93 lines
2.9 KiB
C++
93 lines
2.9 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "sandbox/linux/seccomp-bpf/die.h"
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <sys/prctl.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#include <string>
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#include "base/logging.h"
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#include "base/posix/eintr_wrapper.h"
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#include "sandbox/linux/seccomp-bpf/syscall.h"
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#include "sandbox/linux/services/syscall_wrappers.h"
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#include "sandbox/linux/system_headers/linux_signal.h"
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namespace sandbox {
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void Die::ExitGroup() {
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// exit_group() should exit our program. After all, it is defined as a
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// function that doesn't return. But things can theoretically go wrong.
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// Especially, since we are dealing with system call filters. Continuing
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// execution would be very bad in most cases where ExitGroup() gets called.
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// So, we'll try a few other strategies too.
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Syscall::Call(__NR_exit_group, 1);
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// We have no idea what our run-time environment looks like. So, signal
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// handlers might or might not do the right thing. Try to reset settings
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// to a defined state; but we have not way to verify whether we actually
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// succeeded in doing so. Nonetheless, triggering a fatal signal could help
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// us terminate.
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struct sigaction sa = {};
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sa.sa_handler = LINUX_SIG_DFL;
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sa.sa_flags = LINUX_SA_RESTART;
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sys_sigaction(LINUX_SIGSEGV, &sa, nullptr);
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Syscall::Call(__NR_prctl, PR_SET_DUMPABLE, (void*)0, (void*)0, (void*)0);
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if (*(volatile char*)0) {
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}
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// If there is no way for us to ask for the program to exit, the next
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// best thing we can do is to loop indefinitely. Maybe, somebody will notice
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// and file a bug...
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// We in fact retry the system call inside of our loop so that it will
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// stand out when somebody tries to diagnose the problem by using "strace".
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for (;;) {
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Syscall::Call(__NR_exit_group, 1);
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}
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}
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void Die::SandboxDie(const char* msg, const char* file, int line) {
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if (simple_exit_) {
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LogToStderr(msg, file, line);
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} else {
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logging::LogMessage(file, line, logging::LOG_FATAL).stream() << msg;
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}
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ExitGroup();
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}
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void Die::RawSandboxDie(const char* msg) {
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if (!msg)
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msg = "";
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RAW_LOG(FATAL, msg);
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ExitGroup();
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}
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void Die::SandboxInfo(const char* msg, const char* file, int line) {
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if (!suppress_info_) {
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logging::LogMessage(file, line, logging::LOG_INFO).stream() << msg;
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}
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}
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void Die::LogToStderr(const char* msg, const char* file, int line) {
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if (msg) {
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char buf[40];
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snprintf(buf, sizeof(buf), "%d", line);
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std::string s = std::string(file) + ":" + buf + ":" + msg + "\n";
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// No need to loop. Short write()s are unlikely and if they happen we
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// probably prefer them over a loop that blocks.
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ignore_result(
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HANDLE_EINTR(Syscall::Call(__NR_write, 2, s.c_str(), s.length())));
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}
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}
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bool Die::simple_exit_ = false;
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bool Die::suppress_info_ = false;
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} // namespace sandbox
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