1 // SPDX-License-Identifier: BSD-2-Clause 2 /* 3 * Copyright (c) 2015-2017, Linaro Limited 4 */ 5 6 #include <crypto/crypto.h> 7 #include <signed_hdr.h> 8 #include <stdlib.h> 9 #include <string.h> 10 #include <ta_pub_key.h> 11 #include <tee_api_types.h> 12 #include <tee/tee_cryp_utl.h> 13 #include <utee_defines.h> 14 15 struct shdr *shdr_alloc_and_copy(const struct shdr *img, size_t img_size) 16 { 17 size_t shdr_size; 18 struct shdr *shdr; 19 20 if (img_size < sizeof(struct shdr)) 21 return NULL; 22 23 shdr_size = SHDR_GET_SIZE(img); 24 if (img_size < shdr_size) 25 return NULL; 26 27 shdr = malloc(shdr_size); 28 if (!shdr) 29 return NULL; 30 memcpy(shdr, img, shdr_size); 31 32 /* Check that the data wasn't modified before the copy was completed */ 33 if (shdr_size != SHDR_GET_SIZE(shdr)) { 34 free(shdr); 35 return NULL; 36 } 37 38 return shdr; 39 } 40 41 TEE_Result shdr_verify_signature(const struct shdr *shdr) 42 { 43 struct rsa_public_key key; 44 TEE_Result res; 45 uint32_t e = TEE_U32_TO_BIG_ENDIAN(ta_pub_key_exponent); 46 size_t hash_size; 47 48 if (shdr->magic != SHDR_MAGIC) 49 return TEE_ERROR_SECURITY; 50 51 if (TEE_ALG_GET_MAIN_ALG(shdr->algo) != TEE_MAIN_ALGO_RSA) 52 return TEE_ERROR_SECURITY; 53 54 res = tee_hash_get_digest_size(TEE_DIGEST_HASH_TO_ALGO(shdr->algo), 55 &hash_size); 56 if (res) 57 return TEE_ERROR_SECURITY; 58 if (hash_size != shdr->hash_size) 59 return TEE_ERROR_SECURITY; 60 61 res = crypto_acipher_alloc_rsa_public_key(&key, shdr->sig_size); 62 if (res) 63 return TEE_ERROR_SECURITY; 64 65 res = crypto_bignum_bin2bn((uint8_t *)&e, sizeof(e), key.e); 66 if (res) 67 goto out; 68 res = crypto_bignum_bin2bn(ta_pub_key_modulus, ta_pub_key_modulus_size, 69 key.n); 70 if (res) 71 goto out; 72 73 res = crypto_acipher_rsassa_verify(shdr->algo, &key, -1, 74 SHDR_GET_HASH(shdr), shdr->hash_size, 75 SHDR_GET_SIG(shdr), shdr->sig_size); 76 out: 77 crypto_acipher_free_rsa_public_key(&key); 78 if (res) 79 return TEE_ERROR_SECURITY; 80 return TEE_SUCCESS; 81 } 82