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firefox/security/nss/lib/ssl/ssl3ext.c
Daniel Baumann 5e9a113729
Adding upstream version 140.0. 
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-25 09:37:52 +02:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* SSL3 Protocol
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* TLS extension code moved here from ssl3ecc.c */
#include "nssrenam.h"
#include "nss.h"
#include "pk11pub.h"
#include "ssl.h"
#include "sslimpl.h"
#include "sslproto.h"
#include "ssl3exthandle.h"
#include "tls13ech.h"
#include "tls13err.h"
#include "tls13exthandle.h"
#include "tls13subcerts.h"
/* Callback function that handles a received extension. */
typedef SECStatus (*ssl3ExtensionHandlerFunc)(const sslSocket *ss,
TLSExtensionData *xtnData,
SECItem *data);
/* Row in a table of hello extension handlers. */
typedef struct {
SSLExtensionType ex_type;
ssl3ExtensionHandlerFunc ex_handler;
} ssl3ExtensionHandler;
/* Table of handlers for received TLS hello extensions, one per extension.
* In the second generation, this table will be dynamic, and functions
* will be registered here.
*/
/* This table is used by the server, to handle client hello extensions. */
static const ssl3ExtensionHandler clientHelloHandlers[] = {
{ ssl_server_name_xtn, &ssl3_HandleServerNameXtn },
{ ssl_supported_groups_xtn, &ssl_HandleSupportedGroupsXtn },
{ ssl_ec_point_formats_xtn, &ssl3_HandleSupportedPointFormatsXtn },
{ ssl_session_ticket_xtn, &ssl3_ServerHandleSessionTicketXtn },
{ ssl_renegotiation_info_xtn, &ssl3_HandleRenegotiationInfoXtn },
{ ssl_app_layer_protocol_xtn, &ssl3_ServerHandleAppProtoXtn },
{ ssl_use_srtp_xtn, &ssl3_ServerHandleUseSRTPXtn },
{ ssl_cert_status_xtn, &ssl3_ServerHandleStatusRequestXtn },
{ ssl_tls13_certificate_authorities_xtn, &tls13_ServerHandleCertAuthoritiesXtn },
{ ssl_signature_algorithms_xtn, &ssl3_HandleSigAlgsXtn },
{ ssl_extended_master_secret_xtn, &ssl3_HandleExtendedMasterSecretXtn },
{ ssl_signed_cert_timestamp_xtn, &ssl3_ServerHandleSignedCertTimestampXtn },
{ ssl_delegated_credentials_xtn, &tls13_ServerHandleDelegatedCredentialsXtn },
{ ssl_tls13_key_share_xtn, &tls13_ServerHandleKeyShareXtn },
{ ssl_tls13_pre_shared_key_xtn, &tls13_ServerHandlePreSharedKeyXtn },
{ ssl_tls13_early_data_xtn, &tls13_ServerHandleEarlyDataXtn },
{ ssl_tls13_psk_key_exchange_modes_xtn, &tls13_ServerHandlePskModesXtn },
{ ssl_tls13_cookie_xtn, &tls13_ServerHandleCookieXtn },
{ ssl_tls13_post_handshake_auth_xtn, &tls13_ServerHandlePostHandshakeAuthXtn },
{ ssl_record_size_limit_xtn, &ssl_HandleRecordSizeLimitXtn },
{ ssl_certificate_compression_xtn, &ssl3_HandleCertificateCompressionXtn },
{ 0, NULL }
};
/* These two tables are used by the client, to handle server hello
* extensions. */
static const ssl3ExtensionHandler serverHelloHandlersTLS[] = {
{ ssl_server_name_xtn, &ssl3_HandleServerNameXtn },
/* TODO: add a handler for ssl_ec_point_formats_xtn */
{ ssl_session_ticket_xtn, &ssl3_ClientHandleSessionTicketXtn },
{ ssl_renegotiation_info_xtn, &ssl3_HandleRenegotiationInfoXtn },
{ ssl_app_layer_protocol_xtn, &ssl3_ClientHandleAppProtoXtn },
{ ssl_use_srtp_xtn, &ssl3_ClientHandleUseSRTPXtn },
{ ssl_cert_status_xtn, &ssl3_ClientHandleStatusRequestXtn },
{ ssl_extended_master_secret_xtn, &ssl3_HandleExtendedMasterSecretXtn },
{ ssl_signed_cert_timestamp_xtn, &ssl3_ClientHandleSignedCertTimestampXtn },
{ ssl_tls13_key_share_xtn, &tls13_ClientHandleKeyShareXtn },
{ ssl_tls13_pre_shared_key_xtn, &tls13_ClientHandlePreSharedKeyXtn },
{ ssl_tls13_early_data_xtn, &tls13_ClientHandleEarlyDataXtn },
{ ssl_tls13_encrypted_client_hello_xtn, &tls13_ClientHandleEchXtn },
{ ssl_record_size_limit_xtn, &ssl_HandleRecordSizeLimitXtn },
{ 0, NULL }
};
static const ssl3ExtensionHandler helloRetryRequestHandlers[] = {
{ ssl_tls13_key_share_xtn, tls13_ClientHandleKeyShareXtnHrr },
{ ssl_tls13_cookie_xtn, tls13_ClientHandleHrrCookie },
{ ssl_tls13_encrypted_client_hello_xtn, tls13_ClientHandleHrrEchXtn },
{ 0, NULL }
};
static const ssl3ExtensionHandler serverHelloHandlersSSL3[] = {
{ ssl_renegotiation_info_xtn, &ssl3_HandleRenegotiationInfoXtn },
{ 0, NULL }
};
static const ssl3ExtensionHandler newSessionTicketHandlers[] = {
{ ssl_tls13_early_data_xtn,
&tls13_ClientHandleTicketEarlyDataXtn },
{ 0, NULL }
};
/* This table is used by the client to handle server certificates in TLS 1.3 */
static const ssl3ExtensionHandler serverCertificateHandlers[] = {
{ ssl_signed_cert_timestamp_xtn, &ssl3_ClientHandleSignedCertTimestampXtn },
{ ssl_cert_status_xtn, &ssl3_ClientHandleStatusRequestXtn },
{ ssl_delegated_credentials_xtn, &tls13_ClientHandleDelegatedCredentialsXtn },
{ 0, NULL }
};
static const ssl3ExtensionHandler certificateRequestHandlers[] = {
{ ssl_signature_algorithms_xtn, &ssl3_HandleSigAlgsXtn },
{ ssl_tls13_certificate_authorities_xtn,
&tls13_ClientHandleCertAuthoritiesXtn },
{ ssl_certificate_compression_xtn, &ssl3_HandleCertificateCompressionXtn },
{ 0, NULL }
};
/* Tables of functions to format TLS hello extensions, one function per
* extension.
* These static tables are for the formatting of client hello extensions.
* The server's table of hello senders is dynamic, in the socket struct,
* and sender functions are registered there.
* NB: the order of these extensions can have an impact on compatibility. Some
* servers (e.g. Tomcat) will terminate the connection if the last extension in
* the client hello is empty (for example, the extended master secret
* extension, if it were listed last). See bug 1243641.
*/
static const sslExtensionBuilder clientHelloSendersTLS[] = {
/* TLS 1.3 GREASE extensions - empty. */
{ ssl_tls13_grease_xtn, &tls13_SendEmptyGreaseXtn },
{ ssl_server_name_xtn, &ssl3_ClientSendServerNameXtn },
{ ssl_extended_master_secret_xtn, &ssl3_SendExtendedMasterSecretXtn },
{ ssl_renegotiation_info_xtn, &ssl3_SendRenegotiationInfoXtn },
{ ssl_supported_groups_xtn, &ssl_SendSupportedGroupsXtn },
{ ssl_ec_point_formats_xtn, &ssl3_SendSupportedPointFormatsXtn },
{ ssl_session_ticket_xtn, &ssl3_ClientSendSessionTicketXtn },
{ ssl_app_layer_protocol_xtn, &ssl3_ClientSendAppProtoXtn },
{ ssl_use_srtp_xtn, &ssl3_ClientSendUseSRTPXtn },
{ ssl_cert_status_xtn, &ssl3_ClientSendStatusRequestXtn },
{ ssl_delegated_credentials_xtn, &tls13_ClientSendDelegatedCredentialsXtn },
{ ssl_signed_cert_timestamp_xtn, &ssl3_ClientSendSignedCertTimestampXtn },
{ ssl_tls13_key_share_xtn, &tls13_ClientSendKeyShareXtn },
{ ssl_tls13_early_data_xtn, &tls13_ClientSendEarlyDataXtn },
/* Some servers (e.g. WebSphere Application Server 7.0 and Tomcat) will
* time out or terminate the connection if the last extension in the
* client hello is empty. They are not intolerant of TLS 1.2, so list
* signature_algorithms at the end. See bug 1243641. */
{ ssl_tls13_supported_versions_xtn, &tls13_ClientSendSupportedVersionsXtn },
{ ssl_signature_algorithms_xtn, &ssl3_SendSigAlgsXtn },
{ ssl_tls13_cookie_xtn, &tls13_ClientSendHrrCookieXtn },
{ ssl_tls13_psk_key_exchange_modes_xtn, &tls13_ClientSendPskModesXtn },
{ ssl_tls13_post_handshake_auth_xtn, &tls13_ClientSendPostHandshakeAuthXtn },
{ ssl_record_size_limit_xtn, &ssl_SendRecordSizeLimitXtn },
{ ssl_certificate_compression_xtn, &ssl3_SendCertificateCompressionXtn },
/* TLS 1.3 GREASE extensions - 1 zero byte. */
{ ssl_tls13_grease_xtn, &tls13_SendGreaseXtn },
/* The pre_shared_key extension MUST be last. */
{ ssl_tls13_pre_shared_key_xtn, &tls13_ClientSendPreSharedKeyXtn },
{ 0, NULL }
};
static const sslExtensionBuilder clientHelloSendersSSL3[] = {
{ ssl_renegotiation_info_xtn, &ssl3_SendRenegotiationInfoXtn },
{ 0, NULL }
};
static const sslExtensionBuilder tls13_cert_req_senders[] = {
{ ssl_signature_algorithms_xtn, &ssl3_SendSigAlgsXtn },
{ ssl_tls13_certificate_authorities_xtn, &tls13_SendCertAuthoritiesXtn },
/* TLS 1.3 GREASE extension. */
{ ssl_tls13_grease_xtn, &tls13_SendEmptyGreaseXtn },
{ ssl_certificate_compression_xtn, &ssl3_SendCertificateCompressionXtn },
{ 0, NULL }
};
static const sslExtensionBuilder tls13_hrr_senders[] = {
{ ssl_tls13_key_share_xtn, &tls13_ServerSendHrrKeyShareXtn },
{ ssl_tls13_cookie_xtn, &tls13_ServerSendHrrCookieXtn },
{ ssl_tls13_supported_versions_xtn, &tls13_ServerSendSupportedVersionsXtn },
{ ssl_tls13_encrypted_client_hello_xtn, &tls13_ServerSendHrrEchXtn },
{ 0, NULL }
};
static const struct {
SSLExtensionType type;
SSLExtensionSupport support;
} ssl_supported_extensions[] = {
{ ssl_server_name_xtn, ssl_ext_native_only },
{ ssl_cert_status_xtn, ssl_ext_native },
{ ssl_delegated_credentials_xtn, ssl_ext_native },
{ ssl_supported_groups_xtn, ssl_ext_native_only },
{ ssl_ec_point_formats_xtn, ssl_ext_native },
{ ssl_signature_algorithms_xtn, ssl_ext_native_only },
{ ssl_use_srtp_xtn, ssl_ext_native },
{ ssl_app_layer_protocol_xtn, ssl_ext_native_only },
{ ssl_signed_cert_timestamp_xtn, ssl_ext_native },
{ ssl_padding_xtn, ssl_ext_native },
{ ssl_extended_master_secret_xtn, ssl_ext_native_only },
{ ssl_session_ticket_xtn, ssl_ext_native_only },
{ ssl_tls13_key_share_xtn, ssl_ext_native_only },
{ ssl_tls13_pre_shared_key_xtn, ssl_ext_native_only },
{ ssl_tls13_early_data_xtn, ssl_ext_native_only },
{ ssl_tls13_supported_versions_xtn, ssl_ext_native_only },
{ ssl_tls13_cookie_xtn, ssl_ext_native_only },
{ ssl_tls13_psk_key_exchange_modes_xtn, ssl_ext_native_only },
{ ssl_tls13_ticket_early_data_info_xtn, ssl_ext_native_only },
{ ssl_tls13_certificate_authorities_xtn, ssl_ext_native },
{ ssl_renegotiation_info_xtn, ssl_ext_native },
{ ssl_tls13_encrypted_client_hello_xtn, ssl_ext_native_only },
{ ssl_certificate_compression_xtn, ssl_ext_native },
};
static SSLExtensionSupport
ssl_GetExtensionSupport(PRUint16 type)
{
unsigned int i;
for (i = 0; i < PR_ARRAY_SIZE(ssl_supported_extensions); ++i) {
if (type == ssl_supported_extensions[i].type) {
return ssl_supported_extensions[i].support;
}
}
return ssl_ext_none;
}
SECStatus
SSLExp_GetExtensionSupport(PRUint16 type, SSLExtensionSupport *support)
{
*support = ssl_GetExtensionSupport(type);
return SECSuccess;
}
SECStatus
SSLExp_InstallExtensionHooks(PRFileDesc *fd, PRUint16 extension,
SSLExtensionWriter writer, void *writerArg,
SSLExtensionHandler handler, void *handlerArg)
{
sslSocket *ss = ssl_FindSocket(fd);
PRCList *cursor;
sslCustomExtensionHooks *hook;
if (!ss) {
return SECFailure; /* Code already set. */
}
/* Need to specify both or neither, but not just one. */
if ((writer && !handler) || (!writer && handler)) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ssl_GetExtensionSupport(extension) == ssl_ext_native_only) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (ss->firstHsDone || ((ss->ssl3.hs.ws != idle_handshake) &&
(ss->ssl3.hs.ws != wait_client_hello))) {
PORT_SetError(PR_INVALID_STATE_ERROR);
return SECFailure;
}
/* Remove any old handler. */
for (cursor = PR_NEXT_LINK(&ss->extensionHooks);
cursor != &ss->extensionHooks;
cursor = PR_NEXT_LINK(cursor)) {
hook = (sslCustomExtensionHooks *)cursor;
if (hook->type == extension) {
PR_REMOVE_LINK(&hook->link);
PORT_Free(hook);
break;
}
}
if (!writer && !handler) {
return SECSuccess;
}
hook = PORT_ZNew(sslCustomExtensionHooks);
if (!hook) {
return SECFailure; /* This removed the old one, oh well. */
}
hook->type = extension;
hook->writer = writer;
hook->writerArg = writerArg;
hook->handler = handler;
hook->handlerArg = handlerArg;
PR_APPEND_LINK(&hook->link, &ss->extensionHooks);
return SECSuccess;
}
sslCustomExtensionHooks *
ssl_FindCustomExtensionHooks(sslSocket *ss, PRUint16 extension)
{
PRCList *cursor;
for (cursor = PR_NEXT_LINK(&ss->extensionHooks);
cursor != &ss->extensionHooks;
cursor = PR_NEXT_LINK(cursor)) {
sslCustomExtensionHooks *hook = (sslCustomExtensionHooks *)cursor;
if (hook->type == extension) {
return hook;
}
}
return NULL;
}
static PRBool
arrayContainsExtension(const PRUint16 *array, PRUint32 len, PRUint16 ex_type)
{
unsigned int i;
for (i = 0; i < len; i++) {
if (ex_type == array[i])
return PR_TRUE;
}
return PR_FALSE;
}
PRBool
ssl3_ExtensionNegotiated(const sslSocket *ss, PRUint16 ex_type)
{
const TLSExtensionData *xtnData = &ss->xtnData;
return arrayContainsExtension(xtnData->negotiated,
xtnData->numNegotiated, ex_type);
}
/* This checks for whether an extension was advertised. On the client, this
* covers extensions that are sent in ClientHello; on the server, extensions
* sent in CertificateRequest (TLS 1.3 only). */
PRBool
ssl3_ExtensionAdvertised(const sslSocket *ss, PRUint16 ex_type)
{
const TLSExtensionData *xtnData = &ss->xtnData;
return arrayContainsExtension(xtnData->advertised,
xtnData->numAdvertised, ex_type);
}
PRBool
ssl3_ExtensionAdvertisedClientHelloInner(const sslSocket *ss, PRUint16 ex_type)
{
const TLSExtensionData *xtnData = &ss->xtnData;
return arrayContainsExtension(xtnData->echAdvertised,
xtnData->echNumAdvertised, ex_type);
}
/* Go through hello extensions in |b| and deserialize
* them into the list in |ss->ssl3.hs.remoteExtensions|.
* The only checking we do in this point is for duplicates.
*
* IMPORTANT: This list just contains pointers to the incoming
* buffer so they can only be used during ClientHello processing.
*/
SECStatus
ssl3_ParseExtensions(sslSocket *ss, PRUint8 **b, PRUint32 *length)
{
/* Clean out the extensions list. */
ssl3_DestroyRemoteExtensions(&ss->ssl3.hs.remoteExtensions);
while (*length) {
SECStatus rv;
PRUint32 extension_type;
SECItem extension_data = { siBuffer, NULL, 0 };
TLSExtension *extension;
PRCList *cursor;
/* Get the extension's type field */
rv = ssl3_ConsumeHandshakeNumber(ss, &extension_type, 2, b, length);
if (rv != SECSuccess) {
return SECFailure; /* alert already sent */
}
/* Check whether an extension has been sent multiple times. */
for (cursor = PR_NEXT_LINK(&ss->ssl3.hs.remoteExtensions);
cursor != &ss->ssl3.hs.remoteExtensions;
cursor = PR_NEXT_LINK(cursor)) {
if (((TLSExtension *)cursor)->type == extension_type) {
(void)SSL3_SendAlert(ss, alert_fatal, illegal_parameter);
PORT_SetError(SSL_ERROR_RX_UNEXPECTED_EXTENSION);
return SECFailure;
}
}
/* Get the data for this extension, so we can pass it or skip it. */
rv = ssl3_ConsumeHandshakeVariable(ss, &extension_data, 2, b, length);
if (rv != SECSuccess) {
return rv; /* alert already sent */
}
SSL_TRC(10, ("%d: SSL3[%d]: parsed extension %d len=%u",
SSL_GETPID(), ss->fd, extension_type, extension_data.len));
extension = PORT_ZNew(TLSExtension);
if (!extension) {
return SECFailure;
}
extension->type = (PRUint16)extension_type;
extension->data = extension_data;
PR_APPEND_LINK(&extension->link, &ss->ssl3.hs.remoteExtensions);
}
return SECSuccess;
}
TLSExtension *
ssl3_FindExtension(sslSocket *ss, SSLExtensionType extension_type)
{
PRCList *cursor;
for (cursor = PR_NEXT_LINK(&ss->ssl3.hs.remoteExtensions);
cursor != &ss->ssl3.hs.remoteExtensions;
cursor = PR_NEXT_LINK(cursor)) {
TLSExtension *extension = (TLSExtension *)cursor;
if (extension->type == extension_type) {
return extension;
}
}
return NULL;
}
static SECStatus
ssl_CallExtensionHandler(sslSocket *ss, SSLHandshakeType handshakeMessage,
TLSExtension *extension,
const ssl3ExtensionHandler *handler)
{
SECStatus rv = SECSuccess;
SSLAlertDescription alert = handshake_failure;
sslCustomExtensionHooks *customHooks;
customHooks = ssl_FindCustomExtensionHooks(ss, extension->type);
if (customHooks) {
if (customHooks->handler) {
rv = customHooks->handler(ss->fd, handshakeMessage,
extension->data.data,
extension->data.len,
&alert, customHooks->handlerArg);
}
} else {
/* Find extension_type in table of Hello Extension Handlers. */
for (; handler->ex_handler != NULL; ++handler) {
if (handler->ex_type == extension->type) {
SECItem tmp = extension->data;
rv = (*handler->ex_handler)(ss, &ss->xtnData, &tmp);
break;
}
}
}
if (rv != SECSuccess) {
if (!ss->ssl3.fatalAlertSent) {
/* Send an alert if the handler didn't already. */
(void)SSL3_SendAlert(ss, alert_fatal, alert);
}
return SECFailure;
}
return SECSuccess;
}
/* Go through the hello extensions in |ss->ssl3.hs.remoteExtensions|.
* For each one, find the extension handler in the table, and
* if present, invoke that handler.
* Servers ignore any extensions with unknown extension types.
* Clients reject any extensions with unadvertised extension types
*
* In TLS >= 1.3, the client checks that extensions appear in the
* right phase.
*/
SECStatus
ssl3_HandleParsedExtensions(sslSocket *ss, SSLHandshakeType message)
{
const ssl3ExtensionHandler *handlers;
/* HelloRetryRequest doesn't set ss->version. It might be safe to
* do so, but we weren't entirely sure. TODO(ekr@rtfm.com). */
PRBool isTLS13 = (ss->version >= SSL_LIBRARY_VERSION_TLS_1_3) ||
(message == ssl_hs_hello_retry_request);
/* The following messages can include extensions that were not included in
* the original ClientHello. */
PRBool allowNotOffered = (message == ssl_hs_client_hello) ||
(message == ssl_hs_certificate_request) ||
(message == ssl_hs_new_session_ticket);
PRCList *cursor;
switch (message) {
case ssl_hs_client_hello:
handlers = clientHelloHandlers;
break;
case ssl_hs_new_session_ticket:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
handlers = newSessionTicketHandlers;
break;
case ssl_hs_hello_retry_request:
handlers = helloRetryRequestHandlers;
break;
case ssl_hs_encrypted_extensions:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
/* fall through */
case ssl_hs_server_hello:
if (ss->version > SSL_LIBRARY_VERSION_3_0) {
handlers = serverHelloHandlersTLS;
} else {
handlers = serverHelloHandlersSSL3;
}
break;
case ssl_hs_certificate:
PORT_Assert(!ss->sec.isServer);
handlers = serverCertificateHandlers;
break;
case ssl_hs_certificate_request:
PORT_Assert(!ss->sec.isServer);
handlers = certificateRequestHandlers;
break;
default:
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
PORT_Assert(0);
return SECFailure;
}
for (cursor = PR_NEXT_LINK(&ss->ssl3.hs.remoteExtensions);
cursor != &ss->ssl3.hs.remoteExtensions;
cursor = PR_NEXT_LINK(cursor)) {
TLSExtension *extension = (TLSExtension *)cursor;
SECStatus rv;
/* Check whether the server sent an extension which was not advertised
* in the ClientHello.
*
* Note that a TLS 1.3 server should check if CertificateRequest
* extensions were sent. But the extensions used for CertificateRequest
* do not have any response, so we rely on
* ssl3_ExtensionAdvertised to return false on the server. That
* results in the server only rejecting any extension. */
if (!allowNotOffered && (extension->type != ssl_tls13_cookie_xtn)) {
if (!ssl3_ExtensionAdvertised(ss, extension->type)) {
SSL_TRC(10, ("Server sent xtn type=%d which is invalid for the CHO", extension->type));
(void)SSL3_SendAlert(ss, alert_fatal, unsupported_extension);
PORT_SetError(SSL_ERROR_RX_UNEXPECTED_EXTENSION);
return SECFailure;
}
/* If we offered ECH, we also check whether the extension is compatible with
* the Client Hello Inner. We don't yet know whether the server accepted ECH,
* so we only store this for now. If we later accept, we check this boolean
* and reject with an unsupported_extension alert if it is set. */
if (ss->ssl3.hs.echHpkeCtx && !ssl3_ExtensionAdvertisedClientHelloInner(ss, extension->type)) {
SSL_TRC(10, ("Server sent xtn type=%d which is invalid for the CHI", extension->type));
ss->ssl3.hs.echInvalidExtension = PR_TRUE;
}
}
/* Check that this is a legal extension in TLS 1.3 */
if (isTLS13 &&
!ssl_FindCustomExtensionHooks(ss, extension->type)) {
switch (tls13_ExtensionStatus(extension->type, message)) {
case tls13_extension_allowed:
break;
case tls13_extension_unknown:
if (allowNotOffered) {
continue; /* Skip over unknown extensions. */
}
/* RFC8446 Section 4.2 - Implementations MUST NOT send extension responses if
* the remote endpoint did not send the corresponding extension request ...
* Upon receiving such an extension, an endpoint MUST abort the handshake with
* an "unsupported_extension" alert. */
SSL_TRC(3, ("%d: TLS13: unknown extension %d in message %d",
SSL_GETPID(), extension, message));
tls13_FatalError(ss, SSL_ERROR_RX_UNEXPECTED_EXTENSION,
unsupported_extension);
return SECFailure;
case tls13_extension_disallowed:
/* RFC8446 Section 4.2 - If an implementation receives an extension which it
* recognizes and which is not specified for the message in which it appears,
* it MUST abort the handshake with an "illegal_parameter" alert. */
SSL_TRC(3, ("%d: TLS13: disallowed extension %d in message %d",
SSL_GETPID(), extension, message));
tls13_FatalError(ss, SSL_ERROR_EXTENSION_DISALLOWED_FOR_VERSION,
illegal_parameter);
return SECFailure;
}
}
/* Special check for this being the last extension if it's
* PreSharedKey */
if (ss->sec.isServer && isTLS13 &&
(extension->type == ssl_tls13_pre_shared_key_xtn) &&
(PR_NEXT_LINK(cursor) != &ss->ssl3.hs.remoteExtensions)) {
tls13_FatalError(ss,
SSL_ERROR_RX_MALFORMED_CLIENT_HELLO,
illegal_parameter);
return SECFailure;
}
rv = ssl_CallExtensionHandler(ss, message, extension, handlers);
if (rv != SECSuccess) {
return SECFailure;
}
}
return SECSuccess;
}
/* Syntactic sugar around ssl3_ParseExtensions and
* ssl3_HandleParsedExtensions. */
SECStatus
ssl3_HandleExtensions(sslSocket *ss,
PRUint8 **b, PRUint32 *length,
SSLHandshakeType handshakeMessage)
{
SECStatus rv;
rv = ssl3_ParseExtensions(ss, b, length);
if (rv != SECSuccess)
return rv;
rv = ssl3_HandleParsedExtensions(ss, handshakeMessage);
if (rv != SECSuccess)
return rv;
ssl3_DestroyRemoteExtensions(&ss->ssl3.hs.remoteExtensions);
return SECSuccess;
}
/* Add a callback function to the table of senders of server hello extensions.
*/
SECStatus
ssl3_RegisterExtensionSender(const sslSocket *ss,
TLSExtensionData *xtnData,
PRUint16 ex_type,
sslExtensionBuilderFunc cb)
{
int i;
sslExtensionBuilder *sender;
if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
sender = &xtnData->serverHelloSenders[0];
} else {
if (tls13_ExtensionStatus(ex_type, ssl_hs_server_hello) ==
tls13_extension_allowed) {
PORT_Assert(tls13_ExtensionStatus(ex_type,
ssl_hs_encrypted_extensions) ==
tls13_extension_disallowed);
sender = &xtnData->serverHelloSenders[0];
} else if (tls13_ExtensionStatus(ex_type,
ssl_hs_encrypted_extensions) ==
tls13_extension_allowed) {
sender = &xtnData->encryptedExtensionsSenders[0];
} else if (tls13_ExtensionStatus(ex_type, ssl_hs_certificate) ==
tls13_extension_allowed) {
sender = &xtnData->certificateSenders[0];
} else {
PORT_Assert(0);
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
}
for (i = 0; i < SSL_MAX_EXTENSIONS; ++i, ++sender) {
if (!sender->ex_sender) {
sender->ex_type = ex_type;
sender->ex_sender = cb;
return SECSuccess;
}
/* detect duplicate senders */
PORT_Assert(sender->ex_type != ex_type);
if (sender->ex_type == ex_type) {
/* duplicate */
break;
}
}
PORT_Assert(i < SSL_MAX_EXTENSIONS); /* table needs to grow */
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
SECStatus
ssl_CallCustomExtensionSenders(sslSocket *ss, sslBuffer *buf,
SSLHandshakeType message)
{
sslBuffer tail = SSL_BUFFER_EMPTY;
SECStatus rv;
PRCList *cursor;
/* Save any extensions that want to be last. */
if (ss->xtnData.lastXtnOffset) {
rv = sslBuffer_Append(&tail, buf->buf + ss->xtnData.lastXtnOffset,
buf->len - ss->xtnData.lastXtnOffset);
if (rv != SECSuccess) {
return SECFailure;
}
buf->len = ss->xtnData.lastXtnOffset;
}
/* Reserve the maximum amount of space possible. */
rv = sslBuffer_Grow(buf, 65535);
if (rv != SECSuccess) {
return SECFailure;
}
for (cursor = PR_NEXT_LINK(&ss->extensionHooks);
cursor != &ss->extensionHooks;
cursor = PR_NEXT_LINK(cursor)) {
sslCustomExtensionHooks *hook =
(sslCustomExtensionHooks *)cursor;
PRBool append = PR_FALSE;
unsigned int len = 0;
if (hook->writer) {
/* The writer writes directly into |buf|. Provide space that allows
* for the existing extensions, any tail, plus type and length. */
unsigned int space = buf->space - (buf->len + tail.len + 4);
append = (*hook->writer)(ss->fd, message,
buf->buf + buf->len + 4, &len, space,
hook->writerArg);
if (len > space) {
PORT_SetError(SEC_ERROR_APPLICATION_CALLBACK_ERROR);
goto loser;
}
}
if (!append) {
continue;
}
rv = sslBuffer_AppendNumber(buf, hook->type, 2);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
rv = sslBuffer_AppendNumber(buf, len, 2);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
buf->len += len;
if (message == ssl_hs_client_hello ||
message == ssl_hs_ech_outer_client_hello ||
message == ssl_hs_certificate_request) {
ss->xtnData.advertised[ss->xtnData.numAdvertised++] = hook->type;
}
}
/* Restore saved extension and move the marker. */
if (ss->xtnData.lastXtnOffset) {
ss->xtnData.lastXtnOffset = buf->len;
rv = sslBuffer_Append(buf, tail.buf, tail.len);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
}
sslBuffer_Clear(&tail);
return SECSuccess;
loser:
sslBuffer_Clear(&tail);
return SECFailure;
}
/* Call extension handlers for the given message. */
SECStatus
ssl_ConstructExtensions(sslSocket *ss, sslBuffer *buf, SSLHandshakeType message)
{
const sslExtensionBuilder *sender;
SECStatus rv;
PORT_Assert(buf->len == 0);
/* Clear out any extensions previously advertised */
ss->xtnData.numAdvertised = 0;
ss->xtnData.echNumAdvertised = 0;
switch (message) {
case ssl_hs_client_hello:
if (ss->vrange.max > SSL_LIBRARY_VERSION_3_0) {
/* Use TLS ClientHello Extension Permutation? */
if (ss->opt.enableChXtnPermutation) {
sender = ss->ssl3.hs.chExtensionPermutation;
} else {
sender = clientHelloSendersTLS;
}
} else {
sender = clientHelloSendersSSL3;
}
break;
case ssl_hs_server_hello:
sender = ss->xtnData.serverHelloSenders;
break;
case ssl_hs_certificate_request:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
sender = tls13_cert_req_senders;
break;
case ssl_hs_certificate:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
sender = ss->xtnData.certificateSenders;
break;
case ssl_hs_encrypted_extensions:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
sender = ss->xtnData.encryptedExtensionsSenders;
break;
case ssl_hs_hello_retry_request:
PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
sender = tls13_hrr_senders;
break;
default:
PORT_Assert(0);
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
return SECFailure;
}
for (; sender->ex_sender != NULL; ++sender) {
PRUint16 ex_type = sender->ex_type;
PRBool append = PR_FALSE;
unsigned int start = buf->len;
unsigned int length;
if (ssl_FindCustomExtensionHooks(ss, sender->ex_type)) {
continue;
}
/* Save space for the extension type and length. Note that we don't grow
* the buffer now; rely on sslBuffer_Append* to do that. */
buf->len += 4;
rv = (*sender->ex_sender)(ss, &ss->xtnData, buf, &append);
if (rv != SECSuccess) {
goto loser;
}
/* Save the length and go back to the start. */
length = buf->len - start - 4;
buf->len = start;
if (!append) {
continue;
}
/* If TLS 1.3 GREASE is enabled, replace ssl_tls13_grease_xtn dummy
* GREASE extension types with randomly generated GREASE value. */
rv = tls13_MaybeGreaseExtensionType(ss, message, &ex_type);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
rv = sslBuffer_AppendNumber(buf, ex_type, 2);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
rv = sslBuffer_AppendNumber(buf, length, 2);
if (rv != SECSuccess) {
goto loser; /* Code already set. */
}
/* Skip over the extension body. */
buf->len += length;
if (message == ssl_hs_client_hello ||
message == ssl_hs_certificate_request) {
ss->xtnData.advertised[ss->xtnData.numAdvertised++] =
ex_type;
}
}
if (!PR_CLIST_IS_EMPTY(&ss->extensionHooks)) {
if (message == ssl_hs_client_hello && ss->opt.callExtensionWriterOnEchInner) {
message = ssl_hs_ech_outer_client_hello;
}
rv = ssl_CallCustomExtensionSenders(ss, buf, message);
if (rv != SECSuccess) {
goto loser;
}
}
if (buf->len > 0xffff) {
PORT_SetError(SSL_ERROR_TX_RECORD_TOO_LONG);
goto loser;
}
return SECSuccess;
loser:
sslBuffer_Clear(buf);
return SECFailure;
}
/* This extension sender can be used anywhere that an always empty extension is
* needed. Mostly that is for ServerHello where sender registration is dynamic;
* ClientHello senders are usually conditional in some way. */
SECStatus
ssl_SendEmptyExtension(const sslSocket *ss, TLSExtensionData *xtnData,
sslBuffer *buf, PRBool *append)
{
*append = PR_TRUE;
return SECSuccess;
}
/* Takes the size of the ClientHello, less the record header, and determines how
* much padding is required. */
static unsigned int
ssl_CalculatePaddingExtLen(const sslSocket *ss, unsigned int clientHelloLength)
{
unsigned int extensionLen;
/* Don't pad for DTLS, for SSLv3, or for renegotiation. */
if (IS_DTLS(ss) ||
ss->vrange.max < SSL_LIBRARY_VERSION_TLS_1_0 ||
ss->firstHsDone) {
return 0;
}
/* A padding extension may be included to ensure that the record containing
* the ClientHello doesn't have a length between 256 and 511 bytes
* (inclusive). Initial ClientHello records with such lengths trigger bugs
* in F5 devices. */
if (clientHelloLength < 256 || clientHelloLength >= 512) {
return 0;
}
extensionLen = 512 - clientHelloLength;
/* Extensions take at least four bytes to encode. Always include at least
* one byte of data if we are padding. Some servers will time out or
* terminate the connection if the last ClientHello extension is empty. */
if (extensionLen < 5) {
extensionLen = 5;
}
return extensionLen - 4;
}
/* Manually insert an extension, retaining the position of the PSK
* extension, if present. */
SECStatus
ssl3_EmplaceExtension(sslSocket *ss, sslBuffer *buf, PRUint16 exType,
const PRUint8 *data, unsigned int len, PRBool advertise)
{
SECStatus rv;
unsigned int tailLen;
/* Move the tail if there is one. This only happens if we are sending the
* TLS 1.3 PSK extension, which needs to be at the end. */
if (ss->xtnData.lastXtnOffset) {
PORT_Assert(buf->len > ss->xtnData.lastXtnOffset);
tailLen = buf->len - ss->xtnData.lastXtnOffset;
rv = sslBuffer_Grow(buf, buf->len + 4 + len);
if (rv != SECSuccess) {
return SECFailure;
}
PORT_Memmove(buf->buf + ss->xtnData.lastXtnOffset + 4 + len,
buf->buf + ss->xtnData.lastXtnOffset,
tailLen);
buf->len = ss->xtnData.lastXtnOffset;
} else {
tailLen = 0;
}
if (exType == ssl_tls13_encrypted_client_hello_xtn) {
ss->xtnData.echXtnOffset = buf->len;
}
rv = sslBuffer_AppendNumber(buf, exType, 2);
if (rv != SECSuccess) {
return SECFailure; /* Code already set. */
}
rv = sslBuffer_AppendVariable(buf, data, len, 2);
if (rv != SECSuccess) {
return SECFailure; /* Code already set. */
}
if (ss->xtnData.lastXtnOffset) {
ss->xtnData.lastXtnOffset += 4 + len;
}
buf->len += tailLen;
/* False only to retain behavior with padding_xtn. Maybe
* we can just mark that advertised as well? TODO */
if (advertise) {
ss->xtnData.advertised[ss->xtnData.numAdvertised++] = exType;
}
return SECSuccess;
}
/* ssl3_SendPaddingExtension possibly adds an extension which ensures that a
* ClientHello record is either < 256 bytes or is >= 512 bytes. This ensures
* that we don't trigger bugs in F5 products.
*
* This takes an existing extension buffer, |buf|, and the length of the
* remainder of the ClientHello, |prefixLen|. It modifies the extension buffer
* to insert padding at the right place.
*/
SECStatus
ssl_InsertPaddingExtension(sslSocket *ss, unsigned int prefixLen,
sslBuffer *buf)
{
static unsigned char padding[252] = { 0 };
unsigned int paddingLen;
/* Exit early if an application-provided extension hook
* already added padding. */
if (ssl3_ExtensionAdvertised(ss, ssl_padding_xtn)) {
return SECSuccess;
}
/* Account for the size of the header, the length field of the extensions
* block and the size of the existing extensions. */
paddingLen = ssl_CalculatePaddingExtLen(ss, prefixLen + 2 + buf->len);
if (!paddingLen) {
return SECSuccess;
}
return ssl3_EmplaceExtension(ss, buf, ssl_padding_xtn, padding, paddingLen, PR_FALSE);
}
void
ssl3_MoveRemoteExtensions(PRCList *dst, PRCList *src)
{
PRCList *cur_p;
while (!PR_CLIST_IS_EMPTY(src)) {
cur_p = PR_LIST_TAIL(src);
PR_REMOVE_LINK(cur_p);
PR_INSERT_LINK(cur_p, dst);
}
}
void
ssl3_DestroyRemoteExtensions(PRCList *list)
{
PRCList *cur_p;
while (!PR_CLIST_IS_EMPTY(list)) {
cur_p = PR_LIST_TAIL(list);
PR_REMOVE_LINK(cur_p);
PORT_Free(cur_p);
}
}
/* Initialize the extension data block. */
void
ssl3_InitExtensionData(TLSExtensionData *xtnData, const sslSocket *ss)
{
unsigned int advertisedMax;
PRCList *cursor;
/* Set things up to the right starting state. */
PORT_Memset(xtnData, 0, sizeof(*xtnData));
xtnData->peerSupportsFfdheGroups = PR_FALSE;
PR_INIT_CLIST(&xtnData->remoteKeyShares);
/* Allocate enough to allow for native extensions, plus any custom ones. */
if (ss->sec.isServer) {
advertisedMax = PR_MAX(PR_ARRAY_SIZE(certificateRequestHandlers),
PR_ARRAY_SIZE(tls13_cert_req_senders));
} else {
advertisedMax = PR_MAX(PR_ARRAY_SIZE(clientHelloHandlers),
PR_ARRAY_SIZE(clientHelloSendersTLS));
++advertisedMax; /* For the RI SCSV, which we also track. */
}
for (cursor = PR_NEXT_LINK(&ss->extensionHooks);
cursor != &ss->extensionHooks;
cursor = PR_NEXT_LINK(cursor)) {
++advertisedMax;
}
xtnData->advertised = PORT_ZNewArray(PRUint16, advertisedMax);
xtnData->echAdvertised = PORT_ZNewArray(PRUint16, advertisedMax);
xtnData->peerDelegCred = NULL;
xtnData->peerRequestedDelegCred = PR_FALSE;
xtnData->sendingDelegCredToPeer = PR_FALSE;
xtnData->selectedPsk = NULL;
}
void
ssl3_DestroyExtensionData(TLSExtensionData *xtnData)
{
ssl3_FreeSniNameArray(xtnData);
PORT_Free(xtnData->sigSchemes);
PORT_Free(xtnData->delegCredSigSchemes);
PORT_Free(xtnData->delegCredSigSchemesAdvertised);
SECITEM_FreeItem(&xtnData->nextProto, PR_FALSE);
tls13_DestroyKeyShares(&xtnData->remoteKeyShares);
SECITEM_FreeItem(&xtnData->certReqContext, PR_FALSE);
SECITEM_FreeItem(&xtnData->applicationToken, PR_FALSE);
if (xtnData->certReqAuthorities.arena) {
PORT_FreeArena(xtnData->certReqAuthorities.arena, PR_FALSE);
xtnData->certReqAuthorities.arena = NULL;
}
PORT_Free(xtnData->advertised);
PORT_Free(xtnData->echAdvertised);
tls13_DestroyDelegatedCredential(xtnData->peerDelegCred);
tls13_DestroyEchXtnState(xtnData->ech);
xtnData->ech = NULL;
}
/* Free everything that has been allocated and then reset back to
* the starting state. */
void
ssl3_ResetExtensionData(TLSExtensionData *xtnData, const sslSocket *ss)
{
ssl3_DestroyExtensionData(xtnData);
ssl3_InitExtensionData(xtnData, ss);
}
/* Thunks to let extension handlers operate on const sslSocket* objects. */
void
ssl3_ExtSendAlert(const sslSocket *ss, SSL3AlertLevel level,
SSL3AlertDescription desc)
{
(void)SSL3_SendAlert((sslSocket *)ss, level, desc);
}
void
ssl3_ExtDecodeError(const sslSocket *ss)
{
(void)ssl3_DecodeError((sslSocket *)ss);
}
SECStatus
ssl3_ExtConsumeHandshake(const sslSocket *ss, void *v, PRUint32 bytes,
PRUint8 **b, PRUint32 *length)
{
return ssl3_ConsumeHandshake((sslSocket *)ss, v, bytes, b, length);
}
SECStatus
ssl3_ExtConsumeHandshakeNumber(const sslSocket *ss, PRUint32 *num,
PRUint32 bytes, PRUint8 **b, PRUint32 *length)
{
return ssl3_ConsumeHandshakeNumber((sslSocket *)ss, num, bytes, b, length);
}
SECStatus
ssl3_ExtConsumeHandshakeVariable(const sslSocket *ss, SECItem *i,
PRUint32 bytes, PRUint8 **b,
PRUint32 *length)
{
return ssl3_ConsumeHandshakeVariable((sslSocket *)ss, i, bytes, b, length);
}
SECStatus
tls_ClientHelloExtensionPermutationSetup(sslSocket *ss)
{
size_t buildersLen = PR_ARRAY_SIZE(clientHelloSendersTLS);
const size_t buildersSize = (sizeof(sslExtensionBuilder) * buildersLen);
/* Psk Extension and then NULL entry MUST be last. */
const size_t permutationLen = buildersLen - 2;
/* There shouldn't already be a stored permutation. */
PR_ASSERT(!ss->ssl3.hs.chExtensionPermutation);
/* This shuffle handles up to 256 extensions. */
PR_ASSERT(buildersLen < 256);
uint8_t permutation[256] = { 0 };
sslExtensionBuilder *builders = PORT_ZAlloc(buildersSize);
if (!builders) {
return SECFailure;
}
/* Get a working copy of default builders. */
PORT_Memcpy(builders, clientHelloSendersTLS, buildersSize);
/* Get permutation randoms. */
if (PK11_GenerateRandom(permutation, permutationLen) != SECSuccess) {
PORT_Free(builders);
return SECFailure;
}
/* Fisher-Yates Shuffle */
for (size_t i = permutationLen - 1; i > 0; i--) {
size_t idx = permutation[i - 1] % (i + 1);
sslExtensionBuilder tmp = builders[i];
builders[i] = builders[idx];
builders[idx] = tmp;
}
/* Make sure that Psk extension is penultimate (before NULL entry). */
PR_ASSERT(builders[buildersLen - 2].ex_type == ssl_tls13_pre_shared_key_xtn);
PR_ASSERT(builders[buildersLen - 2].ex_sender == clientHelloSendersTLS[buildersLen - 2].ex_sender);
ss->ssl3.hs.chExtensionPermutation = builders;
return SECSuccess;
}
void
tls_ClientHelloExtensionPermutationDestroy(sslSocket *ss)
{
if (ss->ssl3.hs.chExtensionPermutation) {
PORT_Free(ss->ssl3.hs.chExtensionPermutation);
ss->ssl3.hs.chExtensionPermutation = NULL;
}
}
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