// https://syzkaller.appspot.com/bug?id=0660ec96c45e609f07f6a7a08f343f23b21ae1e7 // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include __attribute__((noreturn)) static void doexit(int status) { volatile unsigned i; syscall(__NR_exit_group, status); for (i = 0;; i++) { } } #include #include #include #include #include #include #include const int kFailStatus = 67; const int kRetryStatus = 69; static void fail(const char* msg, ...) { int e = errno; va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus); } static void exitf(const char* msg, ...) { int e = errno; va_list args; va_start(args, msg); vfprintf(stderr, msg, args); va_end(args); fprintf(stderr, " (errno %d)\n", e); doexit(kRetryStatus); } static uint64_t current_time_ms() { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) fail("clock_gettime failed"); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } static void use_temporary_dir() { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) fail("failed to mkdtemp"); if (chmod(tmpdir, 0777)) fail("failed to chmod"); if (chdir(tmpdir)) fail("failed to chdir"); } static void remove_dir(const char* dir) { DIR* dp; struct dirent* ep; int iter = 0; retry: while (umount2(dir, MNT_DETACH) == 0) { } dp = opendir(dir); if (dp == NULL) { if (errno == EMFILE) { exitf("opendir(%s) failed due to NOFILE, exiting", dir); } exitf("opendir(%s) failed", dir); } while ((ep = readdir(dp))) { if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0) continue; char filename[FILENAME_MAX]; snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name); while (umount2(filename, MNT_DETACH) == 0) { } struct stat st; if (lstat(filename, &st)) exitf("lstat(%s) failed", filename); if (S_ISDIR(st.st_mode)) { remove_dir(filename); continue; } int i; for (i = 0;; i++) { if (unlink(filename) == 0) break; if (errno == EROFS) { break; } if (errno != EBUSY || i > 100) exitf("unlink(%s) failed", filename); if (umount2(filename, MNT_DETACH)) exitf("umount(%s) failed", filename); } } closedir(dp); int i; for (i = 0;; i++) { if (rmdir(dir) == 0) break; if (i < 100) { if (errno == EROFS) { break; } if (errno == EBUSY) { if (umount2(dir, MNT_DETACH)) exitf("umount(%s) failed", dir); continue; } if (errno == ENOTEMPTY) { if (iter < 100) { iter++; goto retry; } } } exitf("rmdir(%s) failed", dir); } } static void execute_one(); extern unsigned long long procid; static void loop() { int iter; for (iter = 0;; iter++) { char cwdbuf[32]; sprintf(cwdbuf, "./%d", iter); if (mkdir(cwdbuf, 0777)) fail("failed to mkdir"); int pid = fork(); if (pid < 0) fail("clone failed"); if (pid == 0) { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); if (chdir(cwdbuf)) fail("failed to chdir"); execute_one(); int fd; for (fd = 3; fd < 30; fd++) close(fd); doexit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { int res = waitpid(-1, &status, __WALL | WNOHANG); if (res == pid) { break; } usleep(1000); if (current_time_ms() - start < 5 * 1000) continue; kill(-pid, SIGKILL); kill(pid, SIGKILL); while (waitpid(-1, &status, __WALL) != pid) { } break; } remove_dir(cwdbuf); } } struct thread_t { int created, running, call; pthread_t th; }; static struct thread_t threads[16]; static void execute_call(int call); static int running; static int collide; static void* thr(void* arg) { struct thread_t* th = (struct thread_t*)arg; for (;;) { while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0); execute_call(th->call); __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED); __atomic_store_n(&th->running, 0, __ATOMIC_RELEASE); syscall(SYS_futex, &th->running, FUTEX_WAKE); } return 0; } static void execute(int num_calls) { int call, thread; running = 0; for (call = 0; call < num_calls; call++) { for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) { struct thread_t* th = &threads[thread]; if (!th->created) { th->created = 1; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setstacksize(&attr, 128 << 10); pthread_create(&th->th, &attr, thr, th); } if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) { th->call = call; __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED); __atomic_store_n(&th->running, 1, __ATOMIC_RELEASE); syscall(SYS_futex, &th->running, FUTEX_WAKE); if (collide && call % 2) break; struct timespec ts; ts.tv_sec = 0; ts.tv_nsec = 20 * 1000 * 1000; syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts); if (__atomic_load_n(&running, __ATOMIC_RELAXED)) usleep((call == num_calls - 1) ? 10000 : 1000); break; } } } } #ifndef __NR_mkdir #define __NR_mkdir 39 #endif #ifndef __NR_mount #define __NR_mount 21 #endif #ifndef __NR_mknod #define __NR_mknod 14 #endif #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_pause #define __NR_pause 29 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 void execute_call(int call) { switch (call) { case 0: syscall(__NR_pause); break; case 1: memcpy((void*)0x200001c0, "./file0", 8); syscall(__NR_mkdir, 0x200001c0, 0); break; case 2: memcpy((void*)0x2000a000, "./file0", 8); memcpy((void*)0x20026ff8, "./file0", 8); memcpy((void*)0x20000300, "ramfs", 6); syscall(__NR_mount, 0x2000a000, 0x20026ff8, 0x20000300, 0, 0x200007c0); break; case 3: memcpy((void*)0x20d04000, "./file0", 8); memcpy((void*)0x20903000, "./file0", 8); memcpy((void*)0x20000340, "bdev", 5); syscall(__NR_mount, 0x20d04000, 0x20903000, 0x20000340, 0x100000, 0x200002c0); break; case 4: memcpy((void*)0x20000240, "./file0", 8); memcpy((void*)0x20000280, ".", 1); memcpy((void*)0x20000040, "\x04\x5b\x89\x8f\x73", 5); syscall(__NR_mount, 0x20000240, 0x20000280, 0x20000040, 0x1004, 0); break; case 5: memcpy((void*)0x20000000, "./file0", 8); memcpy((void*)0x200000c0, ".", 1); memcpy((void*)0x20000140, "vxfs", 5); syscall(__NR_mount, 0x20000000, 0x200000c0, 0x20000140, 0x3080, 0x20000200); break; case 6: memcpy((void*)0x200008c0, ".", 1); memcpy((void*)0x20000080, ".", 1); memcpy((void*)0x20753000, "mslos", 6); syscall(__NR_mount, 0x200008c0, 0x20000080, 0x20753000, 0x5010, 0x20000ac0); break; case 7: memcpy((void*)0x20fb6000, "./file0", 8); memcpy((void*)0x20d78000, ".", 1); memcpy((void*)0x20fdb000, "ubifs", 6); syscall(__NR_mount, 0x20fb6000, 0x20d78000, 0x20fdb000, 0x1003, 0); break; case 8: memcpy((void*)0x20000400, "./file0/file0", 14); syscall(__NR_mkdir, 0x20000400, 0); break; case 9: memcpy((void*)0x200002c0, "./file0/file0/file0", 20); syscall(__NR_mknod, 0x200002c0, 0, 0); break; case 10: memcpy((void*)0x20000100, "./file0/file0", 14); memcpy((void*)0x20000880, "./file0/file0", 14); memcpy((void*)0x20753000, "mslos", 6); syscall(__NR_mount, 0x20000100, 0x20000880, 0x20753000, 0x5010, 0x20000640); break; } } void execute_one() { execute(11); collide = 1; execute(11); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); char* cwd = get_current_dir_name(); for (;;) { if (chdir(cwd)) fail("failed to chdir"); use_temporary_dir(); loop(); } }