// https://syzkaller.appspot.com/bug?id=eeac9b0e8779d2cbbad4c7849cd2f3bffa719a53 // autogenerated by syzkaller (http://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include extern 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 SYZ_memfd_create 319 static uintptr_t syz_mount_image(uintptr_t fs, uintptr_t dir, uintptr_t size, uintptr_t nsegs, uintptr_t segments, uintptr_t flags, uintptr_t opts) { char loopname[64]; int loopfd, err = 0, res = -1; uintptr_t i; struct fs_image_segment* segs = (struct fs_image_segment*)segments; if (nsegs > IMAGE_MAX_SEGMENTS) nsegs = IMAGE_MAX_SEGMENTS; for (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; int memfd = syscall(SYZ_memfd_create, "syz_mount_image", 0); if (memfd == -1) { err = errno; goto error; } if (ftruncate(memfd, size)) { err = errno; goto error_close_memfd; } for (i = 0; i < nsegs; i++) { if (pwrite(memfd, segs[i].data, segs[i].size, segs[i].offset) < 0) { } } snprintf(loopname, sizeof(loopname), "/dev/loop%llu", procid); 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; } } mkdir((char*)dir, 0777); if (strcmp((char*)fs, "iso9660") == 0) flags |= MS_RDONLY; if (mount(loopname, (char*)dir, (char*)fs, flags, (char*)opts)) { err = errno; goto error_clear_loop; } res = 0; error_clear_loop: ioctl(loopfd, LOOP_CLR_FD, 0); error_close_loop: close(loopfd); error_close_memfd: close(memfd); error: errno = err; return res; } unsigned long long procid; void loop() { memcpy((void*)0x20000480, "ext4", 5); memcpy((void*)0x20000100, "./file0", 8); *(uint64_t*)0x20000140 = 0x20000080; memcpy((void*)0x20000080, "\x10\x04\x00\x00\x00\x10\x00\x00\xcc\x00\x00\x00\x49\x0b\x00\x00\xec" "\x03\x00\xed\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20" "\x00\x00\x00\x20\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\xe9\x5d\xbe" "\x5a\x00\x00\xff\xff\x53\xef\x01\x00\x03", 61); *(uint64_t*)0x20000148 = 0x3d; *(uint64_t*)0x20000150 = 0x400; *(uint8_t*)0x20000440 = 0; syz_mount_image(0x20000480, 0x20000100, 0xffff1f0000000000, 1, 0x20000140, 0, 0x20000440); } int main() { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); loop(); return 0; }