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Implement pk_sign() for opaque ECDSA keys

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This commit is contained in:
Manuel Pégourié-Gonnard 2018-10-31 16:22:49 +01:00
parent d97390e97d
commit 3686771dfa
3 changed files with 176 additions and 1 deletions
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113
library/pk_wrap.c
View file

@ -41,10 +41,18 @@
#include "mbedtls/ecdsa.h"
#endif
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "mbedtls/asn1write.h"
#endif
#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
#include "mbedtls/platform_util.h"
#endif
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "mbedtls/psa_util.h"
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
@ -753,13 +761,116 @@ static int pk_psa_can_do( mbedtls_pk_type_t type )
type == MBEDTLS_PK_ECDSA );
}
/* Like mbedtls_asn1_write_mpi, but from a buffer */
static int asn1_write_mpibuf( unsigned char **p, unsigned char *start,
const unsigned char *src, size_t slen )
{
int ret;
size_t len = 0;
if( (size_t)( *p - start ) < slen )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
len = slen;
*p -= len;
memcpy( *p, src, len );
if( **p & 0x80 )
{
if( *p - start < 1 )
return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
*--(*p) = 0x00;
len += 1;
}
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
return( (int) len );
}
/* Transcode signature from PSA format to ASN.1 sequence.
* See ecdsa_signature_to_asn1 in ecdsa.c.
*
* [in] sig: the signature in PSA format
* [in/out] sig_len: signature length pre- and post-transcoding
* [out] dst: the signature in ASN.1 format
*/
static int pk_ecdsa_sig_asn1_from_psa( const unsigned char *sig, size_t *sig_len,
unsigned char *dst )
{
int ret;
unsigned char buf[MBEDTLS_ECDSA_MAX_LEN];
unsigned char *p = buf + sizeof( buf );
size_t len = 0;
const size_t mpi_len = *sig_len / 2;
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, buf, sig + mpi_len, mpi_len ) );
MBEDTLS_ASN1_CHK_ADD( len, asn1_write_mpibuf( &p, buf, sig, mpi_len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &p, buf, len ) );
MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &p, buf,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
memcpy( dst, p, len );
*sig_len = len;
return( 0 );
}
static int pk_psa_sign_wrap( void *ctx, mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hash_len,
unsigned char *sig, size_t *sig_len,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
const psa_key_slot_t *key = (const psa_key_slot_t *) ctx;
psa_status_t status;
psa_algorithm_t alg = PSA_ALG_ECDSA( mbedtls_psa_translate_md( md_alg ) );
/* PSA needs a buffer of know size */
unsigned char buf[2 * MBEDTLS_ECP_MAX_BYTES];
const size_t buf_len = sizeof( buf );
/* PSA has its own RNG */
(void) f_rng;
(void) p_rng;
status = psa_asymmetric_sign( *key, alg, hash, hash_len,
buf, buf_len, sig_len );
/* translate errors to best approximation */
switch( status )
{
case PSA_SUCCESS:
break; /* don't return now */
case PSA_ERROR_NOT_SUPPORTED:
return( MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE );
case PSA_ERROR_INSUFFICIENT_MEMORY:
return( MBEDTLS_ERR_PK_ALLOC_FAILED );
case PSA_ERROR_COMMUNICATION_FAILURE:
case PSA_ERROR_HARDWARE_FAILURE:
case PSA_ERROR_TAMPERING_DETECTED:
return( MBEDTLS_ERR_PK_HW_ACCEL_FAILED );
case PSA_ERROR_INSUFFICIENT_ENTROPY:
return( MBEDTLS_ERR_ECP_RANDOM_FAILED );
case PSA_ERROR_BAD_STATE:
return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
default: /* should never happen */
return( MBEDTLS_ERR_PK_HW_ACCEL_FAILED );
}
pk_ecdsa_sig_asn1_from_psa( buf, sig_len, sig );
return( 0 );
}
const mbedtls_pk_info_t mbedtls_pk_opaque_psa_info = {
MBEDTLS_PK_OPAQUE_PSA,
"Opaque (PSA)",
pk_psa_get_bitlen,
pk_psa_can_do,
NULL, /* verify - will be done later */
NULL, /* coming soon: sign */
pk_psa_sign_wrap,
#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
NULL, /* restartable verify - not relevant */
NULL, /* restartable sign - not relevant */

3
tests/suites/test_suite_pk.data
View file

@ -188,3 +188,6 @@ pk_sign_verify_restart:MBEDTLS_PK_ECDSA:MBEDTLS_ECP_DP_SECP256R1:"C9AFA9D845BA75
ECDSA restartable sign/verify: ECKEY, max_ops=250
depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED:MBEDTLS_SHA256_C
pk_sign_verify_restart:MBEDTLS_PK_ECKEY:MBEDTLS_ECP_DP_SECP256R1:"C9AFA9D845BA75166B5C215767B1D6934E50C3DB36E89B127B8A622B120F6721":"60FED4BA255A9D31C961EB74C6356D68C049B8923B61FA6CE669622E60F29FB6":"7903FE1008B8BC99A41AE9E95628BC64F2F1B20C2D7E9F5177A3C294D4462299":MBEDTLS_MD_SHA256:"test":"3045022100f1abb023518351cd71d881567b1ea663ed3efcf6c5132b354f28d3b0b7d383670220019f4113742a2b14bd25926b49c649155f267e60d3814b4c0cc84250e46f0083":250:2:64
PSA wrapped sign
pk_psa_sign:

61
tests/suites/test_suite_pk.function
View file

@ -72,6 +72,7 @@ size_t mbedtls_rsa_key_len_func( void *ctx )
/*
* Generate a key in a free key slot and return this key slot,
* or PK_PSA_INVALID_SLOT if no slot was available.
* The key uses NIST P-256 and is usable for signing with SHA-256.
*/
psa_key_slot_t pk_psa_genkey( void )
{
@ -80,10 +81,20 @@ psa_key_slot_t pk_psa_genkey( void )
const int curve = PSA_ECC_CURVE_SECP256R1;
const psa_key_type_t type = PSA_KEY_TYPE_ECC_KEYPAIR(curve);
const size_t bits = 256;
psa_key_policy_t policy;
/* find a free key slot */
if( PSA_SUCCESS != mbedtls_psa_get_free_key_slot( &key ) )
return( PK_PSA_INVALID_SLOT );
/* set up policy on key slot */
psa_key_policy_init( &policy );
psa_key_policy_set_usage( &policy, PSA_KEY_USAGE_SIGN,
PSA_ALG_ECDSA(PSA_ALG_SHA_256) );
if( PSA_SUCCESS != psa_set_key_policy( key, &policy ) )
return( PK_PSA_INVALID_SLOT );
/* generate key */
if( PSA_SUCCESS != psa_generate_key( key, type, bits, NULL, 0 ) )
return( PK_PSA_INVALID_SLOT );
@ -760,3 +771,53 @@ exit:
mbedtls_pk_free( &rsa ); mbedtls_pk_free( &alt );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SHA256_C:MBEDTLS_USE_PSA_CRYPTO:MBEDTLS_ECDSA_C:MBEDTLS_ECP_DP_SECP256R1_ENABLED */
void pk_psa_sign( )
{
mbedtls_pk_context pk;
psa_key_slot_t key;
unsigned char hash[50], sig[100], pkey[100];
size_t sig_len, klen = 0;
/*
* This tests making signatures with a wrapped PSA key:
* - generate a fresh PSA key
* - wrap it in a PK context and make a signature this way
* - extract the public key
* - parse it to a PK context and verify the signature this way
*/
mbedtls_pk_init( &pk );
memset( hash, 0x2a, sizeof hash );
memset( sig, 0, sizeof sig );
memset( pkey, 0, sizeof pkey );
key = pk_psa_genkey();
TEST_ASSERT( key != 0 );
TEST_ASSERT( mbedtls_pk_setup_psa( &pk, key ) == 0 );
TEST_ASSERT( mbedtls_pk_sign( &pk, MBEDTLS_MD_SHA256,
hash, sizeof hash, sig, &sig_len,
NULL, NULL ) == 0 );
mbedtls_pk_free( &pk );
TEST_ASSERT( PSA_SUCCESS == psa_export_public_key(
key, pkey, sizeof( pkey ), &klen ) );
TEST_ASSERT( PSA_SUCCESS == psa_destroy_key( key ) );
mbedtls_pk_init( &pk );
TEST_ASSERT( mbedtls_pk_parse_public_key( &pk, pkey, klen ) == 0 );
TEST_ASSERT( mbedtls_pk_verify( &pk, MBEDTLS_MD_SHA256,
hash, sizeof hash, sig, sig_len ) == 0 );
exit:
mbedtls_pk_free( &pk );
}
/* END_CASE */