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/*
* Copyright (C) 2018 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 <fcntl.h>
#include <signal.h>
#include <stdint.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <chrono>
#include <iostream>
#include <string>
#include <android-base/properties.h>
#include <gtest/gtest.h>
#include <log/log_time.h> // for MS_PER_SEC and US_PER_SEC
#include "llkd.h"
using namespace std::chrono;
using namespace std::chrono_literals;
namespace {
milliseconds GetUintProperty(const std::string& key, milliseconds def) {
return milliseconds(android::base::GetUintProperty(key, static_cast<uint64_t>(def.count()),
static_cast<uint64_t>(def.max().count())));
}
seconds GetUintProperty(const std::string& key, seconds def) {
return seconds(android::base::GetUintProperty(key, static_cast<uint64_t>(def.count()),
static_cast<uint64_t>(def.max().count())));
}
// GTEST_LOG_(WARNING) output is fugly, this has much less noise
// ToDo: look into fixing googletest to produce output that matches style of
// all the other status messages, and can switch off __line__ and
// __function__ noise
#define GTEST_LOG_WARNING std::cerr << "[ WARNING ] "
#define GTEST_LOG_INFO std::cerr << "[ INFO ] "
// Properties is _not_ a high performance ABI!
void rest() {
usleep(200000);
}
void execute(const char* command) {
if (getuid() || system(command)) {
system((std::string("su root ") + command).c_str());
}
}
seconds llkdSleepPeriod(char state) {
auto default_eng = android::base::GetProperty(LLK_ENABLE_PROPERTY, "eng") == "eng";
auto default_enable = LLK_ENABLE_DEFAULT;
if (!LLK_ENABLE_DEFAULT && default_eng &&
android::base::GetBoolProperty("ro.debuggable", false)) {
default_enable = true;
}
default_enable = android::base::GetBoolProperty(LLK_ENABLE_PROPERTY, default_enable);
if (default_eng) {
GTEST_LOG_INFO << LLK_ENABLE_PROPERTY " defaults to \"eng\" thus "
<< (default_enable ? "true" : "false") << "\n";
}
// Hail Mary hope is unconfigured.
if ((GetUintProperty(LLK_TIMEOUT_MS_PROPERTY, LLK_TIMEOUT_MS_DEFAULT) !=
duration_cast<milliseconds>(120s)) ||
(GetUintProperty(LLK_CHECK_MS_PROPERTY,
LLK_TIMEOUT_MS_DEFAULT / LLK_CHECKS_PER_TIMEOUT_DEFAULT) !=
duration_cast<milliseconds>(10s))) {
execute("stop llkd-0");
execute("stop llkd-1");
rest();
std::string setprop("setprop ");
execute((setprop + LLK_CHECK_STACK_PROPERTY + " SyS_openat").c_str());
rest();
execute((setprop + LLK_ENABLE_WRITEABLE_PROPERTY + " false").c_str());
rest();
execute((setprop + LLK_TIMEOUT_MS_PROPERTY + " 120000").c_str());
rest();
execute((setprop + KHT_TIMEOUT_PROPERTY + " 130").c_str());
rest();
execute((setprop + LLK_CHECK_MS_PROPERTY + " 10000").c_str());
rest();
if (!default_enable) {
execute((setprop + LLK_ENABLE_PROPERTY + " true").c_str());
rest();
}
execute((setprop + LLK_ENABLE_WRITEABLE_PROPERTY + " true").c_str());
rest();
}
default_enable = LLK_ENABLE_DEFAULT;
if (!LLK_ENABLE_DEFAULT && (android::base::GetProperty(LLK_ENABLE_PROPERTY, "eng") == "eng") &&
android::base::GetBoolProperty("ro.debuggable", false)) {
default_enable = true;
}
default_enable = android::base::GetBoolProperty(LLK_ENABLE_PROPERTY, default_enable);
if (default_enable) {
execute("start llkd-1");
rest();
GTEST_LOG_INFO << "llkd enabled\n";
} else {
GTEST_LOG_WARNING << "llkd disabled\n";
}
/* KISS follows llk_init() */
milliseconds llkTimeoutMs = LLK_TIMEOUT_MS_DEFAULT;
seconds khtTimeout = duration_cast<seconds>(
llkTimeoutMs * (1 + LLK_CHECKS_PER_TIMEOUT_DEFAULT) / LLK_CHECKS_PER_TIMEOUT_DEFAULT);
khtTimeout = GetUintProperty(KHT_TIMEOUT_PROPERTY, khtTimeout);
llkTimeoutMs =
khtTimeout * LLK_CHECKS_PER_TIMEOUT_DEFAULT / (1 + LLK_CHECKS_PER_TIMEOUT_DEFAULT);
llkTimeoutMs = GetUintProperty(LLK_TIMEOUT_MS_PROPERTY, llkTimeoutMs);
if (llkTimeoutMs < LLK_TIMEOUT_MS_MINIMUM) {
llkTimeoutMs = LLK_TIMEOUT_MS_MINIMUM;
}
milliseconds llkCheckMs = llkTimeoutMs / LLK_CHECKS_PER_TIMEOUT_DEFAULT;
auto timeout = GetUintProperty((state == 'Z') ? LLK_Z_TIMEOUT_MS_PROPERTY
: (state == 'S') ? LLK_STACK_TIMEOUT_MS_PROPERTY
: LLK_D_TIMEOUT_MS_PROPERTY,
llkTimeoutMs);
if (timeout < LLK_TIMEOUT_MS_MINIMUM) {
timeout = LLK_TIMEOUT_MS_MINIMUM;
}
if (llkCheckMs > timeout) {
llkCheckMs = timeout;
}
llkCheckMs = GetUintProperty(LLK_CHECK_MS_PROPERTY, llkCheckMs);
timeout += llkCheckMs;
auto sec = duration_cast<seconds>(timeout);
if (sec == 0s) {
++sec;
} else if (sec > 59s) {
GTEST_LOG_WARNING << "llkd is configured for about " << duration_cast<minutes>(sec).count()
<< " minutes to react\n";
}
// 33% margin for the test to naturally timeout waiting for llkd to respond
return (sec * 4 + 2s) / 3;
}
inline void waitForPid(pid_t child_pid) {
int wstatus;
ASSERT_LE(0, waitpid(child_pid, &wstatus, 0));
EXPECT_FALSE(WIFEXITED(wstatus)) << "[ INFO ] exit=" << WEXITSTATUS(wstatus);
ASSERT_TRUE(WIFSIGNALED(wstatus));
ASSERT_EQ(WTERMSIG(wstatus), SIGKILL);
}
bool checkKill(const char* reason) {
if (android::base::GetBoolProperty(LLK_KILLTEST_PROPERTY, LLK_KILLTEST_DEFAULT)) {
return false;
}
auto bootreason = android::base::GetProperty("sys.boot.reason", "nothing");
if (bootreason == reason) {
GTEST_LOG_INFO << "Expected test result confirmed " << reason << "\n";
return true;
}
GTEST_LOG_WARNING << "Expected test result is " << reason << "\n";
// apct adjustment if needed (set LLK_KILLTEST_PROPERTY to "off" to allow test)
//
// if (android::base::GetProperty(LLK_KILLTEST_PROPERTY, "") == "false") {
// GTEST_LOG_WARNING << "Bypassing test\n";
// return true;
// }
return false;
}
} // namespace
// The tests that use this helper are to simulate processes stuck in 'D'
// state that are experiencing forward scheduled progress. As such the
// expectation is that llkd will _not_ perform any mitigations. The sleepfor
// argument helps us set the amount of forward scheduler progress.
static void llkd_driver_ABA(const microseconds sleepfor) {
const auto period = llkdSleepPeriod('D');
if (period <= sleepfor) {
GTEST_LOG_WARNING << "llkd configuration too short for "
<< duration_cast<milliseconds>(sleepfor).count() << "ms work cycle\n";
return;
}
auto child_pid = fork();
ASSERT_LE(0, child_pid);
int wstatus;
if (!child_pid) {
auto ratio = period / sleepfor;
ASSERT_LT(0, ratio);
// vfork() parent is uninterruptable D state waiting for child to exec()
while (--ratio > 0) {
auto driver_pid = vfork();
ASSERT_LE(0, driver_pid);
if (driver_pid) { // parent
waitpid(driver_pid, &wstatus, 0);
if (!WIFEXITED(wstatus)) {
exit(42);
}
if (WEXITSTATUS(wstatus) != 42) {
exit(42);
}
} else {
usleep(sleepfor.count());
exit(42);
}
}
exit(0);
}
ASSERT_LE(0, waitpid(child_pid, &wstatus, 0));
EXPECT_TRUE(WIFEXITED(wstatus));
if (WIFEXITED(wstatus)) {
EXPECT_EQ(0, WEXITSTATUS(wstatus));
}
ASSERT_FALSE(WIFSIGNALED(wstatus)) << "[ INFO ] signo=" << WTERMSIG(wstatus);
}
TEST(llkd, driver_ABA_fast) {
llkd_driver_ABA(5ms);
}
TEST(llkd, driver_ABA_slow) {
llkd_driver_ABA(1s);
}
TEST(llkd, driver_ABA_glacial) {
llkd_driver_ABA(1min);
}
// Following tests must be last in this file to capture possible errant
// kernel_panic mitigation failure.
// The following tests simulate processes stick in 'Z' or 'D' state with
// no forward scheduling progress, but interruptible. As such the expectation
// is that llkd will perform kill mitigation and not progress to kernel_panic.
TEST(llkd, zombie) {
if (checkKill("kernel_panic,sysrq,livelock,zombie")) {
return;
}
const auto period = llkdSleepPeriod('Z');
/* Create a Persistent Zombie Process */
pid_t child_pid = fork();
ASSERT_LE(0, child_pid);
if (!child_pid) {
auto zombie_pid = fork();
ASSERT_LE(0, zombie_pid);
if (!zombie_pid) {
sleep(1);
exit(0);
}
sleep(period.count());
exit(42);
}
waitForPid(child_pid);
}
TEST(llkd, driver) {
if (checkKill("kernel_panic,sysrq,livelock,driver")) {
return;
}
const auto period = llkdSleepPeriod('D');
/* Create a Persistent Device Process */
auto child_pid = fork();
ASSERT_LE(0, child_pid);
if (!child_pid) {
// vfork() parent is uninterruptable D state waiting for child to exec()
auto driver_pid = vfork();
ASSERT_LE(0, driver_pid);
sleep(period.count());
exit(driver_pid ? 42 : 0);
}
waitForPid(child_pid);
}
TEST(llkd, sleep) {
if (checkKill("kernel_panic,sysrq,livelock,sleeping")) {
return;
}
if (!android::base::GetBoolProperty("ro.debuggable", false)) {
GTEST_LOG_WARNING << "Features not available on user builds\n";
}
const auto period = llkdSleepPeriod('S');
/* Create a Persistent SyS_openat for single-ended pipe */
static constexpr char stack_pipe_file[] = "/dev/stack_pipe_file";
unlink(stack_pipe_file);
auto pipe_ret = mknod(stack_pipe_file, S_IFIFO | 0666, 0);
ASSERT_LE(0, pipe_ret);
auto child_pid = fork();
ASSERT_LE(0, child_pid);
if (!child_pid) {
child_pid = fork();
ASSERT_LE(0, child_pid);
if (!child_pid) {
sleep(period.count());
auto fd = open(stack_pipe_file, O_RDONLY | O_CLOEXEC);
close(fd);
exit(0);
} else {
auto fd = open(stack_pipe_file, O_WRONLY | O_CLOEXEC);
close(fd);
exit(42);
}
}
waitForPid(child_pid);
unlink(stack_pipe_file);
}