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Unify parsing of the signature algorithms extension

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Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
This commit is contained in:
Gabor Mezei
2022-04-27 21:17:56 +02:00
parent 5479f5321a
commit 078e803d2c
6 changed files with 167 additions and 281 deletions
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173
library/ssl_tls.c
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@ -616,11 +616,6 @@ static void ssl_handshake_params_init( mbedtls_ssl_handshake_params *handshake )
handshake->update_checksum = ssl_update_checksum_start;
#if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
mbedtls_ssl_sig_hash_set_init( &handshake->hash_algs );
#endif
#if defined(MBEDTLS_DHM_C)
mbedtls_dhm_init( &handshake->dhm_ctx );
#endif
@ -4150,13 +4145,13 @@ static uint16_t ssl_preset_default_sig_algs[] = {
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
static uint16_t ssl_tls12_preset_default_sig_algs[] = {
#if defined(MBEDTLS_SHA512_C)
MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_HASH_SHA512 )
MBEDTLS_SSL_SIG_ALG_SET( MBEDTLS_SSL_HASH_SHA512 )
#endif
#if defined(MBEDTLS_SHA384_C)
MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_HASH_SHA384 )
MBEDTLS_SSL_SIG_ALG_SET( MBEDTLS_SSL_HASH_SHA384 )
#endif
#if defined(MBEDTLS_SHA256_C)
MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_HASH_SHA256 )
MBEDTLS_SSL_SIG_ALG_SET( MBEDTLS_SSL_HASH_SHA256 )
#endif
MBEDTLS_TLS1_3_SIG_NONE
};
@ -4191,10 +4186,10 @@ static uint16_t ssl_preset_suiteb_sig_algs[] = {
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
static uint16_t ssl_tls12_preset_suiteb_sig_algs[] = {
#if defined(MBEDTLS_SHA256_C)
MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_HASH_SHA256 )
MBEDTLS_SSL_SIG_ALG_SET( MBEDTLS_SSL_HASH_SHA256 )
#endif
#if defined(MBEDTLS_SHA384_C)
MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_HASH_SHA384 )
MBEDTLS_SSL_SIG_ALG_SET( MBEDTLS_SSL_HASH_SHA384 )
#endif
MBEDTLS_TLS1_3_SIG_NONE
};
@ -4852,6 +4847,109 @@ int mbedtls_ssl_get_handshake_transcript( mbedtls_ssl_context *ssl,
#endif /* !MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* mbedtls_ssl_parse_sig_alg_ext()
*
* The `extension_data` field of signature algorithm contains a `SignatureSchemeList`
* value (TLS 1.3 RFC8446):
* enum {
* ....
* ecdsa_secp256r1_sha256( 0x0403 ),
* ecdsa_secp384r1_sha384( 0x0503 ),
* ecdsa_secp521r1_sha512( 0x0603 ),
* ....
* } SignatureScheme;
*
* struct {
* SignatureScheme supported_signature_algorithms<2..2^16-2>;
* } SignatureSchemeList;
*
* The `extension_data` field of signature algorithm contains a `SignatureAndHashAlgorithm`
* value (TLS 1.2 RFC5246):
* enum {
* none(0), md5(1), sha1(2), sha224(3), sha256(4), sha384(5),
* sha512(6), (255)
* } HashAlgorithm;
*
* enum { anonymous(0), rsa(1), dsa(2), ecdsa(3), (255) }
* SignatureAlgorithm;
*
* struct {
* HashAlgorithm hash;
* SignatureAlgorithm signature;
* } SignatureAndHashAlgorithm;
*
* SignatureAndHashAlgorithm
* supported_signature_algorithms<2..2^16-2>;
*
* The TLS 1.3 signature algorithm extension was defined to be a compatible
* generalization of the TLS 1.2 signature algorithm extension.
* `SignatureAndHashAlgorithm` field of TLS 1.2 can be represented by
* `SignatureScheme` field of TLS 1.3
*
*/
int mbedtls_ssl_parse_sig_alg_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end )
{
const unsigned char *p = buf;
size_t supported_sig_algs_len = 0;
const unsigned char *supported_sig_algs_end;
uint16_t sig_alg;
uint32_t common_idx = 0;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
supported_sig_algs_len = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
memset( ssl->handshake->received_sig_algs, 0,
sizeof(ssl->handshake->received_sig_algs) );
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, supported_sig_algs_len );
supported_sig_algs_end = p + supported_sig_algs_len;
while( p < supported_sig_algs_end )
{
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, supported_sig_algs_end, 2 );
sig_alg = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 4, ( "received signature algorithm: 0x%x",
sig_alg ) );
if( ! mbedtls_ssl_sig_alg_is_supported( ssl, sig_alg ) ||
! mbedtls_ssl_sig_alg_is_offered( ssl, sig_alg ) )
continue;
if( common_idx + 1 < MBEDTLS_RECEIVED_SIG_ALGS_SIZE )
{
ssl->handshake->received_sig_algs[common_idx] = sig_alg;
common_idx += 1;
}
}
/* Check that we consumed all the message. */
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1,
( "Signature algorithms extension length misaligned" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
if( common_idx == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "no signature algorithm in common" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
ssl->handshake->received_sig_algs[common_idx] = MBEDTLS_TLS1_3_SIG_NONE;
return( 0 );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
@ -7555,49 +7653,26 @@ exit:
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* Find an entry in a signature-hash set matching a given hash algorithm. */
mbedtls_md_type_t mbedtls_ssl_sig_hash_set_find( mbedtls_ssl_sig_hash_set_t *set,
mbedtls_pk_type_t sig_alg )
/* Find an entry in a signature-hash set matching a given sign algorithm. */
mbedtls_md_type_t mbedtls_ssl_sig_hash_set_find( mbedtls_ssl_context *ssl,
mbedtls_pk_type_t pk_alg )
{
switch( sig_alg )
unsigned int i;
uint16_t sig_alg = mbedtls_ssl_sig_from_pk_alg( pk_alg );
uint16_t *set = ssl->handshake->received_sig_algs;
uint16_t invalid_sig_alg = MBEDTLS_SSL_SIG_ALG( MBEDTLS_SSL_SIG_ANON,
MBEDTLS_SSL_HASH_NONE );
if( sig_alg == MBEDTLS_SSL_SIG_ANON )
return( MBEDTLS_MD_NONE );
for( i = 0; set[i] != invalid_sig_alg; i++ )
{
case MBEDTLS_PK_RSA:
return( set->rsa );
case MBEDTLS_PK_ECDSA:
return( set->ecdsa );
default:
return( MBEDTLS_MD_NONE );
if( sig_alg == MBEDTLS_SSL_SIG_FROM_SIG_ALG( set[i] ) )
return MBEDTLS_SSL_HASH_FROM_SIG_ALG( set[i] );
}
}
/* Add a signature-hash-pair to a signature-hash set */
void mbedtls_ssl_sig_hash_set_add( mbedtls_ssl_sig_hash_set_t *set,
mbedtls_pk_type_t sig_alg,
mbedtls_md_type_t md_alg )
{
switch( sig_alg )
{
case MBEDTLS_PK_RSA:
if( set->rsa == MBEDTLS_MD_NONE )
set->rsa = md_alg;
break;
case MBEDTLS_PK_ECDSA:
if( set->ecdsa == MBEDTLS_MD_NONE )
set->ecdsa = md_alg;
break;
default:
break;
}
}
/* Allow exactly one hash algorithm for each signature. */
void mbedtls_ssl_sig_hash_set_const_hash( mbedtls_ssl_sig_hash_set_t *set,
mbedtls_md_type_t md_alg )
{
set->rsa = md_alg;
set->ecdsa = md_alg;
return( MBEDTLS_MD_NONE );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */