yuzu-emu/mbedtls
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Implement write_partial with dummy exts

Browse source 
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
This commit is contained in:
Jerry Yu 2021-08-24 15:59:48 +08:00
parent 7984d9931e
commit bc20bdd3a9
3 changed files with 327 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
library/ssl_misc.h
View file

@ -1385,6 +1385,9 @@ void mbedtls_ssl_add_hs_hdr_to_checksum( mbedtls_ssl_context *ssl,
unsigned hs_type,
size_t total_hs_len );
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
int mbedtls_ssl_write_signature_algorithms_ext(mbedtls_ssl_context* ssl, unsigned char* buf, unsigned char* end, size_t* olen);
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

293
library/ssl_tls13_client.c
View file

@ -25,6 +25,8 @@
#if defined(MBEDTLS_SSL_CLI_C)
#include <string.h>
#include "ssl_misc.h"
#include <mbedtls/debug.h>
@ -137,20 +139,305 @@ static int ssl_client_hello_postprocess( mbedtls_ssl_context* ssl )
return( 0 );
}
/* Write extensions */
static void ssl_write_supported_versions_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen );
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
static int ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen );
static int ssl_write_key_shares_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen );
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
static int ssl_client_hello_write_partial( mbedtls_ssl_context* ssl,
unsigned char* buf, size_t buflen,
size_t* len_without_binders,
size_t* len_with_binders )
{
/* Extensions */
/* extension_start
* Used during extension writing where the
* buffer pointer to the beginning of the
* extension list must be kept to write
* the total extension list size in the end.
*/
int ret;
unsigned char* extension_start;
size_t cur_ext_len; /* Size of the current extension */
size_t total_ext_len; /* Size of list of extensions */
/* Length information */
size_t rand_bytes_len;
size_t version_len;
/* Buffer management */
unsigned char* start = buf;
unsigned char* end = buf + buflen;
/* Ciphersuite-related variables */
const int* ciphersuites;
const mbedtls_ssl_ciphersuite_t* ciphersuite_info;
size_t i; /* used to iterate through ciphersuite list */
/* ciphersuite_start points to the start of the ciphersuite list, i.e. to the length field*/
unsigned char* ciphersuite_start;
size_t ciphersuite_count;
/* Keeping track of the included extensions */
ssl->handshake->extensions_present = MBEDTLS_SSL_EXT_NONE;
rand_bytes_len = 32;
/* NOTE:
* Even for DTLS 1.3, we are writing a TLS handshake header here.
* The actual DTLS 1.3 handshake header is inserted in
* the record writing routine mbedtls_ssl_write_record().
*
* For cTLS the length, and the version field
* are elided. The random bytes are shorter.
*/
version_len = 2;
if( ssl->conf->max_major_ver == 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "configured max major version is invalid, "
"consider using mbedtls_ssl_config_defaults()" ) );
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
}
ssl->major_ver = ssl->conf->min_major_ver;
ssl->minor_ver = ssl->conf->min_minor_ver;
/* For TLS 1.3 we use the legacy version number {0x03, 0x03}
* instead of the true version number.
*
* For DTLS 1.3 we use the legacy version number
* {254,253}.
*
* In cTLS the version number is elided.
*/
*buf++ = 0x03;
*buf++ = 0x03;
buflen -= version_len;
/* Write random bytes */
memcpy( buf, ssl->handshake->randbytes, rand_bytes_len );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes", buf, rand_bytes_len );
buf += rand_bytes_len;
buflen -= rand_bytes_len;
/* Versions of TLS before TLS 1.3 supported a
* "session resumption" feature which has been merged with pre-shared
* keys in this version. A client which has a
* cached session ID set by a pre-TLS 1.3 server SHOULD set this
* field to that value. In compatibility mode,
* this field MUST be non-empty, so a client not offering a
* pre-TLS 1.3 session MUST generate a new 32-byte value. This value
* need not be random but SHOULD be unpredictable to avoid
* implementations fixating on a specific value ( also known as
* ossification ). Otherwise, it MUST be set as a zero-length vector
* ( i.e., a zero-valued single byte length field ).
*/
if( buflen < 1 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
}
*buf++ = 0; /* session id length set to zero */
buflen -= 1;
/*
* Ciphersuite list
*
* This is a list of the symmetric cipher options supported by
* the client, specifically the record protection algorithm
* ( including secret key length ) and a hash to be used with
* HKDF, in descending order of client preference.
*/
ciphersuites = ssl->conf->ciphersuite_list;
if( buflen < 2 /* for ciphersuite list length */ )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
}
/* Skip writing ciphersuite length for now */
ciphersuite_count = 0;
ciphersuite_start = buf;
buf += 2;
buflen -= 2;
for ( i = 0; ciphersuites[i] != 0; i++ )
{
ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuites[i] );
if( ciphersuite_info == NULL )
continue;
if( ciphersuite_info->min_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 ||
ciphersuite_info->max_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 )
continue;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x, %s",
(unsigned int) ciphersuites[i], ciphersuite_info->name ) );
ciphersuite_count++;
if( buflen < 2 /* for ciphersuite list length */ )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
}
*buf++ = (unsigned char)( ciphersuites[i] >> 8 );
*buf++ = (unsigned char)( ciphersuites[i] );
buflen -= 2;
}
/* write ciphersuite length now */
*ciphersuite_start++ = (unsigned char)( ciphersuite_count*2 >> 8 );
*ciphersuite_start++ = (unsigned char)( ciphersuite_count*2 );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, got %" MBEDTLS_PRINTF_SIZET " ciphersuites", ciphersuite_count ) );
/* For every TLS 1.3 ClientHello, this vector MUST contain exactly
* one byte set to zero, which corresponds to the 'null' compression
* method in prior versions of TLS.
*
* For cTLS this field is elided.
*/
if( buflen < 2 /* for ciphersuite list length */ )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
}
*buf++ = 1;
*buf++ = MBEDTLS_SSL_COMPRESS_NULL;
buflen -= 2;
/* First write extensions, then the total length */
extension_start = buf;
total_ext_len = 0;
buf += 2;
/* Supported Versions Extension is mandatory with TLS 1.3.
*
* For cTLS we only need to provide it if there is more than one version
* and currently there is only one.
*/
ssl_write_supported_versions_ext( ssl, buf, end, &cur_ext_len );
total_ext_len += cur_ext_len;
buf += cur_ext_len;
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/* The supported_groups and the key_share extensions are
* REQUIRED for ECDHE ciphersuites.
*/
ret = ssl_write_supported_groups_ext( ssl, buf, end, &cur_ext_len );
if( ret != 0 )
return( ret );
total_ext_len += cur_ext_len;
buf += cur_ext_len;
/* The supported_signature_algorithms extension is REQUIRED for
* certificate authenticated ciphersuites. */
ret = mbedtls_ssl_write_signature_algorithms_ext( ssl, buf, end, &cur_ext_len );
if( ret != 0 )
return( ret );
total_ext_len += cur_ext_len;
buf += cur_ext_len;
/* We need to send the key shares under three conditions:
* 1 ) A certificate-based ciphersuite is being offered. In this case
* supported_groups and supported_signature extensions have been successfully added.
* 2 ) A PSK-based ciphersuite with ECDHE is offered. In this case the
* psk_key_exchange_modes has been added as the last extension.
* 3 ) Or, in case all ciphers are supported ( which includes #1 and #2 from above )
*/
ret = ssl_write_key_shares_ext( ssl, buf, end, &cur_ext_len );
if( ret != 0 )
return( ret );
total_ext_len += cur_ext_len;
buf += cur_ext_len;
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
/* Add more extensions here */
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %" MBEDTLS_PRINTF_SIZET ,
total_ext_len ) );
MBEDTLS_SSL_DEBUG_BUF( 3, "client hello extensions", extension_start, total_ext_len );
/* Write extension length */
*extension_start++ = (unsigned char)( ( total_ext_len >> 8 ) & 0xFF );
*extension_start++ = (unsigned char)( ( total_ext_len ) & 0xFF );
*len_without_binders = buf - start;
*len_with_binders = ( extension_start + total_ext_len ) - start;
return( 0 );
}
static void ssl_write_supported_versions_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen )
{
((void) ssl);
((void) buf);
((void) buflen);
((void) len_without_binders);
((void) len_with_binders);
((void) end);
((void) olen);
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
static int ssl_write_supported_groups_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen )
{
((void) ssl);
((void) buf);
((void) end);
((void) olen);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
static int ssl_write_key_shares_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen )
{
((void) ssl);
((void) buf);
((void) end);
((void) olen);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#endif /* MBEDTLS_SSL_CLI_C */

34
library/ssl_tls13_generic.c
View file

@ -70,6 +70,40 @@ void mbedtls_ssl_add_hs_hdr_to_checksum( mbedtls_ssl_context *ssl,
ssl->handshake->update_checksum( ssl, hs_hdr, sizeof( hs_hdr ) );
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
/*
* mbedtls_ssl_write_signature_algorithms_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_write_signature_algorithms_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen )
{
((void) ssl);
((void) buf);
((void) end);
((void) olen);
return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
}
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#endif /* MBEDTLS_SSL_TLS_C */