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mbedtls/library/ssl_tls13_generic.c
Xiaofei Bai d25fab6f79 Update based on comments 
Signed-off-by: Xiaofei Bai <xiaofei.bai@arm.com>
2021-12-02 06:36:27 +00:00

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/*
* TLS 1.3 functionality shared between client and server
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common.h"
#if defined(MBEDTLS_SSL_TLS_C)
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
#include <string.h>
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "mbedtls/oid.h"
#include "mbedtls/platform.h"
#include "mbedtls/constant_time.h"
#include <string.h>
#include "ssl_misc.h"
#include "ssl_tls13_keys.h"
int mbedtls_ssl_tls13_fetch_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char **buf,
size_t *buf_len )
{
int ret;
if( ( ret = mbedtls_ssl_read_record( ssl, 0 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
goto cleanup;
}
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
ssl->in_msg[0] != hs_type )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Receive unexpected handshake message." ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
ret = MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
goto cleanup;
}
/*
* Jump handshake header (4 bytes, see Section 4 of RFC 8446).
* ...
* HandshakeType msg_type;
* uint24 length;
* ...
*/
*buf = ssl->in_msg + 4;
*buf_len = ssl->in_hslen - 4;
cleanup:
return( ret );
}
int mbedtls_ssl_tls13_start_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char **buf,
size_t *buf_len )
{
/*
* Reserve 4 bytes for hanshake header. ( Section 4,RFC 8446 )
* ...
* HandshakeType msg_type;
* uint24 length;
* ...
*/
*buf = ssl->out_msg + 4;
*buf_len = MBEDTLS_SSL_OUT_CONTENT_LEN - 4;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = hs_type;
return( 0 );
}
int mbedtls_ssl_tls13_finish_handshake_msg( mbedtls_ssl_context *ssl,
size_t buf_len,
size_t msg_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t msg_with_header_len;
((void) buf_len);
/* Add reserved 4 bytes for handshake header */
msg_with_header_len = msg_len + 4;
ssl->out_msglen = msg_with_header_len;
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_write_handshake_msg_ext( ssl, 0 ) );
cleanup:
return( ret );
}
void mbedtls_ssl_tls13_add_hs_msg_to_checksum( mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char const *msg,
size_t msg_len )
{
mbedtls_ssl_tls13_add_hs_hdr_to_checksum( ssl, hs_type, msg_len );
ssl->handshake->update_checksum( ssl, msg, msg_len );
}
void mbedtls_ssl_tls13_add_hs_hdr_to_checksum( mbedtls_ssl_context *ssl,
unsigned hs_type,
size_t total_hs_len )
{
unsigned char hs_hdr[4];
/* Build HS header for checksum update. */
hs_hdr[0] = MBEDTLS_BYTE_0( hs_type );
hs_hdr[1] = MBEDTLS_BYTE_2( total_hs_len );
hs_hdr[2] = MBEDTLS_BYTE_1( total_hs_len );
hs_hdr[3] = MBEDTLS_BYTE_0( total_hs_len );
ssl->handshake->update_checksum( ssl, hs_hdr, sizeof( hs_hdr ) );
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
* mbedtls_ssl_tls13_write_sig_alg_ext( )
*
* enum {
* ....
* ecdsa_secp256r1_sha256( 0x0403 ),
* ecdsa_secp384r1_sha384( 0x0503 ),
* ecdsa_secp521r1_sha512( 0x0603 ),
* ....
* } SignatureScheme;
*
* struct {
* SignatureScheme supported_signature_algorithms<2..2^16-2>;
* } SignatureSchemeList;
*
* Only if we handle at least one key exchange that needs signatures.
*/
int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *out_len )
{
unsigned char *p = buf;
unsigned char *supported_sig_alg; /* Start of supported_signature_algorithms */
size_t supported_sig_alg_len = 0; /* Length of supported_signature_algorithms */
*out_len = 0;
/* Skip the extension on the client if all allowed key exchanges
* are PSK-based. */
#if defined(MBEDTLS_SSL_CLI_C)
if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
!mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
{
return( 0 );
}
#endif /* MBEDTLS_SSL_CLI_C */
MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding signature_algorithms extension" ) );
/* Check if we have space for header and length field:
* - extension_type (2 bytes)
* - extension_data_length (2 bytes)
* - supported_signature_algorithms_length (2 bytes)
*/
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
p += 6;
/*
* Write supported_signature_algorithms
*/
supported_sig_alg = p;
for( const uint16_t *sig_alg = ssl->conf->tls13_sig_algs;
*sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
{
MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
MBEDTLS_PUT_UINT16_BE( *sig_alg, p, 0 );
p += 2;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "signature scheme [%x]", *sig_alg ) );
}
/* Length of supported_signature_algorithms */
supported_sig_alg_len = p - supported_sig_alg;
if( supported_sig_alg_len == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "No signature algorithms defined." ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
/* Write extension_type */
MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SIG_ALG, buf, 0 );
/* Write extension_data_length */
MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len + 2, buf, 2 );
/* Write length of supported_signature_algorithms */
MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len, buf, 4 );
/* Output the total length of signature algorithms extension. */
*out_len = p - buf;
ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SIG_ALG;
return( 0 );
}
/*
* STATE HANDLING: Read CertificateVerify
*/
/* Macro to express the maximum length of the verify structure.
*
* The structure is computed per TLS 1.3 specification as:
* - 64 bytes of octet 32,
* - 33 bytes for the context string
* (which is either "TLS 1.3, client CertificateVerify"
* or "TLS 1.3, server CertificateVerify"),
* - 1 byte for the octet 0x0, which serves as a separator,
* - 32 or 48 bytes for the Transcript-Hash(Handshake Context, Certificate)
* (depending on the size of the transcript_hash)
*
* This results in a total size of
* - 130 bytes for a SHA256-based transcript hash, or
* (64 + 33 + 1 + 32 bytes)
* - 146 bytes for a SHA384-based transcript hash.
* (64 + 33 + 1 + 48 bytes)
*
*/
#define SSL_VERIFY_STRUCT_MAX_SIZE ( 64 + \
33 + \
1 + \
MBEDTLS_TLS1_3_MD_MAX_SIZE \
)
/*
* The ssl_tls13_create_verify_structure() creates the verify structure.
* As input, it requires the transcript hash.
*
* The caller has to ensure that the buffer has size at least
* SSL_VERIFY_STRUCT_MAX_SIZE bytes.
*/
static void ssl_tls13_create_verify_structure( const unsigned char *transcript_hash,
size_t transcript_hash_len,
unsigned char *verify_buffer,
size_t *verify_buffer_len,
int from )
{
size_t idx;
/* RFC 8446, Section 4.4.3:
*
* The digital signature [in the CertificateVerify message] is then
* computed over the concatenation of:
* - A string that consists of octet 32 (0x20) repeated 64 times
* - The context string
* - A single 0 byte which serves as the separator
* - The content to be signed
*/
memset( verify_buffer, 0x20, 64 );
idx = 64;
if( from == MBEDTLS_SSL_IS_CLIENT )
{
memcpy( verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN( client_cv ) );
idx += MBEDTLS_SSL_TLS1_3_LBL_LEN( client_cv );
}
else
{ /* from == MBEDTLS_SSL_IS_SERVER */
memcpy( verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN( server_cv ) );
idx += MBEDTLS_SSL_TLS1_3_LBL_LEN( server_cv );
}
verify_buffer[idx++] = 0x0;
memcpy( verify_buffer + idx, transcript_hash, transcript_hash_len );
idx += transcript_hash_len;
*verify_buffer_len = idx;
}
static int ssl_tls13_sig_alg_is_offered( const mbedtls_ssl_context *ssl,
uint16_t sig_alg )
{
const uint16_t *tls13_sig_alg = ssl->conf->tls13_sig_algs;
for( ; *tls13_sig_alg != MBEDTLS_TLS1_3_SIG_NONE ; tls13_sig_alg++ )
{
if( *tls13_sig_alg == sig_alg )
return( 1 );
}
return( 0 );
}
static int ssl_tls13_parse_certificate_verify( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end,
const unsigned char *verify_buffer,
size_t verify_buffer_len )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
const unsigned char *p = buf;
uint16_t algorithm;
size_t signature_len;
mbedtls_pk_type_t sig_alg;
mbedtls_md_type_t md_alg;
unsigned char verify_hash[MBEDTLS_MD_MAX_SIZE];
size_t verify_hash_len;
void const *options = NULL;
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
mbedtls_pk_rsassa_pss_options rsassa_pss_options;
#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
/*
* struct {
* SignatureScheme algorithm;
* opaque signature<0..2^16-1>;
* } CertificateVerify;
*/
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
algorithm = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
/* RFC 8446 section 4.4.3
*
* If the CertificateVerify message is sent by a server, the signature algorithm
* MUST be one offered in the client's "signature_algorithms" extension unless
* no valid certificate chain can be produced without unsupported algorithms
*
* RFC 8446 section 4.4.2.2
*
* If the client cannot construct an acceptable chain using the provided
* certificates and decides to abort the handshake, then it MUST abort the handshake
* with an appropriate certificate-related alert (by default, "unsupported_certificate").
*
* Check if algorithm is an offered signature algorithm.
*/
if( ! ssl_tls13_sig_alg_is_offered( ssl, algorithm ) )
{
/* algorithm not in offered signature algorithms list */
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Received signature algorithm(%04x) is not "
"offered.",
( unsigned int ) algorithm ) );
goto error;
}
/* We currently only support ECDSA-based signatures */
switch( algorithm )
{
case MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256:
md_alg = MBEDTLS_MD_SHA256;
sig_alg = MBEDTLS_PK_ECDSA;
break;
case MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384:
md_alg = MBEDTLS_MD_SHA384;
sig_alg = MBEDTLS_PK_ECDSA;
break;
case MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512:
md_alg = MBEDTLS_MD_SHA512;
sig_alg = MBEDTLS_PK_ECDSA;
break;
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256:
MBEDTLS_SSL_DEBUG_MSG( 4, ( "Certificate Verify: using RSA PSS" ) );
md_alg = MBEDTLS_MD_SHA256;
sig_alg = MBEDTLS_PK_RSASSA_PSS;
break;
#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "Certificate Verify: Unknown signature algorithm." ) );
goto error;
}
MBEDTLS_SSL_DEBUG_MSG( 3, ( "Certificate Verify: Signature algorithm ( %04x )",
( unsigned int ) algorithm ) );
/*
* Check the certificate's key type matches the signature alg
*/
if( !mbedtls_pk_can_do( &ssl->session_negotiate->peer_cert->pk, sig_alg ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "signature algorithm doesn't match cert key" ) );
goto error;
}
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
signature_len = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, signature_len );
/* Hash verify buffer with indicated hash function */
switch( md_alg )
{
#if defined(MBEDTLS_SHA256_C)
case MBEDTLS_MD_SHA256:
verify_hash_len = 32;
ret = mbedtls_sha256( verify_buffer, verify_buffer_len, verify_hash, 0 );
break;
#endif /* MBEDTLS_SHA256_C */
#if defined(MBEDTLS_SHA384_C)
case MBEDTLS_MD_SHA384:
verify_hash_len = 48;
ret = mbedtls_sha512( verify_buffer, verify_buffer_len, verify_hash, 1 );
break;
#endif /* MBEDTLS_SHA384_C */
#if defined(MBEDTLS_SHA512_C)
case MBEDTLS_MD_SHA512:
verify_hash_len = 64;
ret = mbedtls_sha512( verify_buffer, verify_buffer_len, verify_hash, 0 );
break;
#endif /* MBEDTLS_SHA512_C */
default:
ret = MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
break;
}
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "hash computation error", ret );
goto error;
}
MBEDTLS_SSL_DEBUG_BUF( 3, "verify hash", verify_hash, verify_hash_len );
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
if( sig_alg == MBEDTLS_PK_RSASSA_PSS )
{
const mbedtls_md_info_t* md_info;
rsassa_pss_options.mgf1_hash_id = md_alg;
if( ( md_info = mbedtls_md_info_from_type( md_alg ) ) == NULL )
{
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
rsassa_pss_options.expected_salt_len = mbedtls_md_get_size( md_info );
options = (const void*) &rsassa_pss_options;
}
#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
if( ( ret = mbedtls_pk_verify_ext( sig_alg, options,
&ssl->session_negotiate->peer_cert->pk,
md_alg, verify_hash, verify_hash_len,
p, signature_len ) ) == 0 )
{
return( 0 );
}
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_pk_verify_ext", ret );
error:
/* RFC 8446 section 4.4.3
*
* If the verification fails, the receiver MUST terminate the handshake
* with a "decrypt_error" alert.
*/
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char verify_buffer[SSL_VERIFY_STRUCT_MAX_SIZE];
size_t verify_buffer_len;
unsigned char transcript[MBEDTLS_TLS1_3_MD_MAX_SIZE];
size_t transcript_len;
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate verify" ) );
MBEDTLS_SSL_PROC_CHK(
mbedtls_ssl_tls13_fetch_handshake_msg( ssl,
MBEDTLS_SSL_HS_CERTIFICATE_VERIFY, &buf, &buf_len ) );
/* Need to calculate the hash of the transcript first
* before reading the message since otherwise it gets
* included in the transcript
*/
ret = mbedtls_ssl_get_handshake_transcript( ssl,
ssl->handshake->ciphersuite_info->mac,
transcript, sizeof( transcript ),
&transcript_len );
if( ret != 0 )
{
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_SSL_INTERNAL_ERROR );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "handshake hash", transcript, transcript_len );
/* Create verify structure */
ssl_tls13_create_verify_structure( transcript,
transcript_len,
verify_buffer,
&verify_buffer_len,
( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ) ?
MBEDTLS_SSL_IS_SERVER :
MBEDTLS_SSL_IS_CLIENT );
/* Process the message contents */
MBEDTLS_SSL_PROC_CHK( ssl_tls13_parse_certificate_verify( ssl, buf,
buf + buf_len, verify_buffer, verify_buffer_len ) );
mbedtls_ssl_tls13_add_hs_msg_to_checksum( ssl,
MBEDTLS_SSL_HS_CERTIFICATE_VERIFY, buf, buf_len );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate verify" ) );
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_process_certificate_verify", ret );
return( ret );
#else
((void) ssl);
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
}
/*
*
* STATE HANDLING: Incoming Certificate, client-side only currently.
*
*/
/*
* Implementation
*/
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
/*
* Structure of Certificate message:
*
* enum {
* X509(0),
* RawPublicKey(2),
* (255)
* } CertificateType;
*
* struct {
* select (certificate_type) {
* case RawPublicKey:
* * From RFC 7250 ASN.1_subjectPublicKeyInfo *
* opaque ASN1_subjectPublicKeyInfo<1..2^24-1>;
* case X509:
* opaque cert_data<1..2^24-1>;
* };
* Extension extensions<0..2^16-1>;
* } CertificateEntry;
*
* struct {
* opaque certificate_request_context<0..2^8-1>;
* CertificateEntry certificate_list<0..2^24-1>;
* } Certificate;
*
*/
/* Parse certificate chain send by the server. */
static int ssl_tls13_parse_certificate( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t certificate_request_context_len = 0;
size_t certificate_list_len = 0;
const unsigned char *p = buf;
const unsigned char *certificate_list_end;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 4 );
certificate_request_context_len = p[0];
certificate_list_len = MBEDTLS_GET_UINT24_BE( p, 1 );
p += 4;
/* In theory, the certificate list can be up to 2^24 Bytes, but we don't
* support anything beyond 2^16 = 64K.
*/
if( ( certificate_request_context_len != 0 ) ||
( certificate_list_len >= 0x10000 ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
/* In case we tried to reuse a session but it failed */
if( ssl->session_negotiate->peer_cert != NULL )
{
mbedtls_x509_crt_free( ssl->session_negotiate->peer_cert );
mbedtls_free( ssl->session_negotiate->peer_cert );
}
if( ( ssl->session_negotiate->peer_cert =
mbedtls_calloc( 1, sizeof( mbedtls_x509_crt ) ) ) == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc( %" MBEDTLS_PRINTF_SIZET " bytes ) failed",
sizeof( mbedtls_x509_crt ) ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_SSL_ALLOC_FAILED );
return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
}
mbedtls_x509_crt_init( ssl->session_negotiate->peer_cert );
certificate_list_end = p + certificate_list_len;
while( p < certificate_list_end )
{
size_t cert_data_len, extensions_len;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, certificate_list_end, 3 );
cert_data_len = MBEDTLS_GET_UINT24_BE( p, 0 );
p += 3;
/* In theory, the CRT can be up to 2^24 Bytes, but we don't support
* anything beyond 2^16 = 64K. Otherwise as in the TLS 1.2 code,
* check that we have a minimum of 128 bytes of data, this is not
* clear why we need that though.
*/
if( ( cert_data_len < 128 ) || ( cert_data_len >= 0x10000 ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad Certificate message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, certificate_list_end, cert_data_len );
ret = mbedtls_x509_crt_parse_der( ssl->session_negotiate->peer_cert,
p, cert_data_len );
switch( ret )
{
case 0: /*ok*/
break;
case MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND:
/* Ignore certificate with an unknown algorithm: maybe a
prior certificate was already trusted. */
break;
case MBEDTLS_ERR_X509_ALLOC_FAILED:
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_X509_ALLOC_FAILED );
MBEDTLS_SSL_DEBUG_RET( 1, " mbedtls_x509_crt_parse_der", ret );
return( ret );
case MBEDTLS_ERR_X509_UNKNOWN_VERSION:
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT,
MBEDTLS_ERR_X509_UNKNOWN_VERSION );
MBEDTLS_SSL_DEBUG_RET( 1, " mbedtls_x509_crt_parse_der", ret );
return( ret );
default:
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_BAD_CERT,
ret );
MBEDTLS_SSL_DEBUG_RET( 1, " mbedtls_x509_crt_parse_der", ret );
return( ret );
}
p += cert_data_len;
/* Certificate extensions length */
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, certificate_list_end, 2 );
extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 );
p += 2;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, certificate_list_end, extensions_len );
p += extensions_len;
}
/* Check that all the message is consumed. */
if( p != end )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad Certificate message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, \
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
MBEDTLS_SSL_DEBUG_CRT( 3, "peer certificate", ssl->session_negotiate->peer_cert );
return( ret );
}
#else
static int ssl_tls13_parse_certificate( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end )
{
((void) ssl);
((void) buf);
((void) end);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
/* Validate certificate chain sent by the server. */
static int ssl_tls13_validate_certificate( mbedtls_ssl_context *ssl )
{
int ret = 0;
mbedtls_x509_crt *ca_chain;
mbedtls_x509_crl *ca_crl;
uint32_t verify_result = 0;
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_ca_chain != NULL )
{
ca_chain = ssl->handshake->sni_ca_chain;
ca_crl = ssl->handshake->sni_ca_crl;
}
else
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
{
ca_chain = ssl->conf->ca_chain;
ca_crl = ssl->conf->ca_crl;
}
/*
* Main check: verify certificate
*/
ret = mbedtls_x509_crt_verify_with_profile(
ssl->session_negotiate->peer_cert,
ca_chain, ca_crl,
ssl->conf->cert_profile,
ssl->hostname,
&verify_result,
ssl->conf->f_vrfy, ssl->conf->p_vrfy );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
}
/*
* Secondary checks: always done, but change 'ret' only if it was 0
*/
#if defined(MBEDTLS_ECP_C)
{
const mbedtls_pk_context *pk = &ssl->session_negotiate->peer_cert->pk;
/* If certificate uses an EC key, make sure the curve is OK */
if( mbedtls_pk_can_do( pk, MBEDTLS_PK_ECKEY ) &&
mbedtls_ssl_check_curve( ssl, mbedtls_pk_ec( *pk )->grp.id ) != 0 )
{
verify_result |= MBEDTLS_X509_BADCERT_BAD_KEY;
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate ( EC key curve )" ) );
if( ret == 0 )
ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
}
}
#endif /* MBEDTLS_ECP_C */
if( mbedtls_ssl_check_cert_usage( ssl->session_negotiate->peer_cert,
ssl->handshake->ciphersuite_info,
!ssl->conf->endpoint,
&verify_result ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate ( usage extensions )" ) );
if( ret == 0 )
ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
}
if( ca_chain == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "got no CA chain" ) );
ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
}
if( ret != 0 )
{
/* The certificate may have been rejected for several reasons.
Pick one and send the corresponding alert. Which alert to send
may be a subject of debate in some cases. */
if( verify_result & MBEDTLS_X509_BADCERT_OTHER )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED, ret );
else if( verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_BAD_CERT, ret );
else if( verify_result & ( MBEDTLS_X509_BADCERT_KEY_USAGE |
MBEDTLS_X509_BADCERT_EXT_KEY_USAGE |
MBEDTLS_X509_BADCERT_NS_CERT_TYPE |
MBEDTLS_X509_BADCERT_BAD_PK |
MBEDTLS_X509_BADCERT_BAD_KEY ) )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT, ret );
else if( verify_result & MBEDTLS_X509_BADCERT_EXPIRED )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED, ret );
else if( verify_result & MBEDTLS_X509_BADCERT_REVOKED )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED, ret );
else if( verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED )
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA, ret );
else
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN, ret );
}
#if defined(MBEDTLS_DEBUG_C)
if( verify_result != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "! Certificate verification flags %08x",
(unsigned int) verify_result ) );
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "Certificate verification flags clear" ) );
}
#endif /* MBEDTLS_DEBUG_C */
ssl->session_negotiate->verify_result = verify_result;
return( ret );
}
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
static int ssl_tls13_validate_certificate( mbedtls_ssl_context *ssl )
{
((void) ssl);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate" ) );
#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg(
ssl, MBEDTLS_SSL_HS_CERTIFICATE,
&buf, &buf_len ) );
/* Parse the certificate chain sent by the peer. */
MBEDTLS_SSL_PROC_CHK( ssl_tls13_parse_certificate( ssl, buf, buf + buf_len ) );
/* Validate the certificate chain and set the verification results. */
MBEDTLS_SSL_PROC_CHK( ssl_tls13_validate_certificate( ssl ) );
mbedtls_ssl_tls13_add_hs_msg_to_checksum( ssl, MBEDTLS_SSL_HS_CERTIFICATE,
buf, buf_len );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate" ) );
#else
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;
#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
return( ret );
}
/*
*
* STATE HANDLING: Incoming Finished message.
*/
/*
* Implementation
*/
static int ssl_tls13_preprocess_finished_message( mbedtls_ssl_context *ssl )
{
int ret;
ret = mbedtls_ssl_tls13_calculate_verify_data( ssl,
ssl->handshake->state_local.finished_in.digest,
sizeof( ssl->handshake->state_local.finished_in.digest ),
&ssl->handshake->state_local.finished_in.digest_len,
ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ?
MBEDTLS_SSL_IS_SERVER : MBEDTLS_SSL_IS_CLIENT );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_calculate_verify_data", ret );
return( ret );
}
return( 0 );
}
static int ssl_tls13_parse_finished_message( mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end )
{
/*
* struct {
* opaque verify_data[Hash.length];
* } Finished;
*/
const unsigned char *expected_verify_data =
ssl->handshake->state_local.finished_in.digest;
size_t expected_verify_data_len =
ssl->handshake->state_local.finished_in.digest_len;
/* Structural validation */
if( (size_t)( end - buf ) != expected_verify_data_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
MBEDTLS_SSL_DEBUG_BUF( 4, "verify_data (self-computed):",
expected_verify_data,
expected_verify_data_len );
MBEDTLS_SSL_DEBUG_BUF( 4, "verify_data (received message):", buf,
expected_verify_data_len );
/* Semantic validation */
if( mbedtls_ct_memcmp( buf,
expected_verify_data,
expected_verify_data_len ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
return( 0 );
}
#if defined(MBEDTLS_SSL_CLI_C)
static int ssl_tls13_postprocess_server_finished_message( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ssl_key_set traffic_keys;
mbedtls_ssl_transform *transform_application = NULL;
ret = mbedtls_ssl_tls13_key_schedule_stage_application( ssl );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1,
"mbedtls_ssl_tls13_key_schedule_stage_application", ret );
goto cleanup;
}
ret = mbedtls_ssl_tls13_generate_application_keys( ssl, &traffic_keys );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1,
"mbedtls_ssl_tls13_generate_application_keys", ret );
goto cleanup;
}
transform_application =
mbedtls_calloc( 1, sizeof( mbedtls_ssl_transform ) );
if( transform_application == NULL )
{
ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
goto cleanup;
}
ret = mbedtls_ssl_tls13_populate_transform(
transform_application,
ssl->conf->endpoint,
ssl->session_negotiate->ciphersuite,
&traffic_keys,
ssl );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_populate_transform", ret );
goto cleanup;
}
ssl->transform_application = transform_application;
cleanup:
mbedtls_platform_zeroize( &traffic_keys, sizeof( traffic_keys ) );
if( ret != 0 )
{
mbedtls_free( transform_application );
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
return( ret );
}
#endif /* MBEDTLS_SSL_CLI_C */
static int ssl_tls13_postprocess_finished_message( mbedtls_ssl_context *ssl )
{
#if defined(MBEDTLS_SSL_CLI_C)
if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
{
return( ssl_tls13_postprocess_server_finished_message( ssl ) );
}
#else
((void) ssl);
#endif /* MBEDTLS_SSL_CLI_C */
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
int mbedtls_ssl_tls13_process_finished_message( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse finished message" ) );
/* Preprocessing step: Compute handshake digest */
MBEDTLS_SSL_PROC_CHK( ssl_tls13_preprocess_finished_message( ssl ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg( ssl,
MBEDTLS_SSL_HS_FINISHED,
&buf, &buf_len ) );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_parse_finished_message( ssl, buf, buf + buf_len ) );
mbedtls_ssl_tls13_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_FINISHED, buf, buf_len );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_postprocess_finished_message( ssl ) );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse finished message" ) );
return( ret );
}
/*
*
* STATE HANDLING: Write and send Finished message.
*
*/
/*
* Implement
*/
static int ssl_tls13_prepare_finished_message( mbedtls_ssl_context *ssl )
{
int ret;
/* Compute transcript of handshake up to now. */
ret = mbedtls_ssl_tls13_calculate_verify_data( ssl,
ssl->handshake->state_local.finished_out.digest,
sizeof( ssl->handshake->state_local.finished_out.digest ),
&ssl->handshake->state_local.finished_out.digest_len,
ssl->conf->endpoint );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "calculate_verify_data failed", ret );
return( ret );
}
return( 0 );
}
static int ssl_tls13_finalize_finished_message( mbedtls_ssl_context *ssl )
{
// TODO: Add back resumption keys calculation after MVP.
((void) ssl);
return( 0 );
}
static int ssl_tls13_write_finished_message_body( mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *out_len )
{
size_t verify_data_len = ssl->handshake->state_local.finished_out.digest_len;
/*
* struct {
* opaque verify_data[Hash.length];
* } Finished;
*/
MBEDTLS_SSL_CHK_BUF_PTR( buf, end, verify_data_len );
memcpy( buf, ssl->handshake->state_local.finished_out.digest,
verify_data_len );
*out_len = verify_data_len;
return( 0 );
}
/* Main entry point: orchestrates the other functions */
int mbedtls_ssl_tls13_write_finished_message( mbedtls_ssl_context *ssl )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *buf;
size_t buf_len, msg_len;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write finished message" ) );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_finished_message( ssl ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_start_handshake_msg( ssl,
MBEDTLS_SSL_HS_FINISHED, &buf, &buf_len ) );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_finished_message_body(
ssl, buf, buf + buf_len, &msg_len ) );
mbedtls_ssl_tls13_add_hs_msg_to_checksum( ssl, MBEDTLS_SSL_HS_FINISHED,
buf, msg_len );
MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_finished_message( ssl ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_finish_handshake_msg( ssl,
buf_len, msg_len ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_flush_output( ssl ) );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write finished message" ) );
return( ret );
}
void mbedtls_ssl_tls13_handshake_wrapup( mbedtls_ssl_context *ssl )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
/*
* Free the previous session and switch to the current one.
*/
if( ssl->session )
{
mbedtls_ssl_session_free( ssl->session );
mbedtls_free( ssl->session );
}
ssl->session = ssl->session_negotiate;
ssl->session_negotiate = NULL;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#endif /* MBEDTLS_SSL_TLS_C */
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