Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2499 insertions, 0 deletions

diff --git a/src/shared/seccomp-util.c b/src/shared/seccomp-util.c
new file mode 100644
index 0000000..00a8ced
--- /dev/null
+++ b/src/shared/seccomp-util.c
@@ -0,0 +1,2499 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/seccomp.h>
+#include <stddef.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+
+/* include missing_syscall_def.h earlier to make __SNR_foo mapped to __NR_foo. */
+#include "missing_syscall_def.h"
+#include <seccomp.h>
+
+#include "af-list.h"
+#include "alloc-util.h"
+#include "env-util.h"
+#include "errno-list.h"
+#include "macro.h"
+#include "namespace-util.h"
+#include "nsflags.h"
+#include "nulstr-util.h"
+#include "process-util.h"
+#include "seccomp-util.h"
+#include "set.h"
+#include "string-util.h"
+#include "strv.h"
+
+/* This array will be modified at runtime as seccomp_restrict_archs is called. */
+uint32_t seccomp_local_archs[] = {
+
+        /* Note: always list the native arch we are compiled as last, so that users can deny-list seccomp(), but our own calls to it still succeed */
+
+#if defined(__x86_64__) && defined(__ILP32__)
+                SCMP_ARCH_X86,
+                SCMP_ARCH_X86_64,
+                SCMP_ARCH_X32,         /* native */
+#elif defined(__x86_64__) && !defined(__ILP32__)
+                SCMP_ARCH_X86,
+                SCMP_ARCH_X32,
+                SCMP_ARCH_X86_64,      /* native */
+#elif defined(__i386__)
+                SCMP_ARCH_X86,
+#elif defined(__aarch64__)
+                SCMP_ARCH_ARM,
+                SCMP_ARCH_AARCH64,     /* native */
+#elif defined(__arm__)
+                SCMP_ARCH_ARM,
+#elif defined(__loongarch_lp64)
+                SCMP_ARCH_LOONGARCH64,
+#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI32
+                SCMP_ARCH_MIPSEL,
+                SCMP_ARCH_MIPS,        /* native */
+#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI32
+                SCMP_ARCH_MIPS,
+                SCMP_ARCH_MIPSEL,      /* native */
+#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI64
+                SCMP_ARCH_MIPSEL,
+                SCMP_ARCH_MIPS,
+                SCMP_ARCH_MIPSEL64N32,
+                SCMP_ARCH_MIPS64N32,
+                SCMP_ARCH_MIPSEL64,
+                SCMP_ARCH_MIPS64,      /* native */
+#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI64
+                SCMP_ARCH_MIPS,
+                SCMP_ARCH_MIPSEL,
+                SCMP_ARCH_MIPS64N32,
+                SCMP_ARCH_MIPSEL64N32,
+                SCMP_ARCH_MIPS64,
+                SCMP_ARCH_MIPSEL64,    /* native */
+#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_NABI32
+                SCMP_ARCH_MIPSEL,
+                SCMP_ARCH_MIPS,
+                SCMP_ARCH_MIPSEL64,
+                SCMP_ARCH_MIPS64,
+                SCMP_ARCH_MIPSEL64N32,
+                SCMP_ARCH_MIPS64N32,   /* native */
+#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_NABI32
+                SCMP_ARCH_MIPS,
+                SCMP_ARCH_MIPSEL,
+                SCMP_ARCH_MIPS64,
+                SCMP_ARCH_MIPSEL64,
+                SCMP_ARCH_MIPS64N32,
+                SCMP_ARCH_MIPSEL64N32, /* native */
+#elif defined(__hppa64__) && defined(SCMP_ARCH_PARISC) && defined(SCMP_ARCH_PARISC64)
+                SCMP_ARCH_PARISC,
+                SCMP_ARCH_PARISC64,    /* native */
+#elif defined(__hppa__) && defined(SCMP_ARCH_PARISC)
+                SCMP_ARCH_PARISC,
+#elif defined(__powerpc64__) && __BYTE_ORDER == __BIG_ENDIAN
+                SCMP_ARCH_PPC,
+                SCMP_ARCH_PPC64LE,
+                SCMP_ARCH_PPC64,       /* native */
+#elif defined(__powerpc64__) && __BYTE_ORDER == __LITTLE_ENDIAN
+                SCMP_ARCH_PPC,
+                SCMP_ARCH_PPC64,
+                SCMP_ARCH_PPC64LE,     /* native */
+#elif defined(__powerpc__)
+                SCMP_ARCH_PPC,
+#elif defined(__riscv) && __riscv_xlen == 64 && defined(SCMP_ARCH_RISCV64)
+                SCMP_ARCH_RISCV64,
+#elif defined(__s390x__)
+                SCMP_ARCH_S390,
+                SCMP_ARCH_S390X,      /* native */
+#elif defined(__s390__)
+                SCMP_ARCH_S390,
+#endif
+                SECCOMP_LOCAL_ARCH_END
+        };
+
+const char* seccomp_arch_to_string(uint32_t c) {
+        /* Maintain order used in <seccomp.h>.
+         *
+         * Names used here should be the same as those used for ConditionArchitecture=,
+         * except for "subarchitectures" like x32. */
+
+        switch (c) {
+        case SCMP_ARCH_NATIVE:
+                return "native";
+        case SCMP_ARCH_X86:
+                return "x86";
+        case SCMP_ARCH_X86_64:
+                return "x86-64";
+        case SCMP_ARCH_X32:
+                return "x32";
+        case SCMP_ARCH_ARM:
+                return "arm";
+        case SCMP_ARCH_AARCH64:
+                return "arm64";
+#ifdef SCMP_ARCH_LOONGARCH64
+        case SCMP_ARCH_LOONGARCH64:
+                return "loongarch64";
+#endif
+        case SCMP_ARCH_MIPS:
+                return "mips";
+        case SCMP_ARCH_MIPS64:
+                return "mips64";
+        case SCMP_ARCH_MIPS64N32:
+                return "mips64-n32";
+        case SCMP_ARCH_MIPSEL:
+                return "mips-le";
+        case SCMP_ARCH_MIPSEL64:
+                return "mips64-le";
+        case SCMP_ARCH_MIPSEL64N32:
+                return "mips64-le-n32";
+#ifdef SCMP_ARCH_PARISC
+        case SCMP_ARCH_PARISC:
+                return "parisc";
+#endif
+#ifdef SCMP_ARCH_PARISC64
+        case SCMP_ARCH_PARISC64:
+                return "parisc64";
+#endif
+        case SCMP_ARCH_PPC:
+                return "ppc";
+        case SCMP_ARCH_PPC64:
+                return "ppc64";
+        case SCMP_ARCH_PPC64LE:
+                return "ppc64-le";
+#ifdef SCMP_ARCH_RISCV64
+        case SCMP_ARCH_RISCV64:
+                return "riscv64";
+#endif
+        case SCMP_ARCH_S390:
+                return "s390";
+        case SCMP_ARCH_S390X:
+                return "s390x";
+        default:
+                return NULL;
+        }
+}
+
+int seccomp_arch_from_string(const char *n, uint32_t *ret) {
+        if (!n)
+                return -EINVAL;
+
+        assert(ret);
+
+        if (streq(n, "native"))
+                *ret = SCMP_ARCH_NATIVE;
+        else if (streq(n, "x86"))
+                *ret = SCMP_ARCH_X86;
+        else if (streq(n, "x86-64"))
+                *ret = SCMP_ARCH_X86_64;
+        else if (streq(n, "x32"))
+                *ret = SCMP_ARCH_X32;
+        else if (streq(n, "arm"))
+                *ret = SCMP_ARCH_ARM;
+        else if (streq(n, "arm64"))
+                *ret = SCMP_ARCH_AARCH64;
+#ifdef SCMP_ARCH_LOONGARCH64
+        else if (streq(n, "loongarch64"))
+                *ret = SCMP_ARCH_LOONGARCH64;
+#endif
+        else if (streq(n, "mips"))
+                *ret = SCMP_ARCH_MIPS;
+        else if (streq(n, "mips64"))
+                *ret = SCMP_ARCH_MIPS64;
+        else if (streq(n, "mips64-n32"))
+                *ret = SCMP_ARCH_MIPS64N32;
+        else if (streq(n, "mips-le"))
+                *ret = SCMP_ARCH_MIPSEL;
+        else if (streq(n, "mips64-le"))
+                *ret = SCMP_ARCH_MIPSEL64;
+        else if (streq(n, "mips64-le-n32"))
+                *ret = SCMP_ARCH_MIPSEL64N32;
+#ifdef SCMP_ARCH_PARISC
+        else if (streq(n, "parisc"))
+                *ret = SCMP_ARCH_PARISC;
+#endif
+#ifdef SCMP_ARCH_PARISC64
+        else if (streq(n, "parisc64"))
+                *ret = SCMP_ARCH_PARISC64;
+#endif
+        else if (streq(n, "ppc"))
+                *ret = SCMP_ARCH_PPC;
+        else if (streq(n, "ppc64"))
+                *ret = SCMP_ARCH_PPC64;
+        else if (streq(n, "ppc64-le"))
+                *ret = SCMP_ARCH_PPC64LE;
+#ifdef SCMP_ARCH_RISCV64
+        else if (streq(n, "riscv64"))
+                *ret = SCMP_ARCH_RISCV64;
+#endif
+        else if (streq(n, "s390"))
+                *ret = SCMP_ARCH_S390;
+        else if (streq(n, "s390x"))
+                *ret = SCMP_ARCH_S390X;
+        else
+                return -EINVAL;
+
+        return 0;
+}
+
+int seccomp_init_for_arch(scmp_filter_ctx *ret, uint32_t arch, uint32_t default_action) {
+        _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+        int r;
+
+        /* Much like seccomp_init(), but initializes the filter for one specific architecture only, without affecting
+         * any others. Also, turns off the NNP fiddling. */
+
+        seccomp = seccomp_init(default_action);
+        if (!seccomp)
+                return -ENOMEM;
+
+        if (arch != SCMP_ARCH_NATIVE &&
+            arch != seccomp_arch_native()) {
+
+                r = seccomp_arch_remove(seccomp, seccomp_arch_native());
+                if (r < 0)
+                        return r;
+
+                r = seccomp_arch_add(seccomp, arch);
+                if (r < 0)
+                        return r;
+
+                assert(seccomp_arch_exist(seccomp, arch) >= 0);
+                assert(seccomp_arch_exist(seccomp, SCMP_ARCH_NATIVE) == -EEXIST);
+                assert(seccomp_arch_exist(seccomp, seccomp_arch_native()) == -EEXIST);
+        } else {
+                assert(seccomp_arch_exist(seccomp, SCMP_ARCH_NATIVE) >= 0);
+                assert(seccomp_arch_exist(seccomp, seccomp_arch_native()) >= 0);
+        }
+
+        r = seccomp_attr_set(seccomp, SCMP_FLTATR_ACT_BADARCH, SCMP_ACT_ALLOW);
+        if (r < 0)
+                return r;
+
+        r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+        if (r < 0)
+                return r;
+
+#if SCMP_VER_MAJOR >= 3 || (SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 4)
+        if (getenv_bool("SYSTEMD_LOG_SECCOMP") > 0) {
+                r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_LOG, 1);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to enable seccomp event logging: %m");
+        }
+#endif
+
+        *ret = TAKE_PTR(seccomp);
+        return 0;
+}
+
+static bool is_basic_seccomp_available(void) {
+        return prctl(PR_GET_SECCOMP, 0, 0, 0, 0) >= 0;
+}
+
+static bool is_seccomp_filter_available(void) {
+        return prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL, 0, 0) < 0 &&
+                errno == EFAULT;
+}
+
+bool is_seccomp_available(void) {
+        static int cached_enabled = -1;
+
+        if (cached_enabled < 0) {
+                int b;
+
+                b = getenv_bool_secure("SYSTEMD_SECCOMP");
+                if (b != 0) {
+                        if (b < 0 && b != -ENXIO) /* ENXIO: env var unset */
+                                log_debug_errno(b, "Failed to parse $SYSTEMD_SECCOMP value, ignoring.");
+
+                        cached_enabled =
+                                is_basic_seccomp_available() &&
+                                is_seccomp_filter_available();
+                } else
+                        cached_enabled = false;
+        }
+
+        return cached_enabled;
+}
+
+const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
+        [SYSCALL_FILTER_SET_DEFAULT] = {
+                .name = "@default",
+                .help = "System calls that are always permitted",
+                .value =
+                "arch_prctl\0"      /* Used during platform-specific initialization by ld-linux.so. */
+                "brk\0"
+                "cacheflush\0"
+                "clock_getres\0"
+                "clock_getres_time64\0"
+                "clock_gettime\0"
+                "clock_gettime64\0"
+                "clock_nanosleep\0"
+                "clock_nanosleep_time64\0"
+                "execve\0"
+                "exit\0"
+                "exit_group\0"
+                "futex\0"
+                "futex_time64\0"
+                "futex_waitv\0"
+                "get_robust_list\0"
+                "get_thread_area\0"
+                "getegid\0"
+                "getegid32\0"
+                "geteuid\0"
+                "geteuid32\0"
+                "getgid\0"
+                "getgid32\0"
+                "getgroups\0"
+                "getgroups32\0"
+                "getpgid\0"
+                "getpgrp\0"
+                "getpid\0"
+                "getppid\0"
+                "getrandom\0"
+                "getresgid\0"
+                "getresgid32\0"
+                "getresuid\0"
+                "getresuid32\0"
+                "getrlimit\0"      /* make sure processes can query stack size and such */
+                "getsid\0"
+                "gettid\0"
+                "gettimeofday\0"
+                "getuid\0"
+                "getuid32\0"
+                "membarrier\0"
+                "mmap\0"
+                "mmap2\0"
+                "mprotect\0"
+                "munmap\0"
+                "nanosleep\0"
+                "pause\0"
+                "prlimit64\0"
+                "restart_syscall\0"
+                "riscv_flush_icache\0"
+                "riscv_hwprobe\0"
+                "rseq\0"
+                "rt_sigreturn\0"
+                "sched_getaffinity\0"
+                "sched_yield\0"
+                "set_robust_list\0"
+                "set_thread_area\0"
+                "set_tid_address\0"
+                "set_tls\0"
+                "sigreturn\0"
+                "time\0"
+                "ugetrlimit\0"
+        },
+        [SYSCALL_FILTER_SET_AIO] = {
+                .name = "@aio",
+                .help = "Asynchronous IO",
+                .value =
+                "io_cancel\0"
+                "io_destroy\0"
+                "io_getevents\0"
+                "io_pgetevents\0"
+                "io_pgetevents_time64\0"
+                "io_setup\0"
+                "io_submit\0"
+                "io_uring_enter\0"
+                "io_uring_register\0"
+                "io_uring_setup\0"
+        },
+        [SYSCALL_FILTER_SET_BASIC_IO] = {
+                .name = "@basic-io",
+                .help = "Basic IO",
+                .value =
+                "_llseek\0"
+                "close\0"
+                "close_range\0"
+                "dup\0"
+                "dup2\0"
+                "dup3\0"
+                "lseek\0"
+                "pread64\0"
+                "preadv\0"
+                "preadv2\0"
+                "pwrite64\0"
+                "pwritev\0"
+                "pwritev2\0"
+                "read\0"
+                "readv\0"
+                "write\0"
+                "writev\0"
+        },
+        [SYSCALL_FILTER_SET_CHOWN] = {
+                .name = "@chown",
+                .help = "Change ownership of files and directories",
+                .value =
+                "chown\0"
+                "chown32\0"
+                "fchown\0"
+                "fchown32\0"
+                "fchownat\0"
+                "lchown\0"
+                "lchown32\0"
+        },
+        [SYSCALL_FILTER_SET_CLOCK] = {
+                .name = "@clock",
+                .help = "Change the system time",
+                .value =
+                "adjtimex\0"
+                "clock_adjtime\0"
+                "clock_adjtime64\0"
+                "clock_settime\0"
+                "clock_settime64\0"
+                "settimeofday\0"
+        },
+        [SYSCALL_FILTER_SET_CPU_EMULATION] = {
+                .name = "@cpu-emulation",
+                .help = "System calls for CPU emulation functionality",
+                .value =
+                "modify_ldt\0"
+                "subpage_prot\0"
+                "switch_endian\0"
+                "vm86\0"
+                "vm86old\0"
+        },
+        [SYSCALL_FILTER_SET_DEBUG] = {
+                .name = "@debug",
+                .help = "Debugging, performance monitoring and tracing functionality",
+                .value =
+                "lookup_dcookie\0"
+                "perf_event_open\0"
+                "pidfd_getfd\0"
+                "ptrace\0"
+                "rtas\0"
+                "s390_runtime_instr\0"
+                "sys_debug_setcontext\0"
+        },
+        [SYSCALL_FILTER_SET_FILE_SYSTEM] = {
+                .name = "@file-system",
+                .help = "File system operations",
+                .value =
+                "access\0"
+                "chdir\0"
+                "chmod\0"
+                "close\0"
+                "creat\0"
+                "faccessat\0"
+                "faccessat2\0"
+                "fallocate\0"
+                "fchdir\0"
+                "fchmod\0"
+                "fchmodat\0"
+                "fchmodat2\0"
+                "fcntl\0"
+                "fcntl64\0"
+                "fgetxattr\0"
+                "flistxattr\0"
+                "fremovexattr\0"
+                "fsetxattr\0"
+                "fstat\0"
+                "fstat64\0"
+                "fstatat64\0"
+                "fstatfs\0"
+                "fstatfs64\0"
+                "ftruncate\0"
+                "ftruncate64\0"
+                "futimesat\0"
+                "getcwd\0"
+                "getdents\0"
+                "getdents64\0"
+                "getxattr\0"
+                "inotify_add_watch\0"
+                "inotify_init\0"
+                "inotify_init1\0"
+                "inotify_rm_watch\0"
+                "lgetxattr\0"
+                "link\0"
+                "linkat\0"
+                "listxattr\0"
+                "llistxattr\0"
+                "lremovexattr\0"
+                "lsetxattr\0"
+                "lstat\0"
+                "lstat64\0"
+                "mkdir\0"
+                "mkdirat\0"
+                "mknod\0"
+                "mknodat\0"
+                "newfstatat\0"
+                "oldfstat\0"
+                "oldlstat\0"
+                "oldstat\0"
+                "open\0"
+                "openat\0"
+                "openat2\0"
+                "readlink\0"
+                "readlinkat\0"
+                "removexattr\0"
+                "rename\0"
+                "renameat\0"
+                "renameat2\0"
+                "rmdir\0"
+                "setxattr\0"
+                "stat\0"
+                "stat64\0"
+                "statfs\0"
+                "statfs64\0"
+                "statx\0"
+                "symlink\0"
+                "symlinkat\0"
+                "truncate\0"
+                "truncate64\0"
+                "unlink\0"
+                "unlinkat\0"
+                "utime\0"
+                "utimensat\0"
+                "utimensat_time64\0"
+                "utimes\0"
+        },
+        [SYSCALL_FILTER_SET_IO_EVENT] = {
+                .name = "@io-event",
+                .help = "Event loop system calls",
+                .value =
+                "_newselect\0"
+                "epoll_create\0"
+                "epoll_create1\0"
+                "epoll_ctl\0"
+                "epoll_ctl_old\0"
+                "epoll_pwait\0"
+                "epoll_pwait2\0"
+                "epoll_wait\0"
+                "epoll_wait_old\0"
+                "eventfd\0"
+                "eventfd2\0"
+                "poll\0"
+                "ppoll\0"
+                "ppoll_time64\0"
+                "pselect6\0"
+                "pselect6_time64\0"
+                "select\0"
+        },
+        [SYSCALL_FILTER_SET_IPC] = {
+                .name = "@ipc",
+                .help = "SysV IPC, POSIX Message Queues or other IPC",
+                .value =
+                "ipc\0"
+                "memfd_create\0"
+                "mq_getsetattr\0"
+                "mq_notify\0"
+                "mq_open\0"
+                "mq_timedreceive\0"
+                "mq_timedreceive_time64\0"
+                "mq_timedsend\0"
+                "mq_timedsend_time64\0"
+                "mq_unlink\0"
+                "msgctl\0"
+                "msgget\0"
+                "msgrcv\0"
+                "msgsnd\0"
+                "pipe\0"
+                "pipe2\0"
+                "process_madvise\0"
+                "process_vm_readv\0"
+                "process_vm_writev\0"
+                "semctl\0"
+                "semget\0"
+                "semop\0"
+                "semtimedop\0"
+                "semtimedop_time64\0"
+                "shmat\0"
+                "shmctl\0"
+                "shmdt\0"
+                "shmget\0"
+        },
+        [SYSCALL_FILTER_SET_KEYRING] = {
+                .name = "@keyring",
+                .help = "Kernel keyring access",
+                .value =
+                "add_key\0"
+                "keyctl\0"
+                "request_key\0"
+        },
+        [SYSCALL_FILTER_SET_MEMLOCK] = {
+                .name = "@memlock",
+                .help = "Memory locking control",
+                .value =
+                "mlock\0"
+                "mlock2\0"
+                "mlockall\0"
+                "munlock\0"
+                "munlockall\0"
+        },
+        [SYSCALL_FILTER_SET_MODULE] = {
+                .name = "@module",
+                .help = "Loading and unloading of kernel modules",
+                .value =
+                "delete_module\0"
+                "finit_module\0"
+                "init_module\0"
+        },
+        [SYSCALL_FILTER_SET_MOUNT] = {
+                .name = "@mount",
+                .help = "Mounting and unmounting of file systems",
+                .value =
+                "chroot\0"
+                "fsconfig\0"
+                "fsmount\0"
+                "fsopen\0"
+                "fspick\0"
+                "mount\0"
+                "mount_setattr\0"
+                "move_mount\0"
+                "open_tree\0"
+                "pivot_root\0"
+                "umount\0"
+                "umount2\0"
+        },
+        [SYSCALL_FILTER_SET_NETWORK_IO] = {
+                .name = "@network-io",
+                .help = "Network or Unix socket IO, should not be needed if not network facing",
+                .value =
+                "accept\0"
+                "accept4\0"
+                "bind\0"
+                "connect\0"
+                "getpeername\0"
+                "getsockname\0"
+                "getsockopt\0"
+                "listen\0"
+                "recv\0"
+                "recvfrom\0"
+                "recvmmsg\0"
+                "recvmmsg_time64\0"
+                "recvmsg\0"
+                "send\0"
+                "sendmmsg\0"
+                "sendmsg\0"
+                "sendto\0"
+                "setsockopt\0"
+                "shutdown\0"
+                "socket\0"
+                "socketcall\0"
+                "socketpair\0"
+        },
+        [SYSCALL_FILTER_SET_OBSOLETE] = {
+                /* some unknown even to libseccomp */
+                .name = "@obsolete",
+                .help = "Unusual, obsolete or unimplemented system calls",
+                .value =
+                "_sysctl\0"
+                "afs_syscall\0"
+                "bdflush\0"
+                "break\0"
+                "create_module\0"
+                "ftime\0"
+                "get_kernel_syms\0"
+                "getpmsg\0"
+                "gtty\0"
+                "idle\0"
+                "lock\0"
+                "mpx\0"
+                "prof\0"
+                "profil\0"
+                "putpmsg\0"
+                "query_module\0"
+                "security\0"
+                "sgetmask\0"
+                "ssetmask\0"
+                "stime\0"
+                "stty\0"
+                "sysfs\0"
+                "tuxcall\0"
+                "ulimit\0"
+                "uselib\0"
+                "ustat\0"
+                "vserver\0"
+        },
+        [SYSCALL_FILTER_SET_PKEY] = {
+                .name = "@pkey",
+                .help = "System calls used for memory protection keys",
+                .value =
+                "pkey_alloc\0"
+                "pkey_free\0"
+                "pkey_mprotect\0"
+        },
+        [SYSCALL_FILTER_SET_PRIVILEGED] = {
+                .name = "@privileged",
+                .help = "All system calls which need super-user capabilities",
+                .value =
+                "@chown\0"
+                "@clock\0"
+                "@module\0"
+                "@raw-io\0"
+                "@reboot\0"
+                "@swap\0"
+                "_sysctl\0"
+                "acct\0"
+                "bpf\0"
+                "capset\0"
+                "chroot\0"
+                "fanotify_init\0"
+                "fanotify_mark\0"
+                "nfsservctl\0"
+                "open_by_handle_at\0"
+                "pivot_root\0"
+                "quotactl\0"
+                "quotactl_fd\0"
+                "setdomainname\0"
+                "setfsuid\0"
+                "setfsuid32\0"
+                "setgroups\0"
+                "setgroups32\0"
+                "sethostname\0"
+                "setresuid\0"
+                "setresuid32\0"
+                "setreuid\0"
+                "setreuid32\0"
+                "setuid\0"      /* We list the explicit system calls here, as @setuid also includes setgid() which is not necessarily privileged */
+                "setuid32\0"
+                "vhangup\0"
+        },
+        [SYSCALL_FILTER_SET_PROCESS] = {
+                .name = "@process",
+                .help = "Process control, execution, namespacing operations",
+                .value =
+                "capget\0"      /* Able to query arbitrary processes */
+                "clone\0"
+                /* ia64 as the only architecture has clone2, a replacement for clone, but ia64 doesn't
+                 * implement seccomp, so we don't need to list it at all. C.f.
+                 * acce2f71779c54086962fefce3833d886c655f62 in the kernel. */
+                "clone3\0"
+                "execveat\0"
+                "fork\0"
+                "getrusage\0"
+                "kill\0"
+                "pidfd_open\0"
+                "pidfd_send_signal\0"
+                "prctl\0"
+                "rt_sigqueueinfo\0"
+                "rt_tgsigqueueinfo\0"
+                "setns\0"
+                "swapcontext\0" /* Some archs e.g. powerpc32 are using it to do userspace context switches */
+                "tgkill\0"
+                "times\0"
+                "tkill\0"
+                "unshare\0"
+                "vfork\0"
+                "wait4\0"
+                "waitid\0"
+                "waitpid\0"
+        },
+        [SYSCALL_FILTER_SET_RAW_IO] = {
+                .name = "@raw-io",
+                .help = "Raw I/O port access",
+                .value =
+                "ioperm\0"
+                "iopl\0"
+                "pciconfig_iobase\0"
+                "pciconfig_read\0"
+                "pciconfig_write\0"
+                "s390_pci_mmio_read\0"
+                "s390_pci_mmio_write\0"
+        },
+        [SYSCALL_FILTER_SET_REBOOT] = {
+                .name = "@reboot",
+                .help = "Reboot and reboot preparation/kexec",
+                .value =
+                "kexec_file_load\0"
+                "kexec_load\0"
+                "reboot\0"
+        },
+        [SYSCALL_FILTER_SET_RESOURCES] = {
+                .name = "@resources",
+                .help = "Alter resource settings",
+                .value =
+                "ioprio_set\0"
+                "mbind\0"
+                "migrate_pages\0"
+                "move_pages\0"
+                "nice\0"
+                "sched_setaffinity\0"
+                "sched_setattr\0"
+                "sched_setparam\0"
+                "sched_setscheduler\0"
+                "set_mempolicy\0"
+                "set_mempolicy_home_node\0"
+                "setpriority\0"
+                "setrlimit\0"
+        },
+        [SYSCALL_FILTER_SET_SANDBOX] = {
+                .name = "@sandbox",
+                .help = "Sandbox functionality",
+                .value =
+                "landlock_add_rule\0"
+                "landlock_create_ruleset\0"
+                "landlock_restrict_self\0"
+                "seccomp\0"
+        },
+        [SYSCALL_FILTER_SET_SETUID] = {
+                .name = "@setuid",
+                .help = "Operations for changing user/group credentials",
+                .value =
+                "setgid\0"
+                "setgid32\0"
+                "setgroups\0"
+                "setgroups32\0"
+                "setregid\0"
+                "setregid32\0"
+                "setresgid\0"
+                "setresgid32\0"
+                "setresuid\0"
+                "setresuid32\0"
+                "setreuid\0"
+                "setreuid32\0"
+                "setuid\0"
+                "setuid32\0"
+        },
+        [SYSCALL_FILTER_SET_SIGNAL] = {
+                .name = "@signal",
+                .help = "Process signal handling",
+                .value =
+                "rt_sigaction\0"
+                "rt_sigpending\0"
+                "rt_sigprocmask\0"
+                "rt_sigsuspend\0"
+                "rt_sigtimedwait\0"
+                "rt_sigtimedwait_time64\0"
+                "sigaction\0"
+                "sigaltstack\0"
+                "signal\0"
+                "signalfd\0"
+                "signalfd4\0"
+                "sigpending\0"
+                "sigprocmask\0"
+                "sigsuspend\0"
+        },
+        [SYSCALL_FILTER_SET_SWAP] = {
+                .name = "@swap",
+                .help = "Enable/disable swap devices",
+                .value =
+                "swapoff\0"
+                "swapon\0"
+        },
+        [SYSCALL_FILTER_SET_SYNC] = {
+                .name = "@sync",
+                .help = "Synchronize files and memory to storage",
+                .value =
+                "fdatasync\0"
+                "fsync\0"
+                "msync\0"
+                "sync\0"
+                "sync_file_range\0"
+                "sync_file_range2\0"
+                "syncfs\0"
+        },
+        [SYSCALL_FILTER_SET_SYSTEM_SERVICE] = {
+                .name = "@system-service",
+                .help = "General system service operations",
+                .value =
+                "@aio\0"
+                "@basic-io\0"
+                "@chown\0"
+                "@default\0"
+                "@file-system\0"
+                "@io-event\0"
+                "@ipc\0"
+                "@keyring\0"
+                "@memlock\0"
+                "@network-io\0"
+                "@process\0"
+                "@resources\0"
+                "@setuid\0"
+                "@signal\0"
+                "@sync\0"
+                "@timer\0"
+                "arm_fadvise64_64\0"
+                "capget\0"
+                "capset\0"
+                "copy_file_range\0"
+                "fadvise64\0"
+                "fadvise64_64\0"
+                "flock\0"
+                "get_mempolicy\0"
+                "getcpu\0"
+                "getpriority\0"
+                "ioctl\0"
+                "ioprio_get\0"
+                "kcmp\0"
+                "madvise\0"
+                "mremap\0"
+                "name_to_handle_at\0"
+                "oldolduname\0"
+                "olduname\0"
+                "personality\0"
+                "readahead\0"
+                "readdir\0"
+                "remap_file_pages\0"
+                "sched_get_priority_max\0"
+                "sched_get_priority_min\0"
+                "sched_getattr\0"
+                "sched_getparam\0"
+                "sched_getscheduler\0"
+                "sched_rr_get_interval\0"
+                "sched_rr_get_interval_time64\0"
+                "sched_yield\0"
+                "sendfile\0"
+                "sendfile64\0"
+                "setfsgid\0"
+                "setfsgid32\0"
+                "setfsuid\0"
+                "setfsuid32\0"
+                "setpgid\0"
+                "setsid\0"
+                "splice\0"
+                "sysinfo\0"
+                "tee\0"
+                "umask\0"
+                "uname\0"
+                "userfaultfd\0"
+                "vmsplice\0"
+        },
+        [SYSCALL_FILTER_SET_TIMER] = {
+                .name = "@timer",
+                .help = "Schedule operations by time",
+                .value =
+                "alarm\0"
+                "getitimer\0"
+                "setitimer\0"
+                "timer_create\0"
+                "timer_delete\0"
+                "timer_getoverrun\0"
+                "timer_gettime\0"
+                "timer_gettime64\0"
+                "timer_settime\0"
+                "timer_settime64\0"
+                "timerfd_create\0"
+                "timerfd_gettime\0"
+                "timerfd_gettime64\0"
+                "timerfd_settime\0"
+                "timerfd_settime64\0"
+                "times\0"
+        },
+        [SYSCALL_FILTER_SET_KNOWN] = {
+                .name = "@known",
+                .help = "All known syscalls declared in the kernel",
+                .value =
+                "@obsolete\0"
+#include "syscall-list.h"
+        },
+};
+
+const SyscallFilterSet *syscall_filter_set_find(const char *name) {
+        if (isempty(name) || name[0] != '@')
+                return NULL;
+
+        for (unsigned i = 0; i < _SYSCALL_FILTER_SET_MAX; i++)
+                if (streq(syscall_filter_sets[i].name, name))
+                        return syscall_filter_sets + i;
+
+        return NULL;
+}
+
+static int add_syscall_filter_set(
+                scmp_filter_ctx seccomp,
+                const SyscallFilterSet *set,
+                uint32_t action,
+                char **exclude,
+                bool log_missing,
+                char ***added);
+
+int seccomp_add_syscall_filter_item(
+                scmp_filter_ctx *seccomp,
+                const char *name,
+                uint32_t action,
+                char **exclude,
+                bool log_missing,
+                char ***added) {
+
+        assert(seccomp);
+        assert(name);
+
+        if (strv_contains(exclude, name))
+                return 0;
+
+        /* Any syscalls that are handled are added to the *added strv. The pointer
+         * must be either NULL or point to a valid pre-initialized possibly-empty strv. */
+
+        if (name[0] == '@') {
+                const SyscallFilterSet *other;
+
+                other = syscall_filter_set_find(name);
+                if (!other)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "Filter set %s is not known!",
+                                               name);
+
+                return add_syscall_filter_set(seccomp, other, action, exclude, log_missing, added);
+
+        } else {
+                int id, r;
+
+                id = seccomp_syscall_resolve_name(name);
+                if (id == __NR_SCMP_ERROR) {
+                        if (log_missing)
+                                log_debug("System call %s is not known, ignoring.", name);
+                        return 0;
+                }
+
+                r = seccomp_rule_add_exact(seccomp, action, id, 0);
+                if (r < 0) {
+                        /* If the system call is not known on this architecture, then that's fine, let's ignore it */
+                        bool ignore = r == -EDOM;
+
+                        if (!ignore || log_missing)
+                                log_debug_errno(r, "Failed to add rule for system call %s() / %d%s: %m",
+                                                name, id, ignore ? ", ignoring" : "");
+                        if (!ignore)
+                                return r;
+                }
+
+                if (added) {
+                        r = strv_extend(added, name);
+                        if (r < 0)
+                                return r;
+                }
+
+                return 0;
+        }
+}
+
+static int add_syscall_filter_set(
+                scmp_filter_ctx seccomp,
+                const SyscallFilterSet *set,
+                uint32_t action,
+                char **exclude,
+                bool log_missing,
+                char ***added) {
+
+        int r;
+
+        /* Any syscalls that are handled are added to the *added strv. It needs to be initialized. */
+
+        assert(seccomp);
+        assert(set);
+
+        NULSTR_FOREACH(sys, set->value) {
+                r = seccomp_add_syscall_filter_item(seccomp, sys, action, exclude, log_missing, added);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static uint32_t override_default_action(uint32_t default_action) {
+        /* When the requested filter is an allow-list, and the default action is something critical, we
+         * install ENOSYS as the default action, but it will only apply to syscalls which are not in the
+         * @known set. */
+
+        if (default_action == SCMP_ACT_ALLOW)
+                return default_action;
+
+#ifdef SCMP_ACT_LOG
+        if (default_action == SCMP_ACT_LOG)
+                return default_action;
+#endif
+
+        return SCMP_ACT_ERRNO(ENOSYS);
+}
+
+int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilterSet *set, uint32_t action, bool log_missing) {
+        uint32_t arch, default_action_override;
+        int r;
+
+        assert(set);
+
+        /* The one-stop solution: allocate a seccomp object, add the specified filter to it, and apply it. Once for
+         * each local arch. */
+
+        default_action_override = override_default_action(default_action);
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+                _cleanup_strv_free_ char **added = NULL;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                r = seccomp_init_for_arch(&seccomp, arch, default_action_override);
+                if (r < 0)
+                        return r;
+
+                r = add_syscall_filter_set(seccomp, set, action, NULL, log_missing, &added);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to add filter set: %m");
+
+                if (default_action != default_action_override)
+                        NULSTR_FOREACH(name, syscall_filter_sets[SYSCALL_FILTER_SET_KNOWN].value) {
+                                int id;
+
+                                id = seccomp_syscall_resolve_name(name);
+                                if (id < 0)
+                                        continue;
+
+                                /* Ignore the syscall if it was already handled above */
+                                if (strv_contains(added, name))
+                                        continue;
+
+                                r = seccomp_rule_add_exact(seccomp, default_action, id, 0);
+                                if (r < 0 && r != -EDOM)  /* EDOM means that the syscall is not available for arch */
+                                        return log_debug_errno(r, "Failed to add rule for system call %s() / %d: %m",
+                                                               name, id);
+                        }
+
+#if (SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 5) || SCMP_VER_MAJOR > 2
+                /* We have a large filter here, so let's turn on the binary tree mode if possible. */
+                r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_OPTIMIZE, 2);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to set SCMP_FLTATR_CTL_OPTIMIZE, ignoring: %m");
+#endif
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install filter set for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_load_syscall_filter_set_raw(uint32_t default_action, Hashmap* filter, uint32_t action, bool log_missing) {
+        uint32_t arch, default_action_override;
+        int r;
+
+        /* Similar to seccomp_load_syscall_filter_set(), but takes a raw Hashmap* of syscalls, instead
+         * of a SyscallFilterSet* table. */
+
+        if (hashmap_isempty(filter) && default_action == SCMP_ACT_ALLOW)
+                return 0;
+
+        default_action_override = override_default_action(default_action);
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+                void *syscall_id, *val;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                r = seccomp_init_for_arch(&seccomp, arch, default_action_override);
+                if (r < 0)
+                        return r;
+
+                HASHMAP_FOREACH_KEY(val, syscall_id, filter) {
+                        uint32_t a = action;
+                        int id = PTR_TO_INT(syscall_id) - 1;
+                        int error = PTR_TO_INT(val);
+
+                        if (error == SECCOMP_ERROR_NUMBER_KILL)
+                                a = scmp_act_kill_process();
+#ifdef SCMP_ACT_LOG
+                        else if (action == SCMP_ACT_LOG)
+                                a = SCMP_ACT_LOG;
+#endif
+                        else if (error >= 0)
+                                a = SCMP_ACT_ERRNO(error);
+
+                        r = seccomp_rule_add_exact(seccomp, a, id, 0);
+                        if (r < 0) {
+                                /* If the system call is not known on this architecture, then that's
+                                 * fine, let's ignore it */
+                                _cleanup_free_ char *n = NULL;
+                                bool ignore;
+
+                                n = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, id);
+                                ignore = r == -EDOM;
+                                if (!ignore || log_missing)
+                                        log_debug_errno(r, "Failed to add rule for system call %s() / %d%s: %m",
+                                                        strna(n), id, ignore ? ", ignoring" : "");
+                                if (!ignore)
+                                        return r;
+                        }
+                }
+
+                if (default_action != default_action_override)
+                        NULSTR_FOREACH(name, syscall_filter_sets[SYSCALL_FILTER_SET_KNOWN].value) {
+                                int id;
+
+                                id = seccomp_syscall_resolve_name(name);
+                                if (id < 0)
+                                        continue;
+
+                                /* Ignore the syscall if it was already handled above */
+                                if (hashmap_contains(filter, INT_TO_PTR(id + 1)))
+                                        continue;
+
+                                r = seccomp_rule_add_exact(seccomp, default_action, id, 0);
+                                if (r < 0 && r != -EDOM)  /* EDOM means that the syscall is not available for arch */
+                                        return log_debug_errno(r, "Failed to add rule for system call %s() / %d: %m",
+                                                               name, id);
+                        }
+
+#if (SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 5) || SCMP_VER_MAJOR > 2
+                /* We have a large filter here, so let's turn on the binary tree mode if possible. */
+                r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_OPTIMIZE, 2);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to set SCMP_FLTATR_CTL_OPTIMIZE, ignoring: %m");
+#endif
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install system call filter for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_parse_syscall_filter(
+                const char *name,
+                int errno_num,
+                Hashmap *filter,
+                SeccompParseFlags flags,
+                const char *unit,
+                const char *filename,
+                unsigned line) {
+
+        int r;
+
+        assert(name);
+        assert(filter);
+
+        if (!FLAGS_SET(flags, SECCOMP_PARSE_INVERT) && errno_num >= 0)
+                return -EINVAL;
+
+        if (name[0] == '@') {
+                const SyscallFilterSet *set;
+
+                set = syscall_filter_set_find(name);
+                if (!set) {
+                        if (!FLAGS_SET(flags, SECCOMP_PARSE_PERMISSIVE))
+                                return -EINVAL;
+
+                        log_syntax(unit, FLAGS_SET(flags, SECCOMP_PARSE_LOG) ? LOG_WARNING : LOG_DEBUG, filename, line, 0,
+                                   "Unknown system call group, ignoring: %s", name);
+                        return 0;
+                }
+
+                NULSTR_FOREACH(i, set->value) {
+                        /* Call ourselves again, for the group to parse. Note that we downgrade logging here
+                         * (i.e. take away the SECCOMP_PARSE_LOG flag) since any issues in the group table
+                         * are our own problem, not a problem in user configuration data and we shouldn't
+                         * pretend otherwise by complaining about them. */
+                        r = seccomp_parse_syscall_filter(i, errno_num, filter, flags &~ SECCOMP_PARSE_LOG, unit, filename, line);
+                        if (r < 0)
+                                return r;
+                }
+        } else {
+                int id;
+
+                id = seccomp_syscall_resolve_name(name);
+                if (id == __NR_SCMP_ERROR) {
+                        if (!FLAGS_SET(flags, SECCOMP_PARSE_PERMISSIVE))
+                                return -EINVAL;
+
+                        log_syntax(unit, FLAGS_SET(flags, SECCOMP_PARSE_LOG) ? LOG_WARNING : LOG_DEBUG, filename, line, 0,
+                                   "System call %s is not known, ignoring.", name);
+                        return 0;
+                }
+
+                /* If we previously wanted to forbid a syscall and now we want to allow it, then remove it
+                 * from the list. The entries in allow-list with non-negative error value will be handled
+                 * with SCMP_ACT_ERRNO() instead of the default action. */
+                if (!FLAGS_SET(flags, SECCOMP_PARSE_INVERT) == FLAGS_SET(flags, SECCOMP_PARSE_ALLOW_LIST) ||
+                    (FLAGS_SET(flags, SECCOMP_PARSE_INVERT | SECCOMP_PARSE_ALLOW_LIST) && errno_num >= 0)) {
+                        r = hashmap_put(filter, INT_TO_PTR(id + 1), INT_TO_PTR(errno_num));
+                        if (r < 0)
+                                switch (r) {
+                                case -ENOMEM:
+                                        return FLAGS_SET(flags, SECCOMP_PARSE_LOG) ? log_oom() : -ENOMEM;
+                                case -EEXIST:
+                                        assert_se(hashmap_update(filter, INT_TO_PTR(id + 1), INT_TO_PTR(errno_num)) == 0);
+                                        break;
+                                default:
+                                        return r;
+                                }
+                } else
+                        (void) hashmap_remove(filter, INT_TO_PTR(id + 1));
+        }
+
+        return 0;
+}
+
+int seccomp_restrict_namespaces(unsigned long retain) {
+        uint32_t arch;
+        int r;
+
+        if (DEBUG_LOGGING) {
+                _cleanup_free_ char *s = NULL;
+
+                (void) namespace_flags_to_string(retain, &s);
+                log_debug("Restricting namespace to: %s.", strna(s));
+        }
+
+        /* NOOP? */
+        if (FLAGS_SET(retain, NAMESPACE_FLAGS_ALL))
+                return 0;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                /* We cannot filter on individual flags to clone3(), and we need to disable the
+                 * syscall altogether. ENOSYS is used instead of EPERM, so that glibc and other
+                 * users shall fall back to clone(), as if on an older kernel.
+                 *
+                 * C.f. https://github.com/flatpak/flatpak/commit/a10f52a7565c549612c92b8e736a6698a53db330,
+                 * https://github.com/moby/moby/issues/42680. */
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(ENOSYS),
+                                SCMP_SYS(clone3),
+                                0);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to add clone3() rule for architecture %s, ignoring: %m",
+                                        seccomp_arch_to_string(arch));
+
+                if ((retain & NAMESPACE_FLAGS_ALL) == 0)
+                        /* If every single kind of namespace shall be prohibited, then let's block the whole
+                         * setns() syscall altogether. */
+                        r = seccomp_rule_add_exact(
+                                        seccomp,
+                                        SCMP_ACT_ERRNO(EPERM),
+                                        SCMP_SYS(setns),
+                                        0);
+                else
+                        /* Otherwise, block only the invocations with the appropriate flags in the loop
+                         * below, but also the special invocation with a zero flags argument, right here. */
+                        r = seccomp_rule_add_exact(
+                                        seccomp,
+                                        SCMP_ACT_ERRNO(EPERM),
+                                        SCMP_SYS(setns),
+                                        1,
+                                        SCMP_A1(SCMP_CMP_EQ, 0));
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add setns() rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                for (unsigned i = 0; namespace_info[i].proc_name; i++) {
+                        unsigned long f;
+
+                        f = namespace_info[i].clone_flag;
+                        if (FLAGS_SET(retain, f)) {
+                                log_debug("Permitting %s.", namespace_info[i].proc_name);
+                                continue;
+                        }
+
+                        log_trace("Blocking %s.", namespace_info[i].proc_name);
+
+                        r = seccomp_rule_add_exact(
+                                        seccomp,
+                                        SCMP_ACT_ERRNO(EPERM),
+                                        SCMP_SYS(unshare),
+                                        1,
+                                        SCMP_A0(SCMP_CMP_MASKED_EQ, f, f));
+                        if (r < 0) {
+                                log_debug_errno(r, "Failed to add unshare() rule for architecture %s, skipping: %m",
+                                                seccomp_arch_to_string(arch));
+                                break;
+                        }
+
+                        /* On s390/s390x the first two parameters to clone are switched */
+                        if (!IN_SET(arch, SCMP_ARCH_S390, SCMP_ARCH_S390X))
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EPERM),
+                                                SCMP_SYS(clone),
+                                                1,
+                                                SCMP_A0(SCMP_CMP_MASKED_EQ, f, f));
+                        else
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EPERM),
+                                                SCMP_SYS(clone),
+                                                1,
+                                                SCMP_A1(SCMP_CMP_MASKED_EQ, f, f));
+                        if (r < 0) {
+                                log_debug_errno(r, "Failed to add clone() rule for architecture %s, skipping: %m",
+                                                seccomp_arch_to_string(arch));
+                                break;
+                        }
+
+                        if ((retain & NAMESPACE_FLAGS_ALL) != 0) {
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EPERM),
+                                                SCMP_SYS(setns),
+                                                1,
+                                                SCMP_A1(SCMP_CMP_MASKED_EQ, f, f));
+                                if (r < 0) {
+                                        log_debug_errno(r, "Failed to add setns() rule for architecture %s, skipping: %m",
+                                                        seccomp_arch_to_string(arch));
+                                        break;
+                                }
+                        }
+                }
+                if (r < 0)
+                        continue;
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install namespace restriction rules for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_protect_sysctl(void) {
+        uint32_t arch;
+        int r;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                if (IN_SET(arch,
+                           SCMP_ARCH_AARCH64,
+#ifdef SCMP_ARCH_LOONGARCH64
+                           SCMP_ARCH_LOONGARCH64,
+#endif
+#ifdef SCMP_ARCH_RISCV64
+                           SCMP_ARCH_RISCV64,
+#endif
+                           SCMP_ARCH_X32
+                          ))
+                        /* No _sysctl syscall */
+                        continue;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(EPERM),
+                                SCMP_SYS(_sysctl),
+                                0);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add _sysctl() rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install sysctl protection rules for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_protect_syslog(void) {
+        uint32_t arch;
+        int r;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(EPERM),
+                                SCMP_SYS(syslog),
+                                0);
+
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add syslog() rule for architecture %s, skipping %m", seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install syslog protection rules for architecture %s, skipping %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_restrict_address_families(Set *address_families, bool allow_list) {
+        uint32_t arch;
+        int r;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+                bool supported;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                switch (arch) {
+
+                case SCMP_ARCH_X86_64:
+                case SCMP_ARCH_X32:
+                case SCMP_ARCH_ARM:
+                case SCMP_ARCH_AARCH64:
+#ifdef SCMP_ARCH_LOONGARCH64
+                case SCMP_ARCH_LOONGARCH64:
+#endif
+                case SCMP_ARCH_MIPSEL64N32:
+                case SCMP_ARCH_MIPS64N32:
+                case SCMP_ARCH_MIPSEL64:
+                case SCMP_ARCH_MIPS64:
+#ifdef SCMP_ARCH_RISCV64
+                case SCMP_ARCH_RISCV64:
+#endif
+                        /* These we know we support (i.e. are the ones that do not use socketcall()) */
+                        supported = true;
+                        break;
+
+                case SCMP_ARCH_S390:
+                case SCMP_ARCH_S390X:
+                case SCMP_ARCH_X86:
+                case SCMP_ARCH_MIPSEL:
+                case SCMP_ARCH_MIPS:
+#ifdef SCMP_ARCH_PARISC
+                case SCMP_ARCH_PARISC:
+#endif
+#ifdef SCMP_ARCH_PARISC64
+                case SCMP_ARCH_PARISC64:
+#endif
+                case SCMP_ARCH_PPC:
+                case SCMP_ARCH_PPC64:
+                case SCMP_ARCH_PPC64LE:
+                default:
+                        /* These we either know we don't support (i.e. are the ones that do use socketcall()), or we
+                         * don't know */
+                        supported = false;
+                        break;
+                }
+
+                if (!supported)
+                        continue;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                if (allow_list) {
+                        int first = 0, last = 0;
+                        void *afp;
+
+                        /* If this is an allow list, we first block the address families that are out of
+                         * range and then everything that is not in the set. First, we find the lowest and
+                         * highest address family in the set. */
+
+                        SET_FOREACH(afp, address_families) {
+                                int af = PTR_TO_INT(afp);
+
+                                if (af <= 0 || af >= af_max())
+                                        continue;
+
+                                if (first == 0 || af < first)
+                                        first = af;
+
+                                if (last == 0 || af > last)
+                                        last = af;
+                        }
+
+                        assert((first == 0) == (last == 0));
+
+                        if (first == 0) {
+
+                                /* No entries in the valid range, block everything */
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EAFNOSUPPORT),
+                                                SCMP_SYS(socket),
+                                                0);
+                                if (r < 0) {
+                                        log_debug_errno(r, "Failed to add socket() rule for architecture %s, skipping: %m",
+                                                        seccomp_arch_to_string(arch));
+                                        continue;
+                                }
+
+                        } else {
+
+                                /* Block everything below the first entry */
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EAFNOSUPPORT),
+                                                SCMP_SYS(socket),
+                                                1,
+                                                SCMP_A0(SCMP_CMP_LT, first));
+                                if (r < 0) {
+                                        log_debug_errno(r, "Failed to add socket() rule for architecture %s, skipping: %m",
+                                                        seccomp_arch_to_string(arch));
+                                        continue;
+                                }
+
+                                /* Block everything above the last entry */
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EAFNOSUPPORT),
+                                                SCMP_SYS(socket),
+                                                1,
+                                                SCMP_A0(SCMP_CMP_GT, last));
+                                if (r < 0) {
+                                        log_debug_errno(r, "Failed to add socket() rule for architecture %s, skipping: %m",
+                                                        seccomp_arch_to_string(arch));
+                                        continue;
+                                }
+
+                                /* Block everything between the first and last entry */
+                                for (int af = 1; af < af_max(); af++) {
+
+                                        if (set_contains(address_families, INT_TO_PTR(af)))
+                                                continue;
+
+                                        r = seccomp_rule_add_exact(
+                                                        seccomp,
+                                                        SCMP_ACT_ERRNO(EAFNOSUPPORT),
+                                                        SCMP_SYS(socket),
+                                                        1,
+                                                        SCMP_A0(SCMP_CMP_EQ, af));
+                                        if (r < 0)
+                                                break;
+                                }
+                                if (r < 0) {
+                                        log_debug_errno(r, "Failed to add socket() rule for architecture %s, skipping: %m",
+                                                        seccomp_arch_to_string(arch));
+                                        continue;
+                                }
+                        }
+
+                } else {
+                        void *af;
+
+                        /* If this is a deny list, then generate one rule for each address family that are
+                         * then combined in OR checks. */
+
+                        SET_FOREACH(af, address_families) {
+                                r = seccomp_rule_add_exact(
+                                                seccomp,
+                                                SCMP_ACT_ERRNO(EAFNOSUPPORT),
+                                                SCMP_SYS(socket),
+                                                1,
+                                                SCMP_A0(SCMP_CMP_EQ, PTR_TO_INT(af)));
+                                if (r < 0)
+                                        break;
+                        }
+                        if (r < 0) {
+                                log_debug_errno(r, "Failed to add socket() rule for architecture %s, skipping: %m",
+                                                seccomp_arch_to_string(arch));
+                                continue;
+                        }
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install socket family rules for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_restrict_realtime_full(int error_code) {
+        static const int permitted_policies[] = {
+                SCHED_OTHER,
+                SCHED_BATCH,
+                SCHED_IDLE,
+        };
+
+        int r, max_policy = 0;
+        uint32_t arch;
+        unsigned i;
+
+        assert(error_code > 0);
+
+        /* Determine the highest policy constant we want to allow */
+        for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
+                if (permitted_policies[i] > max_policy)
+                        max_policy = permitted_policies[i];
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+                int p;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                /* Go through all policies with lower values than that, and block them -- unless they appear in the
+                 * allow list. */
+                for (p = 0; p < max_policy; p++) {
+                        bool good = false;
+
+                        /* Check if this is in the allow list. */
+                        for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
+                                if (permitted_policies[i] == p) {
+                                        good = true;
+                                        break;
+                                }
+
+                        if (good)
+                                continue;
+
+                        /* Deny this policy */
+                        r = seccomp_rule_add_exact(
+                                        seccomp,
+                                        SCMP_ACT_ERRNO(error_code),
+                                        SCMP_SYS(sched_setscheduler),
+                                        1,
+                                        SCMP_A1(SCMP_CMP_EQ, p));
+                        if (r < 0) {
+                                log_debug_errno(r, "Failed to add scheduler rule for architecture %s, skipping: %m",
+                                                seccomp_arch_to_string(arch));
+                                continue;
+                        }
+                }
+
+                /* Deny-list all other policies, i.e. the ones with higher values. Note that all comparisons
+                 * are unsigned here, hence no need no check for < 0 values. */
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(error_code),
+                                SCMP_SYS(sched_setscheduler),
+                                1,
+                                SCMP_A1(SCMP_CMP_GT, max_policy));
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add scheduler rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install realtime protection rules for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+static int add_seccomp_syscall_filter(scmp_filter_ctx seccomp,
+                                      uint32_t arch,
+                                      int nr,
+                                      unsigned arg_cnt,
+                                      const struct scmp_arg_cmp arg) {
+        int r;
+
+        r = seccomp_rule_add_exact(seccomp, SCMP_ACT_ERRNO(EPERM), nr, arg_cnt, arg);
+        if (r < 0) {
+                _cleanup_free_ char *n = NULL;
+
+                n = seccomp_syscall_resolve_num_arch(arch, nr);
+                log_debug_errno(r, "Failed to add %s() rule for architecture %s, skipping: %m",
+                                strna(n),
+                                seccomp_arch_to_string(arch));
+        }
+
+        return r;
+}
+
+/* For known architectures, check that syscalls are indeed defined or not. */
+#if defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) || defined(__loongarch_lp64) || (defined(__riscv) && __riscv_xlen == 64)
+assert_cc(SCMP_SYS(shmget) > 0);
+assert_cc(SCMP_SYS(shmat) > 0);
+assert_cc(SCMP_SYS(shmdt) > 0);
+#endif
+
+int seccomp_memory_deny_write_execute(void) {
+        uint32_t arch;
+        unsigned loaded = 0;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+                int filter_syscall = 0, block_syscall = 0, shmat_syscall = 0, r;
+
+                log_trace("Operating on architecture: %s", seccomp_arch_to_string(arch));
+
+                switch (arch) {
+
+                /* Note that on some architectures shmat() isn't available, and the call is multiplexed through ipc().
+                 * We ignore that here, which means there's still a way to get writable/executable
+                 * memory, if an IPC key is mapped like this. That's a pity, but no total loss.
+                 *
+                 * Also, PARISC isn't here right now because it still needs executable memory, but work is in progress
+                 * on that front (kernel work done in 5.18).
+                 */
+
+                case SCMP_ARCH_X86:
+                case SCMP_ARCH_S390:
+                        filter_syscall = SCMP_SYS(mmap2);
+                        block_syscall = SCMP_SYS(mmap);
+                        /* shmat multiplexed, see above */
+                        break;
+
+                case SCMP_ARCH_PPC:
+                case SCMP_ARCH_PPC64:
+                case SCMP_ARCH_PPC64LE:
+                case SCMP_ARCH_S390X:
+                        filter_syscall = SCMP_SYS(mmap);
+                        /* shmat multiplexed, see above */
+                        break;
+
+                case SCMP_ARCH_ARM:
+                        filter_syscall = SCMP_SYS(mmap2); /* arm has only mmap2 */
+                        shmat_syscall = SCMP_SYS(shmat);
+                        break;
+
+                case SCMP_ARCH_X86_64:
+                case SCMP_ARCH_X32:
+                case SCMP_ARCH_AARCH64:
+#ifdef SCMP_ARCH_LOONGARCH64
+                case SCMP_ARCH_LOONGARCH64:
+#endif
+#ifdef SCMP_ARCH_RISCV64
+                case SCMP_ARCH_RISCV64:
+#endif
+                        filter_syscall = SCMP_SYS(mmap); /* amd64, x32, arm64, loongarch64 and riscv64 have only mmap */
+                        shmat_syscall = SCMP_SYS(shmat);
+                        break;
+
+                /* Please add more definitions here, if you port systemd to other architectures! */
+
+#if !defined(__i386__) && !defined(__x86_64__) && !defined(__hppa__) && !defined(__hppa64__) && !defined(__powerpc__) && !defined(__powerpc64__) && !defined(__arm__) && !defined(__aarch64__) && !defined(__s390__) && !defined(__s390x__) && !(defined(__riscv) && __riscv_xlen == 64) && !defined(__loongarch_lp64)
+#warning "Consider adding the right mmap() syscall definitions here!"
+#endif
+                }
+
+                /* Can't filter mmap() on this arch, then skip it */
+                if (filter_syscall == 0)
+                        continue;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = add_seccomp_syscall_filter(seccomp, arch, filter_syscall,
+                                               1,
+                                               SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC|PROT_WRITE, PROT_EXEC|PROT_WRITE));
+                if (r < 0)
+                        continue;
+
+                if (block_syscall != 0) {
+                        r = add_seccomp_syscall_filter(seccomp, arch, block_syscall, 0, (const struct scmp_arg_cmp){} );
+                        if (r < 0)
+                                continue;
+                }
+
+                r = add_seccomp_syscall_filter(seccomp, arch, SCMP_SYS(mprotect),
+                                               1,
+                                               SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC, PROT_EXEC));
+                if (r < 0)
+                        continue;
+
+                r = add_seccomp_syscall_filter(seccomp, arch, SCMP_SYS(pkey_mprotect),
+                                               1,
+                                               SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC, PROT_EXEC));
+                if (r < 0)
+                        continue;
+
+                if (shmat_syscall > 0) {
+                        r = add_seccomp_syscall_filter(seccomp, arch, shmat_syscall,
+                                                       1,
+                                                       SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC));
+                        if (r < 0)
+                                continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to install MemoryDenyWriteExecute= rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                loaded++;
+        }
+
+        if (loaded == 0)
+                log_debug("Failed to install any seccomp rules for MemoryDenyWriteExecute=.");
+
+        return loaded;
+}
+
+int seccomp_restrict_archs(Set *archs) {
+        _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+        int r;
+        bool blocked_new = false;
+
+        /* This installs a filter with no rules, but that restricts the system call architectures to the specified
+         * list.
+         *
+         * There are some qualifications. However the most important use is to stop processes from bypassing
+         * system call restrictions, in case they used a broader (multiplexing) syscall which is only available
+         * in a non-native architecture. There are no holes in this use case, at least so far. */
+
+        /* Note libseccomp includes our "native" (current) architecture in the filter by default.
+         * We do not remove it. For example, our callers expect to be able to call execve() afterwards
+         * to run a program with the restrictions applied. */
+        seccomp = seccomp_init(SCMP_ACT_ALLOW);
+        if (!seccomp)
+                return -ENOMEM;
+
+        for (unsigned i = 0; seccomp_local_archs[i] != SECCOMP_LOCAL_ARCH_END; ++i) {
+                uint32_t arch = seccomp_local_archs[i];
+
+                /* See above comment, our "native" architecture is never blocked. */
+                if (arch == seccomp_arch_native())
+                        continue;
+
+                /* That architecture might have already been blocked by a previous call to seccomp_restrict_archs. */
+                if (arch == SECCOMP_LOCAL_ARCH_BLOCKED)
+                        continue;
+
+                bool block = !set_contains(archs, UINT32_TO_PTR(arch + 1));
+
+                /* The vdso for x32 assumes that x86-64 syscalls are available.  Let's allow them, since x32
+                 * x32 syscalls should basically match x86-64 for everything except the pointer type.
+                 * The important thing is that you can block the old 32-bit x86 syscalls.
+                 * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=850047 */
+                if (block && arch == SCMP_ARCH_X86_64 && seccomp_arch_native() == SCMP_ARCH_X32)
+                        block = !set_contains(archs, UINT32_TO_PTR(SCMP_ARCH_X32 + 1));
+
+                if (block) {
+                        seccomp_local_archs[i] = SECCOMP_LOCAL_ARCH_BLOCKED;
+                        blocked_new = true;
+                } else {
+                        r = seccomp_arch_add(seccomp, arch);
+                        if (r < 0 && r != -EEXIST)
+                                return r;
+                }
+        }
+
+        /* All architectures that will be blocked by the seccomp program were
+         * already blocked. */
+        if (!blocked_new)
+                return 0;
+
+        r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
+        if (r < 0)
+                return r;
+
+        r = seccomp_load(seccomp);
+        if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                return r;
+        if (r < 0)
+                log_debug_errno(r, "Failed to restrict system call architectures, skipping: %m");
+
+        return 0;
+}
+
+int parse_syscall_archs(char **l, Set **ret_archs) {
+        _cleanup_set_free_ Set *archs = NULL;
+        int r;
+
+        assert(l);
+        assert(ret_archs);
+
+        STRV_FOREACH(s, l) {
+                uint32_t a;
+
+                r = seccomp_arch_from_string(*s, &a);
+                if (r < 0)
+                        return -EINVAL;
+
+                r = set_ensure_put(&archs, NULL, UINT32_TO_PTR(a + 1));
+                if (r < 0)
+                        return -ENOMEM;
+        }
+
+        *ret_archs = TAKE_PTR(archs);
+        return 0;
+}
+
+int seccomp_filter_set_add(Hashmap *filter, bool add, const SyscallFilterSet *set) {
+        int r;
+
+        assert(set);
+
+        NULSTR_FOREACH(i, set->value) {
+
+                if (i[0] == '@') {
+                        const SyscallFilterSet *more;
+
+                        more = syscall_filter_set_find(i);
+                        if (!more)
+                                return -ENXIO;
+
+                        r = seccomp_filter_set_add(filter, add, more);
+                        if (r < 0)
+                                return r;
+                } else {
+                        int id;
+
+                        id = seccomp_syscall_resolve_name(i);
+                        if (id == __NR_SCMP_ERROR) {
+                                log_debug("System call %s is not known, ignoring.", i);
+                                continue;
+                        }
+
+                        if (add) {
+                                r = hashmap_put(filter, INT_TO_PTR(id + 1), INT_TO_PTR(-1));
+                                if (r < 0)
+                                        return r;
+                        } else
+                                (void) hashmap_remove(filter, INT_TO_PTR(id + 1));
+                }
+        }
+
+        return 0;
+}
+
+int seccomp_lock_personality(unsigned long personality) {
+        uint32_t arch;
+        int r;
+
+        if (personality >= PERSONALITY_INVALID)
+                return -EINVAL;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(EPERM),
+                                SCMP_SYS(personality),
+                                1,
+                                SCMP_A0(SCMP_CMP_NE, personality));
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add scheduler rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to enable personality lock for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+int seccomp_protect_hostname(void) {
+        uint32_t arch;
+        int r;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(EPERM),
+                                SCMP_SYS(sethostname),
+                                0);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add sethostname() rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_rule_add_exact(
+                                seccomp,
+                                SCMP_ACT_ERRNO(EPERM),
+                                SCMP_SYS(setdomainname),
+                                0);
+                if (r < 0) {
+                        log_debug_errno(r, "Failed to add setdomainname() rule for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+                        continue;
+                }
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to apply hostname restrictions for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+static int seccomp_restrict_sxid(scmp_filter_ctx seccomp, mode_t m) {
+        /* Checks the mode_t parameter of the following system calls:
+         *
+         *       → chmod() + fchmod() + fchmodat() + fchmodat2()
+         *       → open() + creat() + openat()
+         *       → mkdir() + mkdirat()
+         *       → mknod() + mknodat()
+         *
+         * Returns error if *everything* failed, and 0 otherwise.
+         */
+        int r;
+        bool any = false;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(chmod),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for chmod: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(fchmod),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for fchmod: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(fchmodat),
+                        1,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for fchmodat: %m");
+        else
+                any = true;
+
+#if defined(__SNR_fchmodat2)
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(fchmodat2),
+                        1,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
+#else
+        /* It looks like this libseccomp does not know about fchmodat2().
+         * Pretend the fchmodat2() system call is not supported at all,
+         * regardless of the kernel version. */
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(ENOSYS),
+                        __NR_fchmodat2,
+                        0);
+#endif
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for fchmodat2: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(mkdir),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for mkdir: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(mkdirat),
+                        1,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for mkdirat: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(mknod),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for mknod: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(mknodat),
+                        1,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for mknodat: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(open),
+                        2,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for open: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(openat),
+                        2,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
+                        SCMP_A3(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for openat: %m");
+        else
+                any = true;
+
+#if defined(__SNR_openat2)
+        /* The new openat2() system call can't be filtered sensibly, since it moves the flags parameter into
+         * an indirect structure. Let's block it entirely for now. That should be a reasonably OK thing to do
+         * for now, since openat2() is very new and code generally needs fallback logic anyway to be
+         * compatible with kernels that are not absolutely recent. We would normally return EPERM for a
+         * policy check, but this isn't strictly a policy check. Instead, we return ENOSYS to force programs
+         * to call open() or openat() instead. We can properly enforce policy for those functions. */
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(ENOSYS),
+                        SCMP_SYS(openat2),
+                        0);
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for openat2: %m");
+        else
+                any = true;
+#endif
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EPERM),
+                        SCMP_SYS(creat),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for creat: %m");
+        else
+                any = true;
+
+        return any ? 0 : r;
+}
+
+int seccomp_restrict_suid_sgid(void) {
+        uint32_t arch;
+        int r, k;
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                r = seccomp_restrict_sxid(seccomp, S_ISUID);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to add suid rule for architecture %s, ignoring: %m",
+                                        seccomp_arch_to_string(arch));
+
+                k = seccomp_restrict_sxid(seccomp, S_ISGID);
+                if (k < 0)
+                        log_debug_errno(k, "Failed to add sgid rule for architecture %s, ignoring: %m",
+                                        seccomp_arch_to_string(arch));
+
+                if (r < 0 && k < 0)
+                        continue;
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to apply suid/sgid restrictions for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}
+
+uint32_t scmp_act_kill_process(void) {
+
+        /* Returns SCMP_ACT_KILL_PROCESS if it's supported, and SCMP_ACT_KILL_THREAD otherwise. We never
+         * actually want to use SCMP_ACT_KILL_THREAD as its semantics are nuts (killing arbitrary threads of
+         * a program is just a bad idea), but on old kernels/old libseccomp it is all we have, and at least
+         * for single-threaded apps does the right thing. */
+
+#ifdef SCMP_ACT_KILL_PROCESS
+        if (seccomp_api_get() >= 3)
+                return SCMP_ACT_KILL_PROCESS;
+#endif
+
+        return SCMP_ACT_KILL; /* same as SCMP_ACT_KILL_THREAD */
+}
+
+int parse_syscall_and_errno(const char *in, char **name, int *error) {
+        _cleanup_free_ char *n = NULL;
+        char *p;
+        int e = -1;
+
+        assert(in);
+        assert(name);
+        assert(error);
+
+        /*
+         * This parse "syscall:errno" like "uname:EILSEQ", "@sync:255".
+         * If errno is omitted, then error is set to -1.
+         * Empty syscall name is not allowed.
+         * Here, we do not check that the syscall name is valid or not.
+         */
+
+        p = strchr(in, ':');
+        if (p) {
+                e = seccomp_parse_errno_or_action(p + 1);
+                if (e < 0)
+                        return e;
+
+                n = strndup(in, p - in);
+        } else
+                n = strdup(in);
+
+        if (!n)
+                return -ENOMEM;
+
+        if (isempty(n))
+                return -EINVAL;
+
+        *error = e;
+        *name = TAKE_PTR(n);
+
+        return 0;
+}
+
+static int block_open_flag(scmp_filter_ctx seccomp, int flag) {
+        bool any = false;
+        int r;
+
+        /* Blocks open() with the specified flag, where flag is O_SYNC or so. This makes these calls return
+         * EINVAL, in the hope the client code will retry without O_SYNC then.  */
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EINVAL),
+                        SCMP_SYS(open),
+                        1,
+                        SCMP_A1(SCMP_CMP_MASKED_EQ, flag, flag));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for open: %m");
+        else
+                any = true;
+
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(EINVAL),
+                        SCMP_SYS(openat),
+                        1,
+                        SCMP_A2(SCMP_CMP_MASKED_EQ, flag, flag));
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for openat: %m");
+        else
+                any = true;
+
+#if defined(__SNR_openat2)
+        /* The new openat2() system call can't be filtered sensibly, see above. */
+        r = seccomp_rule_add_exact(
+                        seccomp,
+                        SCMP_ACT_ERRNO(ENOSYS),
+                        SCMP_SYS(openat2),
+                        0);
+        if (r < 0)
+                log_debug_errno(r, "Failed to add filter for openat2: %m");
+        else
+                any = true;
+#endif
+
+        return any ? 0 : r;
+}
+
+int seccomp_suppress_sync(void) {
+        uint32_t arch;
+        int r;
+
+        /* This is mostly identical to SystemCallFilter=~@sync:0, but simpler to use, and separately
+         * manageable, and also masks O_SYNC/O_DSYNC */
+
+        SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+                _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+                r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+                if (r < 0)
+                        return r;
+
+                NULSTR_FOREACH(c, syscall_filter_sets[SYSCALL_FILTER_SET_SYNC].value) {
+                        int id;
+
+                        id = seccomp_syscall_resolve_name(c);
+                        if (id == __NR_SCMP_ERROR) {
+                                log_debug("System call %s is not known, ignoring.", c);
+                                continue;
+                        }
+
+                        r = seccomp_rule_add_exact(
+                                        seccomp,
+                                        SCMP_ACT_ERRNO(0), /* success → we want this to be a NOP after all */
+                                        id,
+                                        0);
+                        if (r < 0)
+                                log_debug_errno(r, "Failed to add filter for system call %s, ignoring: %m", c);
+                }
+
+                (void) block_open_flag(seccomp, O_SYNC);
+#if O_DSYNC != O_SYNC
+                (void) block_open_flag(seccomp, O_DSYNC);
+#endif
+
+                r = seccomp_load(seccomp);
+                if (ERRNO_IS_NEG_SECCOMP_FATAL(r))
+                        return r;
+                if (r < 0)
+                        log_debug_errno(r, "Failed to apply sync() suppression for architecture %s, skipping: %m",
+                                        seccomp_arch_to_string(arch));
+        }
+
+        return 0;
+}