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Merge pull request #4953 from yuhaoth/pr/add-tls13-read-certificate-verfify

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TLS1.3: CertificateVerify:add tls13 read certificate verfify
This commit is contained in:
Ronald Cron 2021-11-08 09:36:35 +01:00 committed by GitHub
commit 260f5d9413
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 341 additions and 27 deletions
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5
library/ssl_misc.h
View file

@ -1638,6 +1638,11 @@ int mbedtls_ssl_tls13_start_handshake_msg( mbedtls_ssl_context *ssl,
*/
int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl );
/*
* Generic handler of Certificate Verify
*/
int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl );
/*
* Write TLS 1.3 handshake message tail
*/

7
library/ssl_tls13_client.c
View file

@ -1582,7 +1582,12 @@ static int ssl_tls1_3_process_server_certificate( mbedtls_ssl_context *ssl )
*/
static int ssl_tls1_3_process_certificate_verify( mbedtls_ssl_context *ssl )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "%s hasn't been implemented", __func__ ) );
int ret;
ret = mbedtls_ssl_tls13_process_certificate_verify( ssl );
if( ret != 0 )
return( ret );
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
return( 0 );
}

301
library/ssl_tls13_generic.c
View file

@ -23,14 +23,15 @@
#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 "ssl_misc.h"
#include <mbedtls/debug.h>
#include <mbedtls/oid.h>
#include <mbedtls/platform.h>
#include "ssl_tls13_keys.h"
int mbedtls_ssl_tls1_3_fetch_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
@ -217,8 +218,300 @@ int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
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_TLS13_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;
/*
* 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_TLS13_SIG_ECDSA_SECP256R1_SHA256:
md_alg = MBEDTLS_MD_SHA256;
sig_alg = MBEDTLS_PK_ECDSA;
break;
case MBEDTLS_TLS13_SIG_ECDSA_SECP384R1_SHA384:
md_alg = MBEDTLS_MD_SHA384;
sig_alg = MBEDTLS_PK_ECDSA;
break;
case MBEDTLS_TLS13_SIG_ECDSA_SECP521R1_SHA512:
md_alg = MBEDTLS_MD_SHA512;
sig_alg = MBEDTLS_PK_ECDSA;
break;
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( ( ret = mbedtls_pk_verify_ext( sig_alg, NULL,
&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_tls1_3_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_tls1_3_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.

45
library/ssl_tls13_keys.h
View file

@ -22,25 +22,27 @@
/* This requires MBEDTLS_SSL_TLS1_3_LABEL( idx, name, string ) to be defined at
* the point of use. See e.g. the definition of mbedtls_ssl_tls1_3_labels_union
* below. */
#define MBEDTLS_SSL_TLS1_3_LABEL_LIST \
MBEDTLS_SSL_TLS1_3_LABEL( finished , "finished" ) \
MBEDTLS_SSL_TLS1_3_LABEL( resumption , "resumption" ) \
MBEDTLS_SSL_TLS1_3_LABEL( traffic_upd , "traffic upd" ) \
MBEDTLS_SSL_TLS1_3_LABEL( exporter , "exporter" ) \
MBEDTLS_SSL_TLS1_3_LABEL( key , "key" ) \
MBEDTLS_SSL_TLS1_3_LABEL( iv , "iv" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_hs_traffic, "c hs traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_ap_traffic, "c ap traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_e_traffic , "c e traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_hs_traffic, "s hs traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_ap_traffic, "s ap traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_e_traffic , "s e traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( e_exp_master, "e exp master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( res_master , "res master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( exp_master , "exp master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( ext_binder , "ext binder" ) \
MBEDTLS_SSL_TLS1_3_LABEL( res_binder , "res binder" ) \
MBEDTLS_SSL_TLS1_3_LABEL( derived , "derived" )
#define MBEDTLS_SSL_TLS1_3_LABEL_LIST \
MBEDTLS_SSL_TLS1_3_LABEL( finished , "finished" ) \
MBEDTLS_SSL_TLS1_3_LABEL( resumption , "resumption" ) \
MBEDTLS_SSL_TLS1_3_LABEL( traffic_upd , "traffic upd" ) \
MBEDTLS_SSL_TLS1_3_LABEL( exporter , "exporter" ) \
MBEDTLS_SSL_TLS1_3_LABEL( key , "key" ) \
MBEDTLS_SSL_TLS1_3_LABEL( iv , "iv" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_hs_traffic, "c hs traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_ap_traffic, "c ap traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( c_e_traffic , "c e traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_hs_traffic, "s hs traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_ap_traffic, "s ap traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( s_e_traffic , "s e traffic" ) \
MBEDTLS_SSL_TLS1_3_LABEL( e_exp_master, "e exp master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( res_master , "res master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( exp_master , "exp master" ) \
MBEDTLS_SSL_TLS1_3_LABEL( ext_binder , "ext binder" ) \
MBEDTLS_SSL_TLS1_3_LABEL( res_binder , "res binder" ) \
MBEDTLS_SSL_TLS1_3_LABEL( derived , "derived" ) \
MBEDTLS_SSL_TLS1_3_LABEL( client_cv , "TLS 1.3, client CertificateVerify" ) \
MBEDTLS_SSL_TLS1_3_LABEL( server_cv , "TLS 1.3, server CertificateVerify" )
#define MBEDTLS_SSL_TLS1_3_LABEL( name, string ) \
const unsigned char name [ sizeof(string) - 1 ];
@ -57,9 +59,12 @@ struct mbedtls_ssl_tls1_3_labels_struct
extern const struct mbedtls_ssl_tls1_3_labels_struct mbedtls_ssl_tls1_3_labels;
#define MBEDTLS_SSL_TLS1_3_LBL_LEN( LABEL ) \
sizeof(mbedtls_ssl_tls1_3_labels.LABEL)
#define MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN( LABEL ) \
mbedtls_ssl_tls1_3_labels.LABEL, \
sizeof(mbedtls_ssl_tls1_3_labels.LABEL)
MBEDTLS_SSL_TLS1_3_LBL_LEN( LABEL )
#define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN \
sizeof( union mbedtls_ssl_tls1_3_labels_union )

10
tests/ssl-opt.sh
View file

@ -8831,8 +8831,11 @@ run_test "TLS1.3: Test client hello msg work - openssl" \
-c "server hello, chosen ciphersuite: ( 1301 ) - TLS1-3-AES-128-GCM-SHA256" \
-c "ECDH curve: x25519" \
-c "=> ssl_tls1_3_process_server_hello" \
-c "<= parse encrypted extensions" \
-c "Certificate verification flags clear" \
-c "<= parse encrypted extensions"
-c "=> parse certificate verify" \
-c "<= parse certificate verify" \
-c "mbedtls_ssl_tls13_process_certificate_verify() returned 0"
requires_gnutls_tls1_3
requires_gnutls_next_no_ticket
@ -8861,8 +8864,11 @@ run_test "TLS1.3: Test client hello msg work - gnutls" \
-c "server hello, chosen ciphersuite: ( 1301 ) - TLS1-3-AES-128-GCM-SHA256" \
-c "ECDH curve: x25519" \
-c "=> ssl_tls1_3_process_server_hello" \
-c "<= parse encrypted extensions" \
-c "Certificate verification flags clear" \
-c "<= parse encrypted extensions"
-c "=> parse certificate verify" \
-c "<= parse certificate verify" \
-c "mbedtls_ssl_tls13_process_certificate_verify() returned 0"
# Test heap memory usage after handshake
requires_config_enabled MBEDTLS_MEMORY_DEBUG