mirror of
https://github.com/yuzu-emu/mbedtls.git
synced 2024-11-22 22:25:47 +01:00
Added bounds checking for TLS extensions
IOTSSL-478 - Added checks to prevent buffer overflows.
This commit is contained in:
Simon Butcher
parent
c988f32add
commit
b1e325d6b2
@ -65,6 +65,7 @@ static void ssl_write_hostname_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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@ -74,6 +75,12 @@ static void ssl_write_hostname_ext( ssl_context *ssl,
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SSL_DEBUG_MSG( 3, ( "client hello, adding server name extension: %s",
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ssl->hostname ) );
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if( (size_t)(end - p) < ssl->hostname_len + 9 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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/*
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* struct {
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* NameType name_type;
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@ -117,6 +124,7 @@ static void ssl_write_renegotiation_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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@ -125,6 +133,12 @@ static void ssl_write_renegotiation_ext( ssl_context *ssl,
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SSL_DEBUG_MSG( 3, ( "client hello, adding renegotiation extension" ) );
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if( (size_t)(end - p) < 5 + ssl->verify_data_len )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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/*
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* Secure renegotiation
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*/
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@ -151,6 +165,7 @@ static void ssl_write_signature_algorithms_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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size_t sig_alg_len = 0;
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#if defined(POLARSSL_RSA_C) || defined(POLARSSL_ECDSA_C)
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unsigned char *sig_alg_list = buf + 6;
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@ -163,9 +178,54 @@ static void ssl_write_signature_algorithms_ext( ssl_context *ssl,
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SSL_DEBUG_MSG( 3, ( "client hello, adding signature_algorithms extension" ) );
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#if defined(POLARSSL_RSA_C)
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#if defined(POLARSSL_SHA512_C)
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/* SHA512 + RSA signature, SHA384 + RSA signature */
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sig_alg_len += 4;
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#endif
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#if defined(POLARSSL_SHA256_C)
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/* SHA256 + RSA signature, SHA224 + RSA signature */
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sig_alg_len += 4;
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#endif
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#if defined(POLARSSL_SHA1_C)
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/* SHA1 + RSA signature */
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sig_alg_len += 2;
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#endif
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#if defined(POLARSSL_MD5_C)
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/* MD5 + RSA signature */
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sig_alg_len += 2;
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#endif
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#endif /* POLARSSL_RSA_C */
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#if defined(POLARSSL_ECDSA_C)
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#if defined(POLARSSL_SHA512_C)
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/* SHA512 + ECDSA signature, SHA384 + ECDSA signature */
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sig_alg_len += 4;
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#endif
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#if defined(POLARSSL_SHA256_C)
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/* SHA256 + ECDSA signature, SHA224 + ECDSA signature */
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sig_alg_len += 4;
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#endif
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#if defined(POLARSSL_SHA1_C)
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/* SHA1 + ECDSA signature */
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sig_alg_len += 2;
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#endif
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#if defined(POLARSSL_MD5_C)
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/* MD5 + ECDSA signature */
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sig_alg_len += 2;
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#endif
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#endif /* POLARSSL_ECDSA_C */
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if( end < p || (size_t)( end - p ) < sig_alg_len + 6 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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/*
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* Prepare signature_algorithms extension (TLS 1.2)
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*/
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sig_alg_len = 0;
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#if defined(POLARSSL_RSA_C)
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#if defined(POLARSSL_SHA512_C)
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sig_alg_list[sig_alg_len++] = SSL_HASH_SHA512;
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@ -248,6 +308,7 @@ static void ssl_write_supported_elliptic_curves_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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unsigned char *elliptic_curve_list = p + 6;
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size_t elliptic_curve_len = 0;
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const ecp_curve_info *info;
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@ -269,6 +330,25 @@ static void ssl_write_supported_elliptic_curves_ext( ssl_context *ssl,
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for( info = ecp_curve_list(); info->grp_id != POLARSSL_ECP_DP_NONE; info++ )
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{
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#endif
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elliptic_curve_len += 2;
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}
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if( end < p || (size_t)( end - p ) < 6 + elliptic_curve_len )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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elliptic_curve_len = 0;
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#if defined(POLARSSL_SSL_SET_CURVES)
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for( grp_id = ssl->curve_list; *grp_id != POLARSSL_ECP_DP_NONE; grp_id++ )
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{
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info = ecp_curve_info_from_grp_id( *grp_id );
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#else
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for( info = ecp_curve_list(); info->grp_id != POLARSSL_ECP_DP_NONE; info++ )
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{
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#endif
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elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
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elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
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@ -294,12 +374,18 @@ static void ssl_write_supported_point_formats_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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((void) ssl);
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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SSL_DEBUG_MSG( 3, ( "client hello, adding supported_point_formats extension" ) );
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if( end < p || (size_t)( end - p ) < 6 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_SUPPORTED_POINT_FORMATS ) & 0xFF );
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@ -319,14 +405,21 @@ static void ssl_write_max_fragment_length_ext( ssl_context *ssl,
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size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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if( ssl->mfl_code == SSL_MAX_FRAG_LEN_NONE ) {
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*olen = 0;
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*olen = 0;
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if( ssl->mfl_code == SSL_MAX_FRAG_LEN_NONE )
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding max_fragment_length extension" ) );
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if( end < p || (size_t)( end - p ) < 5 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_MAX_FRAGMENT_LENGTH ) & 0xFF );
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@ -344,15 +437,21 @@ static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
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unsigned char *buf, size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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if( ssl->trunc_hmac == SSL_TRUNC_HMAC_DISABLED )
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{
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*olen = 0;
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding truncated_hmac extension" ) );
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if( end < p || (size_t)( end - p ) < 4 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_TRUNCATED_HMAC ) & 0xFF );
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@ -368,17 +467,25 @@ static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
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unsigned char *buf, size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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if( ssl->encrypt_then_mac == SSL_ETM_DISABLED ||
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ssl->max_minor_ver == SSL_MINOR_VERSION_0 )
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{
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*olen = 0;
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding encrypt_then_mac "
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"extension" ) );
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if( end < p || (size_t)( end - p ) < 4 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
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@ -394,17 +501,25 @@ static void ssl_write_extended_ms_ext( ssl_context *ssl,
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unsigned char *buf, size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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*olen = 0;
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if( ssl->extended_ms == SSL_EXTENDED_MS_DISABLED ||
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ssl->max_minor_ver == SSL_MINOR_VERSION_0 )
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{
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*olen = 0;
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding extended_master_secret "
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"extension" ) );
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if( end < p || (size_t)( end - p ) < 4 )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET ) & 0xFF );
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@ -420,16 +535,22 @@ static void ssl_write_session_ticket_ext( ssl_context *ssl,
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unsigned char *buf, size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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size_t tlen = ssl->session_negotiate->ticket_len;
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*olen = 0;
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if( ssl->session_tickets == SSL_SESSION_TICKETS_DISABLED )
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{
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*olen = 0;
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding session ticket extension" ) );
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if( end < p || (size_t)( end - p ) < 4 + tlen )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_SESSION_TICKET ) & 0xFF );
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@ -457,16 +578,26 @@ static void ssl_write_alpn_ext( ssl_context *ssl,
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unsigned char *buf, size_t *olen )
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{
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unsigned char *p = buf;
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const unsigned char *end = ssl->out_msg + SSL_MAX_CONTENT_LEN;
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size_t alpnlen = 0;
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const char **cur;
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*olen = 0;
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if( ssl->alpn_list == NULL )
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{
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*olen = 0;
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return;
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}
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SSL_DEBUG_MSG( 3, ( "client hello, adding alpn extension" ) );
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for( cur = ssl->alpn_list; *cur != NULL; cur++ )
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alpnlen += (unsigned char)( strlen( *cur ) & 0xFF ) + 1;
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if( end < p || (size_t)( end - p ) < 6 + alpnlen )
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{
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SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
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return;
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}
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*p++ = (unsigned char)( ( TLS_EXT_ALPN >> 8 ) & 0xFF );
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*p++ = (unsigned char)( ( TLS_EXT_ALPN ) & 0xFF );
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