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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 17:32:43 +0000 |
commit | 6bf0a5cb5034a7e684dcc3500e841785237ce2dd (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /security/sandbox/linux/SandboxHooks.cpp | |
parent | Initial commit. (diff) | |
download | thunderbird-upstream.tar.xz thunderbird-upstream.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | security/sandbox/linux/SandboxHooks.cpp | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/security/sandbox/linux/SandboxHooks.cpp b/security/sandbox/linux/SandboxHooks.cpp new file mode 100644 index 0000000000..be1a9b1541 --- /dev/null +++ b/security/sandbox/linux/SandboxHooks.cpp @@ -0,0 +1,110 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "mozilla/Atomics.h" +#include "mozilla/Types.h" + +#include <dlfcn.h> +#include <signal.h> +#include <errno.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/inotify.h> +#ifdef MOZ_X11 +# include <X11/Xlib.h> +#endif + +// Signal number used to enable seccomp on each thread. +extern mozilla::Atomic<int> gSeccompTsyncBroadcastSignum; + +static bool SigSetNeedsFixup(const sigset_t* aSet) { + int tsyncSignum = gSeccompTsyncBroadcastSignum; + + return aSet != nullptr && + (sigismember(aSet, SIGSYS) || + (tsyncSignum != 0 && sigismember(aSet, tsyncSignum))); +} + +static void SigSetFixup(sigset_t* aSet) { + int tsyncSignum = gSeccompTsyncBroadcastSignum; + int rv = sigdelset(aSet, SIGSYS); + MOZ_RELEASE_ASSERT(rv == 0); + if (tsyncSignum != 0) { + rv = sigdelset(aSet, tsyncSignum); + MOZ_RELEASE_ASSERT(rv == 0); + } +} + +// This file defines a hook for sigprocmask() and pthread_sigmask(). +// Bug 1176099: some threads block SIGSYS signal which breaks our seccomp-bpf +// sandbox. To avoid this, we intercept the call and remove SIGSYS. +// +// ENOSYS indicates an error within the hook function itself. +static int HandleSigset(int (*aRealFunc)(int, const sigset_t*, sigset_t*), + int aHow, const sigset_t* aSet, sigset_t* aOldSet, + bool aUseErrno) { + if (!aRealFunc) { + if (aUseErrno) { + errno = ENOSYS; + return -1; + } + + return ENOSYS; + } + + // Avoid unnecessary work + if (aHow == SIG_UNBLOCK || !SigSetNeedsFixup(aSet)) { + return aRealFunc(aHow, aSet, aOldSet); + } + + sigset_t newSet = *aSet; + SigSetFixup(&newSet); + return aRealFunc(aHow, &newSet, aOldSet); +} + +extern "C" MOZ_EXPORT int sigprocmask(int how, const sigset_t* set, + sigset_t* oldset) { + static auto sRealFunc = + (int (*)(int, const sigset_t*, sigset_t*))dlsym(RTLD_NEXT, "sigprocmask"); + + return HandleSigset(sRealFunc, how, set, oldset, true); +} + +extern "C" MOZ_EXPORT int pthread_sigmask(int how, const sigset_t* set, + sigset_t* oldset) { + static auto sRealFunc = (int (*)(int, const sigset_t*, sigset_t*))dlsym( + RTLD_NEXT, "pthread_sigmask"); + + return HandleSigset(sRealFunc, how, set, oldset, false); +} + +extern "C" MOZ_EXPORT int sigaction(int signum, const struct sigaction* act, + struct sigaction* oldact) { + static auto sRealFunc = + (int (*)(int, const struct sigaction*, struct sigaction*))dlsym( + RTLD_NEXT, "sigaction"); + + if (!sRealFunc) { + errno = ENOSYS; + return -1; + } + + if (act == nullptr || !SigSetNeedsFixup(&act->sa_mask)) { + return sRealFunc(signum, act, oldact); + } + + struct sigaction newact = *act; + SigSetFixup(&newact.sa_mask); + return sRealFunc(signum, &newact, oldact); +} + +extern "C" MOZ_EXPORT int inotify_init(void) { return inotify_init1(0); } + +extern "C" MOZ_EXPORT int inotify_init1(int flags) { + errno = ENOSYS; + return -1; +} |