mirror of
https://github.com/google/sandboxed-api.git
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dbaf95c724
This change should make it less confusing where utility code comes from. Having it in two places made sense when we were debating whether to publish Sandbox2 separately, but not any longer. Follow-up changes will move `sandbox2/util.h` and rename the remaining `sandbox2/util` folder. PiperOrigin-RevId: 351601640 Change-Id: I6256845261f610e590c25e2c59851cc51da2d778
341 lines
11 KiB
C++
341 lines
11 KiB
C++
// Copyright 2019 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "sandboxed_api/sandbox2/policy.h"
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#include <sys/resource.h>
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#include <syscall.h>
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#include <cerrno>
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#include <cstdlib>
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#include <string>
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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#include "absl/memory/memory.h"
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#include "absl/strings/string_view.h"
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#include "sandboxed_api/config.h"
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#include "sandboxed_api/sandbox2/executor.h"
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#include "sandboxed_api/sandbox2/limits.h"
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#include "sandboxed_api/sandbox2/policybuilder.h"
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#include "sandboxed_api/sandbox2/result.h"
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#include "sandboxed_api/sandbox2/sandbox2.h"
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#include "sandboxed_api/sandbox2/syscall.h"
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#include "sandboxed_api/sandbox2/util/bpf_helper.h"
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#include "sandboxed_api/testing.h"
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namespace sandbox2 {
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namespace {
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using ::sapi::GetTestSourcePath;
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using ::testing::Eq;
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PolicyBuilder CreatePolicyTestPolicyBuilder() {
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return PolicyBuilder()
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.DisableNamespaces()
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.AllowStaticStartup()
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.AllowExit()
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.AllowRead()
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.AllowWrite()
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.AllowSyscall(__NR_close)
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.AllowSyscall(__NR_getppid)
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.AllowTCGETS()
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#ifdef __NR_open
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.BlockSyscallWithErrno(__NR_open, ENOENT)
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#endif
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.BlockSyscallWithErrno(__NR_openat, ENOENT)
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#ifdef __NR_access
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.BlockSyscallWithErrno(__NR_access, ENOENT)
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#endif
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#ifdef __NR_faccessat
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.BlockSyscallWithErrno(__NR_faccessat, ENOENT)
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#endif
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.BlockSyscallWithErrno(__NR_prlimit64, EPERM);
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}
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std::unique_ptr<Policy> PolicyTestcasePolicy() {
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return CreatePolicyTestPolicyBuilder().BuildOrDie();
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}
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#ifdef SAPI_X86_64
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// Test that 32-bit syscalls from 64-bit are disallowed.
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TEST(PolicyTest, AMD64Syscall32PolicyAllowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "1"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(), Eq(1)); // __NR_exit in 32-bit
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EXPECT_THAT(result.GetSyscallArch(), Eq(sapi::cpu::kX86));
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}
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// Test that 32-bit syscalls from 64-bit for FS checks are disallowed.
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TEST(PolicyTest, AMD64Syscall32FsAllowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "2"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(),
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Eq(33)); // __NR_access in 32-bit
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EXPECT_THAT(result.GetSyscallArch(), Eq(sapi::cpu::kX86));
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}
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#endif
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// Test that ptrace(2) is disallowed.
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TEST(PolicyTest, PtraceDisallowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "3"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(), Eq(__NR_ptrace));
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}
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// Test that clone(2) with flag CLONE_UNTRACED is disallowed.
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TEST(PolicyTest, CloneUntracedDisallowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "4"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(), Eq(__NR_clone));
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}
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// Test that bpf(2) is disallowed.
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TEST(PolicyTest, BpfDisallowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "5"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(), Eq(__NR_bpf));
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}
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// Test that bpf(2) can return EPERM.
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TEST(PolicyTest, BpfPermissionDenied) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "7"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = CreatePolicyTestPolicyBuilder()
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.BlockSyscallWithErrno(__NR_bpf, EPERM)
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.BuildOrDie();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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// bpf(2) is not a violation due to explicit policy. EPERM is expected.
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ASSERT_THAT(result.final_status(), Eq(Result::OK));
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EXPECT_THAT(result.reason_code(), Eq(EPERM));
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}
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TEST(PolicyTest, IsattyAllowed) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/policy");
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std::vector<std::string> args = {path, "6"};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::OK));
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}
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std::unique_ptr<Policy> MinimalTestcasePolicy() {
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return PolicyBuilder()
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.AllowStaticStartup()
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.AllowExit()
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.BlockSyscallWithErrno(__NR_prlimit64, EPERM)
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#ifdef __NR_access
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.BlockSyscallWithErrno(__NR_access, ENOENT)
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#endif
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.BuildOrDie();
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}
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// Test that we can sandbox a minimal static binary returning 0.
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// If this starts failing, it means something changed, maybe in the way we
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// compile static binaries, and we need to update the policy just above.
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TEST(MinimalTest, MinimalBinaryWorks) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path = GetTestSourcePath("sandbox2/testcases/minimal");
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std::vector<std::string> args = {path};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = MinimalTestcasePolicy();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::OK));
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EXPECT_THAT(result.reason_code(), Eq(EXIT_SUCCESS));
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}
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// Test that we can sandbox a minimal non-static binary returning 0.
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TEST(MinimalTest, MinimalSharedBinaryWorks) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path =
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GetTestSourcePath("sandbox2/testcases/minimal_dynamic");
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std::vector<std::string> args = {path};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyBuilder()
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.AllowDynamicStartup()
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.AllowOpen()
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.AllowExit()
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.AllowMmap()
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#ifdef __NR_access
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// New glibc accesses /etc/ld.so.preload
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.BlockSyscallWithErrno(__NR_access, ENOENT)
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#endif
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.BlockSyscallWithErrno(__NR_prlimit64, EPERM)
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.AddLibrariesForBinary(path)
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.BuildOrDie();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::OK));
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EXPECT_THAT(result.reason_code(), Eq(EXIT_SUCCESS));
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}
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// Test that the AllowSystemMalloc helper works as expected.
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TEST(MallocTest, SystemMallocWorks) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path =
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GetTestSourcePath("sandbox2/testcases/malloc_system");
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std::vector<std::string> args = {path};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyBuilder()
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.AllowStaticStartup()
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.AllowSystemMalloc()
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.AllowExit()
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.BlockSyscallWithErrno(__NR_prlimit64, EPERM)
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#ifdef __NR_access
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.BlockSyscallWithErrno(__NR_access, ENOENT)
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#endif
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.BuildOrDie();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::OK));
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EXPECT_THAT(result.reason_code(), Eq(EXIT_SUCCESS));
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}
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// Complicated test to see that AddPolicyOnSyscalls work as
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// expected. Specifically a worrisome corner-case would be that the logic was
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// almost correct, but that the jump targets were off slightly. This uses the
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// AddPolicyOnSyscall multiple times in a row to make any miscalculation
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// unlikely to pass this check.
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TEST(MultipleSyscalls, AddPolicyOnSyscallsWorks) {
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SKIP_SANITIZERS_AND_COVERAGE;
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const std::string path =
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GetTestSourcePath("sandbox2/testcases/add_policy_on_syscalls");
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std::vector<std::string> args = {path};
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auto executor = absl::make_unique<Executor>(path, args);
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auto policy = PolicyBuilder()
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#ifdef __NR_open
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.BlockSyscallWithErrno(__NR_open, ENOENT)
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#endif
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.BlockSyscallWithErrno(__NR_openat, ENOENT)
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.AllowStaticStartup()
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.AllowTcMalloc()
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.AllowExit()
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.AddPolicyOnSyscalls(
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{
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__NR_getuid,
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__NR_getgid,
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__NR_geteuid,
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__NR_getegid,
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#ifdef __NR_getuid32
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__NR_getuid32,
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#endif
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#ifdef __NR_getgid32
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__NR_getgid32,
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#endif
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#ifdef __NR_geteuid32
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__NR_geteuid32,
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#endif
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#ifdef __NR_getegid32
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__NR_getegid32,
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#endif
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},
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{ALLOW})
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.AddPolicyOnSyscalls(
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{
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__NR_getresuid,
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__NR_getresgid,
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#ifdef __NR_getresuid32
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__NR_getresuid32,
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#endif
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#ifdef __NR_getresgid32
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__NR_getresgid32,
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#endif
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},
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{ERRNO(42)})
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.AddPolicyOnSyscalls({__NR_read, __NR_write}, {ERRNO(43)})
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.AddPolicyOnSyscall(__NR_umask, {DENY})
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.BlockSyscallWithErrno(__NR_prlimit64, EPERM)
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#ifdef __NR_access
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.BlockSyscallWithErrno(__NR_access, ENOENT)
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#endif
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.BuildOrDie();
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Sandbox2 s2(std::move(executor), std::move(policy));
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auto result = s2.Run();
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ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
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EXPECT_THAT(result.reason_code(), Eq(__NR_umask));
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}
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} // namespace
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} // namespace sandbox2
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