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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/rtc_base/opensslidentity.h"
#include <memory>
// Must be included first before openssl headers.
#include "webrtc/rtc_base/win32.h" // NOLINT
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/crypto.h>
#include "webrtc/rtc_base/checks.h"
#include "webrtc/rtc_base/helpers.h"
#include "webrtc/rtc_base/logging.h"
#include "webrtc/rtc_base/openssl.h"
#include "webrtc/rtc_base/openssldigest.h"
namespace rtc {
// We could have exposed a myriad of parameters for the crypto stuff,
// but keeping it simple seems best.
// Random bits for certificate serial number
static const int SERIAL_RAND_BITS = 64;
// Generate a key pair. Caller is responsible for freeing the returned object.
static EVP_PKEY* MakeKey(const KeyParams& key_params) {
LOG(LS_INFO) << "Making key pair";
EVP_PKEY* pkey = EVP_PKEY_new();
if (key_params.type() == KT_RSA) {
int key_length = key_params.rsa_params().mod_size;
BIGNUM* exponent = BN_new();
RSA* rsa = RSA_new();
if (!pkey || !exponent || !rsa ||
!BN_set_word(exponent, key_params.rsa_params().pub_exp) ||
!RSA_generate_key_ex(rsa, key_length, exponent, nullptr) ||
!EVP_PKEY_assign_RSA(pkey, rsa)) {
EVP_PKEY_free(pkey);
BN_free(exponent);
RSA_free(rsa);
LOG(LS_ERROR) << "Failed to make RSA key pair";
return nullptr;
}
// ownership of rsa struct was assigned, don't free it.
BN_free(exponent);
} else if (key_params.type() == KT_ECDSA) {
if (key_params.ec_curve() == EC_NIST_P256) {
EC_KEY* ec_key = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
// Ensure curve name is included when EC key is serialized.
// Without this call, OpenSSL versions before 1.1.0 will create
// certificates that don't work for TLS.
// This is a no-op for BoringSSL and OpenSSL 1.1.0+
EC_KEY_set_asn1_flag(ec_key, OPENSSL_EC_NAMED_CURVE);
if (!pkey || !ec_key || !EC_KEY_generate_key(ec_key) ||
!EVP_PKEY_assign_EC_KEY(pkey, ec_key)) {
EVP_PKEY_free(pkey);
EC_KEY_free(ec_key);
LOG(LS_ERROR) << "Failed to make EC key pair";
return nullptr;
}
// ownership of ec_key struct was assigned, don't free it.
} else {
// Add generation of any other curves here.
EVP_PKEY_free(pkey);
LOG(LS_ERROR) << "ECDSA key requested for unknown curve";
return nullptr;
}
} else {
EVP_PKEY_free(pkey);
LOG(LS_ERROR) << "Key type requested not understood";
return nullptr;
}
LOG(LS_INFO) << "Returning key pair";
return pkey;
}
// Generate a self-signed certificate, with the public key from the
// given key pair. Caller is responsible for freeing the returned object.
static X509* MakeCertificate(EVP_PKEY* pkey, const SSLIdentityParams& params) {
LOG(LS_INFO) << "Making certificate for " << params.common_name;
X509* x509 = nullptr;
BIGNUM* serial_number = nullptr;
X509_NAME* name = nullptr;
time_t epoch_off = 0; // Time offset since epoch.
if ((x509 = X509_new()) == nullptr)
goto error;
if (!X509_set_pubkey(x509, pkey))
goto error;
// serial number
// temporary reference to serial number inside x509 struct
ASN1_INTEGER* asn1_serial_number;
if ((serial_number = BN_new()) == nullptr ||
!BN_pseudo_rand(serial_number, SERIAL_RAND_BITS, 0, 0) ||
(asn1_serial_number = X509_get_serialNumber(x509)) == nullptr ||
!BN_to_ASN1_INTEGER(serial_number, asn1_serial_number))
goto error;
if (!X509_set_version(x509, 2L)) // version 3
goto error;
// There are a lot of possible components for the name entries. In
// our P2P SSL mode however, the certificates are pre-exchanged
// (through the secure XMPP channel), and so the certificate
// identification is arbitrary. It can't be empty, so we set some
// arbitrary common_name. Note that this certificate goes out in
// clear during SSL negotiation, so there may be a privacy issue in
// putting anything recognizable here.
if ((name = X509_NAME_new()) == nullptr ||
!X509_NAME_add_entry_by_NID(name, NID_commonName, MBSTRING_UTF8,
(unsigned char*)params.common_name.c_str(),
-1, -1, 0) ||
!X509_set_subject_name(x509, name) || !X509_set_issuer_name(x509, name))
goto error;
if (!X509_time_adj(X509_get_notBefore(x509), params.not_before, &epoch_off) ||
!X509_time_adj(X509_get_notAfter(x509), params.not_after, &epoch_off))
goto error;
if (!X509_sign(x509, pkey, EVP_sha256()))
goto error;
BN_free(serial_number);
X509_NAME_free(name);
LOG(LS_INFO) << "Returning certificate";
return x509;
error:
BN_free(serial_number);
X509_NAME_free(name);
X509_free(x509);
return nullptr;
}
// This dumps the SSL error stack to the log.
static void LogSSLErrors(const std::string& prefix) {
char error_buf[200];
unsigned long err;
while ((err = ERR_get_error()) != 0) {
ERR_error_string_n(err, error_buf, sizeof(error_buf));
LOG(LS_ERROR) << prefix << ": " << error_buf << "\n";
}
}
OpenSSLKeyPair* OpenSSLKeyPair::Generate(const KeyParams& key_params) {
EVP_PKEY* pkey = MakeKey(key_params);
if (!pkey) {
LogSSLErrors("Generating key pair");
return nullptr;
}
return new OpenSSLKeyPair(pkey);
}
OpenSSLKeyPair* OpenSSLKeyPair::FromPrivateKeyPEMString(
const std::string& pem_string) {
BIO* bio = BIO_new_mem_buf(const_cast<char*>(pem_string.c_str()), -1);
if (!bio) {
LOG(LS_ERROR) << "Failed to create a new BIO buffer.";
return nullptr;
}
BIO_set_mem_eof_return(bio, 0);
EVP_PKEY* pkey =
PEM_read_bio_PrivateKey(bio, nullptr, nullptr, const_cast<char*>("\0"));
BIO_free(bio); // Frees the BIO, but not the pointed-to string.
if (!pkey) {
LOG(LS_ERROR) << "Failed to create the private key from PEM string.";
return nullptr;
}
if (EVP_PKEY_missing_parameters(pkey) != 0) {
LOG(LS_ERROR) << "The resulting key pair is missing public key parameters.";
EVP_PKEY_free(pkey);
return nullptr;
}
return new OpenSSLKeyPair(pkey);
}
OpenSSLKeyPair::~OpenSSLKeyPair() {
EVP_PKEY_free(pkey_);
}
OpenSSLKeyPair* OpenSSLKeyPair::GetReference() {
AddReference();
return new OpenSSLKeyPair(pkey_);
}
void OpenSSLKeyPair::AddReference() {
#if defined(OPENSSL_IS_BORINGSSL)
EVP_PKEY_up_ref(pkey_);
#else
CRYPTO_add(&pkey_->references, 1, CRYPTO_LOCK_EVP_PKEY);
#endif
}
std::string OpenSSLKeyPair::PrivateKeyToPEMString() const {
BIO* temp_memory_bio = BIO_new(BIO_s_mem());
if (!temp_memory_bio) {
LOG_F(LS_ERROR) << "Failed to allocate temporary memory bio";
RTC_NOTREACHED();
return "";
}
if (!PEM_write_bio_PrivateKey(
temp_memory_bio, pkey_, nullptr, nullptr, 0, nullptr, nullptr)) {
LOG_F(LS_ERROR) << "Failed to write private key";
BIO_free(temp_memory_bio);
RTC_NOTREACHED();
return "";
}
BIO_write(temp_memory_bio, "\0", 1);
char* buffer;
BIO_get_mem_data(temp_memory_bio, &buffer);
std::string priv_key_str = buffer;
BIO_free(temp_memory_bio);
return priv_key_str;
}
std::string OpenSSLKeyPair::PublicKeyToPEMString() const {
BIO* temp_memory_bio = BIO_new(BIO_s_mem());
if (!temp_memory_bio) {
LOG_F(LS_ERROR) << "Failed to allocate temporary memory bio";
RTC_NOTREACHED();
return "";
}
if (!PEM_write_bio_PUBKEY(temp_memory_bio, pkey_)) {
LOG_F(LS_ERROR) << "Failed to write public key";
BIO_free(temp_memory_bio);
RTC_NOTREACHED();
return "";
}
BIO_write(temp_memory_bio, "\0", 1);
char* buffer;
BIO_get_mem_data(temp_memory_bio, &buffer);
std::string pub_key_str = buffer;
BIO_free(temp_memory_bio);
return pub_key_str;
}
bool OpenSSLKeyPair::operator==(const OpenSSLKeyPair& other) const {
return EVP_PKEY_cmp(this->pkey_, other.pkey_) == 1;
}
bool OpenSSLKeyPair::operator!=(const OpenSSLKeyPair& other) const {
return !(*this == other);
}
#if !defined(NDEBUG)
// Print a certificate to the log, for debugging.
static void PrintCert(X509* x509) {
BIO* temp_memory_bio = BIO_new(BIO_s_mem());
if (!temp_memory_bio) {
LOG_F(LS_ERROR) << "Failed to allocate temporary memory bio";
return;
}
X509_print_ex(temp_memory_bio, x509, XN_FLAG_SEP_CPLUS_SPC, 0);
BIO_write(temp_memory_bio, "\0", 1);
char* buffer;
BIO_get_mem_data(temp_memory_bio, &buffer);
LOG(LS_VERBOSE) << buffer;
BIO_free(temp_memory_bio);
}
#endif
OpenSSLCertificate* OpenSSLCertificate::Generate(
OpenSSLKeyPair* key_pair, const SSLIdentityParams& params) {
SSLIdentityParams actual_params(params);
if (actual_params.common_name.empty()) {
// Use a random string, arbitrarily 8chars long.
actual_params.common_name = CreateRandomString(8);
}
X509* x509 = MakeCertificate(key_pair->pkey(), actual_params);
if (!x509) {
LogSSLErrors("Generating certificate");
return nullptr;
}
#if !defined(NDEBUG)
PrintCert(x509);
#endif
OpenSSLCertificate* ret = new OpenSSLCertificate(x509);
X509_free(x509);
return ret;
}
OpenSSLCertificate* OpenSSLCertificate::FromPEMString(
const std::string& pem_string) {
BIO* bio = BIO_new_mem_buf(const_cast<char*>(pem_string.c_str()), -1);
if (!bio)
return nullptr;
BIO_set_mem_eof_return(bio, 0);
X509* x509 =
PEM_read_bio_X509(bio, nullptr, nullptr, const_cast<char*>("\0"));
BIO_free(bio); // Frees the BIO, but not the pointed-to string.
if (!x509)
return nullptr;
OpenSSLCertificate* ret = new OpenSSLCertificate(x509);
X509_free(x509);
return ret;
}
// NOTE: This implementation only functions correctly after InitializeSSL
// and before CleanupSSL.
bool OpenSSLCertificate::GetSignatureDigestAlgorithm(
std::string* algorithm) const {
int nid = OBJ_obj2nid(x509_->sig_alg->algorithm);
switch (nid) {
case NID_md5WithRSA:
case NID_md5WithRSAEncryption:
*algorithm = DIGEST_MD5;
break;
case NID_ecdsa_with_SHA1:
case NID_dsaWithSHA1:
case NID_dsaWithSHA1_2:
case NID_sha1WithRSA:
case NID_sha1WithRSAEncryption:
*algorithm = DIGEST_SHA_1;
break;
case NID_ecdsa_with_SHA224:
case NID_sha224WithRSAEncryption:
case NID_dsa_with_SHA224:
*algorithm = DIGEST_SHA_224;
break;
case NID_ecdsa_with_SHA256:
case NID_sha256WithRSAEncryption:
case NID_dsa_with_SHA256:
*algorithm = DIGEST_SHA_256;
break;
case NID_ecdsa_with_SHA384:
case NID_sha384WithRSAEncryption:
*algorithm = DIGEST_SHA_384;
break;
case NID_ecdsa_with_SHA512:
case NID_sha512WithRSAEncryption:
*algorithm = DIGEST_SHA_512;
break;
default:
// Unknown algorithm. There are several unhandled options that are less
// common and more complex.
LOG(LS_ERROR) << "Unknown signature algorithm NID: " << nid;
algorithm->clear();
return false;
}
return true;
}
std::unique_ptr<SSLCertChain> OpenSSLCertificate::GetChain() const {
// Chains are not yet supported when using OpenSSL.
// OpenSSLStreamAdapter::SSLVerifyCallback currently requires the remote
// certificate to be self-signed.
return nullptr;
}
bool OpenSSLCertificate::ComputeDigest(const std::string& algorithm,
unsigned char* digest,
size_t size,
size_t* length) const {
return ComputeDigest(x509_, algorithm, digest, size, length);
}
bool OpenSSLCertificate::ComputeDigest(const X509* x509,
const std::string& algorithm,
unsigned char* digest,
size_t size,
size_t* length) {
const EVP_MD* md;
unsigned int n;
if (!OpenSSLDigest::GetDigestEVP(algorithm, &md))
return false;
if (size < static_cast<size_t>(EVP_MD_size(md)))
return false;
X509_digest(x509, md, digest, &n);
*length = n;
return true;
}
OpenSSLCertificate::~OpenSSLCertificate() {
X509_free(x509_);
}
OpenSSLCertificate* OpenSSLCertificate::GetReference() const {
return new OpenSSLCertificate(x509_);
}
std::string OpenSSLCertificate::ToPEMString() const {
BIO* bio = BIO_new(BIO_s_mem());
if (!bio) {
FATAL() << "unreachable code";
}
if (!PEM_write_bio_X509(bio, x509_)) {
BIO_free(bio);
FATAL() << "unreachable code";
}
BIO_write(bio, "\0", 1);
char* buffer;
BIO_get_mem_data(bio, &buffer);
std::string ret(buffer);
BIO_free(bio);
return ret;
}
void OpenSSLCertificate::ToDER(Buffer* der_buffer) const {
// In case of failure, make sure to leave the buffer empty.
der_buffer->SetSize(0);
// Calculates the DER representation of the certificate, from scratch.
BIO* bio = BIO_new(BIO_s_mem());
if (!bio) {
FATAL() << "unreachable code";
}
if (!i2d_X509_bio(bio, x509_)) {
BIO_free(bio);
FATAL() << "unreachable code";
}
char* data;
size_t length = BIO_get_mem_data(bio, &data);
der_buffer->SetData(data, length);
BIO_free(bio);
}
void OpenSSLCertificate::AddReference() const {
RTC_DCHECK(x509_ != nullptr);
#if defined(OPENSSL_IS_BORINGSSL)
X509_up_ref(x509_);
#else
CRYPTO_add(&x509_->references, 1, CRYPTO_LOCK_X509);
#endif
}
bool OpenSSLCertificate::operator==(const OpenSSLCertificate& other) const {
return X509_cmp(this->x509_, other.x509_) == 0;
}
bool OpenSSLCertificate::operator!=(const OpenSSLCertificate& other) const {
return !(*this == other);
}
// Documented in sslidentity.h.
int64_t OpenSSLCertificate::CertificateExpirationTime() const {
ASN1_TIME* expire_time = X509_get_notAfter(x509_);
bool long_format;
if (expire_time->type == V_ASN1_UTCTIME) {
long_format = false;
} else if (expire_time->type == V_ASN1_GENERALIZEDTIME) {
long_format = true;
} else {
return -1;
}
return ASN1TimeToSec(expire_time->data, expire_time->length, long_format);
}
OpenSSLIdentity::OpenSSLIdentity(OpenSSLKeyPair* key_pair,
OpenSSLCertificate* certificate)
: key_pair_(key_pair), certificate_(certificate) {
RTC_DCHECK(key_pair != nullptr);
RTC_DCHECK(certificate != nullptr);
}
OpenSSLIdentity::~OpenSSLIdentity() = default;
OpenSSLIdentity* OpenSSLIdentity::GenerateInternal(
const SSLIdentityParams& params) {
OpenSSLKeyPair* key_pair = OpenSSLKeyPair::Generate(params.key_params);
if (key_pair) {
OpenSSLCertificate* certificate =
OpenSSLCertificate::Generate(key_pair, params);
if (certificate)
return new OpenSSLIdentity(key_pair, certificate);
delete key_pair;
}
LOG(LS_INFO) << "Identity generation failed";
return nullptr;
}
OpenSSLIdentity* OpenSSLIdentity::GenerateWithExpiration(
const std::string& common_name,
const KeyParams& key_params,
time_t certificate_lifetime) {
SSLIdentityParams params;
params.key_params = key_params;
params.common_name = common_name;
time_t now = time(nullptr);
params.not_before = now + kCertificateWindowInSeconds;
params.not_after = now + certificate_lifetime;
if (params.not_before > params.not_after)
return nullptr;
return GenerateInternal(params);
}
OpenSSLIdentity* OpenSSLIdentity::GenerateForTest(
const SSLIdentityParams& params) {
return GenerateInternal(params);
}
SSLIdentity* OpenSSLIdentity::FromPEMStrings(
const std::string& private_key,
const std::string& certificate) {
std::unique_ptr<OpenSSLCertificate> cert(
OpenSSLCertificate::FromPEMString(certificate));
if (!cert) {
LOG(LS_ERROR) << "Failed to create OpenSSLCertificate from PEM string.";
return nullptr;
}
OpenSSLKeyPair* key_pair =
OpenSSLKeyPair::FromPrivateKeyPEMString(private_key);
if (!key_pair) {
LOG(LS_ERROR) << "Failed to create key pair from PEM string.";
return nullptr;
}
return new OpenSSLIdentity(key_pair,
cert.release());
}
const OpenSSLCertificate& OpenSSLIdentity::certificate() const {
return *certificate_;
}
OpenSSLIdentity* OpenSSLIdentity::GetReference() const {
return new OpenSSLIdentity(key_pair_->GetReference(),
certificate_->GetReference());
}
bool OpenSSLIdentity::ConfigureIdentity(SSL_CTX* ctx) {
// 1 is the documented success return code.
if (SSL_CTX_use_certificate(ctx, certificate_->x509()) != 1 ||
SSL_CTX_use_PrivateKey(ctx, key_pair_->pkey()) != 1) {
LogSSLErrors("Configuring key and certificate");
return false;
}
return true;
}
std::string OpenSSLIdentity::PrivateKeyToPEMString() const {
return key_pair_->PrivateKeyToPEMString();
}
std::string OpenSSLIdentity::PublicKeyToPEMString() const {
return key_pair_->PublicKeyToPEMString();
}
bool OpenSSLIdentity::operator==(const OpenSSLIdentity& other) const {
return *this->key_pair_ == *other.key_pair_ &&
*this->certificate_ == *other.certificate_;
}
bool OpenSSLIdentity::operator!=(const OpenSSLIdentity& other) const {
return !(*this == other);
}
} // namespace rtc