-/***
- This file is part of systemd.
-
- Copyright 2016 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/>.
-***/
+/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <linux/netlink.h>
#include <sys/capability.h>
+#include <sys/socket.h>
#include <sys/types.h>
-#ifdef HAVE_SECCOMP
+#if HAVE_SECCOMP
#include <seccomp.h>
#endif
#include "alloc-util.h"
#include "log.h"
#include "nspawn-seccomp.h"
-#ifdef HAVE_SECCOMP
+#if HAVE_SECCOMP
#include "seccomp-util.h"
#endif
#include "string-util.h"
#include "strv.h"
-#ifdef HAVE_SECCOMP
+#if HAVE_SECCOMP
static int seccomp_add_default_syscall_filter(
scmp_filter_ctx ctx,
static const struct {
uint64_t capability;
const char* name;
- } blacklist[] = {
- { 0, "@obsolete" },
- { 0, "@keyring" }, /* keyring is not namespaced */
- { 0, "bpf" },
- { 0, "kexec_file_load" },
- { 0, "kexec_load" },
- { 0, "lookup_dcookie" },
- { 0, "open_by_handle_at" },
- { 0, "perf_event_open" },
- { 0, "quotactl" },
- { 0, "@swap" },
- { CAP_SYSLOG, "syslog" },
- { CAP_SYS_MODULE, "@module" },
- { CAP_SYS_PACCT, "acct" },
- { CAP_SYS_PTRACE, "process_vm_readv" },
- { CAP_SYS_PTRACE, "process_vm_writev" },
- { CAP_SYS_PTRACE, "ptrace" },
- { CAP_SYS_RAWIO, "@raw-io" },
- { CAP_SYS_TIME, "@clock" },
+ } whitelist[] = {
+ /* Let's use set names where we can */
+ { 0, "@aio" },
+ { 0, "@basic-io" },
+ { 0, "@chown" },
+ { 0, "@default" },
+ { 0, "@file-system" },
+ { 0, "@io-event" },
+ { 0, "@ipc" },
+ { 0, "@mount" },
+ { 0, "@network-io" },
+ { 0, "@process" },
+ { 0, "@resources" },
+ { 0, "@setuid" },
+ { 0, "@signal" },
+ { 0, "@sync" },
+ { 0, "@timer" },
+
+ /* The following four are sets we optionally enable, in case the caps have been configured for it */
+ { CAP_SYS_TIME, "@clock" },
+ { CAP_SYS_MODULE, "@module" },
+ { CAP_SYS_RAWIO, "@raw-io" },
+ { CAP_IPC_LOCK, "@memlock" },
+
+ /* Plus a good set of additional syscalls which are not part of any of the groups above */
+ { 0, "brk" },
+ { 0, "capget" },
+ { 0, "capset" },
+ { 0, "copy_file_range" },
+ { 0, "fadvise64" },
+ { 0, "fadvise64_64" },
+ { 0, "flock" },
+ { 0, "get_mempolicy" },
+ { 0, "getcpu" },
+ { 0, "getpriority" },
+ { 0, "getrandom" },
+ { 0, "ioctl" },
+ { 0, "ioprio_get" },
+ { 0, "kcmp" },
+ { 0, "madvise" },
+ { 0, "mincore" },
+ { 0, "mprotect" },
+ { 0, "mremap" },
+ { 0, "name_to_handle_at" },
+ { 0, "oldolduname" },
+ { 0, "olduname" },
+ { 0, "personality" },
+ { 0, "readahead" },
+ { 0, "readdir" },
+ { 0, "remap_file_pages" },
+ { 0, "sched_get_priority_max" },
+ { 0, "sched_get_priority_min" },
+ { 0, "sched_getaffinity" },
+ { 0, "sched_getattr" },
+ { 0, "sched_getparam" },
+ { 0, "sched_getscheduler" },
+ { 0, "sched_rr_get_interval" },
+ { 0, "sched_yield" },
+ { 0, "seccomp" },
+ { 0, "sendfile" },
+ { 0, "sendfile64" },
+ { 0, "setdomainname" },
+ { 0, "setfsgid" },
+ { 0, "setfsgid32" },
+ { 0, "setfsuid" },
+ { 0, "setfsuid32" },
+ { 0, "sethostname" },
+ { 0, "setpgid" },
+ { 0, "setsid" },
+ { 0, "splice" },
+ { 0, "sysinfo" },
+ { 0, "tee" },
+ { 0, "umask" },
+ { 0, "uname" },
+ { 0, "userfaultfd" },
+ { 0, "vmsplice" },
+
+ /* The following individual syscalls are added depending on specified caps */
+ { CAP_SYS_PACCT, "acct" },
+ { CAP_SYS_PTRACE, "process_vm_readv" },
+ { CAP_SYS_PTRACE, "process_vm_writev" },
+ { CAP_SYS_PTRACE, "ptrace" },
+ { CAP_SYS_BOOT, "reboot" },
+ { CAP_SYSLOG, "syslog" },
+ { CAP_SYS_TTY_CONFIG, "vhangup" },
+
+ /*
+ * The following syscalls and groups are knowingly excluded:
+ *
+ * @cpu-emulation
+ * @keyring (NB: keyring is not namespaced!)
+ * @obsolete
+ * @pkey
+ * @swap
+ *
+ * bpf (NB: bpffs is not namespaced!)
+ * fanotify_init
+ * fanotify_mark
+ * kexec_file_load
+ * kexec_load
+ * lookup_dcookie
+ * nfsservctl
+ * open_by_handle_at
+ * perf_event_open
+ * quotactl
+ */
};
- int r, c = 0;
- size_t i;
char **p;
+ int r;
- for (i = 0; i < ELEMENTSOF(blacklist); i++) {
- if (blacklist[i].capability != 0 && (cap_list_retain & (1ULL << blacklist[i].capability)))
+ for (size_t i = 0; i < ELEMENTSOF(whitelist); i++) {
+ if (whitelist[i].capability != 0 && (cap_list_retain & (1ULL << whitelist[i].capability)) == 0)
continue;
- r = seccomp_add_syscall_filter_item(ctx, blacklist[i].name, SCMP_ACT_ERRNO(EPERM), syscall_whitelist);
+ r = seccomp_add_syscall_filter_item(ctx, whitelist[i].name, SCMP_ACT_ALLOW, syscall_blacklist, false);
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", blacklist[i].name);
- else
- c++;
+ return log_error_errno(r, "Failed to add syscall filter item %s: %m", whitelist[i].name);
}
- STRV_FOREACH(p, syscall_blacklist) {
- r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ERRNO(EPERM), syscall_whitelist);
+ STRV_FOREACH(p, syscall_whitelist) {
+ r = seccomp_add_syscall_filter_item(ctx, *p, SCMP_ACT_ALLOW, syscall_blacklist, true);
if (r < 0)
- log_debug_errno(r, "Failed to add rule for system call %s, ignoring: %m", *p);
- else
- c++;
+ log_warning_errno(r, "Failed to add rule for system call %s on %s, ignoring: %m",
+ *p, seccomp_arch_to_string(arch));
}
- return c;
+ return 0;
}
int setup_seccomp(uint64_t cap_list_retain, char **syscall_whitelist, char **syscall_blacklist) {
SECCOMP_FOREACH_LOCAL_ARCH(arch) {
_cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
- int n;
- log_debug("Operating on architecture: %s", seccomp_arch_to_string(arch));
+ log_debug("Applying whitelist on architecture: %s", seccomp_arch_to_string(arch));
- r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+ r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ERRNO(EPERM));
if (r < 0)
return log_error_errno(r, "Failed to allocate seccomp object: %m");
- n = seccomp_add_default_syscall_filter(seccomp, arch, cap_list_retain, syscall_whitelist, syscall_blacklist);
- if (n < 0)
- return n;
+ r = seccomp_add_default_syscall_filter(seccomp, arch, cap_list_retain, syscall_whitelist, syscall_blacklist);
+ if (r < 0)
+ return r;
+
+ r = seccomp_load(seccomp);
+ if (ERRNO_IS_SECCOMP_FATAL(r))
+ return log_error_errno(r, "Failed to install seccomp filter: %m");
+ if (r < 0)
+ log_debug_errno(r, "Failed to install filter set for architecture %s, skipping: %m", seccomp_arch_to_string(arch));
+ }
+
+ SECCOMP_FOREACH_LOCAL_ARCH(arch) {
+ _cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
+
+ log_debug("Applying NETLINK_AUDIT mask on architecture: %s", seccomp_arch_to_string(arch));
+
+ r = seccomp_init_for_arch(&seccomp, arch, SCMP_ACT_ALLOW);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate seccomp object: %m");
/*
Audit is broken in containers, much of the userspace audit hookup will fail if running inside a
2,
SCMP_A0(SCMP_CMP_EQ, AF_NETLINK),
SCMP_A2(SCMP_CMP_EQ, NETLINK_AUDIT));
- if (r < 0)
+ if (r < 0) {
log_debug_errno(r, "Failed to add audit seccomp rule, ignoring: %m");
- else
- n++;
-
- if (n <= 0) /* no rule added? then skip this architecture */
continue;
+ }
r = seccomp_load(seccomp);
- if (IN_SET(r, -EPERM, -EACCES))
+ if (ERRNO_IS_SECCOMP_FATAL(r))
return log_error_errno(r, "Failed to install seccomp audit filter: %m");
if (r < 0)
log_debug_errno(r, "Failed to install filter set for architecture %s, skipping: %m", seccomp_arch_to_string(arch));
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