/*
* Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <arch_helpers.h>
#include <crypto_driver.h>
#include <crypto_mod.h>
#include <debug.h>
#include <mbedtls_common.h>
#include <platform_def.h>
#include <rsa.h>
#include <sbrom_bsv_api.h>
#include <secureboot_base_func.h>
#include <secureboot_gen_defs.h>
#include <stddef.h>
#include <string.h>
#include <util.h>
#include <utils.h>
#include <mbedtls/oid.h>
#define LIB_NAME "CryptoCell SBROM"
#define RSA_SALT_LEN 32
#define RSA_EXPONENT 65537
/*
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm OPTIONAL
* }
*
* SubjectPublicKeyInfo ::= SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING
* }
*
* DigestInfo ::= SEQUENCE {
* digestAlgorithm AlgorithmIdentifier,
* digest OCTET STRING
* }
*
* RSASSA-PSS-params ::= SEQUENCE {
* hashAlgorithm [0] HashAlgorithm,
* maskGenAlgorithm [1] MaskGenAlgorithm,
* saltLength [2] INTEGER,
* trailerField [3] TrailerField DEFAULT trailerFieldBC
* }
*/
/*
* Initialize the library and export the descriptor
*/
static void init(void)
{
CCError_t ret;
uint32_t lcs;
/* Initialize CC SBROM */
ret = CC_BsvSbromInit((uintptr_t)PLAT_CRYPTOCELL_BASE);
if (ret != CC_OK) {
ERROR("CryptoCell CC_BsvSbromInit() error %x\n", ret);
panic();
}
/* Initialize lifecycle state */
ret = CC_BsvLcsGetAndInit((uintptr_t)PLAT_CRYPTOCELL_BASE, &lcs);
if (ret != CC_OK) {
ERROR("CryptoCell CC_BsvLcsGetAndInit() error %x\n", ret);
panic();
}
/* If the lifecyclestate is `SD`, then stop further execution */
if (lcs == CC_BSV_SECURITY_DISABLED_LCS) {
ERROR("CryptoCell LCS is security-disabled\n");
panic();
}
}
/*
* Verify a signature.
*
* Parameters are passed using the DER encoding format following the ASN.1
* structures detailed above.
*/
static int verify_signature(void *data_ptr, unsigned int data_len,
void *sig_ptr, unsigned int sig_len,
void *sig_alg, unsigned int sig_alg_len,
void *pk_ptr, unsigned int pk_len)
{
CCError_t error;
CCSbNParams_t pk;
CCSbSignature_t signature;
int rc, exp;
mbedtls_asn1_buf sig_oid, alg_oid, params;
mbedtls_md_type_t md_alg;
mbedtls_pk_type_t pk_alg;
mbedtls_pk_rsassa_pss_options pss_opts;
size_t len;
uint8_t *p, *end;
/* Temp buf to store the public key modulo (N) in LE format */
uint32_t RevN[SB_RSA_MOD_SIZE_IN_WORDS];
/* Verify the signature algorithm */
/* Get pointers to signature OID and parameters */
p = sig_alg;
end = p + sig_alg_len;
rc = mbedtls_asn1_get_alg(&p, end, &sig_oid, ¶ms);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
/* Get the actual signature algorithm (MD + PK) */
rc = mbedtls_oid_get_sig_alg(&sig_oid, &md_alg, &pk_alg);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
/* The CryptoCell only supports RSASSA-PSS signature */
if (pk_alg != MBEDTLS_PK_RSASSA_PSS || md_alg != MBEDTLS_MD_NONE)
return CRYPTO_ERR_SIGNATURE;
/* Verify the RSASSA-PSS params */
/* The trailer field is verified to be 0xBC internally by this API */
rc = mbedtls_x509_get_rsassa_pss_params(¶ms, &md_alg,
&pss_opts.mgf1_hash_id,
&pss_opts.expected_salt_len);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
/* The CryptoCell only supports SHA256 as hash algorithm */
if (md_alg != MBEDTLS_MD_SHA256 || pss_opts.mgf1_hash_id != MBEDTLS_MD_SHA256)
return CRYPTO_ERR_SIGNATURE;
if (pss_opts.expected_salt_len != RSA_SALT_LEN)
return CRYPTO_ERR_SIGNATURE;
/* Parse the public key */
p = pk_ptr;
end = p + pk_len;
rc = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
end = p + len;
rc = mbedtls_asn1_get_alg_null(&p, end, &alg_oid);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
if (mbedtls_oid_get_pk_alg(&alg_oid, &pk_alg) != 0)
return CRYPTO_ERR_SIGNATURE;
if (pk_alg != MBEDTLS_PK_RSA)
return CRYPTO_ERR_SIGNATURE;
rc = mbedtls_asn1_get_bitstring_null(&p, end, &len);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
rc = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
if (*p == 0) {
p++; len--;
}
if (len != RSA_MOD_SIZE_IN_BYTES || ((p + len) > end))
return CRYPTO_ERR_SIGNATURE;
/*
* The CCSbVerifySignature() API expects N and Np in BE format and
* the signature in LE format. Copy N from certificate.
*/
memcpy(pk.N, p, RSA_MOD_SIZE_IN_BYTES);
/* Verify the RSA exponent */
p += len;
rc = mbedtls_asn1_get_int(&p, end, &exp);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
if (exp != RSA_EXPONENT)
return CRYPTO_ERR_SIGNATURE;
/*
* Calculate the Np (Barrett n' value). The RSA_CalcNp() API expects
* N in LE format. Hence reverse N into a temporary buffer `RevN`.
*/
UTIL_ReverseMemCopy((uint8_t *)RevN, (uint8_t *)pk.N, sizeof(RevN));
RSA_CalcNp((uintptr_t)PLAT_CRYPTOCELL_BASE, RevN, pk.Np);
/* Np is in LE format. Reverse it to BE */
UTIL_ReverseBuff((uint8_t *)pk.Np, sizeof(pk.Np));
/* Get the signature (bitstring) */
p = sig_ptr;
end = p + sig_len;
rc = mbedtls_asn1_get_bitstring_null(&p, end, &len);
if (rc != 0)
return CRYPTO_ERR_SIGNATURE;
if (len != RSA_MOD_SIZE_IN_BYTES || ((p + len) > end))
return CRYPTO_ERR_SIGNATURE;
/*
* The signature is BE format. Convert it to LE before calling
* CCSbVerifySignature().
*/
UTIL_ReverseMemCopy((uint8_t *)signature.sig, p, RSA_MOD_SIZE_IN_BYTES);
/*
* CryptoCell utilises DMA internally to transfer data. Flush the data
* from caches.
*/
flush_dcache_range((uintptr_t)data_ptr, data_len);
/* Verify the signature */
error = CCSbVerifySignature((uintptr_t)PLAT_CRYPTOCELL_BASE,
(uint32_t *)data_ptr, &pk, &signature,
data_len, RSA_PSS_2048);
if (error != CC_OK)
return CRYPTO_ERR_SIGNATURE;
/* Signature verification success */
return CRYPTO_SUCCESS;
}
/*
* Match a hash
*
* Digest info is passed in DER format following the ASN.1 structure detailed
* above.
*/
static int verify_hash(void *data_ptr, unsigned int data_len,
void *digest_info_ptr, unsigned int digest_info_len)
{
mbedtls_asn1_buf hash_oid, params;
mbedtls_md_type_t md_alg;
uint8_t *p, *end, *hash;
CCHashResult_t pubKeyHash;
size_t len;
int rc;
CCError_t error;
/* Digest info should be an MBEDTLS_ASN1_SEQUENCE */
p = digest_info_ptr;
end = p + digest_info_len;
rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE);
if (rc != 0)
return CRYPTO_ERR_HASH;
/* Get the hash algorithm */
rc = mbedtls_asn1_get_alg(&p, end, &hash_oid, ¶ms);
if (rc != 0)
return CRYPTO_ERR_HASH;
rc = mbedtls_oid_get_md_alg(&hash_oid, &md_alg);
if (rc != 0)
return CRYPTO_ERR_HASH;
/* Verify that hash algorithm is SHA256 */
if (md_alg != MBEDTLS_MD_SHA256)
return CRYPTO_ERR_HASH;
/* Hash should be octet string type */
rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
if (rc != 0)
return CRYPTO_ERR_HASH;
/* Length of hash must match the algorithm's size */
if (len != HASH_RESULT_SIZE_IN_BYTES)
return CRYPTO_ERR_HASH;
/*
* CryptoCell utilises DMA internally to transfer data. Flush the data
* from caches.
*/
flush_dcache_range((uintptr_t)data_ptr, data_len);
hash = p;
error = SBROM_CryptoHash((uintptr_t)PLAT_CRYPTOCELL_BASE,
(uintptr_t)data_ptr, data_len, pubKeyHash);
if (error != CC_OK)
return CRYPTO_ERR_HASH;
rc = memcmp(pubKeyHash, hash, HASH_RESULT_SIZE_IN_BYTES);
if (rc != 0)
return CRYPTO_ERR_HASH;
return CRYPTO_SUCCESS;
}
/*
* Register crypto library descriptor
*/
REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash);