// https://syzkaller.appspot.com/bug?id=3c1f47967b7cbd399d3ba3e65f297a29aa1c5f92 // 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 #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 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 __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* uctx) { uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; if (__atomic_load_n(&skip_segv, __ATOMIC_RELAXED) && (addr < prog_start || addr > prog_end)) { _longjmp(segv_env, 1); } doexit(sig); } static void install_segv_handler() { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = SIG_IGN; syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = segv_handler; sa.sa_flags = SA_NODEFER | SA_SIGINFO; sigaction(SIGSEGV, &sa, NULL); sigaction(SIGBUS, &sa, NULL); } #define NONFAILING(...) \ { \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ } static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2) { if (a0 == 0xc || a0 == 0xb) { char buf[128]; sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2); return open(buf, O_RDWR, 0); } else { char buf[1024]; char* hash; NONFAILING(strncpy(buf, (char*)a0, sizeof(buf))); buf[sizeof(buf) - 1] = 0; while ((hash = strchr(buf, '#'))) { *hash = '0' + (char)(a1 % 10); a1 /= 10; } return open(buf, a2, 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 = 128 << 20; setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 8 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 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); #define CLONE_NEWCGROUP 0x02000000 unshare(CLONE_NEWNS); unshare(CLONE_NEWIPC); unshare(CLONE_NEWCGROUP); unshare(CLONE_NEWNET); unshare(CLONE_NEWUTS); unshare(CLONE_SYSVSEM); } static int do_sandbox_none(int executor_pid, bool enable_tun) { unshare(CLONE_NEWPID); int pid = fork(); if (pid < 0) fail("sandbox fork failed"); if (pid) return pid; sandbox_common(); loop(); doexit(1); } static void test(); void loop() { while (1) { test(); } } #ifndef __NR_mmap #define __NR_mmap 192 #endif #ifndef __NR_write #define __NR_write 4 #endif #ifndef __NR_readv #define __NR_readv 145 #endif #undef __NR_mmap #define __NR_mmap __NR_mmap2 long r[1]; void test() { memset(r, -1, sizeof(r)); syscall(__NR_mmap, 0x20000000, 0xfff000, 3, 0x32, -1, 0); NONFAILING(memcpy((void*)0x20000000, "/dev/sg#", 9)); r[0] = syz_open_dev(0x20000000, 0, 2); NONFAILING(*(uint32_t*)0x20001000 = 0); NONFAILING(*(uint32_t*)0x20001004 = 6); NONFAILING(*(uint16_t*)0x20001008 = 0); NONFAILING(*(uint16_t*)0x2000100a = 0); NONFAILING(*(uint32_t*)0x2000100c = 0); NONFAILING(*(uint32_t*)0x20001010 = 0); NONFAILING(*(uint32_t*)0x20001014 = 0); NONFAILING(*(uint16_t*)0x20001018 = 0); NONFAILING(*(uint16_t*)0x2000101a = 0); NONFAILING(*(uint32_t*)0x2000101c = 7); NONFAILING(*(uint32_t*)0x20001020 = 0); NONFAILING(*(uint32_t*)0x20001024 = 0x2710); NONFAILING(*(uint16_t*)0x20001028 = 0); NONFAILING(*(uint16_t*)0x2000102a = 0); NONFAILING(*(uint32_t*)0x2000102c = 0); NONFAILING(*(uint32_t*)0x20001030 = 0); NONFAILING(*(uint32_t*)0x20001034 = 0); NONFAILING(*(uint16_t*)0x20001038 = 0); NONFAILING(*(uint16_t*)0x2000103a = 0); NONFAILING(*(uint32_t*)0x2000103c = 0); syscall(__NR_write, r[0], 0x20001000, 0x60); NONFAILING(*(uint32_t*)0x20a77fc0 = 0x2003c000); NONFAILING(*(uint32_t*)0x20a77fc4 = 0x20); syscall(__NR_readv, r[0], 0x20a77fc0, 1); } int main() { install_segv_handler(); for (;;) { int pid = do_sandbox_none(0, false); int status = 0; while (waitpid(pid, &status, __WALL) != pid) { } } }