// https://syzkaller.appspot.com/bug?id=48ae1f6809d4da0ea27037dc35817318194edbb8 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef __NR_memfd_create #define __NR_memfd_create 319 #endif static unsigned long long procid; static long syz_open_procfs(volatile long a0, volatile long a1) { char buf[128]; memset(buf, 0, sizeof(buf)); if (a0 == 0) { snprintf(buf, sizeof(buf), "/proc/self/%s", (char*)a1); } else if (a0 == -1) { snprintf(buf, sizeof(buf), "/proc/thread-self/%s", (char*)a1); } else { snprintf(buf, sizeof(buf), "/proc/self/task/%d/%s", (int)a0, (char*)a1); } int fd = open(buf, O_RDWR); if (fd == -1) fd = open(buf, O_RDONLY); return fd; } struct fs_image_segment { void* data; uintptr_t size; uintptr_t offset; }; static int setup_loop_device(long unsigned size, long unsigned nsegs, struct fs_image_segment* segs, const char* loopname, int* memfd_p, int* loopfd_p) { int err = 0, loopfd = -1; int memfd = syscall(__NR_memfd_create, "syzkaller", 0); if (memfd == -1) { err = errno; goto error; } if (ftruncate(memfd, size)) { err = errno; goto error_close_memfd; } for (size_t i = 0; i < nsegs; i++) { if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) { } } loopfd = open(loopname, O_RDWR); if (loopfd == -1) { err = errno; goto error_close_memfd; } if (ioctl(loopfd, LOOP_SET_FD, memfd)) { if (errno != EBUSY) { err = errno; goto error_close_loop; } ioctl(loopfd, LOOP_CLR_FD, 0); usleep(1000); if (ioctl(loopfd, LOOP_SET_FD, memfd)) { err = errno; goto error_close_loop; } } *memfd_p = memfd; *loopfd_p = loopfd; return 0; error_close_loop: close(loopfd); error_close_memfd: close(memfd); error: errno = err; return -1; } static long syz_mount_image(volatile long fsarg, volatile long dir, volatile unsigned long size, volatile unsigned long nsegs, volatile long segments, volatile long flags, volatile long optsarg, volatile long change_dir) { struct fs_image_segment* segs = (struct fs_image_segment*)segments; int res = -1, err = 0, loopfd = -1, memfd = -1, need_loop_device = !!segs; char* mount_opts = (char*)optsarg; char* target = (char*)dir; char* fs = (char*)fsarg; char* source = NULL; char loopname[64]; if (need_loop_device) { memset(loopname, 0, sizeof(loopname)); snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid); if (setup_loop_device(size, nsegs, segs, loopname, &memfd, &loopfd) == -1) return -1; source = loopname; } mkdir(target, 0777); char opts[256]; memset(opts, 0, sizeof(opts)); if (strlen(mount_opts) > (sizeof(opts) - 32)) { } strncpy(opts, mount_opts, sizeof(opts) - 32); if (strcmp(fs, "iso9660") == 0) { flags |= MS_RDONLY; } else if (strncmp(fs, "ext", 3) == 0) { if (strstr(opts, "errors=panic") || strstr(opts, "errors=remount-ro") == 0) strcat(opts, ",errors=continue"); } else if (strcmp(fs, "xfs") == 0) { strcat(opts, ",nouuid"); } res = mount(source, target, fs, flags, opts); if (res == -1) { err = errno; goto error_clear_loop; } res = open(target, O_RDONLY | O_DIRECTORY); if (res == -1) { err = errno; goto error_clear_loop; } if (change_dir) { res = chdir(target); if (res == -1) { err = errno; } } error_clear_loop: if (need_loop_device) { ioctl(loopfd, LOOP_CLR_FD, 0); close(loopfd); close(memfd); } errno = err; return res; } uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff}; int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); intptr_t res = 0; memcpy((void*)0x200002c0, "tmpfs\000", 6); memcpy((void*)0x20000100, "./bus\000", 6); memcpy((void*)0x20000000, "huge=always", 11); syz_mount_image(0x200002c0, 0x20000100, 0, 0, 0x20000000, 0, 0x20000000, 0); memcpy((void*)0x20000380, "./bus\000", 6); syscall(__NR_chdir, 0x20000380ul); memcpy((void*)0x200001c0, "memory.current\000", 15); res = syscall(__NR_openat, 0xffffff9c, 0x200001c0ul, 0x275aul, 0ul); if (res != -1) r[0] = res; syscall(__NR_write, r[0], 0x200002c0ul, 0x208e24bul); syscall(__NR_mmap, 0x20000000ul, 0xb36000ul, 2ul, 0x28011ul, r[0], 0ul); memcpy((void*)0x20000240, "clear_refs\000", 11); res = -1; res = syz_open_procfs(0, 0x20000240); if (res != -1) r[1] = res; *(uint64_t*)0x20000140 = 0x20000080; memset((void*)0x20000080, 52, 1); *(uint64_t*)0x20000148 = 1; syscall(__NR_writev, r[1], 0x20000140ul, 1ul); memcpy((void*)0x200002c0, "wg1\000\000\000\000\000\000\000\000\000\000\000\000\000", 16); syscall(__NR_ioctl, -1, 0x8933, 0x200002c0ul); return 0; }