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/* -*- 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,
#include "Sandbox.h"
#include "LinuxSched.h"
#include "SandboxBrokerClient.h"
#include "SandboxChrootProto.h"
#include "SandboxFilter.h"
#include "SandboxInternal.h"
#include "SandboxLogging.h"
#include "SandboxOpenedFiles.h"
#include "SandboxReporterClient.h"
#include <dirent.h>
#ifdef NIGHTLY_BUILD
# include "dlfcn.h"
#endif
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/ptrace.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <unistd.h>
#include "mozilla/Array.h"
#include "mozilla/Atomics.h"
#include "mozilla/Attributes.h"
#include "mozilla/Range.h"
#include "mozilla/SandboxInfo.h"
#include "mozilla/StackWalk.h"
#include "mozilla/Span.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/Unused.h"
#include "mozilla/ipc/UtilityProcessSandboxing.h"
#include "prenv.h"
#include "base/posix/eintr_wrapper.h"
#include "sandbox/linux/bpf_dsl/bpf_dsl.h"
#include "sandbox/linux/bpf_dsl/codegen.h"
#include "sandbox/linux/bpf_dsl/dump_bpf.h"
#include "sandbox/linux/bpf_dsl/policy.h"
#include "sandbox/linux/bpf_dsl/policy_compiler.h"
#include "sandbox/linux/bpf_dsl/seccomp_macros.h"
#include "sandbox/linux/seccomp-bpf/trap.h"
#include "sandbox/linux/system_headers/linux_filter.h"
#include "sandbox/linux/system_headers/linux_seccomp.h"
#include "sandbox/linux/system_headers/linux_syscalls.h"
#if defined(ANDROID)
# include "sandbox/linux/system_headers/linux_ucontext.h"
#endif
#ifndef SECCOMP_FILTER_FLAG_SPEC_ALLOW
# define SECCOMP_FILTER_FLAG_SPEC_ALLOW (1UL << 2)
#endif
#ifdef MOZ_ASAN
// Copy libsanitizer declarations to avoid depending on ASAN headers.
extern "C" {
namespace __sanitizer {
// Win64 uses long long, but this is Linux.
typedef signed long sptr;
} // namespace __sanitizer
typedef struct {
int coverage_sandboxed;
__sanitizer::sptr coverage_fd;
unsigned int coverage_max_block_size;
} __sanitizer_sandbox_arguments;
MOZ_IMPORT_API void __sanitizer_sandbox_on_notify(
__sanitizer_sandbox_arguments* args);
} // extern "C"
#endif // MOZ_ASAN
// Signal number used to enable seccomp on each thread.
mozilla::Atomic<int> gSeccompTsyncBroadcastSignum(0);
namespace mozilla {
static mozilla::Atomic<bool> gSandboxCrashOnError(false);
// This is initialized by SandboxSetCrashFunc().
SandboxCrashFunc gSandboxCrashFunc;
static SandboxReporterClient* gSandboxReporterClient;
static void (*gChromiumSigSysHandler)(int, siginfo_t*, void*);
// Test whether a ucontext, interpreted as the state after a syscall,
// indicates the given error. See also sandbox::Syscall::PutValueInUcontext.
static bool ContextIsError(const ucontext_t* aContext, int aError) {
// Avoid integer promotion warnings. (The unary addition makes
// the decltype not evaluate to a reference type.)
typedef decltype(+SECCOMP_RESULT(aContext)) reg_t;
#ifdef __mips__
return SECCOMP_PARM4(aContext) != 0 &&
SECCOMP_RESULT(aContext) == static_cast<reg_t>(aError);
#else
return SECCOMP_RESULT(aContext) == static_cast<reg_t>(-aError);
#endif
}
/**
* This is the SIGSYS handler function. It delegates to the Chromium
* TrapRegistry handler (see InstallSigSysHandler, below) and, if the
* trap handler installed by the policy would fail with ENOSYS,
* crashes the process. This allows unintentional policy failures to
* be reported as crash dumps and fixed. It also logs information
* about the failed system call.
*
* Note that this could be invoked in parallel on multiple threads and
* that it could be in async signal context (e.g., intercepting an
* open() called from an async signal handler).
*/
MOZ_NEVER_INLINE static void SigSysHandler(int nr, siginfo_t* info,
void* void_context) {
ucontext_t* ctx = static_cast<ucontext_t*>(void_context);
// This shouldn't ever be null, but the Chromium handler checks for
// that and refrains from crashing, so let's not crash release builds:
MOZ_DIAGNOSTIC_ASSERT(ctx);
if (!ctx) {
return;
}
// Save a copy of the context before invoking the trap handler,
// which will overwrite one or more registers with the return value.
ucontext_t savedCtx = *ctx;
gChromiumSigSysHandler(nr, info, ctx);
if (!ContextIsError(ctx, ENOSYS)) {
return;
}
SandboxReport report = gSandboxReporterClient->MakeReportAndSend(&savedCtx);
// TODO, someday when this is enabled on MIPS: include the two extra
// args in the error message.
SANDBOX_LOG(
"seccomp sandbox violation: pid %d, tid %d, syscall %d,"
" args %d %d %d %d %d %d.%s",
report.mPid, report.mTid, report.mSyscall, report.mArgs[0],
report.mArgs[1], report.mArgs[2], report.mArgs[3], report.mArgs[4],
report.mArgs[5], gSandboxCrashOnError ? " Killing process." : "");
if (gSandboxCrashOnError) {
info->si_addr = reinterpret_cast<void*>(report.mSyscall);
gSandboxCrashFunc(nr, info, &savedCtx, CallerPC());
_exit(127);
}
}
/**
* This function installs the SIGSYS handler. This is slightly
* complicated because we want to use Chromium's handler to dispatch
* to specific trap handlers defined in the policy, but we also need
* the full original signal context to give to Breakpad for crash
* dumps. So we install Chromium's handler first, then retrieve its
* address so our replacement can delegate to it.
*/
static void InstallSigSysHandler(void) {
struct sigaction act;
// Ensure that the Chromium handler is installed.
Unused << sandbox::Trap::Registry();
// If the signal handling state isn't as expected, crash now instead
// of crashing later (and more confusingly) when SIGSYS happens.
if (sigaction(SIGSYS, nullptr, &act) != 0) {
MOZ_CRASH("Couldn't read old SIGSYS disposition");
}
if ((act.sa_flags & SA_SIGINFO) != SA_SIGINFO) {
MOZ_CRASH("SIGSYS not already set to a siginfo handler?");
}
MOZ_RELEASE_ASSERT(act.sa_sigaction);
gChromiumSigSysHandler = act.sa_sigaction;
act.sa_sigaction = SigSysHandler;
// Currently, SA_NODEFER should already be set by the Chromium code,
// but it's harmless to ensure that it's set:
MOZ_ASSERT(act.sa_flags & SA_NODEFER);
act.sa_flags |= SA_NODEFER;
if (sigaction(SIGSYS, &act, nullptr) < 0) {
MOZ_CRASH("Couldn't change SIGSYS disposition");
}
}
/**
* This function installs the syscall filter, a.k.a. seccomp. The
* aUseTSync flag indicates whether this should apply to all threads
* in the process -- which will fail if the kernel doesn't support
* that -- or only the current thread.
*
* SECCOMP_MODE_FILTER is the "bpf" mode of seccomp which allows
* to pass a bpf program (in our case, it contains a syscall
* whitelist).
*
* PR_SET_NO_NEW_PRIVS ensures that it is impossible to grant more
* syscalls to the process beyond this point (even after fork()), and
* prevents gaining capabilities (e.g., by exec'ing a setuid root
* program). The kernel won't allow seccomp-bpf without doing this,
* because otherwise it could be used for privilege escalation attacks.
*
* Returns false if the filter was already installed (see the
* PR_SET_NO_NEW_PRIVS rule in SandboxFilter.cpp). Crashes on any
* other error condition.
*
* @see SandboxInfo
* @see BroadcastSetThreadSandbox
*/
[[nodiscard]] static bool InstallSyscallFilter(const sock_fprog* aProg,
bool aUseTSync) {
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) {
if (!aUseTSync && errno == ETXTBSY) {
return false;
}
SANDBOX_LOG_ERRNO("prctl(PR_SET_NO_NEW_PRIVS) failed");
MOZ_CRASH("prctl(PR_SET_NO_NEW_PRIVS)");
}
if (aUseTSync) {
// Try with SECCOMP_FILTER_FLAGS_SPEC_ALLOW, and then without if
// that fails with EINVAL (or if an env var is set, for testing
// purposes).
//
// Context: Linux 4.17 applied some Spectre mitigations (SSBD and
// STIBP) by default when seccomp-bpf is used, but also added that
// flag to opt out (and also sysadmin-level overrides). Later,
// Linux 5.16 turned them off by default; the rationale seems to
// be, roughly: the attacks are impractical or were already
// mitigated in other ways, there are worse attacks that these
// measures don't stop, and the performance impact is severe
// enough that container software was already opting out.
//
// For the full rationale, see
//
// In our case, STIBP causes a noticeable performance hit: WASM
// microbenchmarks of indirect calls regress by up to 2x or 3x
// depending on CPU. Given that upstream Linux has changed the
// default years ago, we opt out.
static const bool kSpecAllow = !PR_GetEnv("MOZ_SANDBOX_NO_SPEC_ALLOW");
const auto setSeccomp = [aProg](int aFlags) -> long {
return syscall(__NR_seccomp, SECCOMP_SET_MODE_FILTER,
SECCOMP_FILTER_FLAG_TSYNC | aFlags, aProg);
};
long rv;
if (kSpecAllow) {
rv = setSeccomp(SECCOMP_FILTER_FLAG_SPEC_ALLOW);
} else {
rv = -1;
errno = EINVAL;
}
if (rv != 0 && errno == EINVAL) {
rv = setSeccomp(0);
}
if (rv != 0) {
SANDBOX_LOG_ERRNO("thread-synchronized seccomp failed");
MOZ_CRASH("seccomp+tsync failed, but kernel supports tsync");
}
} else {
if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, (unsigned long)aProg, 0,
0)) {
SANDBOX_LOG_ERRNO("prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER) failed");
MOZ_CRASH("prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER)");
}
}
return true;
}
// Use signals for permissions that need to be set per-thread.
// The communication channel from the signal handler back to the main thread.
static mozilla::Atomic<int> gSetSandboxDone;
// Pass the filter itself through a global.
const sock_fprog* gSetSandboxFilter;
// This function returns the first realtime signal currently set to
// default handling (i.e., not in use), or 0 if none could be found.
//
// WARNING: if this function or anything similar to it (including in
// external libraries) is used on multiple threads concurrently, there
// will be a race condition.
static int FindFreeSignalNumber() {
for (int signum = SIGRTMAX; signum >= SIGRTMIN; --signum) {
struct sigaction sa;
if (sigaction(signum, nullptr, &sa) == 0 &&
(sa.sa_flags & SA_SIGINFO) == 0 && sa.sa_handler == SIG_DFL) {
return signum;
}
}
return 0;
}
// Returns true if sandboxing was enabled, or false if sandboxing
// already was enabled. Crashes if sandboxing could not be enabled.
static bool SetThreadSandbox() {
return InstallSyscallFilter(gSetSandboxFilter, false);
}
static void SetThreadSandboxHandler(int signum) {
// The non-zero number sent back to the main thread indicates
// whether action was taken.
if (SetThreadSandbox()) {
gSetSandboxDone = 2;
} else {
gSetSandboxDone = 1;
}
// Wake up the main thread. See the FUTEX_WAIT call, below, for an
// explanation.
syscall(__NR_futex, reinterpret_cast<int*>(&gSetSandboxDone), FUTEX_WAKE, 1);
}
static void EnterChroot() {
const char* env = PR_GetEnv(kSandboxChrootEnvFlag);
if (!env || !*env || *env == '0') {
return;
}
char msg = kSandboxChrootRequest;
ssize_t msg_len = HANDLE_EINTR(write(kSandboxChrootClientFd, &msg, 1));
MOZ_RELEASE_ASSERT(msg_len == 1);
msg_len = HANDLE_EINTR(read(kSandboxChrootClientFd, &msg, 1));
MOZ_RELEASE_ASSERT(msg_len == 1);
MOZ_RELEASE_ASSERT(msg == kSandboxChrootResponse);
close(kSandboxChrootClientFd);
}
static void BroadcastSetThreadSandbox(const sock_fprog* aFilter) {
pid_t pid, tid, myTid;
DIR* taskdp;
struct dirent* de;
// This function does not own *aFilter, so this global needs to
// always be zeroed before returning.
gSetSandboxFilter = aFilter;
static_assert(sizeof(mozilla::Atomic<int>) == sizeof(int),
"mozilla::Atomic<int> isn't represented by an int");
pid = getpid();
myTid = syscall(__NR_gettid);
taskdp = opendir("/proc/self/task");
if (taskdp == nullptr) {
SANDBOX_LOG_ERRNO("opendir /proc/self/task");
MOZ_CRASH("failed while trying to open directory /proc/self/task");
}
// In case this races with a not-yet-deprivileged thread cloning
// itself, repeat iterating over all threads until we find none
// that are still privileged.
bool sandboxProgress;
const int tsyncSignum = gSeccompTsyncBroadcastSignum;
do {
sandboxProgress = false;
// For each thread...
while ((de = readdir(taskdp))) {
char* endptr;
tid = strtol(de->d_name, &endptr, 10);
if (*endptr != '\0' || tid <= 0) {
// Not a task ID.
continue;
}
if (tid == myTid) {
// Drop this thread's privileges last, below, so we can
// continue to signal other threads.
continue;
}
MOZ_RELEASE_ASSERT(tsyncSignum != 0);
// Reset the futex cell and signal.
gSetSandboxDone = 0;
if (syscall(__NR_tgkill, pid, tid, tsyncSignum) != 0) {
if (errno == ESRCH) {
SANDBOX_LOG("Thread %d unexpectedly exited.", tid);
// Rescan threads, in case it forked before exiting.
sandboxProgress = true;
continue;
}
SANDBOX_LOG_ERRNO("tgkill(%d,%d)", pid, tid);
MOZ_CRASH("failed while trying to send a signal to a thread");
}
// It's unlikely, but if the thread somehow manages to exit
// after receiving the signal but before entering the signal
// handler, we need to avoid blocking forever.
//
// Using futex directly lets the signal handler send the wakeup
// from an async signal handler (pthread mutex/condvar calls
// aren't allowed), and to use a relative timeout that isn't
// affected by changes to the system clock (not possible with
// POSIX semaphores).
//
// If a thread doesn't respond within a reasonable amount of
// time, but still exists, we crash -- the alternative is either
// blocking forever or silently losing security, and it
// shouldn't actually happen.
static const int crashDelay = 10; // seconds
struct timespec timeLimit;
clock_gettime(CLOCK_MONOTONIC, &timeLimit);
timeLimit.tv_sec += crashDelay;
while (true) {
static const struct timespec futexTimeout = {0,
10 * 1000 * 1000}; // 10ms
// Atomically: if gSetSandboxDone == 0, then sleep.
if (syscall(__NR_futex, reinterpret_cast<int*>(&gSetSandboxDone),
FUTEX_WAIT, 0, &futexTimeout) != 0) {
if (errno != EWOULDBLOCK && errno != ETIMEDOUT && errno != EINTR) {
SANDBOX_LOG_ERRNO("FUTEX_WAIT");
MOZ_CRASH("failed during FUTEX_WAIT");
}
}
// Did the handler finish?
if (gSetSandboxDone > 0) {
if (gSetSandboxDone == 2) {
sandboxProgress = true;
}
break;
}
// Has the thread ceased to exist?
if (syscall(__NR_tgkill, pid, tid, 0) != 0) {
if (errno == ESRCH) {
SANDBOX_LOG("Thread %d unexpectedly exited.", tid);
}
// Rescan threads, in case it forked before exiting.
// Also, if it somehow failed in a way that wasn't ESRCH,
// and still exists, that will be handled on the next pass.
sandboxProgress = true;
break;
}
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
if (now.tv_sec > timeLimit.tv_sec ||
(now.tv_sec == timeLimit.tv_sec &&
now.tv_nsec > timeLimit.tv_nsec)) {
SANDBOX_LOG(
"Thread %d unresponsive for %d seconds."
" Killing process.",
tid, crashDelay);
MOZ_CRASH("failed while waiting for unresponsive thread");
}
}
}
rewinddir(taskdp);
} while (sandboxProgress);
void (*oldHandler)(int);
oldHandler = signal(tsyncSignum, SIG_DFL);
if (oldHandler != SetThreadSandboxHandler) {
// See the comment on FindFreeSignalNumber about race conditions.
SANDBOX_LOG("handler for signal %d was changed to %p!", tsyncSignum,
oldHandler);
MOZ_CRASH("handler for the signal was changed to another");
}
gSeccompTsyncBroadcastSignum = 0;
Unused << closedir(taskdp);
// And now, deprivilege the main thread:
SetThreadSandbox();
gSetSandboxFilter = nullptr;
}
static void ApplySandboxWithTSync(sock_fprog* aFilter) {
// At this point we're committed to using tsync, because we'd have
// needed to allocate a signal and prevent it from being blocked on
// other threads (see SandboxHooks.cpp), so there's no attempt to
// fall back to the non-tsync path.
if (!InstallSyscallFilter(aFilter, true)) {
MOZ_CRASH("failed while trying to install syscall filter");
}
}
#ifdef NIGHTLY_BUILD
static bool IsLibPresent(const char* aName) {
if (const auto handle = dlopen(aName, RTLD_LAZY | RTLD_NOLOAD)) {
dlclose(handle);
return true;
}
return false;
}
static const Array<const char*, 1> kLibsThatWillCrash{
"libesets_pac.so",
};
#endif // NIGHTLY_BUILD
void SandboxEarlyInit() {
if (PR_GetEnv("MOZ_SANDBOXED") == nullptr) {
return;
}
// this can probably go away when audio remoting is mandatory.
const char* oldPreload = PR_GetEnv("MOZ_ORIG_LD_PRELOAD");
char* preloadEntry;
// This string is "leaked" because the environment takes ownership.
if (asprintf(&preloadEntry, "LD_PRELOAD=%s", oldPreload ? oldPreload : "") !=
-1) {
PR_SetEnv(preloadEntry);
}
// If TSYNC is not supported, set up signal handler
// used to enable seccomp on each thread.
if (!SandboxInfo::Get().Test(SandboxInfo::kHasSeccompTSync)) {
// The signal number has to be chosen early, so that the
// interceptions in SandboxHooks.cpp can prevent it from being
// masked.
const int tsyncSignum = FindFreeSignalNumber();
if (tsyncSignum == 0) {
SANDBOX_LOG("No available signal numbers!");
MOZ_CRASH("failed while trying to find a free signal number");
}
gSeccompTsyncBroadcastSignum = tsyncSignum;
// ...and the signal handler also needs to be installed now, to
// indicate to anything else looking for free signals that it's
// claimed.
void (*oldHandler)(int);
oldHandler = signal(tsyncSignum, SetThreadSandboxHandler);
if (oldHandler != SIG_DFL) {
// See the comment on FindFreeSignalNumber about race conditions.
if (oldHandler == SIG_ERR) {
MOZ_CRASH("failed while registering the signal handler");
} else {
MOZ_CRASH("failed because the signal is in use by another handler");
}
SANDBOX_LOG("signal %d in use by handler %p!\n", tsyncSignum, oldHandler);
}
}
}
static void RunGlibcLazyInitializers() {
// Make glibc's lazy initialization of shm_open() run before sandboxing
int fd = shm_open("/dummy", O_RDONLY, 0);
if (fd > 0) {
close(fd); // In the unlikely case we actually opened something
}
}
static void SandboxLateInit() {
#ifdef NIGHTLY_BUILD
gSandboxCrashOnError = true;
for (const char* name : kLibsThatWillCrash) {
if (IsLibPresent(name)) {
gSandboxCrashOnError = false;
break;
}
}
#endif
if (const char* envVar = PR_GetEnv("MOZ_SANDBOX_CRASH_ON_ERROR")) {
if (envVar[0]) {
gSandboxCrashOnError = envVar[0] != '0';
}
}
RunGlibcLazyInitializers();
}
// Common code for sandbox startup.
static void SetCurrentProcessSandbox(
UniquePtr<sandbox::bpf_dsl::Policy> aPolicy) {
MOZ_ASSERT(gSandboxCrashFunc);
MOZ_RELEASE_ASSERT(gSandboxReporterClient != nullptr);
SandboxLateInit();
// Auto-collect child processes -- mainly the chroot helper if
// present, but also anything setns()ed into the pid namespace (not
// yet implemented). This process won't be able to waitpid them
// after the seccomp-bpf policy is applied.
signal(SIGCHLD, SIG_IGN);
// Note: PolicyCompiler borrows the policy and registry for its
// lifetime, but does not take ownership of them.
sandbox::bpf_dsl::PolicyCompiler compiler(aPolicy.get(),
sandbox::Trap::Registry());
// In case of errors detected by the compiler (like ABI violations),
// log and crash normally; the default is SECCOMP_RET_KILL_THREAD,
// which results in hard-to-debug hangs.
compiler.SetPanicFunc([](const char* error) -> sandbox::bpf_dsl::ResultExpr {
// Note: this assumes that `error` is a string literal, which is
// currently the case for all callers. (An intentionally leaked
// heap allocation would also work.)
return sandbox::bpf_dsl::Trap(
[](const sandbox::arch_seccomp_data&, void* aux) -> intptr_t {
auto error = reinterpret_cast<const char*>(aux);
SANDBOX_LOG("Panic: %s", error);
MOZ_CRASH("Sandbox Panic");
// unreachable
},
(void*)error);
});
sandbox::CodeGen::Program program = compiler.Compile();
if (SandboxInfo::Get().Test(SandboxInfo::kVerbose)) {
sandbox::bpf_dsl::DumpBPF::PrintProgram(program);
}
InstallSigSysHandler();
#ifdef MOZ_ASAN
__sanitizer_sandbox_arguments asanArgs;
asanArgs.coverage_sandboxed = 1;
asanArgs.coverage_fd = -1;
asanArgs.coverage_max_block_size = 0;
__sanitizer_sandbox_on_notify(&asanArgs);
#endif
// The syscall takes a C-style array, so copy the vector into one.
size_t programLen = program.size();
UniquePtr<sock_filter[]> flatProgram(new sock_filter[programLen]);
for (auto i = program.begin(); i != program.end(); ++i) {
flatProgram[i - program.begin()] = *i;
}
sock_fprog fprog;
fprog.filter = flatProgram.get();
fprog.len = static_cast<unsigned short>(programLen);
MOZ_RELEASE_ASSERT(static_cast<size_t>(fprog.len) == programLen);
const SandboxInfo info = SandboxInfo::Get();
if (info.Test(SandboxInfo::kHasSeccompTSync)) {
if (info.Test(SandboxInfo::kVerbose)) {
SANDBOX_LOG("using seccomp tsync");
}
ApplySandboxWithTSync(&fprog);
} else {
if (info.Test(SandboxInfo::kVerbose)) {
SANDBOX_LOG("no tsync support; using signal broadcast");
}
BroadcastSetThreadSandbox(&fprog);
}
// Now that all threads' filesystem accesses are being intercepted
// (if a broker is used) it's safe to chroot the process:
EnterChroot();
}
/**
* Starts the seccomp sandbox for a content process. Should be called
* only once, and before any potentially harmful content is loaded.
*
* Will normally make the process exit on failure.
*/
bool SetContentProcessSandbox(ContentProcessSandboxParams&& aParams) {
int brokerFd = aParams.mBrokerFd;
aParams.mBrokerFd = -1;
if (!SandboxInfo::Get().Test(SandboxInfo::kEnabledForContent)) {
if (brokerFd >= 0) {
close(brokerFd);
}
return false;
}
auto procType = aParams.mFileProcess ? SandboxReport::ProcType::FILE
: SandboxReport::ProcType::CONTENT;
gSandboxReporterClient = new SandboxReporterClient(procType);
// This needs to live until the process exits.
static SandboxBrokerClient* sBroker;
if (brokerFd >= 0) {
sBroker = new SandboxBrokerClient(brokerFd);
}
SetCurrentProcessSandbox(
GetContentSandboxPolicy(sBroker, std::move(aParams)));
return true;
}
/**
* Starts the seccomp sandbox for a media plugin process. Should be
* called only once, and before any potentially harmful content is
* loaded -- including the plugin itself, if it's considered untrusted.
*
* The file indicated by aFilePath, if non-null, can be open()ed
* read-only, once, after the sandbox starts; it should be the .so
* file implementing the not-yet-loaded plugin.
*
* Will normally make the process exit on failure.
*/
void SetMediaPluginSandbox(const char* aFilePath) {
MOZ_RELEASE_ASSERT(aFilePath != nullptr);
if (!SandboxInfo::Get().Test(SandboxInfo::kEnabledForMedia)) {
return;
}
gSandboxReporterClient =
new SandboxReporterClient(SandboxReport::ProcType::MEDIA_PLUGIN);
SandboxOpenedFile plugin(aFilePath);
if (!plugin.IsOpen()) {
SANDBOX_LOG_ERRNO("failed to open plugin file %s", aFilePath);
MOZ_CRASH("failed while trying to open the plugin file ");
}
auto files = new SandboxOpenedFiles();
files->Add(std::move(plugin));
files->Add("/dev/urandom", SandboxOpenedFile::Dup::YES);
files->Add("/dev/random", SandboxOpenedFile::Dup::YES);
files->Add("/etc/ld.so.cache"); // Needed for NSS in clearkey.
files->Add("/sys/devices/system/cpu/cpu0/tsc_freq_khz");
files->Add("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq");
files->Add("/proc/cpuinfo"); // Info also available via CPUID instruction.
files->Add("/proc/sys/crypto/fips_enabled"); // Needed for NSS in clearkey.
#ifdef __i386__
files->Add("/proc/self/auxv"); // Info also in process's address space.
#endif
// doesn't appear to need them.
files->Add("/sys/devices/system/cpu/online", SandboxOpenedFile::Error{});
files->Add("/proc/stat", SandboxOpenedFile::Error{});
files->Add("/proc/net/unix", SandboxOpenedFile::Error{});
files->Add("/proc/self/maps", SandboxOpenedFile::Error{});
// Finally, start the sandbox.
SetCurrentProcessSandbox(GetMediaSandboxPolicy(files));
}
void SetRemoteDataDecoderSandbox(int aBroker) {
if (!SandboxInfo::Get().Test(SandboxInfo::kHasSeccompBPF) ||
PR_GetEnv("MOZ_DISABLE_RDD_SANDBOX")) {
if (aBroker >= 0) {
close(aBroker);
}
return;
}
gSandboxReporterClient =
new SandboxReporterClient(SandboxReport::ProcType::RDD);
static SandboxBrokerClient* sBroker;
if (aBroker >= 0) {
sBroker = new SandboxBrokerClient(aBroker);
}
SetCurrentProcessSandbox(GetDecoderSandboxPolicy(sBroker));
}
void SetSocketProcessSandbox(int aBroker) {
if (!SandboxInfo::Get().Test(SandboxInfo::kHasSeccompBPF) ||
PR_GetEnv("MOZ_DISABLE_SOCKET_PROCESS_SANDBOX")) {
if (aBroker >= 0) {
close(aBroker);
}
return;
}
gSandboxReporterClient =
new SandboxReporterClient(SandboxReport::ProcType::SOCKET_PROCESS);
static SandboxBrokerClient* sBroker;
if (aBroker >= 0) {
sBroker = new SandboxBrokerClient(aBroker);
}
SetCurrentProcessSandbox(GetSocketProcessSandboxPolicy(sBroker));
}
void SetUtilitySandbox(int aBroker, ipc::SandboxingKind aKind) {
if (!SandboxInfo::Get().Test(SandboxInfo::kHasSeccompBPF) ||
!IsUtilitySandboxEnabled(aKind)) {
if (aBroker >= 0) {
close(aBroker);
}
return;
}
gSandboxReporterClient =
new SandboxReporterClient(SandboxReport::ProcType::UTILITY);
static SandboxBrokerClient* sBroker;
if (aBroker >= 0) {
sBroker = new SandboxBrokerClient(aBroker);
}
UniquePtr<sandbox::bpf_dsl::Policy> policy;
switch (aKind) {
case ipc::SandboxingKind::GENERIC_UTILITY:
policy = GetUtilitySandboxPolicy(sBroker);
break;
default:
MOZ_ASSERT(false, "Invalid SandboxingKind");
break;
}
SetCurrentProcessSandbox(std::move(policy));
}
bool SetSandboxCrashOnError(bool aValue) {
bool oldValue = gSandboxCrashOnError;
gSandboxCrashOnError = aValue;
return oldValue;
}
} // namespace mozilla