// https://syzkaller.appspot.com/bug?id=88d16d9df3cc443caa90569899ad95b0c8750657 // 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 #include #include #include #include #include static bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setsid(); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 0; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); setup_common(); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } loop(); exit(1); } uint64_t r[1] = {0xffffffffffffffff}; void loop(void) { intptr_t res = 0; memcpy((void*)0x20000300, "./file0\000", 8); syscall(__NR_creat, 0x20000300, 0); memcpy((void*)0x20000080, "/dev/fuse\000", 10); res = syscall(__NR_openat, 0xffffffffffffff9c, 0x20000080, 2, 0); if (res != -1) r[0] = res; memcpy((void*)0x20000200, "./file0\000", 8); memcpy((void*)0x20000240, "fuse\000", 5); memcpy((void*)0x20000400, "fd", 2); *(uint8_t*)0x20000402 = 0x3d; sprintf((char*)0x20000403, "0x%016llx", (long long)r[0]); *(uint8_t*)0x20000415 = 0x2c; memcpy((void*)0x20000416, "rootmode", 8); *(uint8_t*)0x2000041e = 0x3d; sprintf((char*)0x2000041f, "%023llo", (long long)0x6000); *(uint8_t*)0x20000436 = 0x2c; memcpy((void*)0x20000437, "user_id", 7); *(uint8_t*)0x2000043e = 0x3d; sprintf((char*)0x2000043f, "%020llu", (long long)0); *(uint8_t*)0x20000453 = 0x2c; memcpy((void*)0x20000454, "group_id", 8); *(uint8_t*)0x2000045c = 0x3d; sprintf((char*)0x2000045d, "%020llu", (long long)0); *(uint8_t*)0x20000471 = 0x2c; *(uint8_t*)0x20000472 = 0; syscall(__NR_mount, 0, 0x20000200, 0x20000240, 0, 0x20000400); memcpy((void*)0x20000000, "./file0\000", 8); syscall(__NR_open, 0x20000000, 0x4000, 0x202); *(uint32_t*)0x20000040 = 0x29; *(uint32_t*)0x20000044 = 4; *(uint64_t*)0x20000048 = 0; *(uint64_t*)0x20000050 = 1; *(uint64_t*)0x20000058 = 0; *(uint32_t*)0x20000060 = 1; *(uint32_t*)0x20000064 = 0x3f00; *(uint8_t*)0x20000068 = 0; syscall(__NR_write, r[0], 0x20000040, 0x29); } int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); do_sandbox_none(); return 0; }