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/*
* Copyright 2018 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 "rtc_base/openssl_utility.h"
#include "absl/strings/string_view.h"
#if defined(WEBRTC_WIN)
// Must be included first before openssl headers.
#include "rtc_base/win32.h" // NOLINT
#endif // WEBRTC_WIN
#ifdef OPENSSL_IS_BORINGSSL
#include <openssl/pool.h>
#endif
#include <openssl/err.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <stddef.h>
#include "rtc_base/arraysize.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_conversions.h"
#include "rtc_base/openssl.h"
#include "rtc_base/ssl_identity.h"
#ifndef WEBRTC_EXCLUDE_BUILT_IN_SSL_ROOT_CERTS
#include "rtc_base/ssl_roots.h"
#endif // WEBRTC_EXCLUDE_BUILT_IN_SSL_ROOT_CERTS
namespace rtc {
namespace openssl {
// Holds various helper methods.
namespace {
// TODO(crbug.com/webrtc/11710): When OS certificate verification is available,
// and we don't need VerifyPeerCertMatchesHost, don't compile this in order to
// avoid a dependency on OpenSSL X509 objects (see crbug.com/webrtc/11410).
void LogCertificates([[maybe_unused]] SSL* ssl,
[[maybe_unused]] X509* certificate) {
// Logging certificates is extremely verbose. So it is disabled by default.
#ifdef LOG_CERTIFICATES
BIO* mem = BIO_new(BIO_s_mem());
if (mem == nullptr) {
RTC_DLOG(LS_ERROR) << "BIO_new() failed to allocate memory.";
return;
}
RTC_DLOG(LS_INFO) << "Certificate from server:";
X509_print_ex(mem, certificate, XN_FLAG_SEP_CPLUS_SPC, X509_FLAG_NO_HEADER);
BIO_write(mem, "\0", 1);
char* buffer = nullptr;
BIO_get_mem_data(mem, &buffer);
if (buffer != nullptr) {
RTC_DLOG(LS_INFO) << buffer;
} else {
RTC_DLOG(LS_ERROR) << "BIO_get_mem_data() failed to get buffer.";
}
BIO_free(mem);
const char* cipher_name = SSL_CIPHER_get_name(SSL_get_current_cipher(ssl));
if (cipher_name != nullptr) {
RTC_DLOG(LS_INFO) << "Cipher: " << cipher_name;
} else {
RTC_DLOG(LS_ERROR) << "SSL_CIPHER_DESCRIPTION() failed to get cipher_name.";
}
#endif
}
} // namespace
#ifdef OPENSSL_IS_BORINGSSL
bool ParseCertificate(CRYPTO_BUFFER* cert_buffer,
CBS* signature_algorithm_oid,
int64_t* expiration_time) {
CBS cbs;
CRYPTO_BUFFER_init_CBS(cert_buffer, &cbs);
// Certificate ::= SEQUENCE {
CBS certificate;
if (!CBS_get_asn1(&cbs, &certificate, CBS_ASN1_SEQUENCE)) {
return false;
}
// tbsCertificate TBSCertificate,
CBS tbs_certificate;
if (!CBS_get_asn1(&certificate, &tbs_certificate, CBS_ASN1_SEQUENCE)) {
return false;
}
// signatureAlgorithm AlgorithmIdentifier,
CBS signature_algorithm;
if (!CBS_get_asn1(&certificate, &signature_algorithm, CBS_ASN1_SEQUENCE)) {
return false;
}
if (!CBS_get_asn1(&signature_algorithm, signature_algorithm_oid,
CBS_ASN1_OBJECT)) {
return false;
}
// signatureValue BIT STRING }
if (!CBS_get_asn1(&certificate, nullptr, CBS_ASN1_BITSTRING)) {
return false;
}
if (CBS_len(&certificate)) {
return false;
}
// Now parse the inner TBSCertificate.
// version [0] EXPLICIT Version DEFAULT v1,
if (!CBS_get_optional_asn1(
&tbs_certificate, nullptr, nullptr,
CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC)) {
return false;
}
// serialNumber CertificateSerialNumber,
if (!CBS_get_asn1(&tbs_certificate, nullptr, CBS_ASN1_INTEGER)) {
return false;
}
// signature AlgorithmIdentifier
if (!CBS_get_asn1(&tbs_certificate, nullptr, CBS_ASN1_SEQUENCE)) {
return false;
}
// issuer Name,
if (!CBS_get_asn1(&tbs_certificate, nullptr, CBS_ASN1_SEQUENCE)) {
return false;
}
// validity Validity,
CBS validity;
if (!CBS_get_asn1(&tbs_certificate, &validity, CBS_ASN1_SEQUENCE)) {
return false;
}
// Skip over notBefore.
if (!CBS_get_any_asn1_element(&validity, nullptr, nullptr, nullptr)) {
return false;
}
// Parse notAfter.
CBS not_after;
unsigned not_after_tag;
if (!CBS_get_any_asn1(&validity, &not_after, &not_after_tag)) {
return false;
}
bool long_format;
if (not_after_tag == CBS_ASN1_UTCTIME) {
long_format = false;
} else if (not_after_tag == CBS_ASN1_GENERALIZEDTIME) {
long_format = true;
} else {
return false;
}
if (expiration_time) {
*expiration_time =
ASN1TimeToSec(CBS_data(&not_after), CBS_len(&not_after), long_format);
}
// subject Name,
if (!CBS_get_asn1_element(&tbs_certificate, nullptr, CBS_ASN1_SEQUENCE)) {
return false;
}
// subjectPublicKeyInfo SubjectPublicKeyInfo,
if (!CBS_get_asn1(&tbs_certificate, nullptr, CBS_ASN1_SEQUENCE)) {
return false;
}
// issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL
if (!CBS_get_optional_asn1(&tbs_certificate, nullptr, nullptr,
0x01 | CBS_ASN1_CONTEXT_SPECIFIC)) {
return false;
}
// subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL
if (!CBS_get_optional_asn1(&tbs_certificate, nullptr, nullptr,
0x02 | CBS_ASN1_CONTEXT_SPECIFIC)) {
return false;
}
// extensions [3] EXPLICIT Extensions OPTIONAL
if (!CBS_get_optional_asn1(
&tbs_certificate, nullptr, nullptr,
0x03 | CBS_ASN1_CONSTRUCTED | CBS_ASN1_CONTEXT_SPECIFIC)) {
return false;
}
if (CBS_len(&tbs_certificate)) {
return false;
}
return true;
}
#endif // OPENSSL_IS_BORINGSSL
bool VerifyPeerCertMatchesHost(SSL* ssl, absl::string_view host) {
if (host.empty()) {
RTC_DLOG(LS_ERROR) << "Hostname is empty. Cannot verify peer certificate.";
return false;
}
if (ssl == nullptr) {
RTC_DLOG(LS_ERROR) << "SSL is nullptr. Cannot verify peer certificate.";
return false;
}
#ifdef OPENSSL_IS_BORINGSSL
// We can't grab a X509 object directly, as the SSL context may have been
// initialized with TLS_with_buffers_method.
const STACK_OF(CRYPTO_BUFFER)* chain = SSL_get0_peer_certificates(ssl);
if (chain == nullptr || sk_CRYPTO_BUFFER_num(chain) == 0) {
RTC_LOG(LS_ERROR)
<< "SSL_get0_peer_certificates failed. This should never happen.";
return false;
}
CRYPTO_BUFFER* leaf = sk_CRYPTO_BUFFER_value(chain, 0);
bssl::UniquePtr<X509> x509(X509_parse_from_buffer(leaf));
if (!x509) {
RTC_LOG(LS_ERROR) << "Failed to parse certificate to X509 object.";
return false;
}
LogCertificates(ssl, x509.get());
return X509_check_host(x509.get(), host.data(), host.size(), 0, nullptr) == 1;
#else // OPENSSL_IS_BORINGSSL
X509* certificate = SSL_get_peer_certificate(ssl);
if (certificate == nullptr) {
RTC_LOG(LS_ERROR)
<< "SSL_get_peer_certificate failed. This should never happen.";
return false;
}
LogCertificates(ssl, certificate);
bool is_valid_cert_name =
X509_check_host(certificate, host.data(), host.size(), 0, nullptr) == 1;
X509_free(certificate);
return is_valid_cert_name;
#endif // !defined(OPENSSL_IS_BORINGSSL)
}
void LogSSLErrors(absl::string_view prefix) {
char error_buf[200];
unsigned long err; // NOLINT
while ((err = ERR_get_error()) != 0) {
ERR_error_string_n(err, error_buf, sizeof(error_buf));
RTC_LOG(LS_ERROR) << prefix << ": " << error_buf << "\n";
}
}
#ifndef WEBRTC_EXCLUDE_BUILT_IN_SSL_ROOT_CERTS
bool LoadBuiltinSSLRootCertificates(SSL_CTX* ctx) {
int count_of_added_certs = 0;
for (size_t i = 0; i < arraysize(kSSLCertCertificateList); i++) {
const unsigned char* cert_buffer = kSSLCertCertificateList[i];
size_t cert_buffer_len = kSSLCertCertificateSizeList[i];
X509* cert = d2i_X509(nullptr, &cert_buffer,
checked_cast<long>(cert_buffer_len)); // NOLINT
if (cert) {
int return_value = X509_STORE_add_cert(SSL_CTX_get_cert_store(ctx), cert);
if (return_value == 0) {
RTC_LOG(LS_WARNING) << "Unable to add certificate.";
} else {
count_of_added_certs++;
}
X509_free(cert);
}
}
return count_of_added_certs > 0;
}
#endif // WEBRTC_EXCLUDE_BUILT_IN_SSL_ROOT_CERTS
#ifdef OPENSSL_IS_BORINGSSL
CRYPTO_BUFFER_POOL* GetBufferPool() {
static CRYPTO_BUFFER_POOL* instance = CRYPTO_BUFFER_POOL_new();
return instance;
}
#endif
} // namespace openssl
} // namespace rtc