Systemd/src/shared/seccomp-util.h
Lennart Poettering 469830d142 seccomp: rework seccomp code, to improve compat with some archs
This substantially reworks the seccomp code, to ensure better
compatibility with some architectures, including i386.

So far we relied on libseccomp's internal handling of the multiple
syscall ABIs supported on Linux. This is problematic however, as it does
not define clear semantics if an ABI is not able to support specific
seccomp rules we install.

This rework hence changes a couple of things:

- We no longer use seccomp_rule_add(), but only
  seccomp_rule_add_exact(), and fail the installation of a filter if the
  architecture doesn't support it.

- We no longer rely on adding multiple syscall architectures to a single filter,
  but instead install a separate filter for each syscall architecture
  supported. This way, we can install a strict filter for x86-64, while
  permitting a less strict filter for i386.

- All high-level filter additions are now moved from execute.c to
  seccomp-util.c, so that we can test them independently of the service
  execution logic.

- Tests have been added for all types of our seccomp filters.

- SystemCallFilters= and SystemCallArchitectures= are now implemented in
  independent filters and installation logic, as they semantically are
  very much independent of each other.

Fixes: #4575
2017-01-17 22:14:27 -05:00

87 lines
2.9 KiB
C

#pragma once
/***
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 <seccomp.h>
#include <stdbool.h>
#include <stdint.h>
#include "set.h"
const char* seccomp_arch_to_string(uint32_t c);
int seccomp_arch_from_string(const char *n, uint32_t *ret);
int seccomp_init_for_arch(scmp_filter_ctx *ret, uint32_t arch, uint32_t default_action);
bool is_seccomp_available(void);
typedef struct SyscallFilterSet {
const char *name;
const char *help;
const char *value;
} SyscallFilterSet;
enum {
/* Please leave DEFAULT first, but sort the rest alphabetically */
SYSCALL_FILTER_SET_DEFAULT,
SYSCALL_FILTER_SET_BASIC_IO,
SYSCALL_FILTER_SET_CLOCK,
SYSCALL_FILTER_SET_CPU_EMULATION,
SYSCALL_FILTER_SET_DEBUG,
SYSCALL_FILTER_SET_FILE_SYSTEM,
SYSCALL_FILTER_SET_IO_EVENT,
SYSCALL_FILTER_SET_IPC,
SYSCALL_FILTER_SET_KEYRING,
SYSCALL_FILTER_SET_MODULE,
SYSCALL_FILTER_SET_MOUNT,
SYSCALL_FILTER_SET_NETWORK_IO,
SYSCALL_FILTER_SET_OBSOLETE,
SYSCALL_FILTER_SET_PRIVILEGED,
SYSCALL_FILTER_SET_PROCESS,
SYSCALL_FILTER_SET_RAW_IO,
SYSCALL_FILTER_SET_REBOOT,
SYSCALL_FILTER_SET_RESOURCES,
SYSCALL_FILTER_SET_SWAP,
_SYSCALL_FILTER_SET_MAX
};
extern const SyscallFilterSet syscall_filter_sets[];
const SyscallFilterSet *syscall_filter_set_find(const char *name);
int seccomp_load_syscall_filter_set(uint32_t default_action, const SyscallFilterSet *set, uint32_t action);
int seccomp_load_syscall_filter_set_raw(uint32_t default_action, Set* set, uint32_t action);
int seccomp_restrict_archs(Set *archs);
int seccomp_restrict_namespaces(unsigned long retain);
int seccomp_protect_sysctl(void);
int seccomp_restrict_address_families(Set *address_families, bool whitelist);
int seccomp_restrict_realtime(void);
int seccomp_memory_deny_write_execute(void);
extern const uint32_t seccomp_local_archs[];
#define SECCOMP_FOREACH_LOCAL_ARCH(arch) \
for (unsigned _i = ({ (arch) = seccomp_local_archs[0]; 0; }); \
seccomp_local_archs[_i] != (uint32_t) -1; \
(arch) = seccomp_local_archs[++_i])
DEFINE_TRIVIAL_CLEANUP_FUNC(scmp_filter_ctx, seccomp_release);