/*
* Copyright 2017 The Android Open Source Project
*
* 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
*
* http://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 <string>
#include <fcntl.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#define LOG_TAG "IptablesRestoreControllerTest"
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <log/log.h>
#include <netdutils/MockSyscalls.h>
#include <netdutils/Stopwatch.h>
#include "IptablesRestoreController.h"
#include "NetdConstants.h"
#include "bpf/BpfUtils.h"
#define XT_LOCK_NAME "/system/etc/xtables.lock"
#define XT_LOCK_ATTEMPTS 10
#define XT_LOCK_POLL_INTERVAL_MS 100
using android::base::Join;
using android::base::StringPrintf;
using android::netdutils::ScopedMockSyscalls;
using android::netdutils::Stopwatch;
using testing::Return;
using testing::StrictMock;
class IptablesRestoreControllerTest : public ::testing::Test {
public:
IptablesRestoreController con;
int mDefaultMaxRetries = con.MAX_RETRIES;
int mDefaultPollTimeoutMs = con.POLL_TIMEOUT_MS;
int mIptablesLock = -1;
std::string mChainName;
static void SetUpTestCase() {
blockSigpipe();
}
void SetUp() {
ASSERT_EQ(0, createTestChain());
}
void TearDown() {
con.MAX_RETRIES = mDefaultMaxRetries;
con.POLL_TIMEOUT_MS = mDefaultPollTimeoutMs;
deleteTestChain();
}
void Init() {
con.Init();
}
pid_t getIpRestorePid(const IptablesRestoreController::IptablesProcessType type) {
return con.getIpRestorePid(type);
};
void expectNoIptablesRestoreProcess(pid_t pid) {
// We can't readlink /proc/PID/exe, because zombie processes don't have it.
// Parse /proc/PID/stat instead.
std::string statPath = StringPrintf("/proc/%d/stat", pid);
int fd = open(statPath.c_str(), O_RDONLY | O_CLOEXEC);
if (fd == -1) {
// ENOENT means the process is gone (expected).
ASSERT_EQ(errno, ENOENT)
<< "Unexpected error opening " << statPath << ": " << strerror(errno);
return;
}
// If the PID exists, it's possible (though very unlikely) that the PID was reused. Check the
// binary name as well, to ensure the test isn't flaky.
char statBuf[1024];
ASSERT_NE(-1, read(fd, statBuf, sizeof(statBuf)))
<< "Could not read from " << statPath << ": " << strerror(errno);
close(fd);
std::string statString(statBuf);
EXPECT_FALSE(statString.find("iptables-restor") || statString.find("ip6tables-resto"))
<< "Previous iptables-restore pid " << pid << " still alive: " << statString;
}
int createTestChain() {
mChainName = StringPrintf("netd_unit_test_%u", arc4random_uniform(10000)).c_str();
// Create a chain to list.
std::vector<std::string> createCommands = {
"*filter",
StringPrintf(":%s -", mChainName.c_str()),
StringPrintf("-A %s -j RETURN", mChainName.c_str()),
"COMMIT",
""
};
int ret = con.execute(V4V6, Join(createCommands, "\n"), nullptr);
if (ret) mChainName = "";
return ret;
}
void deleteTestChain() {
std::vector<std::string> deleteCommands = {
"*filter",
StringPrintf(":%s -", mChainName.c_str()), // Flush chain (otherwise we can't delete it).
StringPrintf("-X %s", mChainName.c_str()), // Delete it.
"COMMIT",
""
};
con.execute(V4V6, Join(deleteCommands, "\n"), nullptr);
mChainName = "";
}
int acquireIptablesLock() {
mIptablesLock = open(XT_LOCK_NAME, O_CREAT | O_CLOEXEC, 0600);
if (mIptablesLock == -1) return mIptablesLock;
int attempts;
for (attempts = 0; attempts < XT_LOCK_ATTEMPTS; attempts++) {
if (flock(mIptablesLock, LOCK_EX | LOCK_NB) == 0) {
return 0;
}
usleep(XT_LOCK_POLL_INTERVAL_MS * 1000);
}
EXPECT_LT(attempts, XT_LOCK_ATTEMPTS) <<
"Could not acquire iptables lock after " << XT_LOCK_ATTEMPTS << " attempts " <<
XT_LOCK_POLL_INTERVAL_MS << "ms apart";
return -1;
}
void releaseIptablesLock() {
if (mIptablesLock != -1) {
close(mIptablesLock);
}
}
void setRetryParameters(int maxRetries, int pollTimeoutMs) {
con.MAX_RETRIES = maxRetries;
con.POLL_TIMEOUT_MS = pollTimeoutMs;
}
};
TEST_F(IptablesRestoreControllerTest, TestBasicCommand) {
std::string output;
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, "#Test\n", nullptr));
pid_t pid4 = getIpRestorePid(IptablesRestoreController::IPTABLES_PROCESS);
pid_t pid6 = getIpRestorePid(IptablesRestoreController::IP6TABLES_PROCESS);
EXPECT_EQ(0, con.execute(IptablesTarget::V6, "#Test\n", nullptr));
EXPECT_EQ(0, con.execute(IptablesTarget::V4, "#Test\n", nullptr));
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, "#Test\n", &output));
EXPECT_EQ("#Test\n#Test\n", output); // One for IPv4 and one for IPv6.
// Check the PIDs are the same as they were before. If they're not, the child processes were
// restarted, which causes a 30-60ms delay.
EXPECT_EQ(pid4, getIpRestorePid(IptablesRestoreController::IPTABLES_PROCESS));
EXPECT_EQ(pid6, getIpRestorePid(IptablesRestoreController::IP6TABLES_PROCESS));
}
TEST_F(IptablesRestoreControllerTest, TestRestartOnMalformedCommand) {
std::string buffer;
for (int i = 0; i < 50; i++) {
IptablesTarget target = (IptablesTarget) (i % 3);
std::string *output = (i % 2) ? &buffer : nullptr;
ASSERT_EQ(-1, con.execute(target, "malformed command\n", output)) <<
"Malformed command did not fail at iteration " << i;
ASSERT_EQ(0, con.execute(target, "#Test\n", output)) <<
"No-op command did not succeed at iteration " << i;
}
}
TEST_F(IptablesRestoreControllerTest, TestRestartOnProcessDeath) {
std::string output;
// Run a command to ensure that the processes are running.
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, "#Test\n", &output));
pid_t pid4 = getIpRestorePid(IptablesRestoreController::IPTABLES_PROCESS);
pid_t pid6 = getIpRestorePid(IptablesRestoreController::IP6TABLES_PROCESS);
ASSERT_EQ(0, kill(pid4, 0)) << "iptables-restore pid " << pid4 << " does not exist";
ASSERT_EQ(0, kill(pid6, 0)) << "ip6tables-restore pid " << pid6 << " does not exist";
ASSERT_EQ(0, kill(pid4, SIGTERM)) << "Failed to send SIGTERM to iptables-restore pid " << pid4;
ASSERT_EQ(0, kill(pid6, SIGTERM)) << "Failed to send SIGTERM to ip6tables-restore pid " << pid6;
// Wait 100ms for processes to terminate.
TEMP_FAILURE_RETRY(usleep(100 * 1000));
// Ensure that running a new command properly restarts the processes.
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, "#Test\n", nullptr));
EXPECT_NE(pid4, getIpRestorePid(IptablesRestoreController::IPTABLES_PROCESS));
EXPECT_NE(pid6, getIpRestorePid(IptablesRestoreController::IP6TABLES_PROCESS));
// Check there are no zombies.
expectNoIptablesRestoreProcess(pid4);
expectNoIptablesRestoreProcess(pid6);
}
TEST_F(IptablesRestoreControllerTest, TestCommandTimeout) {
// Don't wait 10 seconds for this test to fail.
setRetryParameters(3, 50);
// Expected contents of the chain.
std::vector<std::string> expectedLines = {
StringPrintf("Chain %s (0 references)", mChainName.c_str()),
"target prot opt source destination ",
"RETURN all -- 0.0.0.0/0 0.0.0.0/0 ",
StringPrintf("Chain %s (0 references)", mChainName.c_str()),
"target prot opt source destination ",
"RETURN all ::/0 ::/0 ",
""
};
std::string expected = Join(expectedLines, "\n");
std::vector<std::string> listCommands = {
"*filter",
StringPrintf("-n -L %s", mChainName.c_str()), // List chain.
"COMMIT",
""
};
std::string commandString = Join(listCommands, "\n");
std::string output;
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, commandString, &output));
EXPECT_EQ(expected, output);
ASSERT_EQ(0, acquireIptablesLock());
EXPECT_EQ(-1, con.execute(IptablesTarget::V4V6, commandString, &output));
EXPECT_EQ(-1, con.execute(IptablesTarget::V4V6, commandString, &output));
releaseIptablesLock();
EXPECT_EQ(0, con.execute(IptablesTarget::V4V6, commandString, &output));
EXPECT_EQ(expected, output);
}
TEST_F(IptablesRestoreControllerTest, TestUidRuleBenchmark) {
const std::vector<int> ITERATIONS = { 1, 5, 10 };
const std::string IPTABLES_RESTORE_ADD =
StringPrintf("*filter\n-I %s -m owner --uid-owner 2000000000 -j RETURN\nCOMMIT\n",
mChainName.c_str());
const std::string IPTABLES_RESTORE_DEL =
StringPrintf("*filter\n-D %s -m owner --uid-owner 2000000000 -j RETURN\nCOMMIT\n",
mChainName.c_str());
for (const int iterations : ITERATIONS) {
Stopwatch s;
for (int i = 0; i < iterations; i++) {
EXPECT_EQ(0, con.execute(V4V6, IPTABLES_RESTORE_ADD, nullptr));
EXPECT_EQ(0, con.execute(V4V6, IPTABLES_RESTORE_DEL, nullptr));
}
float timeTaken = s.getTimeAndReset();
fprintf(stderr, " Add/del %d UID rules via restore: %.1fms (%.2fms per operation)\n",
iterations, timeTaken, timeTaken / 2 / iterations);
}
}
TEST_F(IptablesRestoreControllerTest, TestStartup) {
// Tests that IptablesRestoreController::Init never sets its processes to null pointers if
// fork() succeeds.
{
// Mock fork(), and check that initializing 100 times never results in a null pointer.
constexpr int NUM_ITERATIONS = 100; // Takes 100-150ms on angler.
constexpr pid_t FAKE_PID = 2000000001;
StrictMock<ScopedMockSyscalls> sys;
EXPECT_CALL(sys, fork()).Times(NUM_ITERATIONS * 2).WillRepeatedly(Return(FAKE_PID));
for (int i = 0; i < NUM_ITERATIONS; i++) {
Init();
EXPECT_NE(0, getIpRestorePid(IptablesRestoreController::IPTABLES_PROCESS));
EXPECT_NE(0, getIpRestorePid(IptablesRestoreController::IP6TABLES_PROCESS));
}
}
// The controller is now in an invalid state: the pipes are connected to working iptables
// processes, but the PIDs are set to FAKE_PID. Send a malformed command to ensure that the
// processes terminate and close the pipes, then send a valid command to have the controller
// re-initialize properly now that fork() is no longer mocked.
EXPECT_EQ(-1, con.execute(V4V6, "malformed command\n", nullptr));
EXPECT_EQ(0, con.execute(V4V6, "#Test\n", nullptr));
}