зеркало из https://github.com/mozilla/gecko-dev.git
111 строки
3.2 KiB
C++
111 строки
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/Atomics.h"
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#include "mozilla/Types.h"
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#include <dlfcn.h>
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#include <signal.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 <stdlib.h>
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#include <sys/inotify.h>
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#ifdef MOZ_X11
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# include <X11/Xlib.h>
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#endif
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// Signal number used to enable seccomp on each thread.
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extern mozilla::Atomic<int> gSeccompTsyncBroadcastSignum;
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static bool SigSetNeedsFixup(const sigset_t* aSet) {
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int tsyncSignum = gSeccompTsyncBroadcastSignum;
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return aSet != nullptr &&
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(sigismember(aSet, SIGSYS) ||
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(tsyncSignum != 0 && sigismember(aSet, tsyncSignum)));
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}
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static void SigSetFixup(sigset_t* aSet) {
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int tsyncSignum = gSeccompTsyncBroadcastSignum;
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int rv = sigdelset(aSet, SIGSYS);
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MOZ_RELEASE_ASSERT(rv == 0);
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if (tsyncSignum != 0) {
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rv = sigdelset(aSet, tsyncSignum);
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MOZ_RELEASE_ASSERT(rv == 0);
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}
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}
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// This file defines a hook for sigprocmask() and pthread_sigmask().
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// Bug 1176099: some threads block SIGSYS signal which breaks our seccomp-bpf
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// sandbox. To avoid this, we intercept the call and remove SIGSYS.
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//
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// ENOSYS indicates an error within the hook function itself.
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static int HandleSigset(int (*aRealFunc)(int, const sigset_t*, sigset_t*),
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int aHow, const sigset_t* aSet, sigset_t* aOldSet,
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bool aUseErrno) {
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if (!aRealFunc) {
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if (aUseErrno) {
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errno = ENOSYS;
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return -1;
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}
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return ENOSYS;
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}
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// Avoid unnecessary work
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if (aHow == SIG_UNBLOCK || !SigSetNeedsFixup(aSet)) {
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return aRealFunc(aHow, aSet, aOldSet);
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}
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sigset_t newSet = *aSet;
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SigSetFixup(&newSet);
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return aRealFunc(aHow, &newSet, aOldSet);
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}
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extern "C" MOZ_EXPORT int sigprocmask(int how, const sigset_t* set,
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sigset_t* oldset) {
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static auto sRealFunc =
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(int (*)(int, const sigset_t*, sigset_t*))dlsym(RTLD_NEXT, "sigprocmask");
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return HandleSigset(sRealFunc, how, set, oldset, true);
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}
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extern "C" MOZ_EXPORT int pthread_sigmask(int how, const sigset_t* set,
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sigset_t* oldset) {
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static auto sRealFunc = (int (*)(int, const sigset_t*, sigset_t*))dlsym(
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RTLD_NEXT, "pthread_sigmask");
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return HandleSigset(sRealFunc, how, set, oldset, false);
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}
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extern "C" MOZ_EXPORT int sigaction(int signum, const struct sigaction* act,
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struct sigaction* oldact) {
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static auto sRealFunc =
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(int (*)(int, const struct sigaction*, struct sigaction*))dlsym(
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RTLD_NEXT, "sigaction");
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if (!sRealFunc) {
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errno = ENOSYS;
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return -1;
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}
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if (act == nullptr || !SigSetNeedsFixup(&act->sa_mask)) {
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return sRealFunc(signum, act, oldact);
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}
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struct sigaction newact = *act;
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SigSetFixup(&newact.sa_mask);
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return sRealFunc(signum, &newact, oldact);
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}
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extern "C" MOZ_EXPORT int inotify_init(void) { return inotify_init1(0); }
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extern "C" MOZ_EXPORT int inotify_init1(int flags) {
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errno = ENOSYS;
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return -1;
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}
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