fdt_host.h"
- #include "mkimage.h"
- #include <fdt_support.h>
- #endif
- #include <linux/kconfig.h>
- #include <u-boot/rsa-mod-exp.h>
- #include <u-boot/rsa.h>
- #ifndef __UBOOT__
- /*
- * NOTE:
- * Since host tools, like mkimage, make use of openssl library for
- * RSA encryption, rsa_verify_with_pkey()/rsa_gen_key_prop() are
- * of no use and should not be compiled in.
- * So just turn off CONFIG_RSA_VERIFY_WITH_PKEY.
- */
- #undef CONFIG_RSA_VERIFY_WITH_PKEY
- #endif
- /* Default public exponent for backward compatibility */
- #define RSA_DEFAULT_PUBEXP 65537
- /**
- * rsa_verify_padding() - Verify RSA message padding is valid
- *
- * Verify a RSA message's padding is consistent with PKCS1.5
- * padding as described in the RSA PKCS#1 v2.1 standard.
- *
- * @msg: Padded message
- * @pad_len: Number of expected padding bytes
- * @algo: Checksum algo structure having information on DER encoding etc.
- * @return 0 on success, != 0 on failure
- */
- static int rsa_verify_padding(const uint8_t *msg, const int pad_len,
- struct checksum_algo *algo)
- {
- int ff_len;
- int ret;
- /* first byte must be 0x00 */
- ret = *msg++;
- /* second byte must be 0x01 */
- ret |= *msg++ ^ 0x01;
- /* next ff_len bytes must be 0xff */
- ff_len = pad_len - algo->der_len - 3;
- ret |= *msg ^ 0xff;
- ret |= memcmp(msg, msg+1, ff_len-1);
- msg += ff_len;
- /* next byte must be 0x00 */
- ret |= *msg++;
- /* next der_len bytes must match der_prefix */
- ret |= memcmp(msg, algo->der_prefix, algo->der_len);
- return ret;
- }
- int padding_pkcs_15_verify(struct image_sign_info *info,
- uint8_t *msg, int msg_len,
- const uint8_t *hash, int hash_len)
- {
- struct checksum_algo *checksum = info->checksum;
- int ret, pad_len = msg_len - checksum->checksum_len;
- /* Check pkcs1.5 padding bytes. */
- ret = rsa_verify_padding(msg, pad_len, checksum);
- if (ret) {
- debug("In RSAVerify(): Padding check failed!\n");
- return -EINVAL;
- }
- /* Check hash. */
- if (memcmp((uint8_t *)msg + pad_len, hash, msg_len - pad_len)) {
- debug("In RSAVerify(): Hash check failed!\n");
- return -EACCES;
- }
- return 0;
- }
- #ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
- static void u32_i2osp(uint32_t val, uint8_t *buf)
- {
- buf[0] = (uint8_t)((val >> 24) & 0xff);
- buf[1] = (uint8_t)((val >> 16) & 0xff);
- buf[2] = (uint8_t)((val >> 8) & 0xff);
- buf[3] = (uint8_t)((val >> 0) & 0xff);
- }
- /**
- * mask_generation_function1() - generate an octet string
- *
- * Generate an octet string used to check rsa signature.
- * It use an input octet string and a hash function.
- *
- * @checksum: A Hash function
- * @seed: Specifies an input variable octet string
- * @seed_len: Size of the input octet string
- * @output: Specifies the output octet string
- * @output_len: Size of the output octet string
- * @return 0 if the octet string was correctly generated, others on error
- */
- static int mask_generation_function1(struct checksum_algo *checksum,
- uint8_t *seed, int seed_len,
- uint8_t *output, int output_len)
- {
- struct image_region region[2];
- int ret = 0, i, i_output = 0, region_count = 2;
- uint32_t counter = 0;
- uint8_t buf_counter[4], *tmp;
- int hash_len = checksum->checksum_len;
- memset(output, 0, output_len);
- region[0].data = seed;
- region[0].size = seed_len;
- region[1].data = &buf_counter[0];
- region[1].size = 4;
- tmp = malloc(hash_len);
- if (!tmp) {
- debug("%s: can't allocate array tmp\n", __func__);
- ret = -ENOMEM;
- goto out;
- }
- while (i_output < output_len) {
- u32_i2osp(counter, &buf_counter[0]);
- ret = checksum->calculate(checksum->name,
- region, region_count,
- tmp);
- if (ret < 0) {
- debug("%s: Error in checksum calculation\n", __func__);
- goto out;
- }
- i = 0;
- while ((i_output < output_len) && (i < hash_len)) {
- output[i_output] = tmp[i];
- i_output++;
- i++;
- }
- counter++;
- }
- out:
- free(tmp);
- return ret;
- }
- static int compute_hash_prime(struct checksum_algo *checksum,
- uint8_t *pad, int pad_len,
- uint8_t *hash, int hash_len,
- uint8_t *salt, int salt_len,
- uint8_t *hprime)
- {
- struct image_region region[3];
- int ret, region_count = 3;
- region[0].data = pad;
- region[0].size = pad_len;
- region[1].data = hash;
- region[1].size = hash_len;
- region[2].data = salt;
- region[2].size = salt_len;
- ret = checksum->calculate(checksum->name, region, region_count, hprime);
- if (ret < 0) {
- debug("%s: Error in checksum calculation\n", __func__);
- goto out;
- }
- out:
- return ret;
- }
- /*
- * padding_pss_verify() - verify the pss padding of a signature
- *
- * Only works with a rsa_pss_saltlen:-2 (default value) right now
- * saltlen:-1 "set the salt length to the digest length" is currently
- * not supported.
- *
- * @info: Specifies key and FIT information
- * @msg: byte array of message, len equal to msg_len
- * @msg_len: Message length
- * @hash: Pointer to the expected hash
- * @hash_len: Length of the hash
- */
- int padding_pss_verify(struct image_sign_info *info,
- uint8_t *msg, int msg_len,
- const uint8_t *hash, int hash_len)
- {
- uint8_t *masked_db = NULL;
- int masked_db_len = msg_len - hash_len - 1;
- uint8_t *h = NULL, *hprime = NULL;
- int h_len = hash_len;
- uint8_t *db_mask = NULL;
- int db_mask_len = masked_db_len;
- uint8_t *db = NULL, *salt = NULL;
- int db_len = masked_db_len, salt_len = msg_len - hash_len - 2;
- uint8_t pad_zero[8] = { 0 };
- int ret, i, leftmost_bits = 1;
- uint8_t leftmost_mask;
- struct checksum_algo *checksum = info->checksum;
- /* first, allocate everything */
- masked_db = malloc(masked_db_len);
- h = malloc(h_len);
- db_mask = malloc(db_mask_len);
- db = malloc(db_len);
- salt = malloc(salt_len);
- hprime = malloc(hash_len);
- if (!masked_db || !h || !db_mask || !db || !salt || !hprime) {
- printf("%s: can't allocate some buffer\n", __func__);
- ret = -ENOMEM;
- goto out;
- }
- /* step 4: check if the last byte is 0xbc */
- if (msg[msg_len - 1] != 0xbc) {
- printf("%s: invalid pss padding (0xbc is missing)\n", __func__);
- ret = -EINVAL;
- goto out;
- }
- /* step 5 */
- memcpy(masked_db, msg, masked_db_len);
- memcpy(h, msg + masked_db_len, h_len);
- /* step 6 */
- leftmost_mask = (0xff >> (8 - leftmost_bits)) << (8 - leftmost_bits);
- if (masked_db[0] & leftmost_mask) {
- printf("%s: invalid pss padding ", __func__);
- printf("(leftmost bit of maskedDB not zero)\n");
- ret = -EINVAL;
- goto out;
- }
- /* step 7 */
- mask_generation_function1(checksum, h, h_len, db_mask, db_mask_len);
- /* step 8 */
- for (i = 0; i < db_len; i++)
- db[i] = masked_db[i] ^ db_mask[i];
- /* step 9 */
- db[0] &= 0xff >> leftmost_bits;
- /* step 10 */
- if (db[0] != 0x01) {
- printf("%s: invalid pss padding ", __func__);
- printf("(leftmost byte of db isn't 0x01)\n");
- ret = EINVAL;
- goto out;
- }
- /* step 11 */
- memcpy(salt, &db[1], salt_len);
- /* step 12 & 13 */
- compute_hash_prime(checksum, pad_zero, 8,
- (uint8_t *)hash, hash_len,
- salt, salt_len, hprime);
- /* step 14 */
- ret = memcmp(h, hprime, hash_len);
- out:
- free(hprime);
- free(salt);
- free(db);
- free(db_mask);
- free(h);
- free(masked_db);
- return ret;
- }
- #endif
- #if CONFIG_IS_ENABLED(FIT_SIGNATURE) || CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY)
- /**
- * rsa_verify_key() - Verify a signature against some data using RSA Key
- *
- * Verify a RSA PKCS1.5 signature against an expected hash using
- * the RSA Key properties in prop structure.
- *
- * @info: Specifies key and FIT information
- * @prop: Specifies key
- * @sig: Signature
- * @sig_len: Number of bytes in signature
- * @hash: Pointer to the expected hash
- * @key_len: Number of bytes in rsa key
- * @return 0 if verified, -ve on error
- */
- static int rsa_verify_key(struct image_sign_info *info,
- struct key_prop *prop, const uint8_t *sig,
- const uint32_t sig_len, const uint8_t *hash,
- const uint32_t key_len)
- {
- int ret;
- #if !defined(USE_HOSTCC)
- struct udevice *mod_exp_dev;
- #endif
- struct checksum_algo *checksum = info->checksum;
- struct padding_algo *padding = info->padding;
- int hash_len;
- if (!prop || !sig || !hash || !checksum)
- return -EIO;
- if (sig_len != (prop->num_bits / 8)) {
- debug("Signature is of incorrect length %d\n", sig_len);
- return -EINVAL;
- }
- debug("Checksum algorithm: %s", checksum->name);
- /* Sanity check for stack size */
- if (sig_len > RSA_MAX_SIG_BITS / 8) {
- debug("Signature length %u exceeds maximum %d\n", sig_len,
- RSA_MAX_SIG_BITS / 8);
- return -EINVAL;
- }
- uint8_t buf[sig_len];
- hash_len = checksum->checksum_len;
- #if !defined(USE_HOSTCC)
- ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
- if (ret) {
- printf("RSA: Can't find Modular Exp implementation\n");
- return -EINVAL;
- }
- ret = rsa_mod_exp(mod_exp_dev, sig, sig_len, prop, buf);
- #else
- ret = rsa_mod_exp_sw(sig, sig_len, prop, buf);
- #endif
- if (ret) {
- debug("Error in Modular exponentation\n");
- return ret;
- }
- ret = padding->verify(info, buf, key_len, hash, hash_len);
- if (ret) {
- debug("In RSAVerify(): padding check failed!\n");
- return ret;
- }
- return 0;
- }
- #endif
- #if CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY)
- /**
- * rsa_verify_with_pkey() - Verify a signature against some data using
- * only modulus and exponent as RSA key properties.
- * @info: Specifies key information
- * @hash: Pointer to the expected hash
- * @sig: Signature
- * @sig_len: Number of bytes in signature
- *
- * Parse a RSA public key blob in DER format pointed to in @info and fill
- * a key_prop structure with properties of the key. Then verify a RSA PKCS1.5
- * signature against an expected hash using the calculated properties.
- *
- * Return 0 if verified, -ve on error
- */
- int rsa_verify_with_pkey(struct image_sign_info *info,
- const void *hash, uint8_t *sig, uint sig_len)
- {
- struct key_prop *prop;
- int ret;
- /* Public key is self-described to fill key_prop */
- ret = rsa_gen_key_prop(info->key, info->keylen, &prop);
- if (ret) {
- debug("Generating necessary parameter for decoding failed\n");
- return ret;
- }
- ret = rsa_verify_key(info, prop, sig, sig_len, hash,
- info->crypto->key_len);
- rsa_free_key_prop(prop);
- return ret;
- }
- #else
- int rsa_verify_with_pkey(struct image_sign_info *info,
- const void *hash, uint8_t *sig, uint sig_len)
- {
- return -EACCES;
- }
- #endif
- #if CONFIG_IS_ENABLED(FIT_SIGNATURE)
- /**
- * rsa_verify_with_keynode() - Verify a signature against some data using
- * information in node with prperties of RSA Key like modulus, exponent etc.
- *
- * Parse sign-node and fill a key_prop structure with properties of the
- * key. Verify a RSA PKCS1.5 signature against an expected hash using
- * the properties parsed
- *
- * @info: Specifies key and FIT information
- * @hash: Pointer to the expected hash
- * @sig: Signature
- * @sig_len: Number of bytes in signature
- * @node: Node having the RSA Key properties
- * @return 0 if verified, -ve on error
- */
- static int rsa_verify_with_keynode(struct image_sign_info *info,
- const void *hash, uint8_t *sig,
- uint sig_len, int node)
- {
- const void *blob = info->fdt_blob;
- struct key_prop prop;
- int length;
- int ret = 0;
- if (node < 0) {
- debug("%s: Skipping invalid node", __func__);
- return -EBADF;
- }
- prop.num_bits = fdtdec_get_int(blob, node, "rsa,num-bits", 0);
- prop.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0);
- prop.public_exponent = fdt_getprop(blob, node, "rsa,exponent", &length);
- if (!prop.public_exponent || length < sizeof(uint64_t))
- prop.public_exponent = NULL;
- prop.exp_len = sizeof(uint64_t);
- prop.modulus = fdt_getprop(blob, node, "rsa,modulus", NULL);
- prop.rr = fdt_getprop(blob, node, "rsa,r-squared", NULL);
- if (!prop.num_bits || !prop.modulus || !prop.rr) {
- debug("%s: Missing RSA key info", __func__);
- return -EFAULT;
- }
- ret = rsa_verify_key(info, &prop, sig, sig_len, hash,
- info->crypto->key_len);
- return ret;
- }
- #else
- static int rsa_verify_with_keynode(struct image_sign_info *info,
- const void *hash, uint8_t *sig,
- uint sig_len, int node)
- {
- return -EACCES;
- }
- #endif
- int rsa_verify_hash(struct image_sign_info *info,
- const uint8_t *hash, uint8_t *sig, uint sig_len)
- {
- int ret = -EACCES;
- if (CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY) && !info->fdt_blob) {
- /* don't rely on fdt properties */
- ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
- return ret;
- }
- if (CONFIG_IS_ENABLED(FIT_SIGNATURE)) {
- const void *blob = info->fdt_blob;
- int ndepth, noffset;
- int sig_node, node;
- char name[100];
- sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
- if (sig_node < 0) {
- debug("%s: No signature node found\n", __func__);
- return -ENOENT;
- }
- /* See if we must use a particular key */
- if (info->required_keynode != -1) {
- ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
- info->required_keynode);
- return ret;
- }
- /* Look for a key that matches our hint */
- snprintf(name, sizeof(name), "key-%s", info->keyname);
- node = fdt_subnode_offset(blob, sig_node, name);
- ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
- if (!ret)
- return ret;
- /* No luck, so try each of the keys in turn */
- for (ndepth = 0, noffset = fdt_next_node(info->fit, sig_node,
- &ndepth);
- (noffset >= 0) && (ndepth > 0);
- noffset = fdt_next_node(info->fit, noffset, &ndepth)) {
- if (ndepth == 1 && noffset != node) {
- ret = rsa_verify_with_keynode(info, hash,
- sig, sig_len,
- noffset);
- if (!ret)
- break;
- }
- }
- }
- return ret;
- }
- int rsa_verify(struct image_sign_info *info,
- const struct image_region region[], int region_count,
- uint8_t *sig, uint sig_len)
- {
- /* Reserve memory for maximum checksum-length */
- uint8_t hash[info->crypto->key_len];
- int ret = -EACCES;
- /*
- * Verify that the checksum-length does not exceed the
- * rsa-signature-length
- */
- if (info->checksum->checksum_len >
- info->crypto->key_len) {
- debug("%s: invlaid checksum-algorithm %s for %s\n",
- __func__, info->checksum->name, info->crypto->name);
- return -EINVAL;
- }
- /* Calculate checksum with checksum-algorithm */
- ret = info->checksum->calculate(info->checksum->name,
- region, region_count, hash);
- if (ret < 0) {
- debug("%s: Error in checksum calculation\n", __func__);
- return -EINVAL;
- }
- return rsa_verify_hash(info, hash, sig, sig_len);
- }
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