/* Get a PK algorithm identifier
*
* AlgorithmIdentifier ::= SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm OPTIONAL }
*/
static int pk_get_pk_alg( unsigned char **p,
const unsigned char *end,
mbedtls_pk_type_t *pk_alg, mbedtls_asn1_buf *params )
{
int ret;
mbedtls_asn1_buf alg_oid;
memset( params, 0, sizeof(mbedtls_asn1_buf) );
if( ( ret = mbedtls_asn1_get_alg( p, end, &alg_oid, params ) ) != 0 )
return( MBEDTLS_ERR_PK_INVALID_ALG + ret );
if( mbedtls_oid_get_pk_alg( &alg_oid, pk_alg ) != 0 )
return( MBEDTLS_ERR_PK_UNKNOWN_PK_ALG );
/*
* No parameters with RSA (only for EC)
*/
if( *pk_alg == MBEDTLS_PK_RSA &&
( ( params->tag != MBEDTLS_ASN1_NULL && params->tag != 0 ) ||
params->len != 0 ) )
{
return( MBEDTLS_ERR_PK_INVALID_ALG );
}
return( 0 );
}
/*
* Parse an algorithm identifier with (optional) paramaters
*/
int mbedtls_x509_get_alg( unsigned char **p, const unsigned char *end,
mbedtls_x509_buf *alg, mbedtls_x509_buf *params )
{
int ret;
if( ( ret = mbedtls_asn1_get_alg( p, end, alg, params ) ) != 0 )
return( MBEDTLS_ERR_X509_INVALID_ALG + ret );
return( 0 );
}
int mbedtls_asn1_get_alg_null( unsigned char **p,
const unsigned char *end,
mbedtls_asn1_buf *alg )
{
int ret;
mbedtls_asn1_buf params;
memset( ¶ms, 0, sizeof(mbedtls_asn1_buf) );
if( ( ret = mbedtls_asn1_get_alg( p, end, alg, ¶ms ) ) != 0 )
return( ret );
if( ( params.tag != MBEDTLS_ASN1_NULL && params.tag != 0 ) || params.len != 0 )
return( MBEDTLS_ERR_ASN1_INVALID_DATA );
return( 0 );
}
/*
* Parse the public key used for signing.
*/
static int
bootutil_parse_eckey(mbedtls_ecdsa_context *ctx, uint8_t **p, uint8_t *end)
{
size_t len;
mbedtls_asn1_buf alg;
mbedtls_asn1_buf param;
if (mbedtls_asn1_get_tag(p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) {
return -1;
}
end = *p + len;
if (mbedtls_asn1_get_alg(p, end, &alg, ¶m)) {
return -2;
}
if (alg.len != sizeof(ec_pubkey_oid) - 1 ||
memcmp(alg.p, ec_pubkey_oid, sizeof(ec_pubkey_oid) - 1)) {
return -3;
}
if (param.len != sizeof(ec_secp224r1_oid) - 1||
memcmp(param.p, ec_secp224r1_oid, sizeof(ec_secp224r1_oid) - 1)) {
return -4;
}
if (mbedtls_ecp_group_load_secp224r1(&ctx->grp)) {
return -5;
}
if (mbedtls_asn1_get_bitstring_null(p, end, &len)) {
return -6;
}
if (*p + len != end) {
return -7;
}
if (mbedtls_ecp_point_read_binary(&ctx->grp, &ctx->Q, *p, end - *p)) {
return -8;
}
if (mbedtls_ecp_check_pubkey(&ctx->grp, &ctx->Q)) {
return -9;
}
return 0;
}
int mbedtls_ecies_read_content_info(unsigned char **p, const unsigned char *end,
mbedtls_cipher_type_t *cipher_type, unsigned char **iv, size_t *iv_len,
unsigned char **data, size_t *data_len)
{
int result = 0;
size_t len = 0;
mbedtls_asn1_buf cipher_alg;
mbedtls_asn1_buf cipher_params;
if (cipher_type == NULL || iv == NULL || iv_len == NULL || data == NULL || data_len == NULL)
{
return MBEDTLS_ERR_ECIES_BAD_INPUT_DATA;
}
INVOKE_AND_CHECK(result,
mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)
);
INVOKE_AND_CHECK(result,
mbedtls_asn1_get_alg(p, end, &cipher_alg, &cipher_params)
);
if (cipher_params.tag != MBEDTLS_ASN1_OCTET_STRING)
{
INVOKE_AND_CHECK(result, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG);
}
*iv = cipher_params.p;
*iv_len = cipher_params.len;
INVOKE_AND_CHECK(result,
mbedtls_oid_get_cipher_alg(&cipher_alg, cipher_type)
);
INVOKE_AND_CHECK(result,
mbedtls_asn1_get_tag(p, end, data_len, MBEDTLS_ASN1_OCTET_STRING)
);
*data = *p;
*p += *data_len;
return result;
}
static int pk_parse_key_pkcs8_encrypted_der(
mbedtls_pk_context *pk,
const unsigned char *key, size_t keylen,
const unsigned char *pwd, size_t pwdlen )
{
int ret, decrypted = 0;
size_t len;
unsigned char buf[2048];
unsigned char *p, *end;
mbedtls_asn1_buf pbe_alg_oid, pbe_params;
#if defined(MBEDTLS_PKCS12_C)
mbedtls_cipher_type_t cipher_alg;
mbedtls_md_type_t md_alg;
#endif
memset( buf, 0, sizeof( buf ) );
p = (unsigned char *) key;
end = p + keylen;
if( pwdlen == 0 )
return( MBEDTLS_ERR_PK_PASSWORD_REQUIRED );
/*
* This function parses the EncryptedPrivatKeyInfo object (PKCS#8)
*
* EncryptedPrivateKeyInfo ::= SEQUENCE {
* encryptionAlgorithm EncryptionAlgorithmIdentifier,
* encryptedData EncryptedData
* }
*
* EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
*
* EncryptedData ::= OCTET STRING
*
* The EncryptedData OCTET STRING is a PKCS#8 PrivateKeyInfo
*/
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
{
return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );
}
end = p + len;
if( ( ret = mbedtls_asn1_get_alg( &p, end, &pbe_alg_oid, &pbe_params ) ) != 0 )
return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );
if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
return( MBEDTLS_ERR_PK_KEY_INVALID_FORMAT + ret );
if( len > sizeof( buf ) )
return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
/*
* Decrypt EncryptedData with appropriate PDE
*/
#if defined(MBEDTLS_PKCS12_C)
if( mbedtls_oid_get_pkcs12_pbe_alg( &pbe_alg_oid, &md_alg, &cipher_alg ) == 0 )
{
if( ( ret = mbedtls_pkcs12_pbe( &pbe_params, MBEDTLS_PKCS12_PBE_DECRYPT,
cipher_alg, md_alg,
pwd, pwdlen, p, len, buf ) ) != 0 )
{
if( ret == MBEDTLS_ERR_PKCS12_PASSWORD_MISMATCH )
return( MBEDTLS_ERR_PK_PASSWORD_MISMATCH );
return( ret );
}
decrypted = 1;
}
else if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS12_PBE_SHA1_RC4_128, &pbe_alg_oid ) == 0 )
{
if( ( ret = mbedtls_pkcs12_pbe_sha1_rc4_128( &pbe_params,
MBEDTLS_PKCS12_PBE_DECRYPT,
pwd, pwdlen,
p, len, buf ) ) != 0 )
{
return( ret );
}
// Best guess for password mismatch when using RC4. If first tag is
// not MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE
//
if( *buf != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )
return( MBEDTLS_ERR_PK_PASSWORD_MISMATCH );
decrypted = 1;
}
else
#endif /* MBEDTLS_PKCS12_C */
#if defined(MBEDTLS_PKCS5_C)
if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS5_PBES2, &pbe_alg_oid ) == 0 )
{
if( ( ret = mbedtls_pkcs5_pbes2( &pbe_params, MBEDTLS_PKCS5_DECRYPT, pwd, pwdlen,
p, len, buf ) ) != 0 )
{
if( ret == MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH )
return( MBEDTLS_ERR_PK_PASSWORD_MISMATCH );
return( ret );
}
decrypted = 1;
}
else
#endif /* MBEDTLS_PKCS5_C */
{
((void) pwd);
}
if( decrypted == 0 )
return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
return( pk_parse_key_pkcs8_unencrypted_der( pk, buf, len ) );
}
int mbedtls_pkcs5_pbes2( const mbedtls_asn1_buf *pbe_params, int mode,
const unsigned char *pwd, size_t pwdlen,
const unsigned char *data, size_t datalen,
unsigned char *output )
{
int ret, iterations = 0, keylen = 0;
unsigned char *p, *end;
mbedtls_asn1_buf kdf_alg_oid, enc_scheme_oid, kdf_alg_params, enc_scheme_params;
mbedtls_asn1_buf salt;
mbedtls_md_type_t md_type = MBEDTLS_MD_SHA1;
unsigned char key[32], iv[32];
size_t olen = 0;
const mbedtls_md_info_t *md_info;
const mbedtls_cipher_info_t *cipher_info;
mbedtls_md_context_t md_ctx;
mbedtls_cipher_type_t cipher_alg;
mbedtls_cipher_context_t cipher_ctx;
p = pbe_params->p;
end = p + pbe_params->len;
/*
* PBES2-params ::= SEQUENCE {
* keyDerivationFunc AlgorithmIdentifier {{PBES2-KDFs}},
* encryptionScheme AlgorithmIdentifier {{PBES2-Encs}}
* }
*/
if( pbe_params->tag != ( MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) )
return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT +
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG );
if( ( ret = mbedtls_asn1_get_alg( &p, end, &kdf_alg_oid, &kdf_alg_params ) ) != 0 )
return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
// Only PBKDF2 supported at the moment
//
if( MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS5_PBKDF2, &kdf_alg_oid ) != 0 )
return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
if( ( ret = pkcs5_parse_pbkdf2_params( &kdf_alg_params,
&salt, &iterations, &keylen,
&md_type ) ) != 0 )
{
return( ret );
}
md_info = mbedtls_md_info_from_type( md_type );
if( md_info == NULL )
return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
if( ( ret = mbedtls_asn1_get_alg( &p, end, &enc_scheme_oid,
&enc_scheme_params ) ) != 0 )
{
return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT + ret );
}
if( mbedtls_oid_get_cipher_alg( &enc_scheme_oid, &cipher_alg ) != 0 )
return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
cipher_info = mbedtls_cipher_info_from_type( cipher_alg );
if( cipher_info == NULL )
return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
/*
* The value of keylen from pkcs5_parse_pbkdf2_params() is ignored
* since it is optional and we don't know if it was set or not
*/
keylen = cipher_info->key_bitlen / 8;
if( enc_scheme_params.tag != MBEDTLS_ASN1_OCTET_STRING ||
enc_scheme_params.len != cipher_info->iv_size )
{
return( MBEDTLS_ERR_PKCS5_INVALID_FORMAT );
}
mbedtls_md_init( &md_ctx );
mbedtls_cipher_init( &cipher_ctx );
memcpy( iv, enc_scheme_params.p, enc_scheme_params.len );
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 1 ) ) != 0 )
goto exit;
if( ( ret = mbedtls_pkcs5_pbkdf2_hmac( &md_ctx, pwd, pwdlen, salt.p, salt.len,
iterations, keylen, key ) ) != 0 )
{
goto exit;
}
if( ( ret = mbedtls_cipher_setup( &cipher_ctx, cipher_info ) ) != 0 )
goto exit;
if( ( ret = mbedtls_cipher_setkey( &cipher_ctx, key, 8 * keylen, (mbedtls_operation_t) mode ) ) != 0 )
goto exit;
if( ( ret = mbedtls_cipher_crypt( &cipher_ctx, iv, enc_scheme_params.len,
data, datalen, output, &olen ) ) != 0 )
ret = MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH;
exit:
mbedtls_md_free( &md_ctx );
mbedtls_cipher_free( &cipher_ctx );
return( ret );
}
/*
* 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)
{
mbedtls_asn1_buf sig_oid, sig_params;
mbedtls_asn1_buf signature;
mbedtls_md_type_t md_alg;
mbedtls_pk_type_t pk_alg;
mbedtls_pk_context pk;
int rc;
void *sig_opts = NULL;
const mbedtls_md_info_t *md_info;
unsigned char *p, *end;
unsigned char hash[MBEDTLS_MD_MAX_SIZE];
/* Get pointers to signature OID and parameters */
p = (unsigned char *)sig_alg;
end = (unsigned char *)(p + sig_alg_len);
rc = mbedtls_asn1_get_alg(&p, end, &sig_oid, &sig_params);
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;
}
/* Parse the public key */
mbedtls_pk_init(&pk);
p = (unsigned char *)pk_ptr;
end = (unsigned char *)(p + pk_len);
rc = mbedtls_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 = mbedtls_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 = mbedtls_md_info_from_type(md_alg);
if (md_info == NULL) {
rc = CRYPTO_ERR_SIGNATURE;
goto end;
}
p = (unsigned char *)data_ptr;
rc = mbedtls_md(md_info, p, data_len, hash);
if (rc != 0) {
rc = CRYPTO_ERR_SIGNATURE;
goto end;
}
/* Verify the signature */
rc = mbedtls_pk_verify_ext(pk_alg, sig_opts, &pk, md_alg, hash,
mbedtls_md_get_size(md_info),
signature.p, signature.len);
if (rc != 0) {
rc = CRYPTO_ERR_SIGNATURE;
goto end;
}
/* Signature verification success */
rc = CRYPTO_SUCCESS;
end:
mbedtls_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)
{
mbedtls_asn1_buf hash_oid, params;
mbedtls_md_type_t md_alg;
const mbedtls_md_info_t *md_info;
unsigned char *p, *end, *hash;
unsigned char data_hash[MBEDTLS_MD_MAX_SIZE];
size_t len;
int rc;
/* Digest info should be an MBEDTLS_ASN1_SEQUENCE */
p = (unsigned char *)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;
}
md_info = mbedtls_md_info_from_type(md_alg);
if (md_info == NULL) {
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 != mbedtls_md_get_size(md_info)) {
return CRYPTO_ERR_HASH;
}
hash = p;
/* Calculate the hash of the data */
p = (unsigned char *)data_ptr;
rc = mbedtls_md(md_info, p, data_len, data_hash);
if (rc != 0) {
return CRYPTO_ERR_HASH;
}
/* Compare values */
rc = memcmp(data_hash, hash, mbedtls_md_get_size(md_info));
if (rc != 0) {
return CRYPTO_ERR_HASH;
}
return CRYPTO_SUCCESS;
}