/*
*
* honggfuzz - architecture dependent code (LINUX)
* -----------------------------------------
*
* Author: Robert Swiecki <swiecki@google.com>
*
* Copyright 2010-2018 by Google Inc. All Rights Reserved.
*
* 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 "arch.h"
#include <ctype.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <locale.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/personality.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/user.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include "fuzz.h"
#include "libhfcommon/common.h"
#include "libhfcommon/files.h"
#include "libhfcommon/log.h"
#include "libhfcommon/ns.h"
#include "libhfcommon/util.h"
#include "linux/perf.h"
#include "linux/trace.h"
#include "sanitizers.h"
#include "subproc.h"
static uint8_t arch_clone_stack[128 * 1024] __attribute__((aligned(__BIGGEST_ALIGNMENT__)));
static __thread jmp_buf env;
HF_ATTR_NO_SANITIZE_ADDRESS
HF_ATTR_NO_SANITIZE_MEMORY
static int arch_cloneFunc(void* arg HF_ATTR_UNUSED) {
longjmp(env, 1);
abort();
return 0;
}
/* Avoid problem with caching of PID/TID in glibc */
static pid_t arch_clone(uintptr_t flags) {
if (flags & CLONE_VM) {
LOG_E("Cannot use clone(flags & CLONE_VM)");
return -1;
}
if (setjmp(env) == 0) {
void* stack_mid = &arch_clone_stack[sizeof(arch_clone_stack) / 2];
/* Parent */
return clone(arch_cloneFunc, stack_mid, flags, NULL, NULL, NULL);
}
/* Child */
return 0;
}
pid_t arch_fork(run_t* run) {
pid_t pid = run->global->linux.useClone ? arch_clone(CLONE_UNTRACED | SIGCHLD) : fork();
if (pid == -1) {
return pid;
}
if (pid == 0) {
logMutexReset();
if (prctl(PR_SET_PDEATHSIG, (unsigned long)SIGKILL, 0UL, 0UL, 0UL) == -1) {
PLOG_W("prctl(PR_SET_PDEATHSIG, SIGKILL)");
}
return pid;
}
return pid;
}
bool arch_launchChild(run_t* run) {
if ((run->global->linux.cloneFlags & CLONE_NEWNET) && (nsIfaceUp("lo") == false)) {
LOG_W("Cannot bring interface 'lo' up");
}
/*
* Make it attach-able by ptrace()
*/
if (prctl(PR_SET_DUMPABLE, 1UL, 0UL, 0UL, 0UL) == -1) {
PLOG_E("prctl(PR_SET_DUMPABLE, 1)");
return false;
}
/*
* Kill a process which corrupts its own heap (with ABRT)
*/
if (setenv("MALLOC_CHECK_", "7", 0) == -1) {
PLOG_E("setenv(MALLOC_CHECK_=7) failed");
return false;
}
if (setenv("MALLOC_PERTURB_", "85", 0) == -1) {
PLOG_E("setenv(MALLOC_PERTURB_=85) failed");
return false;
}
/*
* Disable ASLR:
* This might fail in Docker, as Docker blocks __NR_personality. Consequently
* it's just a debug warning
*/
if (run->global->linux.disableRandomization &&
syscall(__NR_personality, ADDR_NO_RANDOMIZE) == -1) {
PLOG_D("personality(ADDR_NO_RANDOMIZE) failed");
}
#define ARGS_MAX 512
const char* args[ARGS_MAX + 2];
char argData[PATH_MAX];
char inputFile[PATH_MAX];
snprintf(inputFile, sizeof(inputFile), "/dev/fd/%d", run->dynamicFileCopyFd);
int x = 0;
for (x = 0; x < ARGS_MAX && x < run->global->exe.argc; x++) {
if (run->global->exe.persistent || run->global->exe.fuzzStdin) {
args[x] = run->global->exe.cmdline[x];
} else if (!strcmp(run->global->exe.cmdline[x], _HF_FILE_PLACEHOLDER)) {
args[x] = inputFile;
} else if (strstr(run->global->exe.cmdline[x], _HF_FILE_PLACEHOLDER)) {
const char* off = strstr(run->global->exe.cmdline[x], _HF_FILE_PLACEHOLDER);
snprintf(argData, sizeof(argData), "%.*s%s", (int)(off - run->global->exe.cmdline[x]),
run->global->exe.cmdline[x], inputFile);
args[x] = argData;
} else {
args[x] = run->global->exe.cmdline[x];
}
}
args[x++] = NULL;
LOG_D("Launching '%s' on file '%s'", args[0],
run->global->exe.persistent ? "PERSISTENT_MODE" : inputFile);
/* alarms persist across execve(), so disable it here */
alarm(0);
/* Wait for the ptrace to attach now */
if (kill(syscall(__NR_getpid), SIGSTOP) == -1) {
LOG_F("Couldn't stop itself");
}
#if defined(__NR_execveat)
syscall(__NR_execveat, run->global->linux.exeFd, "", args, environ, AT_EMPTY_PATH);
#endif /* defined__NR_execveat) */
execve(args[0], (char* const*)args, environ);
int errno_cpy = errno;
alarm(1);
LOG_E("execve('%s', fd=%d): %s", args[0], run->global->linux.exeFd, strerror(errno_cpy));
return false;
}
static bool arch_attachToNewPid(run_t* run) {
if (!arch_traceAttach(run)) {
LOG_W("arch_traceAttach(pid=%d) failed", run->pid);
return false;
}
return true;
}
void arch_prepareParentAfterFork(run_t* run) {
/* Parent */
if (run->global->exe.persistent) {
const struct f_owner_ex fown = {
.type = F_OWNER_TID,
.pid = syscall(__NR_gettid),
};
if (fcntl(run->persistentSock, F_SETOWN_EX, &fown)) {
PLOG_F("fcntl(%d, F_SETOWN_EX)", run->persistentSock);
}
if (fcntl(run->persistentSock, F_SETSIG, SIGIO) == -1) {
PLOG_F("fcntl(%d, F_SETSIG, SIGIO)", run->persistentSock);
}
if (fcntl(run->persistentSock, F_SETFL, O_ASYNC) == -1) {
PLOG_F("fcntl(%d, F_SETFL, O_ASYNC)", run->persistentSock);
}
}
if (!arch_perfOpen(run)) {
LOG_F("Couldn't open perf event for pid=%d", (int)run->pid);
}
if (!arch_attachToNewPid(run)) {
LOG_F("Couldn't attach to pid=%d", (int)run->pid);
}
}
void arch_prepareParent(run_t* run) {
if (!arch_perfEnable(run)) {
LOG_F("Couldn't enable perf counters for pid=%d", (int)run->pid);
}
}
static bool arch_checkWait(run_t* run) {
/* All queued wait events must be tested when SIGCHLD was delivered */
for (;;) {
int status;
pid_t pid = TEMP_FAILURE_RETRY(waitpid(-1, &status, __WALL | __WNOTHREAD | WNOHANG));
if (pid == 0) {
return false;
}
if (pid == -1 && errno == ECHILD) {
LOG_D("No more processes to track");
return true;
}
if (pid == -1) {
PLOG_F("waitpid() failed");
}
char statusStr[4096];
LOG_D("pid=%d returned with status: %s", pid,
subproc_StatusToStr(status, statusStr, sizeof(statusStr)));
arch_traceAnalyze(run, status, pid);
if (pid == run->pid && (WIFEXITED(status) || WIFSIGNALED(status))) {
if (run->global->exe.persistent) {
if (!fuzz_isTerminating()) {
LOG_W("Persistent mode: pid=%d exited with status: %s", (int)run->pid,
subproc_StatusToStr(status, statusStr, sizeof(statusStr)));
}
}
return true;
}
}
}
void arch_reapChild(run_t* run) {
for (;;) {
if (subproc_persistentModeStateMachine(run)) {
break;
}
subproc_checkTimeLimit(run);
subproc_checkTermination(run);
const struct timespec ts = {
.tv_sec = 0ULL,
.tv_nsec = (1000ULL * 1000ULL * 250ULL),
};
/* Return with SIGIO, SIGCHLD and with SIGUSR1 */
int sig = sigtimedwait(&run->global->exe.waitSigSet, NULL, &ts /* 0.25s */);
if (sig == -1 && (errno != EAGAIN && errno != EINTR)) {
PLOG_F("sigwaitinfo(SIGIO|SIGCHLD|SIGUSR1)");
}
if (arch_checkWait(run)) {
run->pid = 0;
break;
}
if (run->global->socketFuzzer.enabled) {
// Do not wait for new events
break;
}
}
if (run->global->sanitizer.enable) {
char crashReport[PATH_MAX];
snprintf(crashReport, sizeof(crashReport), "%s/%s.%d", run->global->io.workDir, kLOGPREFIX,
run->pid);
if (files_exists(crashReport)) {
if (run->backtrace) {
unlink(crashReport);
} else {
LOG_W("Un-handled ASan report due to compiler-rt internal error - retry with '%s'",
crashReport);
/* Try to parse report file */
arch_traceExitAnalyze(run, run->pid);
}
}
}
if (run->pid == 0) {
arch_perfClose(run);
}
arch_perfAnalyze(run);
}
bool arch_archInit(honggfuzz_t* hfuzz) {
/* Make %'d work */
setlocale(LC_NUMERIC, "en_US.UTF-8");
if (access(hfuzz->exe.cmdline[0], X_OK) == -1) {
PLOG_E("File '%s' doesn't seem to be executable", hfuzz->exe.cmdline[0]);
return false;
}
if ((hfuzz->linux.exeFd =
TEMP_FAILURE_RETRY(open(hfuzz->exe.cmdline[0], O_RDONLY | O_CLOEXEC))) == -1) {
PLOG_E("Cannot open the executable binary: %s)", hfuzz->exe.cmdline[0]);
return false;
}
for (;;) {
__attribute__((weak)) const char* gnu_get_libc_version(void);
if (!gnu_get_libc_version) {
LOG_W("Unknown libc implementation. Using clone() instead of fork()");
break;
}
const char* gversion = gnu_get_libc_version();
int major, minor;
if (sscanf(gversion, "%d.%d", &major, &minor) != 2) {
LOG_W("Unknown glibc version:'%s'. Using clone() instead of fork()", gversion);
break;
}
if ((major < 2) || (major == 2 && minor < 23)) {
LOG_W("Your glibc version:'%s' will most likely result in malloc()-related "
"deadlocks. Min. version 2.24 (Or, Ubuntu's 2.23-0ubuntu6) suggested. "
"See https://sourceware.org/bugzilla/show_bug.cgi?id=19431 for explanation. "
"Using clone() instead of fork()",
gversion);
break;
}
LOG_D("Glibc version:'%s', OK", gversion);
hfuzz->linux.useClone = false;
break;
}
if (hfuzz->feedback.dynFileMethod != _HF_DYNFILE_NONE) {
unsigned long major = 0, minor = 0;
char* p = NULL;
/*
* Check that Linux kernel is compatible
*
* Compatibility list:
* 1) Perf exclude_callchain_kernel requires kernel >= 3.7
* TODO: Runtime logic to disable it for unsupported kernels
* if it doesn't affect perf counters processing
* 2) If 'PERF_TYPE_HARDWARE' is not supported by kernel, ENOENT
* is returned from perf_event_open(). Unfortunately, no reliable
* way to detect it here. libperf exports some list functions,
* although small guarantees it's installed. Maybe a more targeted
* message at perf_event_open() error handling will help.
* 3) Intel's PT and new Intel BTS format require kernel >= 4.1
*/
unsigned long checkMajor = 3, checkMinor = 7;
if ((hfuzz->feedback.dynFileMethod & _HF_DYNFILE_BTS_EDGE) ||
(hfuzz->feedback.dynFileMethod & _HF_DYNFILE_IPT_BLOCK)) {
checkMajor = 4;
checkMinor = 1;
}
struct utsname uts;
if (uname(&uts) == -1) {
PLOG_F("uname() failed");
return false;
}
p = uts.release;
major = strtoul(p, &p, 10);
if (*p++ != '.') {
LOG_F("Unsupported kernel version (%s)", uts.release);
return false;
}
minor = strtoul(p, &p, 10);
if ((major < checkMajor) || ((major == checkMajor) && (minor < checkMinor))) {
LOG_E("Kernel version '%s' not supporting chosen perf method", uts.release);
return false;
}
if (!arch_perfInit(hfuzz)) {
return false;
}
}
#if defined(__ANDROID__) && defined(__arm__) && defined(OPENSSL_ARMCAP_ABI)
/*
* For ARM kernels running Android API <= 21, if fuzzing target links to
* libcrypto (OpenSSL), OPENSSL_cpuid_setup initialization is triggering a
* SIGILL/ILLOPC at armv7_tick() due to "mrrc p15, #1, r0, r1, c14)" instruction.
* Setups using BoringSSL (API >= 22) are not affected.
*/
if (setenv("OPENSSL_armcap", OPENSSL_ARMCAP_ABI, 1) == -1) {
PLOG_E("setenv(OPENSSL_armcap) failed");
return false;
}
#endif
/* Updates the important signal array based on input args */
arch_traceSignalsInit(hfuzz);
/*
* If sanitizer fuzzing enabled and SIGABRT is monitored (abort_on_error=1),
* increase number of major frames, since top 7-9 frames will be occupied
* with sanitizer runtime library & libc symbols
*/
if (hfuzz->sanitizer.enable && hfuzz->cfg.monitorSIGABRT) {
hfuzz->linux.numMajorFrames = 14;
}
if (hfuzz->linux.cloneFlags && unshare(hfuzz->linux.cloneFlags) == -1) {
LOG_E("unshare(%tx)", hfuzz->linux.cloneFlags);
return false;
}
return true;
}
bool arch_archThreadInit(run_t* run) {
run->linux.perfMmapBuf = NULL;
run->linux.perfMmapAux = NULL;
run->linux.cpuInstrFd = -1;
run->linux.cpuBranchFd = -1;
run->linux.cpuIptBtsFd = -1;
if (prctl(PR_SET_CHILD_SUBREAPER, 1UL, 0UL, 0UL, 0UL) == -1) {
PLOG_W("prctl(PR_SET_CHILD_SUBREAPER, 1)");
}
sigset_t ss;
sigemptyset(&ss);
sigaddset(&ss, SIGUSR1);
if (pthread_sigmask(SIG_BLOCK, &ss, NULL) != 0) {
PLOG_W("Couldn't block SIGUSR1");
return false;
}
return true;
}