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|
// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "sandbox/policy/linux/sandbox_seccomp_bpf_linux.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <memory>
#include <utility>
#include "base/check_op.h"
#include "base/command_line.h"
#include "base/feature_list.h"
#include "base/notreached.h"
#include "build/build_config.h"
#include "media/gpu/buildflags.h"
#include "ppapi/buildflags/buildflags.h"
#include "sandbox/linux/bpf_dsl/bpf_dsl.h"
#include "sandbox/linux/bpf_dsl/trap_registry.h"
#include "sandbox/policy/mojom/sandbox.mojom.h"
#include "sandbox/policy/switches.h"
#include "sandbox/sandbox_buildflags.h"
#if BUILDFLAG(USE_SECCOMP_BPF)
#include "base/files/scoped_file.h"
#include "base/posix/eintr_wrapper.h"
#include "sandbox/linux/seccomp-bpf-helpers/baseline_policy.h"
#include "sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.h"
#include "sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h"
#include "sandbox/linux/seccomp-bpf-helpers/syscall_sets.h"
#include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
#include "sandbox/linux/system_headers/linux_syscalls.h"
#include "sandbox/policy/chromecast_sandbox_allowlist_buildflags.h"
#include "sandbox/policy/linux/bpf_audio_policy_linux.h"
#include "sandbox/policy/linux/bpf_base_policy_linux.h"
#include "sandbox/policy/linux/bpf_cdm_policy_linux.h"
#include "sandbox/policy/linux/bpf_cros_amd_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_cros_arm_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_cros_intel_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_cros_nvidia_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_cros_virtio_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_gpu_policy_linux.h"
#include "sandbox/policy/linux/bpf_network_policy_linux.h"
#include "sandbox/policy/linux/bpf_ppapi_policy_linux.h"
#include "sandbox/policy/linux/bpf_print_backend_policy_linux.h"
#include "sandbox/policy/linux/bpf_print_compositor_policy_linux.h"
#include "sandbox/policy/linux/bpf_renderer_policy_linux.h"
#include "sandbox/policy/linux/bpf_screen_ai_policy_linux.h"
#include "sandbox/policy/linux/bpf_service_policy_linux.h"
#include "sandbox/policy/linux/bpf_speech_recognition_policy_linux.h"
#include "sandbox/policy/linux/bpf_utility_policy_linux.h"
#if BUILDFLAG(IS_CHROMEOS)
#include "chromeos/ash/components/assistant/buildflags.h"
#include "sandbox/policy/features.h"
#include "sandbox/policy/linux/bpf_ime_policy_linux.h"
#include "sandbox/policy/linux/bpf_nearby_policy_linux.h"
#include "sandbox/policy/linux/bpf_tts_policy_linux.h"
#if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
#include "sandbox/policy/linux/bpf_libassistant_policy_linux.h"
#endif // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
#endif // BUILDFLAG(IS_CHROMEOS)
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "sandbox/policy/linux/bpf_hardware_video_decoding_policy_linux.h"
#endif // BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#if BUILDFLAG(IS_LINUX)
#include "sandbox/policy/linux/bpf_on_device_translation_policy_linux.h"
#endif // BUILDFLAG(IS_LINUX)
using sandbox::bpf_dsl::Allow;
using sandbox::bpf_dsl::ResultExpr;
#else // BUILDFLAG(USE_SECCOMP_BPF)
// Make sure that seccomp-bpf does not get disabled by mistake. Also make sure
// that we think twice about this when adding a new architecture.
#if !defined(ARCH_CPU_ARM64) && !defined(ARCH_CPU_MIPS64EL)
#error "Seccomp-bpf disabled on supported architecture!"
#endif // !defined(ARCH_CPU_ARM64) && !defined(ARCH_CPU_MIPS64EL)
#endif // BUILDFLAG(USE_SECCOMP_BPF)
namespace sandbox {
namespace policy {
#if BUILDFLAG(USE_SECCOMP_BPF)
namespace {
// nacl_helper needs to be tiny and includes only part of content/
// in its dependencies. Make sure to not link things that are not needed.
#if !defined(IN_NACL_HELPER)
inline bool IsChromeOS() {
#if BUILDFLAG(IS_CHROMEOS)
return true;
#else
return false;
#endif
}
inline bool UseChromecastSandboxAllowlist() {
#if BUILDFLAG(ENABLE_CHROMECAST_GPU_SANDBOX_ALLOWLIST)
return true;
#else
return false;
#endif
}
inline bool IsArchitectureArm() {
#if defined(ARCH_CPU_ARM_FAMILY)
return true;
#else
return false;
#endif
}
std::unique_ptr<BPFBasePolicy> GetGpuProcessSandbox(
const SandboxSeccompBPF::Options& options) {
if (IsChromeOS() || UseChromecastSandboxAllowlist()) {
if (IsArchitectureArm()) {
return std::make_unique<CrosArmGpuProcessPolicy>(
base::CommandLine::ForCurrentProcess()->HasSwitch(
switches::kGpuSandboxAllowSysVShm));
}
if (options.use_amd_specific_policies) {
return std::make_unique<CrosAmdGpuProcessPolicy>();
}
if (options.use_intel_specific_policies) {
return std::make_unique<CrosIntelGpuProcessPolicy>();
}
if (options.use_nvidia_specific_policies) {
return std::make_unique<CrosNvidiaGpuProcessPolicy>();
}
if (options.use_virtio_specific_policies) {
return std::make_unique<CrosVirtIoGpuProcessPolicy>();
}
}
return std::make_unique<GpuProcessPolicy>();
}
#endif // !defined(IN_NACL_HELPER)
} // namespace
#endif // USE_SECCOMP_BPF
// Is seccomp BPF globally enabled?
bool SandboxSeccompBPF::IsSeccompBPFDesired() {
#if BUILDFLAG(USE_SECCOMP_BPF)
const base::CommandLine& command_line =
*base::CommandLine::ForCurrentProcess();
return !command_line.HasSwitch(switches::kNoSandbox) &&
!command_line.HasSwitch(switches::kDisableSeccompFilterSandbox);
#else
return false;
#endif // USE_SECCOMP_BPF
}
bool SandboxSeccompBPF::SupportsSandbox() {
#if BUILDFLAG(USE_SECCOMP_BPF)
return SandboxBPF::SupportsSeccompSandbox(
SandboxBPF::SeccompLevel::SINGLE_THREADED);
#else
return false;
#endif
}
bool SandboxSeccompBPF::SupportsSandboxWithTsync() {
#if BUILDFLAG(USE_SECCOMP_BPF)
return SandboxBPF::SupportsSeccompSandbox(
SandboxBPF::SeccompLevel::MULTI_THREADED);
#else
return false;
#endif
}
std::unique_ptr<BPFBasePolicy> SandboxSeccompBPF::PolicyForSandboxType(
sandbox::mojom::Sandbox sandbox_type,
const SandboxSeccompBPF::Options& options) {
switch (sandbox_type) {
case sandbox::mojom::Sandbox::kGpu:
return GetGpuProcessSandbox(options);
case sandbox::mojom::Sandbox::kRenderer:
return std::make_unique<RendererProcessPolicy>();
#if BUILDFLAG(ENABLE_PPAPI)
case sandbox::mojom::Sandbox::kPpapi:
return std::make_unique<PpapiProcessPolicy>();
#endif
case sandbox::mojom::Sandbox::kOnDeviceModelExecution:
return GetGpuProcessSandbox(options);
case sandbox::mojom::Sandbox::kUtility:
return std::make_unique<UtilityProcessPolicy>();
case sandbox::mojom::Sandbox::kCdm:
return std::make_unique<CdmProcessPolicy>();
case sandbox::mojom::Sandbox::kPrintCompositor:
return std::make_unique<PrintCompositorProcessPolicy>();
case sandbox::mojom::Sandbox::kPrintBackend:
return std::make_unique<PrintBackendProcessPolicy>();
case sandbox::mojom::Sandbox::kNetwork:
return std::make_unique<NetworkProcessPolicy>();
case sandbox::mojom::Sandbox::kAudio:
return std::make_unique<AudioProcessPolicy>();
case sandbox::mojom::Sandbox::kService:
return std::make_unique<ServiceProcessPolicy>();
case sandbox::mojom::Sandbox::kServiceWithJit:
return std::make_unique<ServiceProcessPolicy>();
case sandbox::mojom::Sandbox::kSpeechRecognition:
return std::make_unique<SpeechRecognitionProcessPolicy>();
#if BUILDFLAG(IS_LINUX)
case sandbox::mojom::Sandbox::kOnDeviceTranslation:
return std::make_unique<OnDeviceTranslationProcessPolicy>();
#endif // BUILDFLAG(IS_LINUX)
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
case sandbox::mojom::Sandbox::kScreenAI:
return std::make_unique<ScreenAIProcessPolicy>();
#endif
#if BUILDFLAG(IS_LINUX)
case sandbox::mojom::Sandbox::kVideoEffects:
return std::make_unique<ServiceProcessPolicy>();
#endif // BUILDFLAG(IS_LINUX)
#if BUILDFLAG(USE_LINUX_VIDEO_ACCELERATION)
case sandbox::mojom::Sandbox::kHardwareVideoDecoding:
return std::make_unique<HardwareVideoDecodingProcessPolicy>(
HardwareVideoDecodingProcessPolicy::ComputePolicyType(
options.use_amd_specific_policies));
case sandbox::mojom::Sandbox::kHardwareVideoEncoding:
// TODO(b/255554267): we're using the GPU process sandbox policy for now
// as a transition step. However, we should create a policy that's tighter
// just for hardware video encoding.
return GetGpuProcessSandbox(options);
#endif
#if BUILDFLAG(IS_CHROMEOS)
case sandbox::mojom::Sandbox::kIme:
return std::make_unique<ImeProcessPolicy>();
case sandbox::mojom::Sandbox::kTts:
return std::make_unique<TtsProcessPolicy>();
case sandbox::mojom::Sandbox::kNearby:
return std::make_unique<NearbyProcessPolicy>();
#if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
case sandbox::mojom::Sandbox::kLibassistant:
return std::make_unique<LibassistantProcessPolicy>();
#endif // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
#endif // BUILDFLAG(IS_CHROMEOS)
case sandbox::mojom::Sandbox::kZygoteIntermediateSandbox:
case sandbox::mojom::Sandbox::kNoSandbox:
NOTREACHED();
}
}
// If a BPF policy is engaged for |process_type|, run a few sanity checks.
void SandboxSeccompBPF::RunSandboxSanityChecks(
sandbox::mojom::Sandbox sandbox_type,
const SandboxSeccompBPF::Options& options) {
switch (sandbox_type) {
case sandbox::mojom::Sandbox::kRenderer:
case sandbox::mojom::Sandbox::kGpu:
#if BUILDFLAG(ENABLE_PPAPI)
case sandbox::mojom::Sandbox::kPpapi:
#endif
case sandbox::mojom::Sandbox::kPrintCompositor:
case sandbox::mojom::Sandbox::kCdm: {
int syscall_ret;
errno = 0;
// Without the sandbox, this would EBADF.
syscall_ret = fchmod(-1, 07777);
CHECK_EQ(-1, syscall_ret);
CHECK_EQ(EPERM, errno);
// Run most of the sanity checks only in DEBUG mode to avoid a perf.
// impact.
#if !defined(NDEBUG)
// open() must be restricted.
syscall_ret = open("/etc/passwd", O_RDONLY);
CHECK_EQ(-1, syscall_ret);
// The broker used with the GPU process sandbox uses EACCES for
// invalid filesystem access. See crbug.com/1233028 for more info.
CHECK_EQ(sandbox_type == sandbox::mojom::Sandbox::kGpu
? EACCES
: BPFBasePolicy::GetFSDeniedErrno(),
errno);
// We should never allow the creation of netlink sockets.
syscall_ret = socket(AF_NETLINK, SOCK_DGRAM, 0);
CHECK_EQ(-1, syscall_ret);
CHECK_EQ(EPERM, errno);
#endif // !defined(NDEBUG)
} break;
#if BUILDFLAG(USE_LINUX_VIDEO_ACCELERATION)
case sandbox::mojom::Sandbox::kHardwareVideoDecoding:
case sandbox::mojom::Sandbox::kHardwareVideoEncoding:
#endif
#if BUILDFLAG(IS_CHROMEOS)
case sandbox::mojom::Sandbox::kIme:
case sandbox::mojom::Sandbox::kTts:
case sandbox::mojom::Sandbox::kNearby:
#if BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
case sandbox::mojom::Sandbox::kLibassistant:
#endif // BUILDFLAG(ENABLE_CROS_LIBASSISTANT)
#endif // BUILDFLAG(IS_CHROMEOS)
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
case sandbox::mojom::Sandbox::kScreenAI:
#endif
#if BUILDFLAG(IS_LINUX)
case sandbox::mojom::Sandbox::kVideoEffects:
case sandbox::mojom::Sandbox::kOnDeviceTranslation:
#endif // BUILDFLAG(IS_LINUX)
case sandbox::mojom::Sandbox::kAudio:
case sandbox::mojom::Sandbox::kService:
case sandbox::mojom::Sandbox::kServiceWithJit:
case sandbox::mojom::Sandbox::kSpeechRecognition:
case sandbox::mojom::Sandbox::kNetwork:
case sandbox::mojom::Sandbox::kPrintBackend:
case sandbox::mojom::Sandbox::kOnDeviceModelExecution:
case sandbox::mojom::Sandbox::kUtility:
case sandbox::mojom::Sandbox::kNoSandbox:
case sandbox::mojom::Sandbox::kZygoteIntermediateSandbox:
// Otherwise, no checks required.
break;
}
}
bool SandboxSeccompBPF::StartSandboxWithExternalPolicy(
std::unique_ptr<bpf_dsl::Policy> policy,
base::ScopedFD proc_fd,
SandboxBPF::SeccompLevel seccomp_level) {
#if BUILDFLAG(USE_SECCOMP_BPF)
if (IsSeccompBPFDesired() && SupportsSandbox()) {
CHECK(policy);
// Starting the sandbox is a one-way operation. The kernel doesn't allow
// us to unload a sandbox policy after it has been started. Nonetheless,
// in order to make the use of the "Sandbox" object easier, we allow for
// the object to be destroyed after the sandbox has been started. Note that
// doing so does not stop the sandbox.
SandboxBPF sandbox(std::move(policy));
sandbox.SetProcFd(std::move(proc_fd));
bool enable_ibpb = true;
#if BUILDFLAG(IS_CHROMEOS)
enable_ibpb =
base::FeatureList::IsEnabled(features::kSpectreVariant2Mitigation);
#endif // BUILDFLAG(IS_CHROMEOS)
CHECK(sandbox.StartSandbox(seccomp_level, enable_ibpb));
return true;
}
#endif // BUILDFLAG(USE_SECCOMP_BPF)
return false;
}
std::unique_ptr<bpf_dsl::Policy> SandboxSeccompBPF::GetBaselinePolicy() {
#if BUILDFLAG(USE_SECCOMP_BPF)
return std::make_unique<BaselinePolicy>();
#else
return nullptr;
#endif // BUILDFLAG(USE_SECCOMP_BPF)
}
} // namespace policy
} // namespace sandbox
|
