| /* |
| |
| honggfuzz - fuzzing routines |
| ----------------------------------------- |
| |
| Author: Robert Swiecki <swiecki@google.com> |
| Felix Gröbert <groebert@google.com> |
| |
| Copyright 2010-2015 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 "common.h" |
| #include "fuzz.h" |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pthread.h> |
| #include <signal.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/param.h> |
| #include <sys/stat.h> |
| #include <sys/time.h> |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include "log.h" |
| #include "arch.h" |
| #include "util.h" |
| #include "files.h" |
| |
| static void fuzz_mangleContent(honggfuzz_t * hfuzz, uint8_t * buf, off_t fileSz) |
| { |
| /* |
| * Just copy the file if "-r 0" |
| */ |
| uint64_t changesCnt = fileSz * hfuzz->flipRate; |
| |
| if (changesCnt == 0ULL) { |
| return; |
| } |
| |
| if (hfuzz->flipMode == 'b') { |
| changesCnt *= 8UL; |
| } |
| |
| changesCnt = util_rndGet(1, changesCnt); |
| |
| for (uint64_t x = 0; x < changesCnt; x++) { |
| off_t pos = util_rndGet(0, fileSz - 1); |
| |
| if (hfuzz->flipMode == 'b') { |
| buf[pos] ^= (1 << util_rndGet(0, 7)); |
| } else { |
| buf[pos] = (uint8_t) util_rndGet(0, 255); |
| } |
| } |
| } |
| |
| static void fuzz_getFileName(honggfuzz_t * hfuzz, char *fileName) |
| { |
| struct timeval tv; |
| gettimeofday(&tv, NULL); |
| |
| snprintf(fileName, PATH_MAX, ".honggfuzz.%d.%lu.%lu.%lu.%lu.%s", (int)getpid(), |
| (unsigned long int)tv.tv_sec, (unsigned long int)tv.tv_usec, |
| (unsigned long int)util_rndGet(0, 1 << 30), (unsigned long int)util_rndGet(0, 1 << 30), |
| hfuzz->fileExtn); |
| |
| return; |
| } |
| |
| static void fuzz_appendOrTrunc(int fd, off_t fileSz) |
| { |
| const int chance_one_in_x = 10; |
| if (util_rndGet(1, chance_one_in_x) != 1) { |
| return; |
| } |
| |
| off_t maxSz = 2 * fileSz; |
| if (fileSz > (1024 * 1024 * 20)) { |
| maxSz = fileSz + (fileSz / 4); |
| } |
| if (fileSz > (1024 * 1024 * 100)) { |
| maxSz = fileSz; |
| } |
| |
| off_t newSz = util_rndGet(1, maxSz); |
| if (ftruncate(fd, newSz) == -1) { |
| LOGMSG_P(l_WARN, "Couldn't truncate file from '%ld' to '%ld' bytes", (long)fileSz, |
| (long)newSz); |
| return; |
| } |
| } |
| |
| static bool fuzz_prepareFile(honggfuzz_t * hfuzz, char *fileName, int rnd_index) |
| { |
| off_t fileSz; |
| int srcfd; |
| |
| uint8_t *buf = files_mapFileToRead(hfuzz->files[rnd_index], &fileSz, &srcfd); |
| if (buf == NULL) { |
| LOGMSG(l_ERROR, "Couldn't open and map '%s' in R/O mode", hfuzz->files[rnd_index]); |
| return false; |
| } |
| |
| LOGMSG(l_DEBUG, "Mmaped '%s' in R/O mode, size: %d", hfuzz->files[rnd_index], fileSz); |
| |
| int dstfd = open(fileName, O_CREAT | O_EXCL | O_RDWR, 0644); |
| if (dstfd == -1) { |
| LOGMSG_P(l_ERROR, "Couldn't create a temporary file '%s' in the current directory", |
| fileName); |
| munmap(buf, fileSz); |
| close(srcfd); |
| return false; |
| } |
| |
| fuzz_mangleContent(hfuzz, buf, fileSz); |
| |
| if (!files_writeToFd(dstfd, buf, fileSz)) { |
| munmap(buf, fileSz); |
| close(srcfd); |
| close(dstfd); |
| return false; |
| } |
| |
| munmap(buf, fileSz); |
| |
| fuzz_appendOrTrunc(dstfd, fileSz); |
| |
| close(srcfd); |
| close(dstfd); |
| return true; |
| } |
| |
| static bool fuzz_prepareFileExternally(honggfuzz_t * hfuzz, char *fileName, int rnd_index) |
| { |
| off_t fileSz; |
| int srcfd; |
| |
| int dstfd = open(fileName, O_CREAT | O_EXCL | O_RDWR, 0644); |
| if (dstfd == -1) { |
| LOGMSG_P(l_ERROR, "Couldn't create a temporary file '%s' in the current directory", |
| fileName); |
| return false; |
| } |
| |
| LOGMSG(l_DEBUG, "Created '%f' as an input file", fileName); |
| |
| if (hfuzz->inputFile) { |
| uint8_t *buf = files_mapFileToRead(hfuzz->files[rnd_index], &fileSz, &srcfd); |
| if (buf == NULL) { |
| LOGMSG(l_ERROR, "Couldn't open and map '%s' in R/O mode", hfuzz->files[rnd_index]); |
| close(dstfd); |
| return false; |
| } |
| |
| LOGMSG(l_DEBUG, "Mmaped '%s' in R/O mode, size: %d", hfuzz->files[rnd_index], fileSz); |
| |
| bool ret = files_writeToFd(dstfd, buf, fileSz); |
| munmap(buf, fileSz); |
| close(srcfd); |
| |
| if (!ret) { |
| close(dstfd); |
| return false; |
| } |
| } |
| |
| close(dstfd); |
| |
| pid_t pid = vfork(); |
| if (pid == -1) { |
| LOGMSG_P(l_ERROR, "Couldn't vfork"); |
| return false; |
| } |
| |
| if (!pid) { |
| #if defined(PR_SET_PDEATHSIG) |
| /* Kill it if the main process goes down */ |
| if (prctl(PR_SET_PDEATHSIG, (long)SIGKILL, 0L, 0L, 0L) == -1) { |
| LOGMSG_P(l_ERROR, "prctl(PR_SET_PDEATHSIG, SIGKILL) failed"); |
| return false; |
| } |
| #endif /* defined(PR_SET_PDEATHSIG) */ |
| /* |
| * child performs the external file modifications |
| */ |
| execl(hfuzz->externalCommand, hfuzz->externalCommand, fileName, NULL); |
| LOGMSG_P(l_FATAL, "Couldn't execute '%s %s'", hfuzz->externalCommand, fileName); |
| return false; |
| } |
| |
| /* |
| * parent waits until child is done fuzzing the input file |
| */ |
| int childStatus; |
| int flags = 0; |
| #if defined(__WNOTHREAD) |
| flags |= __WNOTHREAD; |
| #endif /* defined(__WNOTHREAD) */ |
| while (wait4(pid, &childStatus, flags, NULL) != pid) ; |
| if (WIFEXITED(childStatus)) { |
| LOGMSG(l_DEBUG, "External command exited with status %d", WEXITSTATUS(childStatus)); |
| return true; |
| } |
| if (WIFSIGNALED(childStatus)) { |
| LOGMSG(l_ERROR, "External command terminated with signal %d", WTERMSIG(childStatus)); |
| return false; |
| } |
| LOGMSG(l_FATAL, "External command terminated abnormally, status: %d", childStatus); |
| return false; |
| |
| abort(); /* NOTREACHED */ |
| } |
| |
| static int fuzz_numOfProc(honggfuzz_t * hfuzz) |
| { |
| int i; |
| sem_getvalue(hfuzz->sem, &i); |
| return hfuzz->threadsMax - i; |
| } |
| |
| static void *fuzz_threadNew(void *arg) |
| { |
| honggfuzz_t *hfuzz = (honggfuzz_t *) arg; |
| fuzzer_t fuzzer = { |
| .pid = 0, |
| .timeStarted = time(NULL), |
| .pc = 0ULL, |
| .backtrace = 0ULL, |
| .access = 0ULL, |
| .exception = 0, |
| }; |
| |
| int rnd_index = util_rndGet(0, hfuzz->fileCnt - 1); |
| strncpy(fuzzer.origFileName, files_basename(hfuzz->files[rnd_index]), PATH_MAX); |
| fuzz_getFileName(hfuzz, fuzzer.fileName); |
| |
| if (hfuzz->externalCommand != NULL) { |
| if (!fuzz_prepareFileExternally(hfuzz, fuzzer.fileName, rnd_index)) { |
| exit(EXIT_FAILURE); |
| } |
| } else { |
| if (!fuzz_prepareFile(hfuzz, fuzzer.fileName, rnd_index)) { |
| exit(EXIT_FAILURE); |
| } |
| } |
| |
| fuzzer.pid = fork(); |
| if (fuzzer.pid == -1) { |
| LOGMSG_P(l_FATAL, "Couldn't fork"); |
| exit(EXIT_FAILURE); |
| } |
| |
| if (!fuzzer.pid) { |
| /* |
| * Ok, kill the parent if this fails |
| */ |
| if (!arch_launchChild(hfuzz, fuzzer.fileName)) { |
| LOGMSG(l_DEBUG, "Error launching child process, killing parent"); |
| kill(getppid(), SIGTERM); |
| exit(EXIT_FAILURE); |
| } |
| } |
| |
| LOGMSG(l_INFO, "Launched new process, pid: %d, (%d/%d)", fuzzer.pid, fuzz_numOfProc(hfuzz), |
| hfuzz->threadsMax); |
| |
| arch_reapChild(hfuzz, &fuzzer); |
| unlink(fuzzer.fileName); |
| |
| sem_post(hfuzz->sem); |
| |
| return NULL; |
| } |
| |
| static void *fuzz_threadPid(void *arg) |
| { |
| honggfuzz_t *hfuzz = (honggfuzz_t *) arg; |
| if (!arch_prepareParent(hfuzz)) { |
| LOGMSG(l_FATAL, "Couldn't prepare parent for fuzzing"); |
| } |
| |
| fuzzer_t fuzzer = { |
| .pid = hfuzz->pid, |
| .timeStarted = time(NULL), |
| .pc = 0ULL, |
| .backtrace = 0ULL, |
| .access = 0ULL, |
| .exception = 0, |
| }; |
| |
| char fileName[] = ".honggfuzz.empty.XXXXXX"; |
| int fd; |
| if ((fd = mkstemp(fileName)) == -1) { |
| LOGMSG_P(l_ERROR, "Couldn't create a temporary file"); |
| return NULL; |
| } |
| close(fd); |
| |
| strncpy(fuzzer.origFileName, "PID_FUZZING", PATH_MAX); |
| strncpy(fuzzer.fileName, fileName, PATH_MAX); |
| |
| arch_reapChild(hfuzz, &fuzzer); |
| unlink(fuzzer.fileName); |
| |
| // There's no more hfuzz->pid to analyze. Just exit |
| LOGMSG(l_INFO, "PID: %d exited. Exiting", fuzzer.pid); |
| exit(EXIT_SUCCESS); |
| |
| return NULL; |
| } |
| |
| static void fuzz_runThread(honggfuzz_t * hfuzz, void *(*thread) (void *)) |
| { |
| pthread_attr_t attr; |
| pthread_attr_init(&attr); |
| |
| pthread_t t; |
| pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); |
| |
| if (pthread_create(&t, &attr, thread, (void *)hfuzz) < 0) { |
| LOGMSG_P(l_FATAL, "Couldn't create a new thread"); |
| } |
| |
| return; |
| } |
| |
| void fuzz_main(honggfuzz_t * hfuzz) |
| { |
| char semName[PATH_MAX]; |
| snprintf(semName, sizeof(semName), "honggfuzz.%d.%d.%u", getpid(), (int)time(NULL), |
| util_rndGet(1, 1U << 30)); |
| |
| hfuzz->sem = sem_open(semName, O_CREAT, 0644, hfuzz->threadsMax); |
| if (hfuzz->sem == SEM_FAILED) { |
| LOGMSG_P(l_FATAL, "sem_open() failed"); |
| } |
| // If we're doing a PID fuzzing, the parent of the PID will be a dedicated thread anyway |
| if (hfuzz->pid) { |
| fuzz_runThread(hfuzz, fuzz_threadPid); |
| } else { |
| if (!arch_prepareParent(hfuzz)) { |
| LOGMSG(l_FATAL, "Couldn't prepare parent for fuzzing"); |
| } |
| } |
| |
| for (;;) { |
| if (sem_wait(hfuzz->sem) == -1) { |
| LOGMSG_P(l_FATAL, "sem_wait() failed"); |
| } |
| |
| if (hfuzz->mutationsMax && (hfuzz->mutationsCnt >= hfuzz->mutationsMax)) { |
| /* Sleep a bit to let any running fuzzers terminate */ |
| usleep(1.2 * hfuzz->tmOut * 1000000); |
| LOGMSG(l_INFO, "Finished fuzzing %ld times.", hfuzz->mutationsMax); |
| sem_destroy(hfuzz->sem); |
| exit(EXIT_SUCCESS); |
| } |
| |
| hfuzz->mutationsCnt++; |
| fuzz_runThread(hfuzz, fuzz_threadNew); |
| } |
| } |