// https://syzkaller.appspot.com/bug?id=c14decede92c22649f469b249123199e99e09ab0 // 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 static unsigned long long procid; struct fs_image_segment { void* data; uintptr_t size; uintptr_t offset; }; #define IMAGE_MAX_SEGMENTS 4096 #define IMAGE_MAX_SIZE (129 << 20) #define sys_memfd_create 319 static unsigned long fs_image_segment_check(unsigned long size, unsigned long nsegs, struct fs_image_segment* segs) { if (nsegs > IMAGE_MAX_SEGMENTS) nsegs = IMAGE_MAX_SEGMENTS; for (size_t i = 0; i < nsegs; i++) { if (segs[i].size > IMAGE_MAX_SIZE) segs[i].size = IMAGE_MAX_SIZE; segs[i].offset %= IMAGE_MAX_SIZE; if (segs[i].offset > IMAGE_MAX_SIZE - segs[i].size) segs[i].offset = IMAGE_MAX_SIZE - segs[i].size; if (size < segs[i].offset + segs[i].offset) size = segs[i].offset + segs[i].offset; } if (size > IMAGE_MAX_SIZE) size = IMAGE_MAX_SIZE; return size; } 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; size = fs_image_segment_check(size, nsegs, segs); int memfd = syscall(sys_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) { 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; } error_clear_loop: if (need_loop_device) { ioctl(loopfd, LOOP_CLR_FD, 0); close(loopfd); close(memfd); } errno = err; return res; } 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); memcpy((void*)0x20000040, "ext4\000", 5); memcpy((void*)0x20000100, "./file0\000", 8); *(uint64_t*)0x20000200 = 0x20000140; memcpy((void*)0x20000140, "\x20\x00\x00\x00\x00\x02\x00\x00\x19\x00\x00\x00\x50\x01\x00\x00\x0f" "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00" "\x02\x00\x00\x20\x00\x00\x20\x00\x00\x00\xd8\xf4\x65\x5f\xd8\xf4\x65" "\x5f\x01\x00\xff\xff\x53\xef\x01\x00\x11\x00\x00\x00\xd7\xf4\x65\x5f" "\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x0b" "\x00\x00\x00\x80\x00\x00\x00\x18\x00\x00\x00\xc2\x05\x00\x00\x2b\x02", 102); *(uint64_t*)0x20000208 = 0x66; *(uint64_t*)0x20000210 = 0x400; *(uint64_t*)0x20000218 = 0x20010100; memcpy((void*)0x20010100, "\x00\x00\x00\x00\x00\x00\x00\x00\x11\x00\x00\x00" "\xb1\x38\xd8\x44\x74\x95\xb2\x5a\x38\x51\x7e\x14" "\x11\xf6\x4d\x55\x01\x00\x40", 31); *(uint64_t*)0x20000220 = 0x1f; *(uint64_t*)0x20000228 = 0x4e0; *(uint64_t*)0x20000230 = 0x20010200; memcpy((void*)0x20010200, "\x01\x00\x00\x00\x00\x00\x05\x00\x40", 9); *(uint64_t*)0x20000238 = 9; *(uint64_t*)0x20000240 = 0x560; *(uint64_t*)0x20000248 = 0x20010300; memcpy((void*)0x20010300, "\x03\x00\x00\x00\x04\x00\x00\x00\x05", 9); *(uint64_t*)0x20000250 = 9; *(uint64_t*)0x20000258 = 0x800; *(uint64_t*)0x20000260 = 0x20010d00; memcpy((void*)0x20010d00, "\xed\x41\x00\x00\x6f\x77\x6e\x21\x35\xe7\x7a\xf7" "\xd8\xf4\x65\x5f\xd8\xf4\x65\x5f\x00\x00\x00\x00" "\x00\x00\x04\x00\x20", 29); *(uint64_t*)0x20000268 = 0x1d; *(uint64_t*)0x20000270 = 0x1480; *(uint64_t*)0x20000278 = 0x20012000; memcpy((void*)0x20012000, "\x50\x4d\x4d\x00\x50\x4d\x4d\xff", 8); *(uint64_t*)0x20000280 = 8; *(uint64_t*)0x20000288 = 0x10000; syz_mount_image(0x20000040, 0x20000100, 0x8000c, 6, 0x20000200, 0, 0x200000c0); memcpy((void*)0x20000980, "./file0\000", 8); memcpy((void*)0x200009c0, "trusted.overlay.nlink\000", 22); syscall(__NR_lsetxattr, 0x20000980ul, 0x200009c0ul, 0ul, 0ul, 0ul); return 0; }