Merge pull request #3260 from blenk92/add-keyring-option

config/selinux/lxc.te

@@ -84,5 +84,8 @@ allow lxc_t self:packet_socket create_socket_perms;
 allow lxc_t self:rawip_socket create_socket_perms;
 allow lxc_t self:netlink_route_socket create_netlink_socket_perms;
 
+# Needed to set label that the keyring will be created with
+allow lxc_t self:process { setkeycreate };
+
 dontaudit lxc_t sysctl_kernel_t:file write;
 dontaudit lxc_t sysctl_modprobe_t:file write;

doc/lxc.container.conf.sgml.in

@@ -1932,6 +1932,44 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
             <programlisting>lxc.selinux.context = system_u:system_r:lxc_t:s0:c22</programlisting>
           </listitem>
         </varlistentry>
+        <varlistentry>
+          <term>
+            <option>lxc.selinux.context.keyring</option>
+          </term>
+          <listitem>
+            <para>
+              Specify the SELinux context under which the container's keyring
+              should be created. By default this the same as lxc.selinux.context, or
+              the the context lxc is executed under if lxc.selinux.context has not been set.
+            </para>
+            <programlisting>lxc.selinux.context.keyring = system_u:system_r:lxc_t:s0:c22</programlisting>
+          </listitem>
+        </varlistentry>
+      </variablelist>
+    </refsect2>
+
+    <refsect2>
+      <title>Kernel Keyring</title>
+      <para>
+        The Linux Keyring facility is primarily a way for various
+        kernel components to retain or cache security data, authentication
+        keys, encryption keys, and other data in the kernel. By default lxc
+        will create a new session keyring for the started application.
+      </para>
+      <variablelist>
+        <varlistentry>
+          <term>
+            <option>lxc.keyring.session</option>
+          </term>
+          <listitem>
+            <para>
+              Disable the creation of new session keyring by lxc. The started
+              application will then inherit the current session keyring.
+              By default, or when passing the value 1, a new keyring will be created.
+            </para>
+            <programlisting>lxc.keyring.session = 0</programlisting>
+          </listitem>
+        </varlistentry>
       </variablelist>
     </refsect2>
 

src/lxc/conf.c

@@ -2742,6 +2742,8 @@ struct lxc_conf *lxc_conf_init(void)
 	new->lsm_aa_profile = NULL;
 	lxc_list_init(&new->lsm_aa_raw);
 	new->lsm_se_context = NULL;
+	new->lsm_se_keyring_context = NULL;
+	new->keyring_disable_session = false;
 	new->tmp_umount_proc = false;
 	new->tmp_umount_proc = 0;
 	new->shmount.path_host = NULL;
@@ -3533,6 +3535,7 @@ int lxc_setup(struct lxc_handler *handler)
 	int ret;
 	const char *lxcpath = handler->lxcpath, *name = handler->name;
 	struct lxc_conf *lxc_conf = handler->conf;
+	char *keyring_context = NULL;
 
 	ret = lxc_setup_rootfs_prepare_root(lxc_conf, name, lxcpath);
 	if (ret < 0) {
@@ -3548,9 +3551,17 @@ int lxc_setup(struct lxc_handler *handler)
 		}
 	}
 
-	ret = lxc_setup_keyring();
-	if (ret < 0)
-		return -1;
+	if (!lxc_conf->keyring_disable_session) {
+		if (lxc_conf->lsm_se_keyring_context) {
+			keyring_context = lxc_conf->lsm_se_keyring_context;
+		} else if (lxc_conf->lsm_se_context) {
+			keyring_context = lxc_conf->lsm_se_context;
+		}
+
+		ret = lxc_setup_keyring(keyring_context);
+		if (ret < 0)
+			return -1;
+	}
 
 	if (handler->ns_clone_flags & CLONE_NEWNET) {
 		ret = lxc_setup_network_in_child_namespaces(lxc_conf,

src/lxc/conf.h

@@ -298,6 +298,8 @@ struct lxc_conf {
 	unsigned int lsm_aa_allow_incomplete;
 	struct lxc_list lsm_aa_raw;
 	char *lsm_se_context;
+	char *lsm_se_keyring_context;
+	bool keyring_disable_session;
 	bool tmp_umount_proc;
 	struct lxc_seccomp seccomp;
 	int maincmd_fd;

src/lxc/confile.c

@@ -89,6 +89,7 @@ lxc_config_define(init_cmd);
 lxc_config_define(init_cwd);
 lxc_config_define(init_gid);
 lxc_config_define(init_uid);
+lxc_config_define(keyring_session);
 lxc_config_define(log_file);
 lxc_config_define(log_level);
 lxc_config_define(log_syslog);
@@ -136,6 +137,7 @@ lxc_config_define(seccomp_allow_nesting);
 lxc_config_define(seccomp_notify_cookie);
 lxc_config_define(seccomp_notify_proxy);
 lxc_config_define(selinux_context);
+lxc_config_define(selinux_context_keyring);
 lxc_config_define(signal_halt);
 lxc_config_define(signal_reboot);
 lxc_config_define(signal_stop);
@@ -187,6 +189,7 @@ static struct lxc_config_t config_jump_table[] = {
 	{ "lxc.init.gid",                  set_config_init_gid,                    get_config_init_gid,                    clr_config_init_gid,                  },
 	{ "lxc.init.uid",                  set_config_init_uid,                    get_config_init_uid,                    clr_config_init_uid,                  },
 	{ "lxc.init.cwd",                  set_config_init_cwd,                    get_config_init_cwd,                    clr_config_init_cwd,                  },
+	{ "lxc.keyring.session",           set_config_keyring_session,             get_config_keyring_session,             clr_config_keyring_session            },
 	{ "lxc.log.file",                  set_config_log_file,                    get_config_log_file,                    clr_config_log_file,                  },
 	{ "lxc.log.level",                 set_config_log_level,                   get_config_log_level,                   clr_config_log_level,                 },
 	{ "lxc.log.syslog",                set_config_log_syslog,                  get_config_log_syslog,                  clr_config_log_syslog,                },
@@ -233,6 +236,7 @@ static struct lxc_config_t config_jump_table[] = {
 	{ "lxc.seccomp.notify.proxy",      set_config_seccomp_notify_proxy,        get_config_seccomp_notify_proxy,        clr_config_seccomp_notify_proxy,      },
 	{ "lxc.seccomp.profile",           set_config_seccomp_profile,             get_config_seccomp_profile,             clr_config_seccomp_profile,           },
 	{ "lxc.selinux.context",           set_config_selinux_context,             get_config_selinux_context,             clr_config_selinux_context,           },
+	{ "lxc.selinux.context.keyring",   set_config_selinux_context_keyring,     get_config_selinux_context_keyring,     clr_config_selinux_context_keyring    },
 	{ "lxc.signal.halt",               set_config_signal_halt,                 get_config_signal_halt,                 clr_config_signal_halt,               },
 	{ "lxc.signal.reboot",             set_config_signal_reboot,               get_config_signal_reboot,               clr_config_signal_reboot,             },
 	{ "lxc.signal.stop",               set_config_signal_stop,                 get_config_signal_stop,                 clr_config_signal_stop,               },
@@ -1469,6 +1473,18 @@ static int set_config_selinux_context(const char *key, const char *value,
 	return set_config_string_item(&lxc_conf->lsm_se_context, value);
 }
 
+static int set_config_selinux_context_keyring(const char *key, const char *value,
+					      struct lxc_conf *lxc_conf, void *data)
+{
+	return set_config_string_item(&lxc_conf->lsm_se_keyring_context, value);
+}
+
+static int set_config_keyring_session(const char *key, const char *value,
+				      struct lxc_conf *lxc_conf, void *data)
+{
+	return set_config_bool_item(&lxc_conf->keyring_disable_session, value, false);
+}
+
 static int set_config_log_file(const char *key, const char *value,
 			      struct lxc_conf *c, void *data)
 {
@@ -2539,26 +2555,7 @@ static int set_config_rootfs_path(const char *key, const char *value,
 static int set_config_rootfs_managed(const char *key, const char *value,
 				     struct lxc_conf *lxc_conf, void *data)
 {
-	unsigned int val = 0;
-
-	if (lxc_config_value_empty(value)) {
-		lxc_conf->rootfs.managed = true;
-		return 0;
-	}
-
-	if (lxc_safe_uint(value, &val) < 0)
-		return -EINVAL;
-
-	switch (val) {
-	case 0:
-		lxc_conf->rootfs.managed = false;
-		return 0;
-	case 1:
-		lxc_conf->rootfs.managed = true;
-		return 0;
-	}
-
-	return -EINVAL;
+	return set_config_bool_item(&lxc_conf->rootfs.managed, value, true);
 }
 
 static int set_config_rootfs_mount(const char *key, const char *value,
@@ -3539,6 +3536,19 @@ static int get_config_selinux_context(const char *key, char *retv, int inlen,
 	return lxc_get_conf_str(retv, inlen, c->lsm_se_context);
 }
 
+static int get_config_selinux_context_keyring(const char *key, char *retv, int inlen,
+					      struct lxc_conf *c, void *data)
+{
+	return lxc_get_conf_str(retv, inlen, c->lsm_se_keyring_context);
+}
+
+static int get_config_keyring_session(const char *key, char *retv, int inlen,
+				      struct lxc_conf *c, void *data)
+{
+	return lxc_get_conf_bool(c, retv, inlen, c->keyring_disable_session);
+}
+
+
 /* If you ask for a specific cgroup value, i.e. lxc.cgroup.devices.list, then
  * just the value(s) will be printed. Since there still could be more than one,
  * it is newline-separated.
@@ -4405,6 +4415,21 @@ static inline int clr_config_selinux_context(const char *key,
 	return 0;
 }
 
+static inline int clr_config_selinux_context_keyring(const char *key,
+						     struct lxc_conf *c, void *data)
+{
+	free(c->lsm_se_keyring_context);
+	c->lsm_se_keyring_context = NULL;
+	return 0;
+}
+
+static inline int clr_config_keyring_session(const char *key,
+					     struct lxc_conf *c, void *data)
+{
+	c->keyring_disable_session = false;
+	return 0;
+}
+
 static inline int clr_config_cgroup_controller(const char *key,
 					       struct lxc_conf *c, void *data)
 {
@@ -5951,6 +5976,7 @@ int lxc_list_subkeys(struct lxc_conf *conf, const char *key, char *retv,
 		strprint(retv, inlen, "dir\n");
 	} else if (!strcmp(key, "lxc.selinux")) {
 		strprint(retv, inlen, "context\n");
+		strprint(retv, inlen, "context.keyring\n");
 	} else if (!strcmp(key, "lxc.mount")) {
 		strprint(retv, inlen, "auto\n");
 		strprint(retv, inlen, "entry\n");
@@ -5991,6 +6017,8 @@ int lxc_list_subkeys(struct lxc_conf *conf, const char *key, char *retv,
 		strprint(retv, inlen, "order\n");
 	} else if (!strcmp(key, "lxc.monitor")) {
 		strprint(retv, inlen, "unshare\n");
+	} else if (!strcmp(key, "lxc.keyring")) {
+		strprint(retv, inlen, "session\n");
 	} else {
 		fulllen = -1;
 	}

src/lxc/confile_utils.c

@@ -649,6 +649,30 @@ int set_config_path_item(char **conf_item, const char *value)
 	return set_config_string_item_max(conf_item, value, PATH_MAX);
 }
 
+int set_config_bool_item(bool *conf_item, const char *value, bool empty_conf_action)
+{
+	unsigned int val = 0;
+
+	if (lxc_config_value_empty(value)) {
+		*conf_item = empty_conf_action;
+		return 0;
+	}
+
+	if (lxc_safe_uint(value, &val) < 0)
+		return -EINVAL;
+
+	switch (val) {
+	case 0:
+		*conf_item = false;
+		return 0;
+	case 1:
+		*conf_item = true;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
 int config_ip_prefix(struct in_addr *addr)
 {
 	if (IN_CLASSA(addr->s_addr))

src/lxc/confile_utils.h

@@ -51,6 +51,8 @@ extern int set_config_string_item(char **conf_item, const char *value);
 extern int set_config_string_item_max(char **conf_item, const char *value,
 				      size_t max);
 extern int set_config_path_item(char **conf_item, const char *value);
+extern int set_config_bool_item(bool *conf_item, const char *value,
+                                bool empty_conf_action);
 extern int config_ip_prefix(struct in_addr *addr);
 extern int network_ifname(char *valuep, const char *value, size_t size);
 extern void rand_complete_hwaddr(char *hwaddr);

src/lxc/lsm/lsm.c

@@ -193,3 +193,16 @@ void lsm_process_cleanup(struct lxc_conf *conf, const char *lxcpath)
 
 	drv->cleanup(conf, lxcpath);
 }
+
+int lsm_keyring_label_set(char *label) {
+
+	if (!drv) {
+		ERROR("LSM driver not inited");
+		return -1;
+	}
+
+	if (!drv->keyring_label_set)
+		return 0;
+
+	return drv->keyring_label_set(label);
+}

src/lxc/lsm/lsm.h

@@ -17,6 +17,7 @@ struct lsm_drv {
 	char *(*process_label_get)(pid_t pid);
 	int (*process_label_set)(const char *label, struct lxc_conf *conf,
 				 bool on_exec);
+	int (*keyring_label_set)(char* label);
 	int (*prepare)(struct lxc_conf *conf, const char *lxcpath);
 	void (*cleanup)(struct lxc_conf *conf, const char *lxcpath);
 };
@@ -32,5 +33,6 @@ extern int lsm_process_label_fd_get(pid_t pid, bool on_exec);
 extern int lsm_process_label_set_at(int label_fd, const char *label,
 				    bool on_exec);
 extern void lsm_process_cleanup(struct lxc_conf *conf, const char *lxcpath);
+extern int lsm_keyring_label_set(char *label);
 
 #endif /* __LXC_LSM_H */

src/lxc/lsm/selinux.c

@@ -85,11 +85,24 @@ static int selinux_process_label_set(const char *inlabel, struct lxc_conf *conf,
 	return 0;
 }
 
+/*
+ * selinux_keyring_label_set: Set SELinux context that will be assigned to the keyring
+ *
+ * @label   : label string
+ *
+ * Returns 0 on success, < 0 on failure
+ */
+static int selinux_keyring_label_set(char *label)
+{
+	return setkeycreatecon_raw(label);
+};
+
 static struct lsm_drv selinux_drv = {
 	.name = "SELinux",
 	.enabled           = is_selinux_enabled,
 	.process_label_get = selinux_process_label_get,
 	.process_label_set = selinux_process_label_set,
+	.keyring_label_set = selinux_keyring_label_set,
 };
 
 struct lsm_drv *lsm_selinux_drv_init(void)

src/lxc/utils.c

@@ -27,6 +27,7 @@
 
 #include "config.h"
 #include "log.h"
+#include "lsm/lsm.h"
 #include "lxclock.h"
 #include "memory_utils.h"
 #include "namespace.h"
@@ -1835,11 +1836,17 @@ int recursive_destroy(const char *dirname)
 	return fret;
 }
 
-int lxc_setup_keyring(void)
+int lxc_setup_keyring(char *keyring_label)
 {
 	key_serial_t keyring;
 	int ret = 0;
 
+	if (keyring_label) {
+		if (lsm_keyring_label_set(keyring_label) < 0) {
+			ERROR("Couldn't set keyring label");
+		}
+	}
+
 	/* Try to allocate a new session keyring for the container to prevent
 	 * information leaks.
 	 */

src/lxc/utils.h

@@ -232,6 +232,6 @@ extern uint64_t lxc_find_next_power2(uint64_t n);
 extern int lxc_set_death_signal(int signal, pid_t parent, int parent_status_fd);
 extern int fd_cloexec(int fd, bool cloexec);
 extern int recursive_destroy(const char *dirname);
-extern int lxc_setup_keyring(void);
+extern int lxc_setup_keyring(char *keyring_label);
 
 #endif /* __LXC_UTILS_H */