sandboxed-api/sandboxed_api/sandbox2/notify_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/notify.h"
#include <syscall.h>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include <glog/logging.h>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/memory/memory.h"
#include "absl/strings/str_join.h"
#include "sandboxed_api/sandbox2/comms.h"
#include "sandboxed_api/sandbox2/executor.h"
#include "sandboxed_api/sandbox2/policy.h"
#include "sandboxed_api/sandbox2/policybuilder.h"
#include "sandboxed_api/sandbox2/sandbox2.h"
#include "sandboxed_api/sandbox2/syscall.h"
#include "sandboxed_api/sandbox2/util/bpf_helper.h"
#include "sandboxed_api/testing.h"
namespace sandbox2 {
namespace {
using ::sapi::GetTestSourcePath;
using ::testing::Eq;
// Allow typical syscalls and call SECCOMP_RET_TRACE for personality syscall,
// chosen because unlikely to be called by a regular program.
std::unique_ptr<Policy> NotifyTestcasePolicy() {
return PolicyBuilder()
.DisableNamespaces()
.AllowDynamicStartup() // For PrintPidAndComms and includes
// AllowStaticStartup
.AllowExit()
.AllowRead()
.AllowWrite()
.AllowSyscall(__NR_close)
.AddPolicyOnSyscall(__NR_personality, {SANDBOX2_TRACE})
.BlockSyscallsWithErrno(
{
#ifdef __NR_open
__NR_open,
#endif
__NR_openat,
#ifdef __NR_access
__NR_access,
#endif
},
ENOENT)
.BlockSyscallWithErrno(__NR_prlimit64, EPERM)
.BuildOrDie();
}
// If syscall and its arguments don't match the expected ones, return the
// opposite of the requested values (allow/disallow) to indicate an error.
class PersonalityNotify : public Notify {
public:
explicit PersonalityNotify(bool allow) : allow_(allow) {}
bool EventSyscallTrap(const Syscall& syscall) override {
if (syscall.nr() != __NR_personality) {
LOG(ERROR) << "kSyscall==" << syscall.nr();
return (!allow_);
}
Syscall::Args expected_args = {0x1, 0x2, 0x3, 0x4, 0x5, 0x6};
if (syscall.args() != expected_args) {
LOG(ERROR) << "args=={" << absl::StrJoin(syscall.args(), ", ") << "}";
return (!allow_);
}
return allow_;
}
private:
// The intended return value from EventSyscallTrap in case all registers
// match.
bool allow_;
};
// Print the newly created PID, and exchange data over Comms before sandboxing.
class PidCommsNotify : public Notify {
public:
bool EventStarted(pid_t pid, Comms* comms) final {
LOG(INFO) << "The newly created PID: " << pid;
bool v;
return comms->RecvBool(&v);
}
};
// Test EventSyscallTrap on personality syscall and allow it.
TEST(NotifyTest, AllowPersonality) {
SKIP_SANITIZERS_AND_COVERAGE;
const std::string path = GetTestSourcePath("sandbox2/testcases/personality");
std::vector<std::string> args = {path};
Sandbox2 s2(absl::make_unique<Executor>(path, args), NotifyTestcasePolicy(),
absl::make_unique<PersonalityNotify>(/*allow=*/true));
auto result = s2.Run();
ASSERT_THAT(result.final_status(), Eq(Result::OK));
EXPECT_THAT(result.reason_code(), Eq(22));
}
// Test EventSyscallTrap on personality syscall and disallow it.
TEST(NotifyTest, DisallowPersonality) {
SKIP_SANITIZERS_AND_COVERAGE;
const std::string path = GetTestSourcePath("sandbox2/testcases/personality");
std::vector<std::string> args = {path};
Sandbox2 s2(absl::make_unique<Executor>(path, args), NotifyTestcasePolicy(),
absl::make_unique<PersonalityNotify>(/*allow=*/false));
auto result = s2.Run();
ASSERT_THAT(result.final_status(), Eq(Result::VIOLATION));
EXPECT_THAT(result.reason_code(), Eq(__NR_personality));
}
// Test EventStarted by exchanging data after started but before sandboxed.
TEST(NotifyTest, PrintPidAndComms) {
SKIP_SANITIZERS_AND_COVERAGE;
const std::string path = GetTestSourcePath("sandbox2/testcases/pidcomms");
std::vector<std::string> args = {path};
auto executor = absl::make_unique<Executor>(path, args);
executor->set_enable_sandbox_before_exec(false);
Sandbox2 s2(std::move(executor), NotifyTestcasePolicy(),
absl::make_unique<PidCommsNotify>());
auto result = s2.Run();
ASSERT_THAT(result.final_status(), Eq(Result::OK));
EXPECT_THAT(result.reason_code(), Eq(33));
}
} // namespace
} // namespace sandbox2