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// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "util/crypto/openssl_util.h"
#include <openssl/crypto.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <stddef.h>
#include <stdint.h>
#include <sstream>
#include <string>
#include <utility>
#include "absl/strings/string_view.h"
#include "util/osp_logging.h"
namespace openscreen {
namespace {
// Callback routine for OpenSSL to print error messages. |str| is a
// nullptr-terminated string of length |len| containing diagnostic information
// such as the library, function and reason for the error, the file and line
// where the error originated, plus potentially any context-specific
// information about the error. |context| contains a pointer to user-supplied
// data, which is currently unused.
// If this callback returns a value <= 0, OpenSSL will stop processing the
// error queue and return, otherwise it will continue calling this function
// until all errors have been removed from the queue.
int OpenSSLErrorCallback(const char* str, size_t len, void* context) {
OSP_DVLOG << "\t" << absl::string_view(str, len);
return 1;
}
} // namespace
void EnsureOpenSSLInit() {
// If SSL fails to initialize, we can't run crypto.
OSP_CHECK(OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS, nullptr) == 1);
}
void EnsureOpenSSLCleanup() {
EVP_cleanup();
}
void ClearOpenSSLERRStack(const Location& location) {
if (OSP_DCHECK_IS_ON()) {
uint32_t error_num = ERR_peek_error();
if (error_num == 0) {
return;
}
OSP_DVLOG << "OpenSSL ERR_get_error stack from " << location.ToString();
ERR_print_errors_cb(&OpenSSLErrorCallback, nullptr);
} else {
ERR_clear_error();
}
}
// General note about SSL errors. Error messages are pushed to the general
// OpenSSL error queue. Call ClearOpenSSLERRStack before calling any
// SSL methods.
Error GetSSLError(const SSL* ssl, int return_code) {
const int error_code = SSL_get_error(ssl, return_code);
if (error_code == SSL_ERROR_NONE) {
return Error::None();
}
// Create error message w/ unwind of error stack + original SSL error string.
std::stringstream msg;
msg << "boringssl error (" << error_code
<< "): " << SSL_error_description(error_code);
while (uint32_t packed_error = ERR_get_error()) {
msg << "\nerr stack: " << ERR_reason_error_string(packed_error);
}
std::string message = msg.str();
switch (error_code) {
case SSL_ERROR_ZERO_RETURN:
return Error(Error::Code::kSocketClosedFailure, std::move(message));
case SSL_ERROR_WANT_READ: // fallthrough
case SSL_ERROR_WANT_WRITE: // fallthrough
case SSL_ERROR_WANT_CONNECT: // fallthrough
case SSL_ERROR_WANT_ACCEPT: // fallthrough
case SSL_ERROR_WANT_X509_LOOKUP:
return Error(Error::Code::kAgain, std::move(message));
case SSL_ERROR_SYSCALL: // fallthrough
case SSL_ERROR_SSL:
return Error(Error::Code::kFatalSSLError, std::move(message));
}
OSP_NOTREACHED();
}
} // namespace openscreen