mirror of
https://github.com/yuzu-emu/mbedtls.git
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pk_wrap: rework and tidy up signature extraction
Improve comments, use a normal buffer instead of mbedtls_asn1_buf, remove unneeded variables and use shared utilities where possible.
This commit is contained in:
Andrzej Kurek
parent
688ea8d10d
commit
73bf6b9e00
@ -480,151 +480,71 @@ static int ecdsa_can_do( mbedtls_pk_type_t type )
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#if defined(MBEDTLS_USE_PSA_CRYPTO)
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/*
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* Extract one signature part of an ASN.1 integer type to a given buffer
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* and adjust padding according to part_size.
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* An ASN.1 encoded signature is a sequence of two ASN.1 integers. Parse one of
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* those integers and convert it to the fixed-length encoding expected by PSA.
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*/
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static int extract_ecdsa_sig_part( unsigned char **from, const unsigned char *end,
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unsigned char *to, size_t part_size )
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static int extract_ecdsa_sig_int( unsigned char **from, const unsigned char *end,
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unsigned char *to, size_t to_len )
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{
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int ret;
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size_t len_total, len_partial, zero_padding;
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size_t unpadded_len, padding_len;
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if( ( ret = mbedtls_asn1_get_tag( from, end, &len_partial,
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if( ( ret = mbedtls_asn1_get_tag( from, end, &unpadded_len,
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MBEDTLS_ASN1_INTEGER ) ) != 0 )
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{
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return( ret );
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}
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while( **from == '\0' && len_partial > 0 )
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while( unpadded_len > 0 && **from == 0x00 )
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{
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( *from )++;
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len_partial--;
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unpadded_len--;
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}
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if( len_partial > part_size || len_partial == 0 )
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return( MBEDTLS_ERR_PK_SIG_LEN_MISMATCH );
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if( unpadded_len > to_len || unpadded_len == 0 )
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return( MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
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zero_padding = part_size - len_partial;
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memcpy( to + zero_padding, *from, len_partial );
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len_total = len_partial + zero_padding;
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while( zero_padding > 0 )
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{
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zero_padding--;
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to[zero_padding] = 0;
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}
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padding_len = to_len - unpadded_len;
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memcpy( to + padding_len, *from, unpadded_len );
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( *from ) += unpadded_len;
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( *from ) += len_partial;
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return len_total;
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memset( to, 0x00, padding_len );
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return( 0 );
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}
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/*
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* Convert a signature from an ASN.1 sequence of two integers
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* to a raw {r,s} buffer. Note: the provided sig buffer should be at least
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* to a raw {r,s} buffer. Note: the provided sig buffer must be at least
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* twice as big as int_size.
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*/
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static int extract_ecdsa_sig( unsigned char **p, const unsigned char *end,
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mbedtls_asn1_buf *sig, size_t int_size )
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unsigned char *sig, size_t int_size )
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{
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int ret;
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size_t tmp_size;
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if( ( end - *p ) < 1 )
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{
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return( MBEDTLS_ERR_ASN1_OUT_OF_DATA );
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}
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if( sig->p == NULL )
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if( sig == NULL )
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return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
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sig->tag = **p;
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if( ( ret = mbedtls_asn1_get_tag( p, end, &sig->len,
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if( ( ret = mbedtls_asn1_get_tag( p, end, &tmp_size,
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MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
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{
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goto cleanup;
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}
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return( ret );
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/* Extract r */
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if( ( ret = extract_ecdsa_sig_part( p, end, sig->p, int_size ) ) < 0)
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{
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goto cleanup;
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}
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sig->len = ret;
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/* Extract s */
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if( ( ret = extract_ecdsa_sig_part( p, end, sig->p + sig->len, int_size ) ) < 0)
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{
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goto cleanup;
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}
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sig->len += ret;
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return( 0 );
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cleanup:
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sig->len = 0;
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sig->tag = 0;
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if( ( ret = extract_ecdsa_sig_int( p, end, sig, int_size ) ) != 0 )
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return( ret );
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/* Extract s */
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if( ( ret = extract_ecdsa_sig_int( p, end, sig + int_size, int_size ) ) != 0 )
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return( ret );
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}
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static psa_ecc_curve_t mbedtls_ecc_group_to_psa( mbedtls_ecp_group_id grpid )
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{
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switch( grpid )
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{
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#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
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case MBEDTLS_ECP_DP_SECP192R1:
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return( PSA_ECC_CURVE_SECP192R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED)
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case MBEDTLS_ECP_DP_SECP224R1:
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return( PSA_ECC_CURVE_SECP224R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
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case MBEDTLS_ECP_DP_SECP256R1:
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return( PSA_ECC_CURVE_SECP256R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
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case MBEDTLS_ECP_DP_SECP384R1:
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return( PSA_ECC_CURVE_SECP384R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
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case MBEDTLS_ECP_DP_SECP521R1:
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return( PSA_ECC_CURVE_SECP521R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
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case MBEDTLS_ECP_DP_BP256R1:
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return( PSA_ECC_CURVE_BRAINPOOL_P256R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
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case MBEDTLS_ECP_DP_BP384R1:
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return( PSA_ECC_CURVE_BRAINPOOL_P384R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
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case MBEDTLS_ECP_DP_BP512R1:
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return( PSA_ECC_CURVE_BRAINPOOL_P512R1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
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case MBEDTLS_ECP_DP_CURVE25519:
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return( PSA_ECC_CURVE_CURVE25519 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED)
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case MBEDTLS_ECP_DP_SECP192K1:
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return( PSA_ECC_CURVE_SECP192K1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED)
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case MBEDTLS_ECP_DP_SECP224K1:
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return( PSA_ECC_CURVE_SECP224K1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
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case MBEDTLS_ECP_DP_SECP256K1:
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return( PSA_ECC_CURVE_SECP256K1 );
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#endif
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#if defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
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case MBEDTLS_ECP_DP_CURVE448:
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return( PSA_ECC_CURVE_CURVE448 );
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#endif
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default:
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return( 0 );
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}
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}
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static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
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const unsigned char *hash, size_t hash_len,
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@ -635,36 +555,36 @@ static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
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psa_key_policy_t policy;
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psa_key_type_t psa_type;
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mbedtls_pk_context key;
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mbedtls_asn1_buf signature;
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int key_len;
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const unsigned buf_len = 30 + 2 * MBEDTLS_ECP_MAX_BYTES; // Equivalent of ECP_PUB_DER_MAX_BYTES
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unsigned char buf[buf_len];
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/* see ECP_PUB_DER_MAX_BYTES in pkwrite.c */
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unsigned char buf[30 + 2 * MBEDTLS_ECP_MAX_BYTES];
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unsigned char *p = (unsigned char*) sig;
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mbedtls_pk_info_t pk_info = mbedtls_eckey_info;
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psa_algorithm_t psa_sig_md = mbedtls_psa_translate_md( md_alg );
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psa_ecc_curve_t curve = mbedtls_ecc_group_to_psa ( ( (mbedtls_ecdsa_context *) ctx )->grp.id );
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psa_algorithm_t psa_sig_md, psa_md;
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psa_ecc_curve_t curve = mbedtls_psa_translate_ecc_group (
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( (mbedtls_ecdsa_context *) ctx )->grp.id );
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size_t signature_part_size = ( ( (mbedtls_ecdsa_context *) ctx ) ->grp.nbits + 7 ) / 8;
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if( curve == 0 )
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return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
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if( psa_sig_md == 0 )
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return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
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psa_sig_md = PSA_ALG_ECDSA( psa_sig_md );
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memset( &signature, 0, sizeof( mbedtls_asn1_buf ) );
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/* mbedlts_pk_write_pubkey_der() expects a full PK context,
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* re-construct one to make it happy */
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key.pk_info = &pk_info;
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key.pk_ctx = ctx;
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psa_type = PSA_KEY_TYPE_ECC_PUBLIC_KEY( curve );
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key_len = mbedtls_pk_write_pubkey_der( &key, buf, buf_len );
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key_len = mbedtls_pk_write_pubkey_der( &key, buf, sizeof( buf ) );
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if( key_len <= 0 )
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return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
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if( ( ret = mbedtls_psa_get_free_key_slot( &key_slot ) ) != PSA_SUCCESS )
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return( mbedtls_psa_err_translate_pk( ret ) );
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psa_md = mbedtls_psa_translate_md( md_alg );
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if( psa_md == 0 )
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return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
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psa_sig_md = PSA_ALG_ECDSA( psa_md );
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psa_type = PSA_KEY_TYPE_ECC_PUBLIC_KEY( curve );
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psa_key_policy_init( &policy );
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psa_key_policy_set_usage( &policy, PSA_KEY_USAGE_VERIFY, psa_sig_md );
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if( ( ret = psa_set_key_policy( key_slot, &policy ) ) != PSA_SUCCESS )
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@ -673,7 +593,7 @@ static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
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goto cleanup;
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}
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if( psa_import_key( key_slot, psa_type, buf+buf_len-key_len, key_len )
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if( psa_import_key( key_slot, psa_type, buf + sizeof( buf ) - key_len, key_len )
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!= PSA_SUCCESS )
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{
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ret = MBEDTLS_ERR_PK_BAD_INPUT_DATA;
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@ -681,14 +601,13 @@ static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
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}
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/* Reuse the buffer of an already imported key */
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if( 2 * signature_part_size > buf_len )
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if( 2 * signature_part_size > sizeof( buf ) )
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{
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ret = MBEDTLS_ERR_PK_BAD_INPUT_DATA;
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goto cleanup;
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}
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signature.p = buf;
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if( ( ret = extract_ecdsa_sig( &p, p + sig_len, &signature,
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if( ( ret = extract_ecdsa_sig( &p, p + sig_len, buf,
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signature_part_size ) ) != 0 )
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{
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goto cleanup;
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@ -696,7 +615,7 @@ static int ecdsa_verify_wrap( void *ctx, mbedtls_md_type_t md_alg,
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if( psa_asymmetric_verify( key_slot, psa_sig_md,
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hash, hash_len,
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signature.p, signature.len )
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buf, 2 * signature_part_size )
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!= PSA_SUCCESS )
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{
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ret = MBEDTLS_ERR_ECP_VERIFY_FAILED;
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