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310 lines (256 loc) · 8.35 KB
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#include "SSLCert.hpp"
namespace httpsserver {
SSLCert::SSLCert(unsigned char * certData, uint16_t certLength, unsigned char * pkData, uint16_t pkLength):
_certLength(certLength),
_certData(certData),
_pkLength(pkLength),
_pkData(pkData) {
}
SSLCert::~SSLCert() {
// TODO Auto-generated destructor stub
}
uint16_t SSLCert::getCertLength() {
return _certLength;
}
uint16_t SSLCert::getPKLength() {
return _pkLength;
}
unsigned char * SSLCert::getCertData() {
return _certData;
}
unsigned char * SSLCert::getPKData() {
return _pkData;
}
void SSLCert::setPK(unsigned char * pkData, uint16_t length) {
_pkData = pkData;
_pkLength = length;
}
void SSLCert::setCert(unsigned char * certData, uint16_t length) {
_certData = certData;
_certLength = length;
}
void SSLCert::clear() {
for(uint16_t i = 0; i < _certLength; i++) _certData[i]=0;
delete _certData;
_certLength = 0;
for(uint16_t i = 0; i < _pkLength; i++) _pkData[i] = 0;
delete _pkData;
_pkLength = 0;
}
#ifndef HTTPS_DISABLE_SELFSIGNING
/**
* Function to create the key for a self-signed certificate.
*
* Writes private key as DER in certCtx
*
* Based on programs/pkey/gen_key.c
*/
static int gen_key(SSLCert &certCtx, SSLKeySize keySize) {
// Initialize the entropy source
mbedtls_entropy_context entropy;
mbedtls_entropy_init( &entropy );
// Initialize the RNG
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ctr_drbg_init( &ctr_drbg );
int rngRes = mbedtls_ctr_drbg_seed(
&ctr_drbg, mbedtls_entropy_func, &entropy,
NULL, 0
);
if (rngRes != 0) {
mbedtls_entropy_free( &entropy );
return HTTPS_SERVER_ERROR_KEYGEN_RNG;
}
// Initialize the private key
mbedtls_pk_context key;
mbedtls_pk_init( &key );
int resPkSetup = mbedtls_pk_setup( &key, mbedtls_pk_info_from_type( MBEDTLS_PK_RSA ) );
if ( resPkSetup != 0) {
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
return HTTPS_SERVER_ERROR_KEYGEN_SETUP_PK;
}
// Actual key generation
int resPkGen = mbedtls_rsa_gen_key(
mbedtls_pk_rsa( key ),
mbedtls_ctr_drbg_random,
&ctr_drbg,
keySize,
65537
);
if ( resPkGen != 0) {
mbedtls_pk_free( &key );
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
return HTTPS_SERVER_ERROR_KEYGEN_GEN_PK;
}
// Free the entropy source and the RNG as they are no longer needed
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
// Allocate the space on the heap, as stack size is quite limited
unsigned char * output_buf = new unsigned char[4096];
if (output_buf == NULL) {
mbedtls_pk_free( &key );
return HTTPS_SERVER_ERROR_KEY_OUT_OF_MEM;
}
memset(output_buf, 0, 4096);
// Write the key to the temporary buffer and determine its length
int resPkWrite = mbedtls_pk_write_key_der( &key, output_buf, 4096 );
if (resPkWrite < 0) {
delete[] output_buf;
mbedtls_pk_free( &key );
return HTTPS_SERVER_ERROR_KEY_WRITE_PK;
}
size_t pkLength = resPkWrite;
unsigned char *pkOffset = output_buf + sizeof(unsigned char) * 4096 - pkLength;
// Copy the key into a new, fitting space on the heap
unsigned char * output_pk = new unsigned char[pkLength];
if (output_pk == NULL) {
delete[] output_buf;
mbedtls_pk_free( &key );
return HTTPS_SERVER_ERROR_KEY_WRITE_PK;
}
memcpy(output_pk, pkOffset, pkLength);
// Clean up the temporary buffer and clear the key context
delete[] output_buf;
mbedtls_pk_free( &key );
// Set the private key in the context
certCtx.setPK(output_pk, pkLength);
return 0;
}
/**
* Function to generate the X509 certificate data for a private key
*
* Writes certificate in certCtx
*
* Based on programs/x509/cert_write.c
*/
static int cert_write(SSLCert &certCtx, std::string dn, std::string validityFrom, std::string validityTo) {
int funcRes = 0;
int stepRes = 0;
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_pk_context key;
mbedtls_x509write_cert crt;
mbedtls_mpi serial;
unsigned char * primary_buffer;
unsigned char *certOffset;
unsigned char * output_buffer;
size_t certLength;
// Make a C-friendly version of the distinguished name
char dn_cstr[dn.length()+1];
strcpy(dn_cstr, dn.c_str());
// Initialize the entropy source
mbedtls_entropy_init( &entropy );
// Initialize the RNG
mbedtls_ctr_drbg_init( &ctr_drbg );
stepRes = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, NULL, 0 );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_RNG;
goto error_after_entropy;
}
mbedtls_pk_init( &key );
stepRes = mbedtls_pk_parse_key( &key, certCtx.getPKData(), certCtx.getPKLength(), NULL, 0 );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_READKEY;
goto error_after_key;
}
// Start configuring the certificate
mbedtls_x509write_crt_init( &crt );
// Set version and hash algorithm
mbedtls_x509write_crt_set_version( &crt, MBEDTLS_X509_CRT_VERSION_3 );
mbedtls_x509write_crt_set_md_alg( &crt, MBEDTLS_MD_SHA256 );
// Set the keys (same key as we self-sign)
mbedtls_x509write_crt_set_subject_key( &crt, &key );
mbedtls_x509write_crt_set_issuer_key( &crt, &key );
// Set issuer and subject (same, as we self-sign)
stepRes = mbedtls_x509write_crt_set_subject_name( &crt, dn_cstr );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_NAME;
goto error_after_cert;
}
stepRes = mbedtls_x509write_crt_set_issuer_name( &crt, dn_cstr );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_NAME;
goto error_after_cert;
}
// Set the validity of the certificate. At the moment, it's fixed from 2019 to end of 2029.
stepRes = mbedtls_x509write_crt_set_validity( &crt, validityFrom.c_str(), validityTo.c_str());
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_VALIDITY;
goto error_after_cert;
}
// Make this a CA certificate
stepRes = mbedtls_x509write_crt_set_basic_constraints( &crt, 1, 0 );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_VALIDITY;
goto error_after_cert;
}
// Initialize the serial number
mbedtls_mpi_init( &serial );
stepRes = mbedtls_mpi_read_string( &serial, 10, "1" );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_SERIAL;
goto error_after_cert_serial;
}
stepRes = mbedtls_x509write_crt_set_serial( &crt, &serial );
if (stepRes != 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_SERIAL;
goto error_after_cert_serial;
}
// Create buffer to write the certificate
primary_buffer = new unsigned char[4096];
if (primary_buffer == NULL) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_OUT_OF_MEM;
goto error_after_cert_serial;
}
// Write the actual certificate
stepRes = mbedtls_x509write_crt_der(&crt, primary_buffer, 4096, mbedtls_ctr_drbg_random, &ctr_drbg );
if (stepRes < 0) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_WRITE;
goto error_after_primary_buffer;
}
// Create a matching buffer
certLength = stepRes;
certOffset = primary_buffer + sizeof(unsigned char) * 4096 - certLength;
// Copy the cert into a new, fitting space on the heap
output_buffer = new unsigned char[certLength];
if (output_buffer == NULL) {
funcRes = HTTPS_SERVER_ERROR_CERTGEN_OUT_OF_MEM;
goto error_after_primary_buffer;
}
memcpy(output_buffer, certOffset, certLength);
// Configure the cert in the context
certCtx.setCert(output_buffer, certLength);
// Run through the cleanup process
error_after_primary_buffer:
delete[] primary_buffer;
error_after_cert_serial:
mbedtls_mpi_free( &serial );
error_after_cert:
mbedtls_x509write_crt_free( &crt );
error_after_key:
mbedtls_pk_free(&key);
error_after_entropy:
mbedtls_ctr_drbg_free( &ctr_drbg );
mbedtls_entropy_free( &entropy );
return funcRes;
}
int createSelfSignedCert(SSLCert &certCtx, SSLKeySize keySize, std::string dn, std::string validFrom, std::string validUntil) {
// Add the private key
int keyRes = gen_key(certCtx, keySize);
if (keyRes != 0) {
// Key-generation failed, return the failure code
return keyRes;
}
// Add the self-signed certificate
int certRes = cert_write(certCtx, dn, validFrom, validUntil);
if (certRes != 0) {
// Cert writing failed, reset the pk and return failure code
certCtx.setPK(NULL, 0);
return certRes;
}
// If all went well, return 0
return 0;
}
#endif // !HTTPS_DISABLE_SELFSIGNING
} /* namespace httpsserver */
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