| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2014 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <errno.h> |
| #include <linux/seccomp.h> |
| #include <seccomp.h> |
| #include <stddef.h> |
| #include <sys/mman.h> |
| #include <sys/prctl.h> |
| #include <sys/shm.h> |
| |
| #include "af-list.h" |
| #include "alloc-util.h" |
| #include "macro.h" |
| #include "nsflags.h" |
| #include "process-util.h" |
| #include "seccomp-util.h" |
| #include "set.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "util.h" |
| #include "errno-list.h" |
| |
| const uint32_t seccomp_local_archs[] = { |
| |
| /* Note: always list the native arch we are compiled as last, so that users can blacklist 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(__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(__s390x__) |
| SCMP_ARCH_S390, |
| SCMP_ARCH_S390X, /* native */ |
| #elif defined(__s390__) |
| SCMP_ARCH_S390, |
| #endif |
| (uint32_t) -1 |
| }; |
| |
| 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"; |
| case SCMP_ARCH_PPC: |
| return "ppc"; |
| case SCMP_ARCH_PPC64: |
| return "ppc64"; |
| case SCMP_ARCH_PPC64LE: |
| return "ppc64-le"; |
| 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; |
| 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; |
| 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) { |
| scmp_filter_ctx seccomp; |
| 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) |
| goto finish; |
| |
| r = seccomp_arch_add(seccomp, arch); |
| if (r < 0) |
| goto finish; |
| |
| 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) |
| goto finish; |
| |
| r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0); |
| if (r < 0) |
| goto finish; |
| |
| *ret = seccomp; |
| return 0; |
| |
| finish: |
| seccomp_release(seccomp); |
| return r; |
| } |
| |
| 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) |
| cached_enabled = |
| is_basic_seccomp_available() && |
| is_seccomp_filter_available(); |
| |
| 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 = |
| "clock_getres\0" |
| "clock_gettime\0" |
| "clock_nanosleep\0" |
| "execve\0" |
| "exit\0" |
| "exit_group\0" |
| "futex\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" |
| "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" |
| "nanosleep\0" |
| "pause\0" |
| "prlimit64\0" |
| "restart_syscall\0" |
| "rt_sigreturn\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_setup\0" |
| "io_submit\0" |
| }, |
| [SYSCALL_FILTER_SET_BASIC_IO] = { |
| .name = "@basic-io", |
| .help = "Basic IO", |
| .value = |
| "_llseek\0" |
| "close\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_settime\0" |
| "settimeofday\0" |
| "stime\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" |
| "process_vm_readv\0" |
| "process_vm_writev\0" |
| "ptrace\0" |
| "rtas\0" |
| #ifdef __NR_s390_runtime_instr |
| "s390_runtime_instr\0" |
| #endif |
| "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" |
| "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" |
| "mmap\0" |
| "mmap2\0" |
| "munmap\0" |
| "newfstatat\0" |
| "oldfstat\0" |
| "oldlstat\0" |
| "oldstat\0" |
| "open\0" |
| "openat\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" |
| #ifdef __NR_statx |
| "statx\0" |
| #endif |
| "symlink\0" |
| "symlinkat\0" |
| "truncate\0" |
| "truncate64\0" |
| "unlink\0" |
| "unlinkat\0" |
| "utime\0" |
| "utimensat\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_wait\0" |
| "epoll_wait_old\0" |
| "eventfd\0" |
| "eventfd2\0" |
| "poll\0" |
| "ppoll\0" |
| "pselect6\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_timedsend\0" |
| "mq_unlink\0" |
| "msgctl\0" |
| "msgget\0" |
| "msgrcv\0" |
| "msgsnd\0" |
| "pipe\0" |
| "pipe2\0" |
| "process_vm_readv\0" |
| "process_vm_writev\0" |
| "semctl\0" |
| "semget\0" |
| "semop\0" |
| "semtimedop\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" |
| "mount\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" |
| "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" |
| "stty\0" |
| "sysfs\0" |
| "tuxcall\0" |
| "ulimit\0" |
| "uselib\0" |
| "ustat\0" |
| "vserver\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" |
| "nfsservctl\0" |
| "pivot_root\0" |
| "quotactl\0" |
| "setdomainname\0" |
| "setfsuid\0" |
| "setfsuid32\0" |
| "setgroups\0" |
| "setgroups32\0" |
| "sethostname\0" |
| "setresuid\0" |
| "setresuid32\0" |
| "setreuid\0" |
| "setreuid32\0" |
| "setuid\0" |
| "setuid32\0" |
| "vhangup\0" |
| }, |
| [SYSCALL_FILTER_SET_PROCESS] = { |
| .name = "@process", |
| .help = "Process control, execution, namespaceing operations", |
| .value = |
| "arch_prctl\0" |
| "capget\0" /* Able to query arbitrary processes */ |
| "clone\0" |
| "execveat\0" |
| "fork\0" |
| "getrusage\0" |
| "kill\0" |
| "prctl\0" |
| "rt_sigqueueinfo\0" |
| "rt_tgsigqueueinfo\0" |
| "setns\0" |
| "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" |
| #ifdef __NR_s390_pci_mmio_read |
| "s390_pci_mmio_read\0" |
| #endif |
| #ifdef __NR_s390_pci_mmio_write |
| "s390_pci_mmio_write\0" |
| #endif |
| }, |
| [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" |
| "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" |
| "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" |
| "syncfs\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_settime\0" |
| "timerfd_create\0" |
| "timerfd_gettime\0" |
| "timerfd_settime\0" |
| "times\0" |
| }, |
| }; |
| |
| const SyscallFilterSet *syscall_filter_set_find(const char *name) { |
| unsigned i; |
| |
| if (isempty(name) || name[0] != '@') |
| return NULL; |
| |
| for (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 seccomp_add_syscall_filter_set(scmp_filter_ctx seccomp, const SyscallFilterSet *set, uint32_t action, char **exclude); |
| |
| int seccomp_add_syscall_filter_item(scmp_filter_ctx *seccomp, const char *name, uint32_t action, char **exclude) { |
| int r; |
| |
| assert(seccomp); |
| assert(name); |
| |
| if (strv_contains(exclude, name)) |
| return 0; |
| |
| if (name[0] == '@') { |
| const SyscallFilterSet *other; |
| |
| other = syscall_filter_set_find(name); |
| if (!other) { |
| log_debug("Filter set %s is not known!", name); |
| return -EINVAL; |
| } |
| |
| r = seccomp_add_syscall_filter_set(seccomp, other, action, exclude); |
| if (r < 0) |
| return r; |
| } else { |
| int id; |
| |
| id = seccomp_syscall_resolve_name(name); |
| if (id == __NR_SCMP_ERROR) { |
| 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 */ |
| log_debug_errno(r, "Failed to add rule for system call %s() / %d, ignoring: %m", name, id); |
| } |
| |
| return 0; |
| } |
| |
| static int seccomp_add_syscall_filter_set( |
| scmp_filter_ctx seccomp, |
| const SyscallFilterSet *set, |
| uint32_t action, |
| char **exclude) { |
| |
| const char *sys; |
| int r; |
| |
| assert(seccomp); |
| assert(set); |
| |
| NULSTR_FOREACH(sys, set->value) { |
| r = seccomp_add_syscall_filter_item(seccomp, sys, action, exclude); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilterSet *set, uint32_t action) { |
| 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 |
| * earch local arch. */ |
| |
| SECCOMP_FOREACH_LOCAL_ARCH(arch) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| |
| log_debug("Operating on architecture: %s", seccomp_arch_to_string(arch)); |
| |
| r = seccomp_init_for_arch(&seccomp, arch, default_action); |
| if (r < 0) |
| return r; |
| |
| r = seccomp_add_syscall_filter_set(seccomp, set, action, NULL); |
| if (r < 0) { |
| log_debug_errno(r, "Failed to add filter set, ignoring: %m"); |
| continue; |
| } |
| |
| r = seccomp_load(seccomp); |
| if (IN_SET(r, -EPERM, -EACCES)) |
| 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* set, uint32_t action) { |
| uint32_t arch; |
| int r; |
| |
| /* Similar to seccomp_load_syscall_filter_set(), but takes a raw Set* of syscalls, instead of a |
| * SyscallFilterSet* table. */ |
| |
| if (hashmap_isempty(set) && default_action == SCMP_ACT_ALLOW) |
| return 0; |
| |
| SECCOMP_FOREACH_LOCAL_ARCH(arch) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| Iterator i; |
| void *id, *val; |
| |
| log_debug("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, id, set, i) { |
| uint32_t a = action; |
| int e = PTR_TO_INT(val); |
| |
| if (action != SCMP_ACT_ALLOW && e >= 0) |
| a = SCMP_ACT_ERRNO(e); |
| |
| r = seccomp_rule_add_exact(seccomp, a, PTR_TO_INT(id) - 1, 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; |
| |
| n = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1); |
| log_debug_errno(r, "Failed to add rule for system call %s() / %d, ignoring: %m", strna(n), PTR_TO_INT(id) - 1); |
| } |
| } |
| |
| r = seccomp_load(seccomp); |
| if (IN_SET(r, -EPERM, -EACCES)) |
| 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_parse_syscall_filter_internal( |
| bool invert, |
| const char *name, |
| int errno_num, |
| Hashmap *filter, |
| bool whitelist, |
| bool warn, |
| const char *unit, |
| const char *filename, |
| unsigned line) { |
| |
| int r; |
| |
| assert(name); |
| assert(filter); |
| |
| if (name[0] == '@') { |
| const SyscallFilterSet *set; |
| const char *i; |
| |
| set = syscall_filter_set_find(name); |
| if (!set) { |
| if (warn) { |
| log_syntax(unit, LOG_WARNING, filename, line, 0, "Unknown system call group, ignoring: %s", name); |
| return 0; |
| } else |
| return -EINVAL; |
| } |
| |
| NULSTR_FOREACH(i, set->value) { |
| r = seccomp_parse_syscall_filter_internal(invert, i, errno_num, filter, whitelist, warn, unit, filename, line); |
| if (r < 0) |
| return r; |
| } |
| } else { |
| int id; |
| |
| id = seccomp_syscall_resolve_name(name); |
| if (id == __NR_SCMP_ERROR) { |
| if (warn) { |
| log_syntax(unit, LOG_WARNING, filename, line, 0, "Failed to parse system call, ignoring: %s", name); |
| return 0; |
| } else |
| return -EINVAL; |
| } |
| |
| /* If we previously wanted to forbid a syscall and now |
| * we want to allow it, then remove it from the list. */ |
| if (!invert == whitelist) { |
| r = hashmap_put(filter, INT_TO_PTR(id + 1), INT_TO_PTR(errno_num)); |
| if (r < 0) |
| return warn ? log_oom() : -ENOMEM; |
| } 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_flag_to_string_many(retain, &s); |
| log_debug("Restricting namespace to: %s.", strna(s)); |
| } |
| |
| /* NOOP? */ |
| if ((retain & NAMESPACE_FLAGS_ALL) == NAMESPACE_FLAGS_ALL) |
| return 0; |
| |
| SECCOMP_FOREACH_LOCAL_ARCH(arch) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| unsigned i; |
| |
| log_debug("Operating on architecture: %s", seccomp_arch_to_string(arch)); |
| |
| r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW); |
| if (r < 0) |
| return r; |
| |
| 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 (i = 0; namespace_flag_map[i].name; i++) { |
| unsigned long f; |
| |
| f = namespace_flag_map[i].flag; |
| if ((retain & f) == f) { |
| log_debug("Permitting %s.", namespace_flag_map[i].name); |
| continue; |
| } |
| |
| log_debug("Blocking %s.", namespace_flag_map[i].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 (IN_SET(r, -EPERM, -EACCES)) |
| 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_debug("Operating on architecture: %s", seccomp_arch_to_string(arch)); |
| |
| if (IN_SET(arch, SCMP_ARCH_X32, SCMP_ARCH_AARCH64)) |
| /* 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 (IN_SET(r, -EPERM, -EACCES)) |
| 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_restrict_address_families(Set *address_families, bool whitelist) { |
| uint32_t arch; |
| int r; |
| |
| SECCOMP_FOREACH_LOCAL_ARCH(arch) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| bool supported; |
| Iterator i; |
| |
| log_debug("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_PPC64: |
| case SCMP_ARCH_PPC64LE: |
| /* 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_PPC: |
| case SCMP_ARCH_X86: |
| 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 (whitelist) { |
| int af, first = 0, last = 0; |
| void *afp; |
| |
| /* If this is a whitelist, 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, i) { |
| 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 (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 blacklist, then generate one rule for |
| * each address family that are then combined in OR |
| * checks. */ |
| |
| SET_FOREACH(af, address_families, i) { |
| |
| 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 (IN_SET(r, -EPERM, -EACCES)) |
| 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(void) { |
| static const int permitted_policies[] = { |
| SCHED_OTHER, |
| SCHED_BATCH, |
| SCHED_IDLE, |
| }; |
| |
| int r, max_policy = 0; |
| uint32_t arch; |
| unsigned i; |
| |
| /* 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_debug("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 |
| * whitelist. */ |
| for (p = 0; p < max_policy; p++) { |
| bool good = false; |
| |
| /* Check if this is in the whitelist. */ |
| 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(EPERM), |
| 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; |
| } |
| } |
| |
| /* Blacklist 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(EPERM), |
| 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 (IN_SET(r, -EPERM, -EACCES)) |
| 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 int 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__) |
| assert_cc(SCMP_SYS(shmget) > 0); |
| assert_cc(SCMP_SYS(shmat) > 0); |
| assert_cc(SCMP_SYS(shmdt) > 0); |
| #elif defined(__i386__) || defined(__powerpc64__) |
| 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; |
| int r; |
| |
| SECCOMP_FOREACH_LOCAL_ARCH(arch) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| int filter_syscall = 0, block_syscall = 0, shmat_syscall = 0; |
| |
| log_debug("Operating on architecture: %s", seccomp_arch_to_string(arch)); |
| |
| switch (arch) { |
| |
| case SCMP_ARCH_X86: |
| filter_syscall = SCMP_SYS(mmap2); |
| block_syscall = SCMP_SYS(mmap); |
| break; |
| |
| case SCMP_ARCH_PPC: |
| case SCMP_ARCH_PPC64: |
| case SCMP_ARCH_PPC64LE: |
| filter_syscall = SCMP_SYS(mmap); |
| |
| /* Note that 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. */ |
| |
| 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: |
| filter_syscall = SCMP_SYS(mmap); /* amd64, x32, and arm64 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(__powerpc__) && !defined(__powerpc64__) && !defined(__arm__) && !defined(__aarch64__) |
| #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; |
| |
| #ifdef __NR_pkey_mprotect |
| 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; |
| #endif |
| |
| if (shmat_syscall != 0) { |
| r = add_seccomp_syscall_filter(seccomp, arch, SCMP_SYS(shmat), |
| 1, |
| SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC)); |
| if (r < 0) |
| continue; |
| } |
| |
| r = seccomp_load(seccomp); |
| if (IN_SET(r, -EPERM, -EACCES)) |
| return r; |
| if (r < 0) |
| log_debug_errno(r, "Failed to install MemoryDenyWriteExecute= rule for architecture %s, skipping: %m", seccomp_arch_to_string(arch)); |
| } |
| |
| return 0; |
| } |
| |
| int seccomp_restrict_archs(Set *archs) { |
| _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL; |
| Iterator i; |
| void *id; |
| int r; |
| |
| /* 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; |
| |
| SET_FOREACH(id, archs, i) { |
| r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1); |
| if (r < 0 && r != -EEXIST) |
| return r; |
| } |
| |
| /* 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 (seccomp_arch_native() == SCMP_ARCH_X32 || |
| set_contains(archs, UINT32_TO_PTR(SCMP_ARCH_X32 + 1))) { |
| |
| r = seccomp_arch_add(seccomp, SCMP_ARCH_X86_64); |
| if (r < 0 && r != -EEXIST) |
| return r; |
| } |
| |
| r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0); |
| if (r < 0) |
| return r; |
| |
| r = seccomp_load(seccomp); |
| if (IN_SET(r, -EPERM, -EACCES)) |
| 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 **archs) { |
| _cleanup_set_free_ Set *_archs; |
| char **s; |
| int r; |
| |
| assert(l); |
| assert(archs); |
| |
| r = set_ensure_allocated(&_archs, NULL); |
| if (r < 0) |
| return r; |
| |
| STRV_FOREACH(s, l) { |
| uint32_t a; |
| |
| r = seccomp_arch_from_string(*s, &a); |
| if (r < 0) |
| return -EINVAL; |
| |
| r = set_put(_archs, UINT32_TO_PTR(a + 1)); |
| if (r < 0) |
| return -ENOMEM; |
| } |
| |
| *archs = _archs; |
| _archs = NULL; |
| |
| 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 (IN_SET(r, -EPERM, -EACCES)) |
| 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; |
| } |