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tls_client_misc.c
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tls_client_misc.c
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/**
* @file tls_client_misc.c
* @brief Helper functions for TLS client
*
* @section License
*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* Copyright (C) 2010-2022 Oryx Embedded SARL. All rights reserved.
*
* This file is part of CycloneSSL Open.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* @author Oryx Embedded SARL (www.oryx-embedded.com)
* @version 2.1.4
**/
//Switch to the appropriate trace level
#define TRACE_LEVEL TLS_TRACE_LEVEL
//Dependencies
#include <string.h>
#include "tls.h"
#include "tls_cipher_suites.h"
#include "tls_client.h"
#include "tls_client_misc.h"
#include "tls_common.h"
#include "tls_extensions.h"
#include "tls_signature.h"
#include "tls_cache.h"
#include "tls_ffdhe.h"
#include "tls_record.h"
#include "tls_misc.h"
#include "debug.h"
//Check TLS library configuration
#if (TLS_SUPPORT == ENABLED && TLS_CLIENT_SUPPORT == ENABLED)
/**
* @brief Format initial ClientHello message
* @param[in] context Pointer to the TLS context
* @return Error code
**/
error_t tlsFormatInitialClientHello(TlsContext *context)
{
error_t error;
size_t length;
TlsRecord *record;
TlsHandshake *message;
//Point to the buffer where to format the TLS record
record = (TlsRecord *) context->txBuffer;
//Point to the buffer where to format the handshake message
message = (TlsHandshake *) record->data;
//Format ClientHello message
error = tlsFormatClientHello(context, (TlsClientHello *) message->data,
&length);
//Check status code
if(!error)
{
//Set the type of the handshake message
message->msgType = TLS_TYPE_CLIENT_HELLO;
//Fix the length of the handshake message
STORE24BE(length, message->length);
//Total length of the handshake message
length += sizeof(TlsHandshake);
//Fix the length of the TLS record
record->length = htons(length);
}
//Return status code
return error;
}
/**
* @brief Format session ID
* @param[in] context Pointer to the TLS context
* @param[in] p Output stream where to write session ID
* @param[out] written Total number of bytes that have been written
* @return Error code
**/
error_t tlsFormatSessionId(TlsContext *context, uint8_t *p,
size_t *written)
{
size_t n;
//TLS 1.3 supported by the client?
if(context->versionMax >= TLS_VERSION_1_3 &&
context->transportProtocol == TLS_TRANSPORT_PROTOCOL_STREAM)
{
//A client which has a cached session ID set by a pre-TLS 1.3 server
//should set this field to that value
osMemcpy(p, context->sessionId, context->sessionIdLen);
n = context->sessionIdLen;
}
else
{
#if (TLS_SESSION_RESUME_SUPPORT == ENABLED)
//The session ID value identifies a session the client wishes to reuse
//for this connection
osMemcpy(p, context->sessionId, context->sessionIdLen);
n = context->sessionIdLen;
#else
//Session resumption is not supported
n = 0;
#endif
}
#if (TLS_SECURE_RENEGOTIATION_SUPPORT == ENABLED)
//Secure renegotiation?
if(context->secureRenegoEnabled && context->secureRenegoFlag)
{
//Do not offer a session ID when renegotiating
n = 0;
}
#endif
//Total number of bytes that have been written
*written = n;
//Successful processing
return NO_ERROR;
}
/**
* @brief Format the list of cipher suites supported by the client
* @param[in] context Pointer to the TLS context
* @param[out] cipherSuiteTypes Types of cipher suites proposed by the client
* @param[in] p Output stream where to write the list of cipher suites
* @param[out] written Total number of bytes that have been written
* @return Error code
**/
error_t tlsFormatCipherSuites(TlsContext *context, uint_t *cipherSuiteTypes,
uint8_t *p, size_t *written)
{
uint_t i;
uint_t j;
uint_t k;
uint_t n;
uint16_t identifier;
TlsCipherSuites *cipherSuites;
//Types of cipher suites proposed by the client
*cipherSuiteTypes = TLS_CIPHER_SUITE_TYPE_UNKNOWN;
//Point to the list of cryptographic algorithms supported by the client
cipherSuites = (TlsCipherSuites *) p;
//Number of cipher suites in the array
n = 0;
//Determine the number of supported cipher suites
k = tlsGetNumSupportedCipherSuites();
//Debug message
TRACE_DEBUG("Cipher suites:\r\n");
//Any preferred cipher suites?
if(context->numCipherSuites > 0)
{
//Loop through the list of preferred cipher suites
for(i = 0; i < context->numCipherSuites; i++)
{
//Loop through the list of supported cipher suites
for(j = 0; j < k; j++)
{
//Retrieve cipher suite identifier
identifier = tlsSupportedCipherSuites[j].identifier;
//Supported cipher suite?
if(identifier == context->cipherSuites[i])
{
//Check whether the cipher suite can be negotiated with the
//current protocol version
if(tlsIsCipherSuiteAcceptable(&tlsSupportedCipherSuites[j],
context->versionMin, context->versionMax,
context->transportProtocol))
{
//Copy cipher suite identifier
cipherSuites->value[n++] = htons(identifier);
//Debug message
TRACE_DEBUG(" 0x%04" PRIX16 " (%s)\r\n", identifier,
tlsGetCipherSuiteName(identifier));
//Check whether the identifier matches an ECC or FFDHE cipher
//suite
*cipherSuiteTypes |= tlsGetCipherSuiteType(identifier);
}
}
}
}
}
else
{
//Loop through the list of supported cipher suites
for(j = 0; j < k; j++)
{
//Retrieve cipher suite identifier
identifier = tlsSupportedCipherSuites[j].identifier;
//Check whether the cipher suite can be negotiated with the
//current protocol version
if(tlsIsCipherSuiteAcceptable(&tlsSupportedCipherSuites[j],
context->versionMin, context->versionMax,
context->transportProtocol))
{
//Copy cipher suite identifier
cipherSuites->value[n++] = htons(identifier);
//Debug message
TRACE_DEBUG(" 0x%04" PRIX16 " (%s)\r\n", identifier,
tlsGetCipherSuiteName(identifier));
//Check whether the identifier matches an ECC or FFDHE cipher
//suite
*cipherSuiteTypes |= tlsGetCipherSuiteType(identifier);
}
}
}
#if (TLS_SECURE_RENEGOTIATION_SUPPORT == ENABLED)
//Check whether secure renegotiation is enabled
if(context->secureRenegoEnabled)
{
//Initial handshake?
if(context->clientVerifyDataLen == 0)
{
//The client includes the TLS_EMPTY_RENEGOTIATION_INFO_SCSV signaling
//cipher suite value in its ClientHello
cipherSuites->value[n++] = HTONS(TLS_EMPTY_RENEGOTIATION_INFO_SCSV);
}
}
#endif
#if (TLS_FALLBACK_SCSV_SUPPORT == ENABLED)
//Check whether support for FALLBACK_SCSV is enabled
if(context->fallbackScsvEnabled)
{
//The TLS_FALLBACK_SCSV cipher suite value is meant for use by clients
//that repeat a connection attempt with a downgraded protocol
if(context->versionMax != TLS_MAX_VERSION)
{
//The client should put TLS_FALLBACK_SCSV after all cipher suites
//that it actually intends to negotiate
cipherSuites->value[n++] = HTONS(TLS_FALLBACK_SCSV);
}
}
#endif
//Length of the array, in bytes
cipherSuites->length = htons(n * 2);
//Total number of bytes that have been written
*written = sizeof(TlsCipherSuites) + n * 2;
//Successful processing
return NO_ERROR;
}
/**
* @brief Format the list of compression methods supported by the client
* @param[in] context Pointer to the TLS context
* @param[in] p Output stream where to write the list of compression methods
* @param[out] written Total number of bytes that have been written
* @return Error code
**/
error_t tlsFormatCompressMethods(TlsContext *context, uint8_t *p,
size_t *written)
{
TlsCompressMethods *compressMethods;
//List of compression algorithms supported by the client
compressMethods = (TlsCompressMethods *) p;
//The CRIME exploit takes advantage of TLS compression, so conservative
//implementations do not enable compression at the TLS level
compressMethods->length = 1;
compressMethods->value[0] = TLS_COMPRESSION_METHOD_NULL;
//Total number of bytes that have been written
*written = sizeof(TlsCompressMethods) + compressMethods->length;
//Successful processing
return NO_ERROR;
}
/**
* @brief Format PSK identity
* @param[in] context Pointer to the TLS context
* @param[in] p Output stream where to write the PSK identity hint
* @param[out] written Total number of bytes that have been written
* @return Error code
**/
error_t tlsFormatPskIdentity(TlsContext *context, uint8_t *p,
size_t *written)
{
size_t n;
TlsPskIdentity *pskIdentity;
//Point to the PSK identity
pskIdentity = (TlsPskIdentity *) p;
#if (TLS_PSK_KE_SUPPORT == ENABLED || TLS_RSA_PSK_KE_SUPPORT == ENABLED || \
TLS_DHE_PSK_KE_SUPPORT == ENABLED || TLS_ECDHE_PSK_KE_SUPPORT == ENABLED)
//Any PSK identity defined?
if(context->pskIdentity != NULL)
{
//Determine the length of the PSK identity
n = osStrlen(context->pskIdentity);
//Copy PSK identity
osMemcpy(pskIdentity->value, context->pskIdentity, n);
}
else
#endif
{
//No PSK identity is provided
n = 0;
}
//The PSK identity is preceded by a 2-byte length field
pskIdentity->length = htons(n);
//Total number of bytes that have been written
*written = sizeof(TlsPskIdentity) + n;
//Successful processing
return NO_ERROR;
}
/**
* @brief Format client's key exchange parameters
* @param[in] context Pointer to the TLS context
* @param[in] p Output stream where to write the client's key exchange parameters
* @param[out] written Total number of bytes that have been written
* @return Error code
**/
error_t tlsFormatClientKeyParams(TlsContext *context, uint8_t *p,
size_t *written)
{
#if (TLS_MAX_VERSION >= TLS_VERSION_1_0 && TLS_MIN_VERSION <= TLS_VERSION_1_2)
error_t error;
size_t n;
#if (TLS_RSA_KE_SUPPORT == ENABLED || TLS_RSA_PSK_KE_SUPPORT == ENABLED)
//RSA key exchange method?
if(context->keyExchMethod == TLS_KEY_EXCH_RSA ||
context->keyExchMethod == TLS_KEY_EXCH_RSA_PSK)
{
//Sanity check
if(TLS_PREMASTER_SECRET_SIZE < 48)
return ERROR_BUFFER_OVERFLOW;
//If RSA is being used for key agreement and authentication, the
//client generates a 48-byte premaster secret
context->premasterSecretLen = 48;
//The first 2 bytes code the latest version supported by the client
STORE16BE(context->clientVersion, context->premasterSecret);
//The last 46 bytes contain securely-generated random bytes
error = context->prngAlgo->read(context->prngContext,
context->premasterSecret + 2, 46);
//Any error to report?
if(error)
return error;
//Encrypt the premaster secret using the server public key
error = rsaesPkcs1v15Encrypt(context->prngAlgo, context->prngContext,
&context->peerRsaPublicKey, context->premasterSecret, 48, p + 2, &n);
//RSA encryption failed?
if(error)
return error;
//The RSA-encrypted premaster secret in a ClientKeyExchange is preceded by
//two length bytes
STORE16BE(n, p);
//Total number of bytes that have been written
*written = n + 2;
}
else
#endif
#if (TLS_DH_ANON_KE_SUPPORT == ENABLED || TLS_DHE_RSA_KE_SUPPORT == ENABLED || \
TLS_DHE_DSS_KE_SUPPORT == ENABLED || TLS_DHE_PSK_KE_SUPPORT == ENABLED)
//Diffie-Hellman key exchange method?
if(context->keyExchMethod == TLS_KEY_EXCH_DH_ANON ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_RSA ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_DSS ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_PSK)
{
//Generate an ephemeral key pair
error = dhGenerateKeyPair(&context->dhContext,
context->prngAlgo, context->prngContext);
//Any error to report?
if(error)
return error;
//Encode the client's public value to an opaque vector
error = tlsWriteMpi(&context->dhContext.ya, p, &n);
//Any error to report?
if(error)
return error;
//Total number of bytes that have been written
*written = n;
//Calculate the negotiated key Z
error = dhComputeSharedSecret(&context->dhContext,
context->premasterSecret, TLS_PREMASTER_SECRET_SIZE,
&context->premasterSecretLen);
//Any error to report?
if(error)
return error;
//Leading bytes of Z that contain all zero bits are stripped before
//it is used as the premaster secret (RFC 4346, section 8.2.1)
for(n = 0; n < context->premasterSecretLen; n++)
{
if(context->premasterSecret[n] != 0x00)
break;
}
//Any leading zero bytes?
if(n > 0)
{
//Strip leading zero bytes from the negotiated key
osMemmove(context->premasterSecret, context->premasterSecret + n,
context->premasterSecretLen - n);
//Adjust the length of the premaster secret
context->premasterSecretLen -= n;
}
}
else
#endif
#if (TLS_ECDH_ANON_KE_SUPPORT == ENABLED || TLS_ECDHE_RSA_KE_SUPPORT == ENABLED || \
TLS_ECDHE_ECDSA_KE_SUPPORT == ENABLED || TLS_ECDHE_PSK_KE_SUPPORT == ENABLED)
//ECDH key exchange method?
if(context->keyExchMethod == TLS_KEY_EXCH_ECDH_ANON ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_RSA ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_ECDSA ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_PSK)
{
#if (TLS_ECC_CALLBACK_SUPPORT == ENABLED)
//Any registered callback?
if(context->ecdhCallback != NULL)
{
//Invoke user callback function
error = context->ecdhCallback(context);
}
else
#endif
{
//No callback function defined
error = ERROR_UNSUPPORTED_ELLIPTIC_CURVE;
}
//Check status code
if(error == ERROR_UNSUPPORTED_ELLIPTIC_CURVE)
{
//Generate an ephemeral key pair
error = ecdhGenerateKeyPair(&context->ecdhContext,
context->prngAlgo, context->prngContext);
//Any error to report?
if(error)
return error;
//Calculate the negotiated key Z
error = ecdhComputeSharedSecret(&context->ecdhContext,
context->premasterSecret, TLS_PREMASTER_SECRET_SIZE,
&context->premasterSecretLen);
//Any error to report?
if(error)
return error;
}
else if(error != NO_ERROR)
{
//Report an error
return error;
}
//Encode the client's public key to an opaque vector
error = tlsWriteEcPoint(&context->ecdhContext.params,
&context->ecdhContext.qa.q, p, &n);
//Any error to report?
if(error)
return error;
//Total number of bytes that have been written
*written = n;
}
else
#endif
//Invalid key exchange method?
{
//Just for sanity
(void) error;
(void) n;
//The specified key exchange method is not supported
return ERROR_UNSUPPORTED_KEY_EXCH_ALGO;
}
//Successful processing
return NO_ERROR;
#else
//Not implemented
return ERROR_NOT_IMPLEMENTED;
#endif
}
/**
* @brief Parse PSK identity hint
* @param[in] context Pointer to the TLS context
* @param[in] p Input stream where to read the PSK identity hint
* @param[in] length Number of bytes available in the input stream
* @param[out] consumed Total number of bytes that have been consumed
* @return Error code
**/
error_t tlsParsePskIdentityHint(TlsContext *context, const uint8_t *p,
size_t length, size_t *consumed)
{
size_t n;
TlsPskIdentityHint *pskIdentityHint;
//Point to the PSK identity hint
pskIdentityHint = (TlsPskIdentityHint *) p;
//Malformed ServerKeyExchange message?
if(length < sizeof(TlsPskIdentityHint))
return ERROR_DECODING_FAILED;
if(length < (sizeof(TlsPskIdentityHint) + ntohs(pskIdentityHint->length)))
return ERROR_DECODING_FAILED;
//Retrieve the length of the PSK identity hint
n = ntohs(pskIdentityHint->length);
#if (TLS_PSK_KE_SUPPORT == ENABLED || TLS_RSA_PSK_KE_SUPPORT == ENABLED || \
TLS_DHE_PSK_KE_SUPPORT == ENABLED || TLS_ECDHE_PSK_KE_SUPPORT == ENABLED)
//Any registered callback?
if(context->pskCallback != NULL)
{
error_t error;
//The client selects which identity to use depending on the PSK identity
//hint provided by the server
error = context->pskCallback(context, pskIdentityHint->value, n);
//Any error to report?
if(error)
return ERROR_UNKNOWN_IDENTITY;
}
#endif
//Total number of bytes that have been consumed
*consumed = sizeof(TlsPskIdentityHint) + n;
//Successful processing
return NO_ERROR;
}
/**
* @brief Parse server's key exchange parameters
* @param[in] context Pointer to the TLS context
* @param[in] p Input stream where to read the server's key exchange parameters
* @param[in] length Number of bytes available in the input stream
* @param[out] consumed Total number of bytes that have been consumed
* @return Error code
**/
error_t tlsParseServerKeyParams(TlsContext *context, const uint8_t *p,
size_t length, size_t *consumed)
{
#if (TLS_MAX_VERSION >= TLS_VERSION_1_0 && TLS_MIN_VERSION <= TLS_VERSION_1_2)
error_t error;
const uint8_t *params;
//Initialize status code
error = NO_ERROR;
//Point to the server's key exchange parameters
params = p;
#if (TLS_DH_ANON_KE_SUPPORT == ENABLED || TLS_DHE_RSA_KE_SUPPORT == ENABLED || \
TLS_DHE_DSS_KE_SUPPORT == ENABLED || TLS_DHE_PSK_KE_SUPPORT == ENABLED)
//Diffie-Hellman key exchange method?
if(context->keyExchMethod == TLS_KEY_EXCH_DH_ANON ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_RSA ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_DSS ||
context->keyExchMethod == TLS_KEY_EXCH_DHE_PSK)
{
uint_t k;
size_t n;
//Convert the prime modulus to a multiple precision integer
error = tlsReadMpi(&context->dhContext.params.p, p, length, &n);
//Check status code
if(!error)
{
//Get the length of the prime modulus, in bits
k = mpiGetBitLength(&context->dhContext.params.p);
//Make sure the prime modulus is acceptable
if(k < TLS_MIN_DH_MODULUS_SIZE || k > TLS_MAX_DH_MODULUS_SIZE)
error = ERROR_ILLEGAL_PARAMETER;
}
//Check status code
if(!error)
{
//Advance data pointer
p += n;
//Remaining bytes to process
length -= n;
//Convert the generator to a multiple precision integer
error = tlsReadMpi(&context->dhContext.params.g, p, length, &n);
}
//Check status code
if(!error)
{
//Advance data pointer
p += n;
//Remaining bytes to process
length -= n;
//Convert the server's public value to a multiple precision integer
error = tlsReadMpi(&context->dhContext.yb, p, length, &n);
}
//Check status code
if(!error)
{
//Advance data pointer
p += n;
//Remaining bytes to process
length -= n;
//Verify peer's public value
error = dhCheckPublicKey(&context->dhContext.params,
&context->dhContext.yb);
}
//Check status code
if(!error)
{
//Debug message
TRACE_DEBUG("Diffie-Hellman parameters:\r\n");
TRACE_DEBUG(" Prime modulus:\r\n");
TRACE_DEBUG_MPI(" ", &context->dhContext.params.p);
TRACE_DEBUG(" Generator:\r\n");
TRACE_DEBUG_MPI(" ", &context->dhContext.params.g);
TRACE_DEBUG(" Server public value:\r\n");
TRACE_DEBUG_MPI(" ", &context->dhContext.yb);
}
}
else
#endif
#if (TLS_ECDH_ANON_KE_SUPPORT == ENABLED || TLS_ECDHE_RSA_KE_SUPPORT == ENABLED || \
TLS_ECDHE_ECDSA_KE_SUPPORT == ENABLED || TLS_ECDHE_PSK_KE_SUPPORT == ENABLED)
//ECDH key exchange method?
if(context->keyExchMethod == TLS_KEY_EXCH_ECDH_ANON ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_RSA ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_ECDSA ||
context->keyExchMethod == TLS_KEY_EXCH_ECDHE_PSK)
{
size_t n;
uint8_t curveType;
const EcCurveInfo *curveInfo;
//Initialize curve parameters
curveInfo = NULL;
//Malformed ServerKeyExchange message?
if(length < sizeof(curveType))
error = ERROR_DECODING_FAILED;
//Check status code
if(!error)
{
//Retrieve the type of the elliptic curve domain parameters
curveType = *p;
//Advance data pointer
p += sizeof(curveType);
//Remaining bytes to process
length -= sizeof(curveType);
//Only named curves are supported
if(curveType != TLS_EC_CURVE_TYPE_NAMED_CURVE)
error = ERROR_ILLEGAL_PARAMETER;
}
//Check status code
if(!error)
{
//Malformed ServerKeyExchange message?
if(length < sizeof(uint16_t))
error = ERROR_DECODING_FAILED;
}
//Check status code
if(!error)
{
//Get elliptic curve identifier
context->namedGroup = LOAD16BE(p);
//Advance data pointer
p += sizeof(uint16_t);
//Remaining bytes to process
length -= sizeof(uint16_t);
//Retrieve the corresponding EC domain parameters
curveInfo = tlsGetCurveInfo(context, context->namedGroup);
//Make sure the elliptic curve is supported
if(curveInfo == NULL)
{
//The elliptic curve is not supported
error = ERROR_ILLEGAL_PARAMETER;
}
}
//Check status code
if(!error)
{
//Load EC domain parameters
error = ecLoadDomainParameters(&context->ecdhContext.params,
curveInfo);
}
//Check status code
if(!error)
{
//Read server's public key
error = tlsReadEcPoint(&context->ecdhContext.params,
&context->ecdhContext.qb.q, p, length, &n);
}
//Check status code
if(!error)
{
//Advance data pointer
p += n;
//Remaining bytes to process
length -= n;
//Verify peer's public key
error = ecdhCheckPublicKey(&context->ecdhContext.params,
&context->ecdhContext.qb.q);
}
//Check status code
if(!error)
{
//Debug message
TRACE_DEBUG(" Server public key X:\r\n");
TRACE_DEBUG_MPI(" ", &context->ecdhContext.qb.q.x);
TRACE_DEBUG(" Server public key Y:\r\n");
TRACE_DEBUG_MPI(" ", &context->ecdhContext.qb.q.y);
}
}
else
#endif
//Invalid key exchange method?
{
//It is not legal to send the ServerKeyExchange message when a key
//exchange method other than DHE_DSS, DHE_RSA, DH_anon, ECDHE_RSA,
//ECDHE_ECDSA or ECDH_anon is selected
error = ERROR_UNEXPECTED_MESSAGE;
}
//Total number of bytes that have been consumed
*consumed = p - params;
//Return status code
return error;
#else
//Not implemented
return ERROR_NOT_IMPLEMENTED;
#endif
}
/**
* @brief Verify server's key exchange parameters signature (TLS 1.0 and TLS 1.1)
* @param[in] context Pointer to the TLS context
* @param[in] signature Pointer to the digital signature
* @param[in] length Number of bytes available in the input stream
* @param[in] params Pointer to the server's key exchange parameters
* @param[in] paramsLen Length of the server's key exchange parameters
* @param[out] consumed Total number of bytes that have been consumed
* @return Error code
**/
error_t tlsVerifyServerKeySignature(TlsContext *context,
const TlsDigitalSignature *signature, size_t length,
const uint8_t *params, size_t paramsLen, size_t *consumed)
{
error_t error;
#if (TLS_MAX_VERSION >= TLS_VERSION_1_0 && TLS_MIN_VERSION <= TLS_VERSION_1_1)
//Initialize status code
error = NO_ERROR;
//Check the length of the digitally-signed element
if(length < sizeof(TlsDigitalSignature))
return ERROR_DECODING_FAILED;
if(length < (sizeof(TlsDigitalSignature) + ntohs(signature->length)))
return ERROR_DECODING_FAILED;
#if (TLS_RSA_SIGN_SUPPORT == ENABLED)
//RSA signature algorithm?
if(context->peerCertType == TLS_CERT_RSA_SIGN)
{
Md5Context *md5Context;
Sha1Context *sha1Context;
//Allocate a memory buffer to hold the MD5 context
md5Context = tlsAllocMem(sizeof(Md5Context));
//Successful memory allocation?
if(md5Context != NULL)
{
//Compute MD5(ClientHello.random + ServerHello.random +
//ServerKeyExchange.params)
md5Init(md5Context);
md5Update(md5Context, context->clientRandom, TLS_RANDOM_SIZE);
md5Update(md5Context, context->serverRandom, TLS_RANDOM_SIZE);
md5Update(md5Context, params, paramsLen);
md5Final(md5Context, context->serverVerifyData);
//Release previously allocated memory
tlsFreeMem(md5Context);
}
else
{
//Failed to allocate memory
error = ERROR_OUT_OF_MEMORY;
}
//Check status code
if(!error)
{
//Allocate a memory buffer to hold the SHA-1 context
sha1Context = tlsAllocMem(sizeof(Sha1Context));
//Successful memory allocation?
if(sha1Context != NULL)
{
//Compute SHA(ClientHello.random + ServerHello.random +
//ServerKeyExchange.params)
sha1Init(sha1Context);
sha1Update(sha1Context, context->clientRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, context->serverRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, params, paramsLen);
sha1Final(sha1Context, context->serverVerifyData + MD5_DIGEST_SIZE);
//Release previously allocated memory
tlsFreeMem(sha1Context);
}
else
{
//Failed to allocate memory
error = ERROR_OUT_OF_MEMORY;
}
}
//Check status code
if(!error)
{
//RSA signature verification
error = tlsVerifyRsaSignature(&context->peerRsaPublicKey,
context->serverVerifyData, signature->value, ntohs(signature->length));
}
}
else
#endif
#if (TLS_DSA_SIGN_SUPPORT == ENABLED)
//DSA signature algorithm?
if(context->peerCertType == TLS_CERT_DSS_SIGN)
{
Sha1Context *sha1Context;
//Allocate a memory buffer to hold the SHA-1 context
sha1Context = tlsAllocMem(sizeof(Sha1Context));
//Successful memory allocation?
if(sha1Context != NULL)
{
//Compute SHA(ClientHello.random + ServerHello.random +
//ServerKeyExchange.params)
sha1Init(sha1Context);
sha1Update(sha1Context, context->clientRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, context->serverRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, params, paramsLen);
sha1Final(sha1Context, context->serverVerifyData);
//Release previously allocated memory
tlsFreeMem(sha1Context);
}
else
{
//Failed to allocate memory
error = ERROR_OUT_OF_MEMORY;
}
//Check status code
if(!error)
{
//DSA signature verification
error = tlsVerifyDsaSignature(context, context->serverVerifyData,
SHA1_DIGEST_SIZE, signature->value, ntohs(signature->length));
}
}
else
#endif
#if (TLS_ECDSA_SIGN_SUPPORT == ENABLED)
//ECDSA signature algorithm?
if(context->peerCertType == TLS_CERT_ECDSA_SIGN)
{
Sha1Context *sha1Context;
//Allocate a memory buffer to hold the SHA-1 context
sha1Context = tlsAllocMem(sizeof(Sha1Context));
//Successful memory allocation?
if(sha1Context != NULL)
{
//Compute SHA(ClientHello.random + ServerHello.random +
//ServerKeyExchange.params)
sha1Init(sha1Context);
sha1Update(sha1Context, context->clientRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, context->serverRandom, TLS_RANDOM_SIZE);
sha1Update(sha1Context, params, paramsLen);
sha1Final(sha1Context, context->serverVerifyData);
//Release previously allocated memory
tlsFreeMem(sha1Context);
}
//Check status code
if(!error)
{
//ECDSA signature verification
error = tlsVerifyEcdsaSignature(context, context->serverVerifyData,
SHA1_DIGEST_SIZE, signature->value, ntohs(signature->length));
}
}
else
#endif
//Invalid signature algorithm?
{
//Report an error
error = ERROR_INVALID_SIGNATURE;
}
//Total number of bytes that have been consumed
*consumed = sizeof(TlsDigitalSignature) + ntohs(signature->length);
#else
//Not implemented
error = ERROR_NOT_IMPLEMENTED;
#endif
//Return status code
return error;
}