// https://syzkaller.appspot.com/bug?id=66dc2136b2b4d8fa664dff2d8a3e6e74b3745ee7 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #ifndef __NR_mmap #define __NR_mmap 222 #endif #ifndef __NR_mprotect #define __NR_mprotect 226 #endif #ifndef __NR_ppoll #define __NR_ppoll 73 #endif static __thread int clone_ongoing; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) { exit(sig); } uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0; int valid = addr < prog_start || addr > prog_end; if (skip && valid) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { 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(...) \ ({ \ int ok = 1; \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } else \ ok = 0; \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ ok; \ }) int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); const char* reason; (void)reason; install_segv_handler(); if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } // mprotect arguments: [ // addr: VMA[0x800000] // len: len = 0x800000 (8 bytes) // prot: mmap_prot = 0x5 (8 bytes) // ] syscall(__NR_mprotect, /*addr=*/0x20000000ul, /*len=*/0x800000ul, /*prot=PROT_READ|PROT_EXEC*/ 5ul); // ppoll arguments: [ // fds: ptr[in, array[pollfd]] { // array[pollfd] { // pollfd { // fd: fd (resource) // events: pollfd_events = 0x12 (2 bytes) // revents: const = 0x0 (2 bytes) // } // } // } // nfds: len = 0x1 (8 bytes) // tsp: nil // sigmask: nil // size: len = 0x0 (8 bytes) // ] NONFAILING(*(uint32_t*)0x20000000 = -1); NONFAILING(*(uint16_t*)0x20000004 = 0x12); NONFAILING(*(uint16_t*)0x20000006 = 0); syscall(__NR_ppoll, /*fds=*/0x20000000ul, /*nfds=*/1ul, /*tsp=*/0ul, /*sigmask=*/0ul, /*size=*/0ul); return 0; }