sandboxed-api/sandboxed_api/sandbox2/stack_trace_test.cc

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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "sandboxed_api/sandbox2/stack_trace.h"
#include <sys/types.h>
#include <cstdio>
#include <functional>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/log_severity.h"
#include "absl/flags/declare.h"
#include "absl/flags/flag.h"
#include "absl/flags/reflection.h"
#include "absl/log/check.h"
#include "absl/log/scoped_mock_log.h"
#include "absl/strings/str_cat.h"
#include "absl/time/time.h"
#include "sandboxed_api/sandbox2/executor.h"
#include "sandboxed_api/sandbox2/global_forkclient.h"
#include "sandboxed_api/sandbox2/policy.h"
#include "sandboxed_api/sandbox2/policybuilder.h"
#include "sandboxed_api/sandbox2/result.h"
#include "sandboxed_api/sandbox2/sandbox2.h"
#include "sandboxed_api/testing.h"
#include "sandboxed_api/util/fileops.h"
#include "sandboxed_api/util/status_matchers.h"
ABSL_DECLARE_FLAG(bool, sandbox_libunwind_crash_handler);
namespace sandbox2 {
class StackTraceTestPeer {
public:
static StackTraceTestPeer& GetInstance() {
static auto* peer = new StackTraceTestPeer();
return *peer;
}
std::unique_ptr<internal::SandboxPeer> SpawnFn(
std::unique_ptr<Executor> executor, std::unique_ptr<Policy> policy) {
if (crash_unwind_) {
policy = PolicyBuilder().BuildOrDie();
crash_unwind_ = false;
}
return old_spawn_fn_(std::move(executor), std::move(policy));
}
void ReplaceSpawnFn() {
old_spawn_fn_ = internal::SandboxPeer::spawn_fn_;
internal::SandboxPeer::spawn_fn_ = +[](std::unique_ptr<Executor> executor,
std::unique_ptr<Policy> policy) {
return GetInstance().SpawnFn(std::move(executor), std::move(policy));
};
}
void RestoreSpawnFn() { internal::SandboxPeer::spawn_fn_ = old_spawn_fn_; }
void CrashNextUnwind() { crash_unwind_ = true; }
private:
internal::SandboxPeer::SpawnFn old_spawn_fn_;
bool crash_unwind_ = false;
};
struct ScopedSpawnOverride {
ScopedSpawnOverride() { StackTraceTestPeer::GetInstance().ReplaceSpawnFn(); }
~ScopedSpawnOverride() { StackTraceTestPeer::GetInstance().RestoreSpawnFn(); }
ScopedSpawnOverride(ScopedSpawnOverride&&) = delete;
ScopedSpawnOverride& operator=(ScopedSpawnOverride&&) = delete;
ScopedSpawnOverride(const ScopedSpawnOverride&) = delete;
ScopedSpawnOverride& operator=(const ScopedSpawnOverride&) = delete;
void CrashNextUnwind() {
StackTraceTestPeer::GetInstance().CrashNextUnwind();
}
};
namespace {
namespace file_util = ::sapi::file_util;
using ::sapi::CreateDefaultPermissiveTestPolicy;
using ::sapi::GetTestSourcePath;
using ::testing::_;
using ::testing::Contains;
using ::testing::ContainsRegex;
using ::testing::ElementsAre;
using ::testing::Eq;
using ::testing::IsEmpty;
using ::testing::StartsWith;
struct TestCase {
std::string testname = "CrashMe";
int testno = 1;
int testmode = 1;
int final_status = Result::SIGNALED;
std::string function_name = testname;
std::string full_function_description = "CrashMe(char)";
std::function<void(PolicyBuilder*)> modify_policy;
absl::Duration wall_time_limit = absl::ZeroDuration();
};
class StackTraceTest : public ::testing::TestWithParam<TestCase> {};
// Test that symbolization of stack traces works.
void SymbolizationWorksCommon(TestCase param) {
const std::string path = GetTestSourcePath("sandbox2/testcases/symbolize");
std::vector<std::string> args = {path, absl::StrCat(param.testno),
absl::StrCat(param.testmode)};
PolicyBuilder builder = CreateDefaultPermissiveTestPolicy(path);
if (param.modify_policy) {
param.modify_policy(&builder);
}
SAPI_ASSERT_OK_AND_ASSIGN(auto policy, builder.TryBuild());
Sandbox2 s2(std::make_unique<Executor>(path, args), std::move(policy));
ASSERT_TRUE(s2.RunAsync());
s2.set_walltime_limit(param.wall_time_limit);
auto result = s2.AwaitResult();
EXPECT_THAT(result.final_status(), Eq(param.final_status));
EXPECT_THAT(result.stack_trace(), Contains(StartsWith(param.function_name)));
// Check that demangling works as well.
EXPECT_THAT(result.stack_trace(),
Contains(StartsWith(param.full_function_description)));
EXPECT_THAT(result.stack_trace(), Contains(StartsWith("RunTest")));
EXPECT_THAT(result.stack_trace(), Contains(StartsWith("main")));
if (param.testmode == 2) {
EXPECT_THAT(result.stack_trace(),
Contains(StartsWith("RecurseA")).Times(5));
EXPECT_THAT(result.stack_trace(),
Contains(StartsWith("RecurseB")).Times(5));
} else if (param.testmode == 3) {
EXPECT_THAT(result.stack_trace(), Contains(StartsWith("LibCallCallback")));
EXPECT_THAT(result.stack_trace(), Contains(StartsWith("LibRecurse")));
EXPECT_THAT(result.stack_trace(),
Contains(StartsWith("LibRecurseA")).Times(5));
EXPECT_THAT(result.stack_trace(),
Contains(StartsWith("LibRecurseB")).Times(5));
}
}
void SymbolizationWorksWithModifiedPolicy(
std::function<void(PolicyBuilder*)> modify_policy) {
TestCase test_case;
test_case.modify_policy = std::move(modify_policy);
SymbolizationWorksCommon(test_case);
}
TEST_P(StackTraceTest, SymbolizationWorksNonSandboxedLibunwind) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, false);
SymbolizationWorksCommon(GetParam());
}
TEST_P(StackTraceTest, SymbolizationWorksSandboxedLibunwind) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
SymbolizationWorksCommon(GetParam());
}
TEST(StackTraceTest, SymbolizationWorksSandboxedLibunwindProcDirMounted) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
SymbolizationWorksWithModifiedPolicy(
[](PolicyBuilder* builder) { builder->AddDirectory("/proc"); });
}
TEST(StackTraceTest, SymbolizationWorksSandboxedLibunwindProcFileMounted) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
SymbolizationWorksWithModifiedPolicy([](PolicyBuilder* builder) {
builder->AddFile("/proc/sys/vm/overcommit_memory");
});
}
TEST(StackTraceTest, SymbolizationWorksSandboxedLibunwindSysDirMounted) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
SymbolizationWorksWithModifiedPolicy(
[](PolicyBuilder* builder) { builder->AddDirectory("/sys"); });
}
TEST(StackTraceTest, SymbolizationWorksSandboxedLibunwindSysFileMounted) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
SymbolizationWorksWithModifiedPolicy([](PolicyBuilder* builder) {
builder->AddFile("/sys/devices/system/cpu/online");
});
}
size_t FileCountInDirectory(const std::string& path) {
std::vector<std::string> fds;
std::string error;
CHECK(file_util::fileops::ListDirectoryEntries(path, &fds, &error));
return fds.size();
}
TEST(StackTraceTest, ForkEnterNsLibunwindDoesNotLeakFDs) {
absl::FlagSaver fs;
absl::SetFlag(&FLAGS_sandbox_libunwind_crash_handler, true);
// Very first sanitization might create some fds (e.g. for initial
// namespaces).
SymbolizationWorksCommon({});
// Get list of open FDs in the global forkserver.
pid_t forkserver_pid = GlobalForkClient::GetPid();
std::string forkserver_fd_path =
absl::StrCat("/proc/", forkserver_pid, "/fd");
size_t filecount_before = FileCountInDirectory(forkserver_fd_path);
SymbolizationWorksCommon({});
EXPECT_THAT(filecount_before, Eq(FileCountInDirectory(forkserver_fd_path)));
}
TEST(StackTraceTest, CompactStackTrace) {
EXPECT_THAT(CompactStackTrace({}), IsEmpty());
EXPECT_THAT(CompactStackTrace({"_start"}), ElementsAre("_start"));
EXPECT_THAT(CompactStackTrace({
"_start",
"main",
"recursive_call",
"recursive_call",
"recursive_call",
"tail_call",
}),
ElementsAre("_start", "main", "recursive_call",
"(previous frame repeated 2 times)", "tail_call"));
EXPECT_THAT(CompactStackTrace({
"_start",
"main",
"recursive_call",
"recursive_call",
"recursive_call",
"recursive_call",
}),
ElementsAre("_start", "main", "recursive_call",
"(previous frame repeated 3 times)"));
}
TEST(StackTraceTest, RecursiveStackTrace) {
// Very first sandbox run will initialize spawn_fn_
SKIP_SANITIZERS;
ScopedSpawnOverride spawn_override;
SymbolizationWorksCommon({});
absl::ScopedMockLog log;
EXPECT_CALL(
log,
Log(absl::LogSeverity::kInfo, _,
ContainsRegex(
"Libunwind execution status: SYSCALL VIOLATION.*Stack: \\w+")));
spawn_override.CrashNextUnwind();
const std::string path = GetTestSourcePath("sandbox2/testcases/symbolize");
std::vector<std::string> args = {path, absl::StrCat(1), absl::StrCat(1)};
PolicyBuilder builder = CreateDefaultPermissiveTestPolicy(path);
SAPI_ASSERT_OK_AND_ASSIGN(auto policy, builder.TryBuild());
Sandbox2 s2(std::make_unique<Executor>(path, args), std::move(policy));
log.StartCapturingLogs();
ASSERT_TRUE(s2.RunAsync());
auto result = s2.AwaitResult();
EXPECT_THAT(result.final_status(), Eq(Result::SIGNALED));
}
INSTANTIATE_TEST_SUITE_P(
Instantiation, StackTraceTest,
::testing::Values(
TestCase{
.testname = "CrashMe",
.testno = 1,
.final_status = Result::SIGNALED,
.full_function_description = "CrashMe(char)",
},
TestCase{
.testname = "ViolatePolicy",
.testno = 2,
.final_status = Result::VIOLATION,
.full_function_description = "ViolatePolicy(int)",
},
TestCase{
.testname = "ExitNormally",
.testno = 3,
.final_status = Result::OK,
.full_function_description = "ExitNormally(int)",
.modify_policy =
[](PolicyBuilder* builder) {
builder->CollectStacktracesOnExit(true);
},
},
TestCase{
.testname = "SleepForXSeconds",
.testno = 4,
.final_status = Result::TIMEOUT,
.full_function_description = "SleepForXSeconds(int)",
.wall_time_limit = absl::Seconds(1),
},
TestCase{
.testname = "ViolatePolicyRecursive",
.testno = 2,
.testmode = 2,
.final_status = Result::VIOLATION,
.function_name = "ViolatePolicy",
.full_function_description = "ViolatePolicy(int)",
},
TestCase{
.testname = "ViolatePolicyRecursiveLib",
.testno = 2,
.testmode = 3,
.final_status = Result::VIOLATION,
.function_name = "ViolatePolicy",
.full_function_description = "ViolatePolicy(int)",
}),
[](const ::testing::TestParamInfo<TestCase>& info) {
return info.param.testname;
});
} // namespace
} // namespace sandbox2