// https://syzkaller.appspot.com/bug?id=407694f4971a798cb1530bab77b4754a33af9efb // 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 #include #include #include #include #ifndef __NR_fsetxattr #define __NR_fsetxattr 7 #endif #ifndef __NR_memfd_create #define __NR_memfd_create 279 #endif #ifndef __NR_mmap #define __NR_mmap 222 #endif static unsigned long long procid; 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 void use_temporary_dir(void) { char tmpdir_template[] = "./syzkaller.XXXXXX"; char* tmpdir = mkdtemp(tmpdir_template); if (!tmpdir) exit(1); if (chmod(tmpdir, 0777)) exit(1); if (chdir(tmpdir)) exit(1); } 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; } #define MAX_FDS 30 static void mount_cgroups(const char* dir, const char** controllers, int count) { if (mkdir(dir, 0777)) { return; } char enabled[128] = {0}; int i = 0; for (; i < count; i++) { if (mount("none", dir, "cgroup", 0, controllers[i])) { continue; } umount(dir); strcat(enabled, ","); strcat(enabled, controllers[i]); } if (enabled[0] == 0) { if (rmdir(dir) && errno != EBUSY) exit(1); return; } if (mount("none", dir, "cgroup", 0, enabled + 1)) { if (rmdir(dir) && errno != EBUSY) exit(1); } if (chmod(dir, 0777)) { } } static void mount_cgroups2(const char** controllers, int count) { if (mkdir("/syzcgroup/unified", 0777)) { return; } if (mount("none", "/syzcgroup/unified", "cgroup2", 0, NULL)) { if (rmdir("/syzcgroup/unified") && errno != EBUSY) exit(1); return; } if (chmod("/syzcgroup/unified", 0777)) { } int control = open("/syzcgroup/unified/cgroup.subtree_control", O_WRONLY); if (control == -1) return; int i; for (i = 0; i < count; i++) if (write(control, controllers[i], strlen(controllers[i])) < 0) { } close(control); } static void setup_cgroups() { const char* unified_controllers[] = {"+cpu", "+memory", "+io", "+pids"}; const char* net_controllers[] = {"net", "net_prio", "devices", "blkio", "freezer"}; const char* cpu_controllers[] = {"cpuset", "cpuacct", "hugetlb", "rlimit"}; if (mkdir("/syzcgroup", 0777)) { return; } mount_cgroups2(unified_controllers, sizeof(unified_controllers) / sizeof(unified_controllers[0])); mount_cgroups("/syzcgroup/net", net_controllers, sizeof(net_controllers) / sizeof(net_controllers[0])); mount_cgroups("/syzcgroup/cpu", cpu_controllers, sizeof(cpu_controllers) / sizeof(cpu_controllers[0])); write_file("/syzcgroup/cpu/cgroup.clone_children", "1"); write_file("/syzcgroup/cpu/cpuset.memory_pressure_enabled", "1"); } static void setup_cgroups_loop() { int pid = getpid(); char file[128]; char cgroupdir[64]; snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/pids.max", cgroupdir); write_file(file, "32"); snprintf(file, sizeof(file), "%s/memory.low", cgroupdir); write_file(file, "%d", 298 << 20); snprintf(file, sizeof(file), "%s/memory.high", cgroupdir); write_file(file, "%d", 299 << 20); snprintf(file, sizeof(file), "%s/memory.max", cgroupdir); write_file(file, "%d", 300 << 20); snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid); if (mkdir(cgroupdir, 0777)) { } snprintf(file, sizeof(file), "%s/cgroup.procs", cgroupdir); write_file(file, "%d", pid); } static void setup_cgroups_test() { char cgroupdir[64]; snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/unified/syz%llu", procid); if (symlink(cgroupdir, "./cgroup")) { } snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/cpu/syz%llu", procid); if (symlink(cgroupdir, "./cgroup.cpu")) { } snprintf(cgroupdir, sizeof(cgroupdir), "/syzcgroup/net/syz%llu", procid); if (symlink(cgroupdir, "./cgroup.net")) { } } static void setup_common() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void setup_binderfs() { if (mkdir("/dev/binderfs", 0777)) { } if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); 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 = 128 << 20; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } 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); } static 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)) { } write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535"); setup_binderfs(); loop(); exit(1); } #define FS_IOC_SETFLAGS _IOW('f', 2, long) static void remove_dir(const char* dir) { int iter = 0; DIR* dp = 0; retry: while (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) { } dp = opendir(dir); if (dp == NULL) { if (errno == EMFILE) { exit(1); } exit(1); } struct dirent* ep = 0; while ((ep = readdir(dp))) { if (strcmp(ep->d_name, ".") == 0 || strcmp(ep->d_name, "..") == 0) continue; char filename[FILENAME_MAX]; snprintf(filename, sizeof(filename), "%s/%s", dir, ep->d_name); while (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW) == 0) { } struct stat st; if (lstat(filename, &st)) exit(1); if (S_ISDIR(st.st_mode)) { remove_dir(filename); continue; } int i; for (i = 0;; i++) { if (unlink(filename) == 0) break; if (errno == EPERM) { int fd = open(filename, O_RDONLY); if (fd != -1) { long flags = 0; if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) { } close(fd); continue; } } if (errno == EROFS) { break; } if (errno != EBUSY || i > 100) exit(1); if (umount2(filename, MNT_DETACH | UMOUNT_NOFOLLOW)) exit(1); } } closedir(dp); for (int i = 0;; i++) { if (rmdir(dir) == 0) break; if (i < 100) { if (errno == EPERM) { int fd = open(dir, O_RDONLY); if (fd != -1) { long flags = 0; if (ioctl(fd, FS_IOC_SETFLAGS, &flags) == 0) { } close(fd); continue; } } if (errno == EROFS) { break; } if (errno == EBUSY) { if (umount2(dir, MNT_DETACH | UMOUNT_NOFOLLOW)) exit(1); continue; } if (errno == ENOTEMPTY) { if (iter < 100) { iter++; goto retry; } } } exit(1); } } 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_loop() { setup_cgroups_loop(); } static void setup_test() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); setpgrp(); setup_cgroups_test(); write_file("/proc/self/oom_score_adj", "1000"); if (symlink("/dev/binderfs", "./binderfs")) { } } static void close_fds() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } static void execute_one(void); #define WAIT_FLAGS __WALL static void loop(void) { setup_loop(); int iter = 0; for (;; iter++) { char cwdbuf[32]; sprintf(cwdbuf, "./%d", iter); if (mkdir(cwdbuf, 0777)) exit(1); int pid = fork(); if (pid < 0) exit(1); if (pid == 0) { if (chdir(cwdbuf)) exit(1); setup_test(); execute_one(); close_fds(); 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; } remove_dir(cwdbuf); } } uint64_t r[1] = {0xffffffffffffffff}; void execute_one(void) { intptr_t res = 0; memcpy( (void*)0x20002740, "\335#\000\346Z\000\257q6\261\343N3\034%\245\203\246#" "\r\203y\363\262\346b\000\000\000\000\000\000\000\001\000\371\377\377\377" "\000\027?$^" "\341Ob\341Y\003\000\000\000\000\000\000\000\316\345\031THP\364O\342\237" "\331\256\317>/" "\334\252<\2265p>{\005\000\000\000\025\000\000\000\241\242\340g\230\277*" "\242c\022.\267\276`\'\313\266\257\334\240\2604\267T5\2257\354\373\346|" "\\\344h\374\024\006\265\003\212\3040\276\343\223A\025\354\333\252\334\n" "\313C\025\374p\021\332i\f{\265\202q\031\254S\210|" "\231\375\236S\200\313\024G\372\377\377\377\377\377\377\377\315\360%\227!" "\272\343J\202t\226\370\261\322\0268\277`$\277\312\352\243\203\216-" "k\022\337\271\207\266^" "r\324\265X\\\333D\n\003G\000\004\000\000\274\254\030\263%" "QF\003\b\235h\313)\364f\022[\371w\322\r\t\357{h\260\300:\217|" "\217\006\370T[\267\244\260\bk&" "\355e\213\302\262\315\357\317\017E\305\206]\300]}\335^\366&\026>" "c\235\234\311\001\004\000\000\351h\275\020p\217\024\0372\"\033;" "\375a\031\213o^\226\232~Q\316\225\002\270e\273G\260V[\376\200\224$" "y\212\\@\251^\225!IJ\317\367\257oX/" "qG\227ITp\001\256\f\"n;%\354T\326\266\277;\336\354\264z\252\331%\245;wy~" "\313\232\327\r\342\315\360C\026\2770\211\264\365\206\363\231\233q\323" "\025\341:\206\344\024\2005K\317\366\332\321A>\364r>" "\375\000\000\000\000\000\000\000\336\227\246\035\016p\276\2568u|" "\321I\272N\367 " "\203\026\360\321\325\363g\312\200\302&\317j\263\221\332\332\366\024>" "\312\350\273\232\000\026\221\212Px;" "\312\035\364t\2022\232M\215\274\210\360\235\213L\357\226\r\307o\235y\211" "LE " "[-\f\200,\207+\335?" "\373\b\214\251\263\327\352b9Y\241e\353\017\333\034\314d\023}" "H\243\361\222\020]\004l\345\034\f\263+\026i\223,\324\247\366\252*" "E\355\374\024\t\373+:\024\a\304/" "\345\262\303\3023\236\367^" "\026\277\312\364f\344x\335F\241F\231o\027\t\323\371tR\235h.\333Tm?" "\330I\215M\374A\024\242\257\261{\236Urm\227\245\375g6!%" "r\vjiIi\217\311y\245Wd\212\271\027\206\340\204(" "\231gK\0033\325\227\257\313\253`\177\002\341$\206\"5\225x\271p\342\317~" "\312k*[\030\351\317\036\020~" "\255\021\373\310\272\367\316n\210\272\tq\264\366\343\250\002QA|" "\022\352\272z\301\235\376?\304\342\000\000\000\000\000", 703); res = syscall(__NR_memfd_create, 0x20002740ul, 7ul); if (res != -1) r[0] = res; memcpy((void*)0x20000080, "security.ima\000", 13); *(uint8_t*)0x200000c0 = 3; *(uint8_t*)0x200000c1 = 2; *(uint8_t*)0x200000c2 = 0; *(uint32_t*)0x200000c3 = htobe32(0); *(uint16_t*)0x200000c7 = htobe16(1); memset((void*)0x200000c9, 137, 1); syscall(__NR_fsetxattr, r[0], 0x20000080ul, 0x200000c0ul, 0xaul, 0ul); syscall(__NR_mmap, 0x20000000ul, 0xff5000ul, 0ul, 0x200000005c832ul, -1, 0ul); } int main(void) { syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); setup_cgroups(); use_temporary_dir(); do_sandbox_none(); return 0; }