// https://syzkaller.appspot.com/bug?id=2fee650ad5556cef0890b93d78bcc147553a8b67 // 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 #ifndef __NR_bpf #define __NR_bpf 321 #endif static unsigned long long procid; 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; \ }) static void sleep_ms(uint64_t ms) { usleep(ms * 1000); } static uint64_t current_time_ms(void) { struct timespec ts; if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1); return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000; } 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 kill_and_wait(int pid, int* status) { kill(-pid, SIGKILL); kill(pid, SIGKILL); for (int i = 0; i < 100; i++) { if (waitpid(-1, status, WNOHANG | __WALL) == pid) return; usleep(1000); } DIR* dir = opendir("/sys/fs/fuse/connections"); if (dir) { for (;;) { struct dirent* ent = readdir(dir); if (!ent) break; if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0) continue; char abort[300]; snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort", ent->d_name); int fd = open(abort, O_WRONLY); if (fd == -1) { continue; } if (write(fd, abort, 1) < 0) { } close(fd); } closedir(dir); } else { } while (waitpid(-1, status, __WALL) != pid) { } } static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); write_file("/proc/self/oom_score_adj", "1000"); } static void setup_sysctl() { char mypid[32]; snprintf(mypid, sizeof(mypid), "%d", getpid()); struct { const char* name; const char* data; } files[] = { {"/sys/kernel/debug/x86/nmi_longest_ns", "10000000000"}, {"/proc/sys/kernel/hung_task_check_interval_secs", "20"}, {"/proc/sys/net/core/bpf_jit_kallsyms", "1"}, {"/proc/sys/net/core/bpf_jit_harden", "0"}, {"/proc/sys/kernel/kptr_restrict", "0"}, {"/proc/sys/kernel/softlockup_all_cpu_backtrace", "1"}, {"/proc/sys/fs/mount-max", "100"}, {"/proc/sys/vm/oom_dump_tasks", "0"}, {"/proc/sys/debug/exception-trace", "0"}, {"/proc/sys/kernel/printk", "7 4 1 3"}, {"/proc/sys/kernel/keys/gc_delay", "1"}, {"/proc/sys/vm/oom_kill_allocating_task", "1"}, {"/proc/sys/kernel/ctrl-alt-del", "0"}, {"/proc/sys/kernel/cad_pid", mypid}, }; for (size_t i = 0; i < sizeof(files) / sizeof(files[0]); i++) { if (!write_file(files[i].name, files[i].data)) printf("write to %s failed: %s\n", files[i].name, strerror(errno)); } } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { int iter = 0; for (;; iter++) { int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { setup_test(); execute_one(); exit(0); } int status = 0; uint64_t start = current_time_ms(); for (;;) { if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break; sleep_ms(1); if (current_time_ms() - start < 5000) continue; kill_and_wait(pid, &status); break; } } } uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; NONFAILING(*(uint32_t*)0x200009c0 = 0xf); NONFAILING(*(uint32_t*)0x200009c4 = 4); NONFAILING(*(uint32_t*)0x200009c8 = 8); NONFAILING(*(uint32_t*)0x200009cc = 0xc); NONFAILING(*(uint32_t*)0x200009d0 = 0); NONFAILING(*(uint32_t*)0x200009d4 = -1); NONFAILING(*(uint32_t*)0x200009d8 = 0); NONFAILING(memset((void*)0x200009dc, 0, 16)); NONFAILING(*(uint32_t*)0x200009ec = 0); NONFAILING(*(uint32_t*)0x200009f0 = -1); NONFAILING(*(uint32_t*)0x200009f4 = 0); NONFAILING(*(uint32_t*)0x200009f8 = 0); NONFAILING(*(uint32_t*)0x200009fc = 0); NONFAILING(*(uint64_t*)0x20000a00 = 0); res = syscall(__NR_bpf, /*cmd=*/0ul, /*arg=*/0x200009c0ul, /*size=*/0x48ul); if (res != -1) r[0] = res; NONFAILING(*(uint32_t*)0x200000c0 = 0x1b); NONFAILING(*(uint32_t*)0x200000c4 = 0); NONFAILING(*(uint32_t*)0x200000c8 = 0); NONFAILING(*(uint32_t*)0x200000cc = 0x8000); NONFAILING(*(uint32_t*)0x200000d0 = 0); NONFAILING(*(uint32_t*)0x200000d4 = -1); NONFAILING(*(uint32_t*)0x200000d8 = 0); NONFAILING(memset((void*)0x200000dc, 0, 16)); NONFAILING(*(uint32_t*)0x200000ec = 0); NONFAILING(*(uint32_t*)0x200000f0 = -1); NONFAILING(*(uint32_t*)0x200000f4 = 0); NONFAILING(*(uint32_t*)0x200000f8 = 0); NONFAILING(*(uint32_t*)0x200000fc = 0); NONFAILING(*(uint64_t*)0x20000100 = 0); res = syscall(__NR_bpf, /*cmd=*/0ul, /*arg=*/0x200000c0ul, /*size=*/0x48ul); if (res != -1) r[1] = res; NONFAILING(*(uint32_t*)0x200000c0 = 0x11); NONFAILING(*(uint32_t*)0x200000c4 = 0x10); NONFAILING(*(uint64_t*)0x200000c8 = 0x20000280); NONFAILING(memcpy((void*)0x20000280, "\x18\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" "\x00\x00\x18\x11\x00\x00", 20)); NONFAILING(*(uint32_t*)0x20000294 = r[1]); NONFAILING(memcpy((void*)0x20000298, "\x00\x00\x00\x00\x00\x00\x00\x00\xb7\x02\x00\x00\x02\x00" "\x00\x00\x85\x00\x00\x00\x86\x00\x00\x00\x18\x11\x00\x00", 28)); NONFAILING(*(uint32_t*)0x200002b4 = r[0]); NONFAILING(memcpy( (void*)0x200002b8, "\x00\x00\x00\x00\x00\x00\x00\x00\xb7\x08\x00\x00\x00\x00\x00\x00\x7b\x8a" "\xf8\xff\x00\x00\x00\x00\xbf\xa2\x00\x00\x00\x00\x00\x00\x07\x02\x00\x00" "\xf8\xff\xff\xff\xb7\x03\x00\x00\x08\x00\x00\x00\xb7\x04\x00\x00\x00\x00" "\x00\x00\x85\x00\x00\x00\x03\x00\x00\x00\x95", 65)); NONFAILING(*(uint64_t*)0x200000d0 = 0x20000040); NONFAILING(memcpy((void*)0x20000040, "syzkaller\000", 10)); NONFAILING(*(uint32_t*)0x200000d8 = 0); NONFAILING(*(uint32_t*)0x200000dc = 0); NONFAILING(*(uint64_t*)0x200000e0 = 0); NONFAILING(*(uint32_t*)0x200000e8 = 0); NONFAILING(*(uint32_t*)0x200000ec = 0); NONFAILING(memset((void*)0x200000f0, 0, 16)); NONFAILING(*(uint32_t*)0x20000100 = 0); NONFAILING(*(uint32_t*)0x20000104 = 0); NONFAILING(*(uint32_t*)0x20000108 = -1); NONFAILING(*(uint32_t*)0x2000010c = 0); NONFAILING(*(uint64_t*)0x20000110 = 0); NONFAILING(*(uint32_t*)0x20000118 = 0); NONFAILING(*(uint32_t*)0x2000011c = 0); NONFAILING(*(uint64_t*)0x20000120 = 0); NONFAILING(*(uint32_t*)0x20000128 = 0); NONFAILING(*(uint32_t*)0x2000012c = 0); NONFAILING(*(uint32_t*)0x20000130 = 0); NONFAILING(*(uint32_t*)0x20000134 = 0); NONFAILING(*(uint64_t*)0x20000138 = 0); NONFAILING(*(uint64_t*)0x20000140 = 0); NONFAILING(*(uint32_t*)0x20000148 = 0); NONFAILING(*(uint32_t*)0x2000014c = 0); res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x200000c0ul, /*size=*/0x90ul); if (res != -1) r[2] = res; NONFAILING(*(uint64_t*)0x200001c0 = 0x20000180); NONFAILING(memcpy((void*)0x20000180, "kfree\000", 6)); NONFAILING(*(uint32_t*)0x200001c8 = r[2]); syscall(__NR_bpf, /*cmd=*/0x11ul, /*arg=*/0x200001c0ul, /*size=*/0x10ul); syscall(__NR_openat, /*fd=*/0xffffff9c, /*file=*/0ul, /*flags=*/0x7a05ul, /*mode=*/0x1700ul); } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-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=*/-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/-1, /*offset=*/0ul); setup_sysctl(); install_segv_handler(); for (procid = 0; procid < 5; procid++) { if (fork() == 0) { loop(); } } sleep(1000000); return 0; }