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Private EC key format: remove ASN.1-based sanity checks

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In preparation for the import/export format change for private
elliptic curve keys from RFC 5915 to the raw secret value,
remove ASN.1-based sanity checks. For the raw secret value, most byte
strings of the correct length are valid (the details depend on the
curve), so as a sanity check, just check the length.
This commit is contained in:
Gilles Peskine 2018-10-29 19:21:41 +01:00
parent e783d34543
commit 5b802a366a
1 changed files with 3 additions and 36 deletions
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39
tests/suites/test_suite_psa_crypto.function
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@ -564,42 +564,9 @@ static int exported_key_sanity_check( psa_key_type_t type, size_t bits,
#if defined(MBEDTLS_ECP_C)
if( PSA_KEY_TYPE_IS_ECC_KEYPAIR( type ) )
{
uint8_t *p = exported;
uint8_t *end = exported + exported_length;
size_t len;
int version;
/* ECPrivateKey ::= SEQUENCE {
* version INTEGER, -- must be 1
* privateKey OCTET STRING,
* -- `ceiling(log_{256}(n))`-byte string, big endian,
* -- where n is the order of the curve.
* parameters ECParameters {{ NamedCurve }}, -- mandatory
* publicKey BIT STRING -- mandatory
* }
*/
TEST_ASSERT( mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_SEQUENCE |
MBEDTLS_ASN1_CONSTRUCTED ) == 0 );
TEST_ASSERT( p + len == end );
TEST_ASSERT( mbedtls_asn1_get_int( &p, end, &version ) == 0 );
TEST_ASSERT( version == 1 );
TEST_ASSERT( mbedtls_asn1_get_tag( &p, end, &len,
MBEDTLS_ASN1_OCTET_STRING ) == 0 );
/* Bug in Mbed TLS: the length of the octet string depends on the value */
// TEST_ASSERT( len == PSA_BITS_TO_BYTES( bits ) );
p += len;
TEST_ASSERT( asn1_get_implicit_tag( &p, end, &len, 0,
MBEDTLS_ASN1_OID ) == 0 );
p += len;
/* publicKey: ECPoint in uncompressed representation (as below) */
TEST_ASSERT( asn1_get_implicit_tag( &p, end, &len, 1,
MBEDTLS_ASN1_BIT_STRING ) == 0 );
TEST_ASSERT( p + len == end );
TEST_ASSERT( p[0] == 0 ); /* 0 unused bits in the bit string */
++p;
TEST_ASSERT( p + 1 + 2 * PSA_BITS_TO_BYTES( bits ) == end );
TEST_ASSERT( p[0] == 4 );
}
/* Just the secret value */
TEST_ASSERT( exported_length == PSA_BITS_TO_BYTES( bits ) );
}
else
#endif /* MBEDTLS_ECP_C */