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-rw-r--r--src/shared/seccomp-util.c2353
1 files changed, 2353 insertions, 0 deletions
diff --git a/src/shared/seccomp-util.c b/src/shared/seccomp-util.c
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--- /dev/null
+++ b/src/shared/seccomp-util.c
@@ -0,0 +1,2353 @@
+/* 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(__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";
+ 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;
+ 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"
+ "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_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) {
+
+ const char *sys;
+ 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;
+}
+
+int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilterSet *set, uint32_t action, bool log_missing) {
+ uint32_t arch;
+ 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. */
+
+ 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, default_action);
+ if (r < 0)
+ return r;
+
+ r = add_syscall_filter_set(seccomp, set, action, NULL, log_missing, NULL);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to add filter set: %m");
+
+ r = seccomp_load(seccomp);
+ if (ERRNO_IS_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;
+ 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;
+
+ 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);
+ 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;
+ }
+ }
+
+ r = seccomp_load(seccomp);
+ if (ERRNO_IS_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;
+ const char *i;
+
+ 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,
+ "Failed to parse system call, ignoring: %s", 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_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_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_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_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:
+ 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_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_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(__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_RISCV64
+ case SCMP_ARCH_RISCV64:
+#endif
+ filter_syscall = SCMP_SYS(mmap); /* amd64, x32, arm64 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)
+#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_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_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) {
+ const char *i;
+ 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("Couldn't resolve system call, ignoring: %s", 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_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_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()
+ * → 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;
+
+ 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(r, "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_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;
+ const char *c;
+
+ 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_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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 23:22:37 +0000