Cleanup client_hello body.
cleanup `ssl_tls13_write_client_hello_body`, fix comments issues. And move ciphersuites to separate function Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
This commit is contained in:
Jerry Yu
parent
67d4ed5b22
commit
6a64310002
@ -115,8 +115,79 @@ static int ssl_tls13_write_key_shares_ext( mbedtls_ssl_context *ssl,
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#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
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/* Functions for writing ClientHello message */
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/* Write ciphersuites
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* CipherSuite cipher_suites<2..2^16-2>;
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*/
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static int ssl_tls13_write_client_hello_ciphersuites(
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mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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/* Ciphersuite-related variables */
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const int *ciphersuites;
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const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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/* ciphersuite_start points to the start of
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the ciphersuite list, i.e. to the length field*/
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unsigned char *ciphersuite_start, *ciphersuite_iter;
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size_t buf_len;
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*olen = 0 ;
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/*
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* Ciphersuite list
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*
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* This is a list of the symmetric cipher options supported by
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* the client, specifically the record protection algorithm
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* ( including secret key length ) and a hash to be used with
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* HKDF, in descending order of client preference.
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*/
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ciphersuites = ssl->conf->ciphersuite_list;
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/* Check available spaces for ciphersuite */
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 2 );
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/* Write ciphersuites */
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ciphersuite_start = buf + 2;
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ciphersuite_iter = ciphersuite_start;
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for ( size_t i = 0; ciphersuites[i] != 0; i++ )
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{
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ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuites[i] );
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if( ciphersuite_info == NULL )
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continue;
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if( ciphersuite_info->min_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 ||
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ciphersuite_info->max_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 )
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continue;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x, %s",
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(unsigned int) ciphersuites[i],
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ciphersuite_info->name ) );
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/* Check for available spaces */
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 2 );
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MBEDTLS_PUT_UINT16_BE( ciphersuites[i], ciphersuite_iter, 0);
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ciphersuite_iter += 2;
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}
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buf_len = ciphersuite_iter - ciphersuite_start;
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/* write ciphersuite buf length */
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MBEDTLS_PUT_UINT16_BE( buf_len, buf, 0 );
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "client hello, got %" MBEDTLS_PRINTF_SIZET " ciphersuites",
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buf_len/2 ) );
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return( 0 );
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}
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/* Functions for writing ClientHello message */
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static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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size_t buflen,
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@ -139,13 +210,7 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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unsigned char *start = buf;
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unsigned char *end = buf + buflen;
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/* Ciphersuite-related variables */
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const int *ciphersuites;
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const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
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/* ciphersuite_start points to the start of
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the ciphersuite list, i.e. to the length field*/
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unsigned char *ciphersuite_start;
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size_t ciphersuite_count;
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*len_with_binders = 0;
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/* Keeping track of the included extensions */
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ssl->handshake->extensions_present = MBEDTLS_SSL_EXT_NONE;
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@ -169,7 +234,9 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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ssl->major_ver = ssl->conf->min_major_ver;
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ssl->minor_ver = ssl->conf->min_minor_ver;
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/* For TLS 1.3 we use the legacy version number {0x03, 0x03}
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/* Write legacy_version
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* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
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* For TLS 1.3 we use the legacy version number {0x03, 0x03}
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* instead of the true version number.
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*
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* For DTLS 1.3 we use the legacy version number
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@ -180,16 +247,16 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, CLIENT_HELLO_LEGACY_VERSION_LEN );
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MBEDTLS_PUT_UINT16_BE( 0x0303, buf, 0);
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buf += CLIENT_HELLO_LEGACY_VERSION_LEN;
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buflen -= CLIENT_HELLO_LEGACY_VERSION_LEN;
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/* Write random bytes */
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/* Write random bytes
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Random random
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, CLIENT_HELLO_RANDOM_LEN );
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memcpy( buf, ssl->handshake->randbytes, CLIENT_HELLO_RANDOM_LEN );
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, random bytes",
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buf, CLIENT_HELLO_RANDOM_LEN );
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buf += CLIENT_HELLO_RANDOM_LEN;
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buflen -= CLIENT_HELLO_RANDOM_LEN;
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/* Versions of TLS before TLS 1.3 supported a
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* "session resumption" feature which has been merged with pre-shared
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@ -203,74 +270,14 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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* ossification ). Otherwise, it MUST be set as a zero-length vector
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* ( i.e., a zero-valued single byte length field ).
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*/
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if( buflen < 1 )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
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return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
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}
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 1 );
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*buf++ = 0; /* session id length set to zero */
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buflen -= 1;
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/*
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* Ciphersuite list
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*
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* This is a list of the symmetric cipher options supported by
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* the client, specifically the record protection algorithm
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* ( including secret key length ) and a hash to be used with
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* HKDF, in descending order of client preference.
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*/
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ciphersuites = ssl->conf->ciphersuite_list;
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if( buflen < 2 /* for ciphersuite list length */ )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
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return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
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}
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/* Skip writing ciphersuite length for now */
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ciphersuite_count = 0;
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ciphersuite_start = buf;
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buf += 2;
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buflen -= 2;
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for ( size_t i = 0; ciphersuites[i] != 0; i++ )
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{
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ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( ciphersuites[i] );
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if( ciphersuite_info == NULL )
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continue;
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if( ciphersuite_info->min_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 ||
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ciphersuite_info->max_minor_ver != MBEDTLS_SSL_MINOR_VERSION_4 )
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continue;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x, %s",
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(unsigned int) ciphersuites[i],
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ciphersuite_info->name ) );
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ciphersuite_count++;
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if( buflen < 2 /* for ciphersuite list length */ )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
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return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
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}
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MBEDTLS_PUT_UINT16_BE( ciphersuites[i], buf, 0);
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buf += 2;
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buflen -= 2;
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}
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/* write ciphersuite length now */
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MBEDTLS_PUT_UINT16_BE( ciphersuite_count*2, ciphersuite_start, 0 );
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ciphersuite_start += 2;
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MBEDTLS_SSL_DEBUG_MSG( 3,
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( "client hello, got %" MBEDTLS_PRINTF_SIZET " ciphersuites",
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ciphersuite_count ) );
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/* Write ciphersuites */
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ret = ssl_tls13_write_client_hello_ciphersuites( ssl, buf, end, &cur_ext_len );
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if( ret != 0)
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return( ret );
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buf += cur_ext_len;
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/* For every TLS 1.3 ClientHello, this vector MUST contain exactly
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* one byte set to zero, which corresponds to the 'null' compression
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@ -278,20 +285,13 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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*
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* For cTLS this field is elided.
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*/
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if( buflen < 2 /* for ciphersuite list length */ )
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{
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MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small to hold ClientHello" ) );
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return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
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}
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MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 2 );
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*buf++ = 1;
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*buf++ = MBEDTLS_SSL_COMPRESS_NULL;
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buflen -= 2;
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/* First write extensions, then the total length */
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extension_start = buf;
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total_ext_len = 0;
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buf += 2;
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/* Supported Versions Extension is mandatory with TLS 1.3.
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@ -302,7 +302,6 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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ret = ssl_tls13_write_supported_versions_ext( ssl, buf, end, &cur_ext_len );
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if( ret != 0 )
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return( ret );
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total_ext_len += cur_ext_len;
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buf += cur_ext_len;
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#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
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@ -312,8 +311,6 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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ret = ssl_tls13_write_supported_groups_ext( ssl, buf, end, &cur_ext_len );
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if( ret != 0 )
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return( ret );
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total_ext_len += cur_ext_len;
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buf += cur_ext_len;
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/* The supported_signature_algorithms extension is REQUIRED for
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@ -321,8 +318,6 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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ret = mbedtls_ssl_tls13_write_sig_alg_ext( ssl, buf, end, &cur_ext_len );
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if( ret != 0 )
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return( ret );
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total_ext_len += cur_ext_len;
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buf += cur_ext_len;
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/* We need to send the key shares under three conditions:
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@ -338,13 +333,13 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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ret = ssl_tls13_write_key_shares_ext( ssl, buf, end, &cur_ext_len );
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if( ret != 0 )
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return( ret );
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total_ext_len += cur_ext_len;
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buf += cur_ext_len;
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#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
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/* Add more extensions here */
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total_ext_len = buf - extension_start - 2;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, total extension length: %" MBEDTLS_PRINTF_SIZET ,
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total_ext_len ) );
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@ -354,7 +349,7 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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MBEDTLS_PUT_UINT16_BE( total_ext_len, extension_start, 0 );
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extension_start += 2;
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*len_with_binders = ( extension_start + total_ext_len ) - start;
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*len_with_binders = buf - start;
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return( 0 );
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}
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@ -390,9 +385,6 @@ static int ssl_tls13_prepare_client_hello( mbedtls_ssl_context *ssl )
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*
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* Structure of this message:
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*
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* uint16 ProtocolVersion;
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* opaque Random[32];
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* uint8 CipherSuite[2]; // Cryptographic suite selector
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* struct {
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* ProtocolVersion legacy_version = 0x0303; // TLS v1.2
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* Random random;
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