// https://syzkaller.appspot.com/bug?id=8488bfce607804a84385264fcbb7b57fb99bf75e // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #ifndef __NR_execve #define __NR_execve 221 #endif #ifndef __NR_mmap #define __NR_mmap 222 #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)) { } // mmap arguments: [ // addr: VMA[0xc00000] // len: len = 0xc00000 (8 bytes) // prot: mmap_prot = 0x0 (8 bytes) // flags: mmap_flags = 0x3032 (8 bytes) // fd: fd (resource) // offset: intptr = 0x0 (8 bytes) // ] syscall(__NR_mmap, /*addr=*/0x20001000ul, /*len=*/0xc00000ul, /*prot=*/0ul, /*flags=MAP_LOCKED|MAP_FIXED|MAP_EXECUTABLE|0x22*/ 0x3032ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); // execve arguments: [ // file: ptr[in, buffer] { // buffer: {2e 2f 66 69 6c 65 30 00} (length 0x8) // } // argv: nil // envp: ptr[in, argv_array] { // argv_array { // args: array[ptr[in, buffer]] { // } // z: const = 0x0 (8 bytes) // } // } // ] NONFAILING(memcpy((void*)0x200001c0, "./file0\000", 8)); NONFAILING(*(uint64_t*)0x200022c0 = 0); syscall(__NR_execve, /*file=*/0x200001c0ul, /*argv=*/0ul, /*envp=*/0x200022c0ul); return 0; }