diff options
Diffstat (limited to 'drivers/auth/mbedtls/mbedtls_crypto.c')
| -rw-r--r-- | drivers/auth/mbedtls/mbedtls_crypto.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/auth/mbedtls/mbedtls_crypto.c b/drivers/auth/mbedtls/mbedtls_crypto.c new file mode 100644 index 00000000..f69f9308 --- /dev/null +++ b/drivers/auth/mbedtls/mbedtls_crypto.c @@ -0,0 +1,229 @@ +/* + * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + + +#include <crypto_mod.h> +#include <debug.h> +#include <mbedtls_common.h> +#include <stddef.h> +#include <string.h> + +/* mbedTLS headers */ +#include <polarssl/md_wrap.h> +#include <polarssl/memory_buffer_alloc.h> +#include <polarssl/oid.h> +#include <polarssl/platform.h> + +#define LIB_NAME "mbedTLS" + +/* + * 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 + * } + */ + +/* + * Initialize the library and export the descriptor + */ +static void init(void) +{ + /* Initialize mbedTLS */ + mbedtls_init(); +} + +/* + * 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) +{ + asn1_buf sig_oid, sig_params; + asn1_buf signature; + md_type_t md_alg; + pk_type_t pk_alg; + pk_context pk; + int rc; + void *sig_opts = NULL; + const md_info_t *md_info; + unsigned char *p, *end; + unsigned char hash[POLARSSL_MD_MAX_SIZE]; + + /* Get pointers to signature OID and parameters */ + p = (unsigned char *)sig_alg; + end = (unsigned char *)(p + sig_alg_len); + rc = asn1_get_alg(&p, end, &sig_oid, &sig_params); + if (rc != 0) { + return CRYPTO_ERR_SIGNATURE; + } + + /* Get the actual signature algorithm (MD + PK) */ + rc = oid_get_sig_alg(&sig_oid, &md_alg, &pk_alg); + if (rc != 0) { + return CRYPTO_ERR_SIGNATURE; + } + + /* Parse the public key */ + pk_init(&pk); + p = (unsigned char *)pk_ptr; + end = (unsigned char *)(p + pk_len); + rc = pk_parse_subpubkey(&p, end, &pk); + if (rc != 0) { + return CRYPTO_ERR_SIGNATURE; + } + + /* Get the signature (bitstring) */ + p = (unsigned char *)sig_ptr; + end = (unsigned char *)(p + sig_len); + signature.tag = *p; + rc = asn1_get_bitstring_null(&p, end, &signature.len); + if (rc != 0) { + rc = CRYPTO_ERR_SIGNATURE; + goto end; + } + signature.p = p; + + /* Calculate the hash of the data */ + md_info = md_info_from_type(md_alg); + if (md_info == NULL) { + rc = CRYPTO_ERR_SIGNATURE; + goto end; + } + p = (unsigned char *)data_ptr; + rc = md(md_info, p, data_len, hash); + if (rc != 0) { + rc = CRYPTO_ERR_SIGNATURE; + goto end; + } + + /* Verify the signature */ + rc = pk_verify_ext(pk_alg, sig_opts, &pk, md_alg, hash, + md_info->size, signature.p, signature.len); + if (rc != 0) { + rc = CRYPTO_ERR_SIGNATURE; + goto end; + } + + /* Signature verification success */ + rc = CRYPTO_SUCCESS; + +end: + pk_free(&pk); + return rc; +} + +/* + * 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) +{ + asn1_buf hash_oid, params; + md_type_t md_alg; + const md_info_t *md_info; + unsigned char *p, *end, *hash; + unsigned char data_hash[POLARSSL_MD_MAX_SIZE]; + size_t len; + int rc; + + /* Digest info should be an ASN1_SEQUENCE */ + p = (unsigned char *)digest_info_ptr; + end = (unsigned char *)(digest_info_ptr + digest_info_len); + rc = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + /* Get the hash algorithm */ + rc = asn1_get_alg(&p, end, &hash_oid, ¶ms); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + rc = oid_get_md_alg(&hash_oid, &md_alg); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + md_info = md_info_from_type(md_alg); + if (md_info == NULL) { + return CRYPTO_ERR_HASH; + } + + /* Hash should be octet string type */ + rc = asn1_get_tag(&p, end, &len, ASN1_OCTET_STRING); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + /* Length of hash must match the algorithm's size */ + if (len != md_info->size) { + return CRYPTO_ERR_HASH; + } + hash = p; + + /* Calculate the hash of the data */ + p = (unsigned char *)data_ptr; + rc = md(md_info, p, data_len, data_hash); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + /* Compare values */ + rc = memcmp(data_hash, hash, md_info->size); + if (rc != 0) { + return CRYPTO_ERR_HASH; + } + + return CRYPTO_SUCCESS; +} + +/* + * Register crypto library descriptor + */ +REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash); |