1315 lines
48 KiB
C
1315 lines
48 KiB
C
/***
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This file is part of systemd.
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Copyright 2014 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <linux/seccomp.h>
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#include <seccomp.h>
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#include <stddef.h>
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#include <sys/mman.h>
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#include <sys/prctl.h>
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#include <sys/shm.h>
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#include "af-list.h"
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#include "alloc-util.h"
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#include "macro.h"
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#include "nsflags.h"
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#include "seccomp-util.h"
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#include "string-util.h"
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#include "util.h"
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#include "errno-list.h"
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const uint32_t seccomp_local_archs[] = {
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/* 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 */
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#if defined(__x86_64__) && defined(__ILP32__)
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SCMP_ARCH_X86,
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SCMP_ARCH_X86_64,
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SCMP_ARCH_X32, /* native */
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#elif defined(__x86_64__) && !defined(__ILP32__)
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SCMP_ARCH_X86,
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SCMP_ARCH_X32,
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SCMP_ARCH_X86_64, /* native */
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#elif defined(__i386__)
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SCMP_ARCH_X86,
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#elif defined(__aarch64__)
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SCMP_ARCH_ARM,
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SCMP_ARCH_AARCH64, /* native */
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#elif defined(__arm__)
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SCMP_ARCH_ARM,
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#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI32
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SCMP_ARCH_MIPSEL,
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SCMP_ARCH_MIPS, /* native */
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#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI32
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SCMP_ARCH_MIPS,
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SCMP_ARCH_MIPSEL, /* native */
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#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI64
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SCMP_ARCH_MIPSEL,
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SCMP_ARCH_MIPS,
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SCMP_ARCH_MIPSEL64N32,
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SCMP_ARCH_MIPS64N32,
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SCMP_ARCH_MIPSEL64,
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SCMP_ARCH_MIPS64, /* native */
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#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_ABI64
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SCMP_ARCH_MIPS,
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SCMP_ARCH_MIPSEL,
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SCMP_ARCH_MIPS64N32,
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SCMP_ARCH_MIPSEL64N32,
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SCMP_ARCH_MIPS64,
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SCMP_ARCH_MIPSEL64, /* native */
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#elif defined(__mips__) && __BYTE_ORDER == __BIG_ENDIAN && _MIPS_SIM == _MIPS_SIM_NABI32
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SCMP_ARCH_MIPSEL,
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SCMP_ARCH_MIPS,
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SCMP_ARCH_MIPSEL64,
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SCMP_ARCH_MIPS64,
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SCMP_ARCH_MIPSEL64N32,
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SCMP_ARCH_MIPS64N32, /* native */
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#elif defined(__mips__) && __BYTE_ORDER == __LITTLE_ENDIAN && _MIPS_SIM == _MIPS_SIM_NABI32
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SCMP_ARCH_MIPS,
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SCMP_ARCH_MIPSEL,
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SCMP_ARCH_MIPS64,
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SCMP_ARCH_MIPSEL64,
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SCMP_ARCH_MIPS64N32,
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SCMP_ARCH_MIPSEL64N32, /* native */
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#elif defined(__powerpc64__) && __BYTE_ORDER == __BIG_ENDIAN
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SCMP_ARCH_PPC,
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SCMP_ARCH_PPC64LE,
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SCMP_ARCH_PPC64, /* native */
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#elif defined(__powerpc64__) && __BYTE_ORDER == __LITTLE_ENDIAN
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SCMP_ARCH_PPC,
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SCMP_ARCH_PPC64,
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SCMP_ARCH_PPC64LE, /* native */
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#elif defined(__powerpc__)
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SCMP_ARCH_PPC,
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#elif defined(__s390x__)
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SCMP_ARCH_S390,
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SCMP_ARCH_S390X, /* native */
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#elif defined(__s390__)
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SCMP_ARCH_S390,
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#endif
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(uint32_t) -1
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};
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const char* seccomp_arch_to_string(uint32_t c) {
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/* Maintain order used in <seccomp.h>.
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*
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* Names used here should be the same as those used for ConditionArchitecture=,
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* except for "subarchitectures" like x32. */
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switch(c) {
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case SCMP_ARCH_NATIVE:
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return "native";
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case SCMP_ARCH_X86:
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return "x86";
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case SCMP_ARCH_X86_64:
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return "x86-64";
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case SCMP_ARCH_X32:
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return "x32";
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case SCMP_ARCH_ARM:
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return "arm";
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case SCMP_ARCH_AARCH64:
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return "arm64";
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case SCMP_ARCH_MIPS:
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return "mips";
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case SCMP_ARCH_MIPS64:
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return "mips64";
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case SCMP_ARCH_MIPS64N32:
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return "mips64-n32";
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case SCMP_ARCH_MIPSEL:
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return "mips-le";
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case SCMP_ARCH_MIPSEL64:
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return "mips64-le";
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case SCMP_ARCH_MIPSEL64N32:
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return "mips64-le-n32";
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case SCMP_ARCH_PPC:
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return "ppc";
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case SCMP_ARCH_PPC64:
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return "ppc64";
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case SCMP_ARCH_PPC64LE:
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return "ppc64-le";
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case SCMP_ARCH_S390:
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return "s390";
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case SCMP_ARCH_S390X:
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return "s390x";
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default:
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return NULL;
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}
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}
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int seccomp_arch_from_string(const char *n, uint32_t *ret) {
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if (!n)
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return -EINVAL;
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assert(ret);
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if (streq(n, "native"))
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*ret = SCMP_ARCH_NATIVE;
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else if (streq(n, "x86"))
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*ret = SCMP_ARCH_X86;
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else if (streq(n, "x86-64"))
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*ret = SCMP_ARCH_X86_64;
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else if (streq(n, "x32"))
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*ret = SCMP_ARCH_X32;
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else if (streq(n, "arm"))
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*ret = SCMP_ARCH_ARM;
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else if (streq(n, "arm64"))
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*ret = SCMP_ARCH_AARCH64;
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else if (streq(n, "mips"))
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*ret = SCMP_ARCH_MIPS;
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else if (streq(n, "mips64"))
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*ret = SCMP_ARCH_MIPS64;
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else if (streq(n, "mips64-n32"))
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*ret = SCMP_ARCH_MIPS64N32;
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else if (streq(n, "mips-le"))
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*ret = SCMP_ARCH_MIPSEL;
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else if (streq(n, "mips64-le"))
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*ret = SCMP_ARCH_MIPSEL64;
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else if (streq(n, "mips64-le-n32"))
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*ret = SCMP_ARCH_MIPSEL64N32;
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else if (streq(n, "ppc"))
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*ret = SCMP_ARCH_PPC;
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else if (streq(n, "ppc64"))
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*ret = SCMP_ARCH_PPC64;
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else if (streq(n, "ppc64-le"))
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*ret = SCMP_ARCH_PPC64LE;
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else if (streq(n, "s390"))
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*ret = SCMP_ARCH_S390;
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else if (streq(n, "s390x"))
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*ret = SCMP_ARCH_S390X;
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else
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return -EINVAL;
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return 0;
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}
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int seccomp_init_for_arch(scmp_filter_ctx *ret, uint32_t arch, uint32_t default_action) {
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scmp_filter_ctx seccomp;
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int r;
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/* Much like seccomp_init(), but initializes the filter for one specific architecture only, without affecting
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* any others. Also, turns off the NNP fiddling. */
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seccomp = seccomp_init(default_action);
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if (!seccomp)
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return -ENOMEM;
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if (arch != SCMP_ARCH_NATIVE &&
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arch != seccomp_arch_native()) {
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r = seccomp_arch_remove(seccomp, seccomp_arch_native());
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if (r < 0)
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goto finish;
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r = seccomp_arch_add(seccomp, arch);
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if (r < 0)
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goto finish;
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assert(seccomp_arch_exist(seccomp, arch) >= 0);
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assert(seccomp_arch_exist(seccomp, SCMP_ARCH_NATIVE) == -EEXIST);
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assert(seccomp_arch_exist(seccomp, seccomp_arch_native()) == -EEXIST);
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} else {
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assert(seccomp_arch_exist(seccomp, SCMP_ARCH_NATIVE) >= 0);
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assert(seccomp_arch_exist(seccomp, seccomp_arch_native()) >= 0);
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}
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r = seccomp_attr_set(seccomp, SCMP_FLTATR_ACT_BADARCH, SCMP_ACT_ALLOW);
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if (r < 0)
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goto finish;
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r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
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if (r < 0)
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goto finish;
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*ret = seccomp;
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return 0;
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finish:
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seccomp_release(seccomp);
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return r;
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}
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static bool is_basic_seccomp_available(void) {
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return prctl(PR_GET_SECCOMP, 0, 0, 0, 0) >= 0;
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}
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static bool is_seccomp_filter_available(void) {
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return prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, NULL, 0, 0) < 0 &&
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errno == EFAULT;
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}
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bool is_seccomp_available(void) {
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static int cached_enabled = -1;
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if (cached_enabled < 0)
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cached_enabled =
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is_basic_seccomp_available() &&
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is_seccomp_filter_available();
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return cached_enabled;
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}
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const SyscallFilterSet syscall_filter_sets[_SYSCALL_FILTER_SET_MAX] = {
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[SYSCALL_FILTER_SET_DEFAULT] = {
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.name = "@default",
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.help = "System calls that are always permitted",
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.value =
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"clock_getres\0"
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"clock_gettime\0"
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"clock_nanosleep\0"
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"execve\0"
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"exit\0"
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"exit_group\0"
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"getrlimit\0" /* make sure processes can query stack size and such */
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"gettimeofday\0"
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"nanosleep\0"
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"pause\0"
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"rt_sigreturn\0"
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"sigreturn\0"
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"time\0"
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},
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[SYSCALL_FILTER_SET_BASIC_IO] = {
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.name = "@basic-io",
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.help = "Basic IO",
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.value =
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"close\0"
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"dup2\0"
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"dup3\0"
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"dup\0"
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"lseek\0"
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"pread64\0"
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"preadv\0"
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"pwrite64\0"
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"pwritev\0"
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"read\0"
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"readv\0"
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"write\0"
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"writev\0"
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},
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[SYSCALL_FILTER_SET_CLOCK] = {
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.name = "@clock",
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.help = "Change the system time",
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.value =
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"adjtimex\0"
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"clock_adjtime\0"
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"clock_settime\0"
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"settimeofday\0"
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"stime\0"
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},
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[SYSCALL_FILTER_SET_CPU_EMULATION] = {
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.name = "@cpu-emulation",
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.help = "System calls for CPU emulation functionality",
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.value =
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"modify_ldt\0"
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"subpage_prot\0"
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"switch_endian\0"
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"vm86\0"
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"vm86old\0"
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},
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[SYSCALL_FILTER_SET_DEBUG] = {
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.name = "@debug",
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.help = "Debugging, performance monitoring and tracing functionality",
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.value =
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"lookup_dcookie\0"
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"perf_event_open\0"
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"process_vm_readv\0"
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"process_vm_writev\0"
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"ptrace\0"
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"rtas\0"
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#ifdef __NR_s390_runtime_instr
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"s390_runtime_instr\0"
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#endif
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"sys_debug_setcontext\0"
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},
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[SYSCALL_FILTER_SET_FILE_SYSTEM] = {
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.name = "@file-system",
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.help = "File system operations",
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.value =
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"access\0"
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"chdir\0"
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"chmod\0"
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"close\0"
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"creat\0"
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"faccessat\0"
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"fallocate\0"
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"fchdir\0"
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"fchmod\0"
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"fchmodat\0"
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"fcntl64\0"
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"fcntl\0"
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"fgetxattr\0"
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"flistxattr\0"
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"fsetxattr\0"
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"fstat64\0"
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"fstat\0"
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"fstatat64\0"
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"fstatfs64\0"
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"fstatfs\0"
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"ftruncate64\0"
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"ftruncate\0"
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"futimesat\0"
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"getcwd\0"
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"getdents64\0"
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"getdents\0"
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"getxattr\0"
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"inotify_add_watch\0"
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"inotify_init1\0"
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"inotify_rm_watch\0"
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"lgetxattr\0"
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"link\0"
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"linkat\0"
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"listxattr\0"
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"llistxattr\0"
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"lremovexattr\0"
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"lsetxattr\0"
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"lstat64\0"
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"lstat\0"
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"mkdir\0"
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"mkdirat\0"
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"mknod\0"
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"mknodat\0"
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"mmap2\0"
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"mmap\0"
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"munmap\0"
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"newfstatat\0"
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"open\0"
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"openat\0"
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"readlink\0"
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"readlinkat\0"
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"removexattr\0"
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"rename\0"
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"renameat2\0"
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"renameat\0"
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"rmdir\0"
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"setxattr\0"
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"stat64\0"
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"stat\0"
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"statfs\0"
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"symlink\0"
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"symlinkat\0"
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"truncate64\0"
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"truncate\0"
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"unlink\0"
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"unlinkat\0"
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"utimensat\0"
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"utimes\0"
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},
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[SYSCALL_FILTER_SET_IO_EVENT] = {
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.name = "@io-event",
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.help = "Event loop system calls",
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.value =
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"_newselect\0"
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"epoll_create1\0"
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"epoll_create\0"
|
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"epoll_ctl\0"
|
|
"epoll_ctl_old\0"
|
|
"epoll_pwait\0"
|
|
"epoll_wait\0"
|
|
"epoll_wait_old\0"
|
|
"eventfd2\0"
|
|
"eventfd\0"
|
|
"poll\0"
|
|
"ppoll\0"
|
|
"pselect6\0"
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|
"select\0"
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|
},
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|
[SYSCALL_FILTER_SET_IPC] = {
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.name = "@ipc",
|
|
.help = "SysV IPC, POSIX Message Queues or other IPC",
|
|
.value =
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"ipc\0"
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"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"
|
|
"pipe2\0"
|
|
"pipe\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 =
|
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"add_key\0"
|
|
"keyctl\0"
|
|
"request_key\0"
|
|
},
|
|
[SYSCALL_FILTER_SET_MODULE] = {
|
|
.name = "@module",
|
|
.help = "Loading and unloading of kernel modules",
|
|
.value =
|
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"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"
|
|
"umount2\0"
|
|
"umount\0"
|
|
},
|
|
[SYSCALL_FILTER_SET_NETWORK_IO] = {
|
|
.name = "@network-io",
|
|
.help = "Network or Unix socket IO, should not be needed if not network facing",
|
|
.value =
|
|
"accept4\0"
|
|
"accept\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"
|
|
"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 =
|
|
"@clock\0"
|
|
"@module\0"
|
|
"@raw-io\0"
|
|
"acct\0"
|
|
"bpf\0"
|
|
"capset\0"
|
|
"chown32\0"
|
|
"chown\0"
|
|
"chroot\0"
|
|
"fchown32\0"
|
|
"fchown\0"
|
|
"fchownat\0"
|
|
"kexec_file_load\0"
|
|
"kexec_load\0"
|
|
"lchown32\0"
|
|
"lchown\0"
|
|
"nfsservctl\0"
|
|
"pivot_root\0"
|
|
"quotactl\0"
|
|
"reboot\0"
|
|
"setdomainname\0"
|
|
"setfsuid32\0"
|
|
"setfsuid\0"
|
|
"setgroups32\0"
|
|
"setgroups\0"
|
|
"sethostname\0"
|
|
"setresuid32\0"
|
|
"setresuid\0"
|
|
"setreuid32\0"
|
|
"setreuid\0"
|
|
"setuid32\0"
|
|
"setuid\0"
|
|
"swapoff\0"
|
|
"swapon\0"
|
|
"_sysctl\0"
|
|
"vhangup\0"
|
|
},
|
|
[SYSCALL_FILTER_SET_PROCESS] = {
|
|
.name = "@process",
|
|
.help = "Process control, execution, namespaceing operations",
|
|
.value =
|
|
"arch_prctl\0"
|
|
"clone\0"
|
|
"execveat\0"
|
|
"fork\0"
|
|
"kill\0"
|
|
"prctl\0"
|
|
"setns\0"
|
|
"tgkill\0"
|
|
"tkill\0"
|
|
"unshare\0"
|
|
"vfork\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\0"
|
|
"kexec_file_load\0"
|
|
"reboot\0"
|
|
},
|
|
[SYSCALL_FILTER_SET_RESOURCES] = {
|
|
.name = "@resources",
|
|
.help = "Alter resource settings",
|
|
.value =
|
|
"sched_setparam\0"
|
|
"sched_setscheduler\0"
|
|
"sched_setaffinity\0"
|
|
"setpriority\0"
|
|
"setrlimit\0"
|
|
"set_mempolicy\0"
|
|
"migrate_pages\0"
|
|
"move_pages\0"
|
|
"mbind\0"
|
|
"sched_setattr\0"
|
|
"prlimit64\0"
|
|
},
|
|
[SYSCALL_FILTER_SET_SWAP] = {
|
|
.name = "@swap",
|
|
.help = "Enable/disable swap devices",
|
|
.value =
|
|
"swapoff\0"
|
|
"swapon\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,
|
|
uint32_t default_action,
|
|
const SyscallFilterSet *set,
|
|
uint32_t action) {
|
|
|
|
const char *sys;
|
|
int r;
|
|
|
|
assert(seccomp);
|
|
assert(set);
|
|
|
|
NULSTR_FOREACH(sys, set->value) {
|
|
int id;
|
|
|
|
if (sys[0] == '@') {
|
|
const SyscallFilterSet *other;
|
|
|
|
other = syscall_filter_set_find(sys);
|
|
if (!other)
|
|
return -EINVAL;
|
|
|
|
r = seccomp_add_syscall_filter_set(seccomp, default_action, other, action);
|
|
if (r < 0)
|
|
return r;
|
|
} else {
|
|
id = seccomp_syscall_resolve_name(sys);
|
|
if (id == __NR_SCMP_ERROR)
|
|
return -EINVAL; /* Not known at all? Then that's a real error */
|
|
|
|
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, ignoring: %m", sys);
|
|
}
|
|
}
|
|
|
|
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, default_action, set, action);
|
|
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, Set* 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 (set_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;
|
|
|
|
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;
|
|
|
|
SET_FOREACH(id, set, i) {
|
|
r = seccomp_rule_add_exact(seccomp, action, 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(arch, PTR_TO_INT(id) - 1);
|
|
log_debug_errno(r, "Failed to add rule for system call %s, ignoring: %m", strna(n));
|
|
}
|
|
}
|
|
|
|
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_restrict_namespaces(unsigned long retain) {
|
|
uint32_t arch;
|
|
int r;
|
|
|
|
if (log_get_max_level() >= LOG_DEBUG) {
|
|
_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));
|
|
|
|
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_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_AARCH64:
|
|
block_syscall = SCMP_SYS(mmap);
|
|
/* fall through */
|
|
|
|
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:
|
|
filter_syscall = SCMP_SYS(mmap); /* amd64 and x32 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(__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;
|
|
|
|
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. */
|
|
|
|
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 == -EEXIST)
|
|
continue;
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
return seccomp_load(seccomp);
|
|
}
|