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authorDjalal Harouni <tixxdz@opendz.org>2016-10-12 14:11:16 +0200
committerDjalal Harouni <tixxdz@opendz.org>2016-10-12 14:11:16 +0200
commitc575770b75b6cd15684fbacd249147bf5fd6ead7 (patch)
tree1dbde008e50d9ab2780168dd26ead86a762959dc /src/core
parentac246d9868bd476297e2702e0a7ef52294f9cfa8 (diff)
core:sandbox: lets make /lib/modules/ inaccessible on ProtectKernelModules=
Lets go further and make /lib/modules/ inaccessible for services that do not have business with modules, this is a minor improvment but it may help on setups with custom modules and they are limited... in regard of kernel auto-load feature. This change introduce NameSpaceInfo struct which we may embed later inside ExecContext but for now lets just reduce the argument number to setup_namespace() and merge ProtectKernelModules feature.
Diffstat (limited to 'src/core')
-rw-r--r--src/core/execute.c11
-rw-r--r--src/core/namespace.c54
-rw-r--r--src/core/namespace.h14
3 files changed, 56 insertions, 23 deletions
diff --git a/src/core/execute.c b/src/core/execute.c
index 7a278b7d31..dc078d96f0 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1766,6 +1766,7 @@ static bool exec_needs_mount_namespace(
context->protect_system != PROTECT_SYSTEM_NO ||
context->protect_home != PROTECT_HOME_NO ||
context->protect_kernel_tunables ||
+ context->protect_kernel_modules ||
context->protect_control_groups)
return true;
@@ -2493,6 +2494,12 @@ static int exec_child(
if (needs_mount_namespace) {
_cleanup_free_ char **rw = NULL;
char *tmp = NULL, *var = NULL;
+ NameSpaceInfo ns_info = {
+ .private_dev = context->private_devices,
+ .protect_control_groups = context->protect_control_groups,
+ .protect_kernel_tunables = context->protect_kernel_tunables,
+ .protect_kernel_modules = context->protect_kernel_modules,
+ };
/* The runtime struct only contains the parent
* of the private /tmp, which is
@@ -2515,14 +2522,12 @@ static int exec_child(
r = setup_namespace(
(params->flags & EXEC_APPLY_CHROOT) ? context->root_directory : NULL,
+ &ns_info,
rw,
context->read_only_paths,
context->inaccessible_paths,
tmp,
var,
- context->private_devices,
- context->protect_kernel_tunables,
- context->protect_control_groups,
context->protect_home,
context->protect_system,
context->mount_flags);
diff --git a/src/core/namespace.c b/src/core/namespace.c
index 43a2f4ba6e..1195e9a854 100644
--- a/src/core/namespace.c
+++ b/src/core/namespace.c
@@ -97,6 +97,14 @@ static const TargetMount protect_kernel_tunables_table[] = {
{ "/sys/fs/cgroup", READWRITE, false }, /* READONLY is set by ProtectControlGroups= option */
};
+/* ProtectKernelModules= option */
+static const TargetMount protect_kernel_modules_table[] = {
+#ifdef HAVE_SPLIT_USR
+ { "/lib/modules", INACCESSIBLE, true },
+#endif
+ { "/usr/lib/modules", INACCESSIBLE, true },
+};
+
/*
* ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of
* system should be protected by ProtectSystem=
@@ -207,6 +215,13 @@ static int append_protect_kernel_tunables(BindMount **p, const char *root_direct
ELEMENTSOF(protect_kernel_tunables_table));
}
+static int append_protect_kernel_modules(BindMount **p, const char *root_directory) {
+ assert(p);
+
+ return append_target_mounts(p, root_directory, protect_kernel_modules_table,
+ ELEMENTSOF(protect_kernel_modules_table));
+}
+
static int append_protect_home(BindMount **p, const char *root_directory, ProtectHome protect_home) {
int r = 0;
@@ -660,14 +675,12 @@ static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned
}
static unsigned namespace_calculate_mounts(
+ const NameSpaceInfo *ns_info,
char** read_write_paths,
char** read_only_paths,
char** inaccessible_paths,
const char* tmp_dir,
const char* var_tmp_dir,
- bool private_dev,
- bool protect_sysctl,
- bool protect_cgroups,
ProtectHome protect_home,
ProtectSystem protect_system) {
@@ -690,22 +703,21 @@ static unsigned namespace_calculate_mounts(
strv_length(read_write_paths) +
strv_length(read_only_paths) +
strv_length(inaccessible_paths) +
- private_dev +
- (protect_sysctl ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
- (protect_cgroups ? 1 : 0) +
+ ns_info->private_dev +
+ (ns_info->protect_kernel_tunables ? ELEMENTSOF(protect_kernel_tunables_table) : 0) +
+ (ns_info->protect_control_groups ? 1 : 0) +
+ (ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) +
protect_home_cnt + protect_system_cnt;
}
int setup_namespace(
const char* root_directory,
+ const NameSpaceInfo *ns_info,
char** read_write_paths,
char** read_only_paths,
char** inaccessible_paths,
const char* tmp_dir,
const char* var_tmp_dir,
- bool private_dev,
- bool protect_sysctl,
- bool protect_cgroups,
ProtectHome protect_home,
ProtectSystem protect_system,
unsigned long mount_flags) {
@@ -718,13 +730,12 @@ int setup_namespace(
if (mount_flags == 0)
mount_flags = MS_SHARED;
- n = namespace_calculate_mounts(read_write_paths,
+ n = namespace_calculate_mounts(ns_info,
+ read_write_paths,
read_only_paths,
inaccessible_paths,
tmp_dir, var_tmp_dir,
- private_dev, protect_sysctl,
- protect_cgroups, protect_home,
- protect_system);
+ protect_home, protect_system);
/* Set mount slave mode */
if (root_directory || n > 0)
@@ -756,16 +767,25 @@ int setup_namespace(
m++;
}
- if (private_dev) {
+ if (ns_info->private_dev) {
m->path = prefix_roota(root_directory, "/dev");
m->mode = PRIVATE_DEV;
m++;
}
- if (protect_sysctl)
- append_protect_kernel_tunables(&m, root_directory);
+ if (ns_info->protect_kernel_tunables) {
+ r = append_protect_kernel_tunables(&m, root_directory);
+ if (r < 0)
+ return r;
+ }
+
+ if (ns_info->protect_kernel_modules) {
+ r = append_protect_kernel_modules(&m, root_directory);
+ if (r < 0)
+ return r;
+ }
- if (protect_cgroups) {
+ if (ns_info->protect_control_groups) {
m->path = prefix_roota(root_directory, "/sys/fs/cgroup");
m->mode = READONLY;
m++;
diff --git a/src/core/namespace.h b/src/core/namespace.h
index 6505bcc499..6310638e9a 100644
--- a/src/core/namespace.h
+++ b/src/core/namespace.h
@@ -4,6 +4,7 @@
This file is part of systemd.
Copyright 2010 Lennart Poettering
+ Copyright 2016 Djalal Harouni
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
@@ -19,6 +20,8 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
+typedef struct NameSpaceInfo NameSpaceInfo;
+
#include <stdbool.h>
#include "macro.h"
@@ -40,15 +43,20 @@ typedef enum ProtectSystem {
_PROTECT_SYSTEM_INVALID = -1
} ProtectSystem;
+struct NameSpaceInfo {
+ bool private_dev:1;
+ bool protect_control_groups:1;
+ bool protect_kernel_tunables:1;
+ bool protect_kernel_modules:1;
+};
+
int setup_namespace(const char *chroot,
+ const NameSpaceInfo *ns_info,
char **read_write_paths,
char **read_only_paths,
char **inaccessible_paths,
const char *tmp_dir,
const char *var_tmp_dir,
- bool private_dev,
- bool protect_sysctl,
- bool protect_cgroups,
ProtectHome protect_home,
ProtectSystem protect_system,
unsigned long mount_flags);