From f79283a86531e3bbf0854b5f126b7b291fadfb43 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 20 Mar 2019 19:09:09 +0100
Subject: [PATCH] core: expose SUID/SGID restriction as new unit setting
RestrictSUIDSGID=
(cherry picked from commit f69567cbe26d09eac9d387c0be0fc32c65a83ada)
Related: #1687512
---
src/core/dbus-execute.c | 4 ++++
src/core/execute.c | 22 +++++++++++++++++++++
src/core/execute.h | 1 +
src/core/load-fragment-gperf.gperf.m4 | 2 ++
src/shared/bus-unit-util.c | 2 +-
test/fuzz/fuzz-unit-file/directives.service | 1 +
6 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index 198f149210..e7c0b893d1 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -815,6 +815,7 @@ const sd_bus_vtable bus_exec_vtable[] = {
SD_BUS_PROPERTY("ConfigurationDirectory", "as", NULL, offsetof(ExecContext, directories[EXEC_DIRECTORY_CONFIGURATION].paths), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("MemoryDenyWriteExecute", "b", bus_property_get_bool, offsetof(ExecContext, memory_deny_write_execute), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("RestrictRealtime", "b", bus_property_get_bool, offsetof(ExecContext, restrict_realtime), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("RestrictSUIDSGID", "b", bus_property_get_bool, offsetof(ExecContext, restrict_suid_sgid), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("RestrictNamespaces", "t", bus_property_get_ulong, offsetof(ExecContext, restrict_namespaces), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("BindPaths", "a(ssbt)", property_get_bind_paths, 0, SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("BindReadOnlyPaths", "a(ssbt)", property_get_bind_paths, 0, SD_BUS_VTABLE_PROPERTY_CONST),
@@ -1179,6 +1180,9 @@ int bus_exec_context_set_transient_property(
if (streq(name, "RestrictRealtime"))
return bus_set_transient_bool(u, name, &c->restrict_realtime, message, flags, error);
+ if (streq(name, "RestrictSUIDSGID"))
+ return bus_set_transient_bool(u, name, &c->restrict_suid_sgid, message, flags, error);
+
if (streq(name, "DynamicUser"))
return bus_set_transient_bool(u, name, &c->dynamic_user, message, flags, error);
diff --git a/src/core/execute.c b/src/core/execute.c
index 56aa89e1ec..f012023224 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1366,6 +1366,7 @@ static bool context_has_no_new_privileges(const ExecContext *c) {
return context_has_address_families(c) ||
c->memory_deny_write_execute ||
c->restrict_realtime ||
+ c->restrict_suid_sgid ||
exec_context_restrict_namespaces_set(c) ||
c->protect_kernel_tunables ||
c->protect_kernel_modules ||
@@ -1470,6 +1471,19 @@ static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
return seccomp_restrict_realtime();
}
+static int apply_restrict_suid_sgid(const Unit* u, const ExecContext *c) {
+ assert(u);
+ assert(c);
+
+ if (!c->restrict_suid_sgid)
+ return 0;
+
+ if (skip_seccomp_unavailable(u, "RestrictSUIDSGID="))
+ return 0;
+
+ return seccomp_restrict_suid_sgid();
+}
+
static int apply_protect_sysctl(const Unit *u, const ExecContext *c) {
assert(u);
assert(c);
@@ -3404,6 +3418,12 @@ static int exec_child(
return log_unit_error_errno(unit, r, "Failed to apply realtime restrictions: %m");
}
+ r = apply_restrict_suid_sgid(unit, context);
+ if (r < 0) {
+ *exit_status = EXIT_SECCOMP;
+ return log_unit_error_errno(unit, r, "Failed to apply SUID/SGID restrictions: %m");
+ }
+
r = apply_restrict_namespaces(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
@@ -4023,6 +4043,7 @@ void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix) {
"%sIgnoreSIGPIPE: %s\n"
"%sMemoryDenyWriteExecute: %s\n"
"%sRestrictRealtime: %s\n"
+ "%sRestrictSUIDSGID: %s\n"
"%sKeyringMode: %s\n",
prefix, c->umask,
prefix, c->working_directory ? c->working_directory : "/",
@@ -4041,6 +4062,7 @@ void exec_context_dump(const ExecContext *c, FILE* f, const char *prefix) {
prefix, yes_no(c->ignore_sigpipe),
prefix, yes_no(c->memory_deny_write_execute),
prefix, yes_no(c->restrict_realtime),
+ prefix, yes_no(c->restrict_suid_sgid),
prefix, exec_keyring_mode_to_string(c->keyring_mode));
if (c->root_image)
diff --git a/src/core/execute.h b/src/core/execute.h
index b2eb55f8f5..2266355962 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -245,6 +245,7 @@ struct ExecContext {
* that the autofs logic detects that it belongs to us and we
* don't enter a trigger loop. */
bool same_pgrp;
+ bool restrict_suid_sgid;
unsigned long personality;
bool lock_personality;
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index cdf4d14c4e..49e938d0ce 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -76,6 +76,7 @@ $1.SystemCallErrorNumber, config_parse_syscall_errno, 0,
$1.MemoryDenyWriteExecute, config_parse_bool, 0, offsetof($1, exec_context.memory_deny_write_execute)
$1.RestrictNamespaces, config_parse_restrict_namespaces, 0, offsetof($1, exec_context)
$1.RestrictRealtime, config_parse_bool, 0, offsetof($1, exec_context.restrict_realtime)
+$1.RestrictSUIDSGID, config_parse_bool, 0, offsetof($1, exec_context.restrict_suid_sgid)
$1.RestrictAddressFamilies, config_parse_address_families, 0, offsetof($1, exec_context)
$1.LockPersonality, config_parse_bool, 0, offsetof($1, exec_context.lock_personality)',
`$1.SystemCallFilter, config_parse_warn_compat, DISABLED_CONFIGURATION, 0
@@ -84,6 +85,7 @@ $1.SystemCallErrorNumber, config_parse_warn_compat, DISABLED_CO
$1.MemoryDenyWriteExecute, config_parse_warn_compat, DISABLED_CONFIGURATION, 0
$1.RestrictNamespaces, config_parse_warn_compat, DISABLED_CONFIGURATION, 0
$1.RestrictRealtime, config_parse_warn_compat, DISABLED_CONFIGURATION, 0
+$1.RestrictSUIDSGID, config_parse_warn_compat, DISABLED_CONFIGURATION 0
$1.RestrictAddressFamilies, config_parse_warn_compat, DISABLED_CONFIGURATION, 0
$1.LockPersonality, config_parse_warn_compat, DISABLED_CONFIGURATION, 0')
$1.LimitCPU, config_parse_rlimit, RLIMIT_CPU, offsetof($1, exec_context.rlimit)
diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c
index 055edd6e22..3c42e97b7a 100644
--- a/src/shared/bus-unit-util.c
+++ b/src/shared/bus-unit-util.c
@@ -697,7 +697,7 @@ static int bus_append_execute_property(sd_bus_message *m, const char *field, con
"PrivateMounts", "NoNewPrivileges", "SyslogLevelPrefix",
"MemoryDenyWriteExecute", "RestrictRealtime", "DynamicUser", "RemoveIPC",
"ProtectKernelTunables", "ProtectKernelModules", "ProtectControlGroups",
- "MountAPIVFS", "CPUSchedulingResetOnFork", "LockPersonality"))
+ "MountAPIVFS", "CPUSchedulingResetOnFork", "LockPersonality" "RestrictSUIDSGID"))
return bus_append_parse_boolean(m, field, eq);
diff --git a/test/fuzz/fuzz-unit-file/directives.service b/test/fuzz/fuzz-unit-file/directives.service
index d8d1fc68b8..eab1820e20 100644
--- a/test/fuzz/fuzz-unit-file/directives.service
+++ b/test/fuzz/fuzz-unit-file/directives.service
@@ -849,6 +849,7 @@ ReserveVT=
RestrictAddressFamilies=
RestrictNamespaces=
RestrictRealtime=
+RestrictSUIDSGID=
RuntimeDirectory=
RuntimeDirectoryMode=
RuntimeDirectoryPreserve=