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-rw-r--r--src/core/.gitignore4
-rw-r--r--src/core/dbus-execute.c31
-rw-r--r--src/core/dbus-execute.h5
-rw-r--r--src/core/execute.c70
-rw-r--r--src/core/execute.h4
-rw-r--r--src/core/load-fragment-gperf.gperf.m42
-rw-r--r--src/core/load-fragment.c85
-rw-r--r--src/core/load-fragment.h1
-rw-r--r--src/core/syscall-list.c55
-rw-r--r--src/core/syscall-list.h30
10 files changed, 284 insertions, 3 deletions
diff --git a/src/core/.gitignore b/src/core/.gitignore
index f293bbdc93..a763f72507 100644
--- a/src/core/.gitignore
+++ b/src/core/.gitignore
@@ -1,2 +1,6 @@
+/syscall-from-name.gperf
+/syscall-from-name.h
+/syscall-list.txt
+/syscall-to-name.h
/macros.systemd
/systemd.pc
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 9322cdfd86..a00ad50795 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -28,6 +28,7 @@
#include "ioprio.h"
#include "strv.h"
#include "dbus-common.h"
+#include "syscall-list.h"
DEFINE_BUS_PROPERTY_APPEND_ENUM(bus_execute_append_kill_mode, kill_mode, KillMode);
@@ -348,6 +349,32 @@ int bus_execute_append_command(DBusMessageIter *i, const char *property, void *d
return 0;
}
+int bus_execute_append_syscall_filter(DBusMessageIter *i, const char *property, void *data) {
+ ExecContext *c = data;
+ dbus_bool_t b;
+ DBusMessageIter sub;
+
+ assert(i);
+ assert(property);
+ assert(c);
+
+ if (!dbus_message_iter_open_container(i, DBUS_TYPE_ARRAY, "u", &sub))
+ return -ENOMEM;
+
+ if (c->syscall_filter)
+ b = dbus_message_iter_append_fixed_array(&sub, DBUS_TYPE_UINT32, &c->syscall_filter, (syscall_max() + 31) >> 4);
+ else
+ b = dbus_message_iter_append_fixed_array(&sub, DBUS_TYPE_UINT32, &c->syscall_filter, 0);
+
+ if (!b)
+ return -ENOMEM;
+
+ if (!dbus_message_iter_close_container(i, &sub))
+ return -ENOMEM;
+
+ return 0;
+}
+
const BusProperty bus_exec_context_properties[] = {
{ "Environment", bus_property_append_strv, "as", offsetof(ExecContext, environment), true },
{ "EnvironmentFiles", bus_execute_append_env_files, "a(sb)", offsetof(ExecContext, environment_files), true },
@@ -409,6 +436,8 @@ const BusProperty bus_exec_context_properties[] = {
{ "UtmpIdentifier", bus_property_append_string, "s", offsetof(ExecContext, utmp_id), true },
{ "ControlGroupModify", bus_property_append_bool, "b", offsetof(ExecContext, control_group_modify) },
{ "ControlGroupPersistent", bus_property_append_tristate_false, "b", offsetof(ExecContext, control_group_persistent) },
- { "IgnoreSIGPIPE", bus_property_append_bool, "b", offsetof(ExecContext, ignore_sigpipe ) },
+ { "IgnoreSIGPIPE", bus_property_append_bool, "b", offsetof(ExecContext, ignore_sigpipe) },
+ { "NoNewPrivileges", bus_property_append_bool, "b", offsetof(ExecContext, no_new_privileges) },
+ { "SystemCallFilter", bus_execute_append_syscall_filter, "au", 0 },
{ NULL, }
};
diff --git a/src/core/dbus-execute.h b/src/core/dbus-execute.h
index b8bbe1c9f2..dc267e6ccc 100644
--- a/src/core/dbus-execute.h
+++ b/src/core/dbus-execute.h
@@ -96,7 +96,9 @@
" <property name=\"ControlGroupModify\" type=\"b\" access=\"read\"/>\n" \
" <property name=\"ControlGroupPersistent\" type=\"b\" access=\"read\"/>\n" \
" <property name=\"PrivateNetwork\" type=\"b\" access=\"read\"/>\n" \
- " <property name=\"IgnoreSIGPIPE\" type=\"b\" access=\"read\"/>\n"
+ " <property name=\"IgnoreSIGPIPE\" type=\"b\" access=\"read\"/>\n" \
+ " <property name=\"NoNewPrivileges\" type=\"b\" access=\"read\"/>\n" \
+ " <property name=\"SystemCallFilter\" type=\"au\" access=\"read\"/>\n"
#define BUS_EXEC_COMMAND_INTERFACE(name) \
" <property name=\"" name "\" type=\"a(sasbttuii)\" access=\"read\"/>\n"
@@ -121,5 +123,6 @@ int bus_execute_append_rlimits(DBusMessageIter *i, const char *property, void *d
int bus_execute_append_command(DBusMessageIter *u, const char *property, void *data);
int bus_execute_append_kill_mode(DBusMessageIter *i, const char *property, void *data);
int bus_execute_append_env_files(DBusMessageIter *i, const char *property, void *data);
+int bus_execute_append_syscall_filter(DBusMessageIter *i, const char *property, void *data);
#endif
diff --git a/src/core/execute.c b/src/core/execute.c
index daba1a3846..7a72aa486c 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -38,6 +38,7 @@
#include <linux/fs.h>
#include <linux/oom.h>
#include <sys/poll.h>
+#include <linux/seccomp-bpf.h>
#ifdef HAVE_PAM
#include <security/pam_appl.h>
@@ -60,6 +61,7 @@
#include "def.h"
#include "loopback-setup.h"
#include "path-util.h"
+#include "syscall-list.h"
#define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
@@ -924,6 +926,59 @@ static void rename_process_from_path(const char *path) {
rename_process(process_name);
}
+static int apply_seccomp(uint32_t *syscall_filter) {
+ static const struct sock_filter header[] = {
+ VALIDATE_ARCHITECTURE,
+ EXAMINE_SYSCALL
+ };
+ static const struct sock_filter footer[] = {
+ _KILL_PROCESS
+ };
+
+ int i;
+ unsigned n;
+ struct sock_filter *f;
+ struct sock_fprog prog;
+
+ assert(syscall_filter);
+
+ /* First: count the syscalls to check for */
+ for (i = 0, n = 0; i < syscall_max(); i++)
+ if (syscall_filter[i >> 4] & (1 << (i & 31)))
+ n++;
+
+ /* Second: build the filter program from a header the syscall
+ * matches and the footer */
+ f = alloca(sizeof(struct sock_filter) * (ELEMENTSOF(header) + 2*n + ELEMENTSOF(footer)));
+ memcpy(f, header, sizeof(header));
+
+ for (i = 0, n = 0; i < syscall_max(); i++)
+ if (syscall_filter[i >> 4] & (1 << (i & 31))) {
+ struct sock_filter item[] = {
+ BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, i, 0, 1),
+ BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
+ };
+
+ assert_cc(ELEMENTSOF(item) == 2);
+
+ f[ELEMENTSOF(header) + 2*n] = item[0];
+ f[ELEMENTSOF(header) + 2*n+1] = item[1];
+
+ n++;
+ }
+
+ memcpy(f + (ELEMENTSOF(header) + 2*n), footer, sizeof(footer));
+
+ /* Third: install the filter */
+ zero(prog);
+ prog.len = ELEMENTSOF(header) + ELEMENTSOF(footer) + 2*n;
+ prog.filter = f;
+ if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog) < 0)
+ return -errno;
+
+ return 0;
+}
+
int exec_spawn(ExecCommand *command,
char **argv,
const ExecContext *context,
@@ -1355,6 +1410,21 @@ int exec_spawn(ExecCommand *command,
r = EXIT_CAPABILITIES;
goto fail_child;
}
+
+ if (context->no_new_privileges)
+ if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
+ err = -errno;
+ r = EXIT_NO_NEW_PRIVILEGES;
+ goto fail_child;
+ }
+
+ if (context->syscall_filter) {
+ err = apply_seccomp(context->syscall_filter);
+ if (err < 0) {
+ r = EXIT_SECCOMP;
+ goto fail_child;
+ }
+ }
}
if (!(our_env = new0(char*, 7))) {
diff --git a/src/core/execute.h b/src/core/execute.h
index 2083c2971b..187165cdc2 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -164,6 +164,8 @@ struct ExecContext {
bool private_tmp;
bool private_network;
+ bool no_new_privileges;
+
bool control_group_modify;
int control_group_persistent;
@@ -174,6 +176,8 @@ struct ExecContext {
* don't enter a trigger loop. */
bool same_pgrp;
+ uint32_t *syscall_filter;
+
bool oom_score_adjust_set:1;
bool nice_set:1;
bool ioprio_set:1;
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 192c2b2780..140cb9c0a3 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -48,6 +48,8 @@ $1.Capabilities, config_parse_exec_capabilities, 0,
$1.SecureBits, config_parse_exec_secure_bits, 0, offsetof($1, exec_context)
$1.CapabilityBoundingSet, config_parse_bounding_set, 0, offsetof($1, exec_context.capability_bounding_set_drop)
$1.TimerSlackNSec, config_parse_nsec, 0, offsetof($1, exec_context.timer_slack_nsec)
+$1.NoNewPrivileges config_parse_bool, 0, offsetof($1, exec_context.no_new_privileges)
+$1.SystemCallFilter, config_parse_syscall_filter, 0, offsetof($1, exec_context)
$1.LimitCPU, config_parse_limit, RLIMIT_CPU, offsetof($1, exec_context.rlimit)
$1.LimitFSIZE, config_parse_limit, RLIMIT_FSIZE, offsetof($1, exec_context.rlimit)
$1.LimitDATA, config_parse_limit, RLIMIT_DATA, offsetof($1, exec_context.rlimit)
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index 748ab55d54..7fcd63a17a 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -45,6 +45,7 @@
#include "bus-errors.h"
#include "utf8.h"
#include "path-util.h"
+#include "syscall-list.h"
#ifndef HAVE_SYSV_COMPAT
int config_parse_warn_compat(
@@ -879,7 +880,7 @@ int config_parse_bounding_set(
if (r < 0) {
log_error("[%s:%u] Failed to parse capability bounding set, ignoring: %s", filename, line, rvalue);
- return 0;
+ continue;
}
sum |= ((uint64_t) 1ULL) << (uint64_t) cap;
@@ -2001,6 +2002,88 @@ int config_parse_documentation(
return r;
}
+static void syscall_set(uint32_t *p, int nr) {
+ p[nr >> 4] |= 1 << (nr & 31);
+}
+
+static void syscall_unset(uint32_t *p, int nr) {
+ p[nr >> 4] &= ~(1 << (nr & 31));
+}
+
+int config_parse_syscall_filter(
+ const char *filename,
+ unsigned line,
+ const char *section,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+
+ ExecContext *c = data;
+ Unit *u = userdata;
+ bool invert;
+ char *w;
+ size_t l;
+ char *state;
+
+ assert(filename);
+ assert(lvalue);
+ assert(rvalue);
+ assert(u);
+
+ if (rvalue[0] == '~') {
+ invert = true;
+ rvalue++;
+ }
+
+ if (!c->syscall_filter) {
+ size_t n;
+
+ n = (syscall_max() + 31) >> 4;
+ c->syscall_filter = new(uint32_t, n);
+ if (!c->syscall_filter)
+ return -ENOMEM;
+
+ memset(c->syscall_filter, invert ? 0xFF : 0, n * sizeof(uint32_t));
+
+ /* Add these by default */
+ syscall_set(c->syscall_filter, __NR_execve);
+ syscall_set(c->syscall_filter, __NR_rt_sigreturn);
+#ifdef __NR_sigreturn
+ syscall_set(c->syscall_filter, __NR_sigreturn);
+#endif
+ syscall_set(c->syscall_filter, __NR_exit_group);
+ syscall_set(c->syscall_filter, __NR_exit);
+ }
+
+ FOREACH_WORD_QUOTED(w, l, rvalue, state) {
+ int id;
+ char *t;
+
+ t = strndup(w, l);
+ if (!t)
+ return -ENOMEM;
+
+ id = syscall_from_name(t);
+ free(t);
+
+ if (id < 0) {
+ log_error("[%s:%u] Failed to parse syscall, ignoring: %s", filename, line, rvalue);
+ continue;
+ }
+
+ if (invert)
+ syscall_unset(c->syscall_filter, id);
+ else
+ syscall_set(c->syscall_filter, id);
+ }
+
+ c->no_new_privileges = true;
+
+ return 0;
+}
+
#define FOLLOW_MAX 8
static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
index 501ea4ad47..543e32968f 100644
--- a/src/core/load-fragment.h
+++ b/src/core/load-fragment.h
@@ -82,6 +82,7 @@ int config_parse_unit_device_allow(const char *filename, unsigned line, const ch
int config_parse_unit_blkio_weight(const char *filename, unsigned line, const char *section, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_unit_blkio_bandwidth(const char *filename, unsigned line, const char *section, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_unit_requires_mounts_for(const char *filename, unsigned line, const char *section, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_syscall_filter(const char *filename, unsigned line, const char *section, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
/* gperf prototypes */
const struct ConfigPerfItem* load_fragment_gperf_lookup(const char *key, unsigned length);
diff --git a/src/core/syscall-list.c b/src/core/syscall-list.c
new file mode 100644
index 0000000000..05fad3e158
--- /dev/null
+++ b/src/core/syscall-list.c
@@ -0,0 +1,55 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2012 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 <sys/syscall.h>
+#include <string.h>
+
+#include "util.h"
+
+#include "syscall-list.h"
+
+const struct syscall_name *lookup_syscall(register const char *str, register unsigned int len);
+
+#include "syscall-to-name.h"
+#include "syscall-from-name.h"
+
+const char *syscall_to_name(int id) {
+ if (id < 0 || id >= (int) ELEMENTSOF(syscall_names))
+ return NULL;
+
+ return syscall_names[id];
+}
+
+int syscall_from_name(const char *name) {
+ const struct syscall_name *sc;
+
+ assert(name);
+
+ sc = lookup_syscall(name, strlen(name));
+ if (!sc)
+ return -1;
+
+ return sc->id;
+}
+
+int syscall_max(void) {
+ return ELEMENTSOF(syscall_names);
+}
diff --git a/src/core/syscall-list.h b/src/core/syscall-list.h
new file mode 100644
index 0000000000..0fc6859605
--- /dev/null
+++ b/src/core/syscall-list.h
@@ -0,0 +1,30 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosyscalllisthfoo
+#define foosyscalllisthfoo
+
+/***
+ This file is part of systemd.
+
+ Copyright 2012 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/>.
+***/
+
+const char *syscall_to_name(int id);
+int syscall_from_name(const char *name);
+
+int syscall_max(void);
+
+#endif
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-17 16:26:55 +0000