[PATCH 1/2] hostapd: run as user 'network'

Daniel Golle daniel at makrotopia.org
Mon Dec 7 13:14:09 EST 2020


Granting capabilities CAP_NET_ADMIN and CAP_NET_RAW allows running
hostapd and wpa_supplicant without root priviledges.
Add ubus acl allowing the necessary ubus interactions for the 'network'
user running hostapd/wpa_supplicant.
To still allow netifd to acquire the PID of wpa_supplicant and hostapd
introduce a new ubus method 'getpid' for both of them and make use of
that instead of querying procd (which will not work, as procd will
return the PID of ujail)

Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 package/network/services/hostapd/Makefile     |  9 ++++++--
 .../network/services/hostapd/files/hostapd.sh |  2 +-
 .../network/services/hostapd/files/wpad.init  | 16 ++++++++++++++
 .../network/services/hostapd/files/wpad.json  | 22 +++++++++++++++++++
 .../services/hostapd/files/wpad_acl.json      | 10 +++++++++
 .../services/hostapd/src/src/ap/ubus.c        | 16 ++++++++++++++
 .../hostapd/src/wpa_supplicant/ubus.c         | 16 ++++++++++++++
 7 files changed, 88 insertions(+), 3 deletions(-)
 create mode 100644 package/network/services/hostapd/files/wpad.json
 create mode 100644 package/network/services/hostapd/files/wpad_acl.json

diff --git a/package/network/services/hostapd/Makefile b/package/network/services/hostapd/Makefile
index 61b2a548ef..386c17f99d 100644
--- a/package/network/services/hostapd/Makefile
+++ b/package/network/services/hostapd/Makefile
@@ -7,7 +7,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=hostapd
-PKG_RELEASE:=18
+PKG_RELEASE:=19
 
 PKG_SOURCE_URL:=http://w1.fi/hostap.git
 PKG_SOURCE_PROTO:=git
@@ -149,6 +149,7 @@ define Package/hostapd/Default
   TITLE:=IEEE 802.1x Authenticator
   URL:=http://hostap.epitest.fi/
   DEPENDS:=$(DRV_DEPENDS) +hostapd-common +libubus
+  USERID:=network=101:network=101
   PROVIDES:=hostapd
   CONFLICTS:=$(HOSTAPD_PROVIDERS)
   HOSTAPD_PROVIDERS+=$(1)
@@ -232,6 +233,7 @@ define Package/wpad/Default
   SUBMENU:=WirelessAPD
   TITLE:=IEEE 802.1x Auth/Supplicant
   DEPENDS:=$(DRV_DEPENDS) +hostapd-common +libubus
+  USERID:=network=101:network=101
   URL:=http://hostap.epitest.fi/
   PROVIDES:=hostapd wpa-supplicant
   CONFLICTS:=$(HOSTAPD_PROVIDERS) $(SUPPLICANT_PROVIDERS)
@@ -346,6 +348,7 @@ define Package/wpa-supplicant/Default
   TITLE:=WPA Supplicant
   URL:=http://hostap.epitest.fi/wpa_supplicant/
   DEPENDS:=$(DRV_DEPENDS) +hostapd-common +libubus
+  USERID:=network=101:network=101
   PROVIDES:=wpa-supplicant
   CONFLICTS:=$(SUPPLICANT_PROVIDERS)
   SUPPLICANT_PROVIDERS+=$(1)
@@ -597,10 +600,12 @@ define Install/supplicant
 endef
 
 define Package/hostapd-common/install
-	$(INSTALL_DIR) $(1)/lib/netifd $(1)/etc/rc.button $(1)/etc/hotplug.d/ieee80211 $(1)/etc/init.d
+	$(INSTALL_DIR) $(1)/etc/capabilities $(1)/etc/rc.button $(1)/etc/hotplug.d/ieee80211 $(1)/etc/init.d $(1)/lib/netifd  $(1)/usr/share/acl.d
 	$(INSTALL_DATA) ./files/hostapd.sh $(1)/lib/netifd/hostapd.sh
 	$(INSTALL_BIN) ./files/wpad.init $(1)/etc/init.d/wpad
 	$(INSTALL_BIN) ./files/wps-hotplug.sh $(1)/etc/rc.button/wps
+	$(INSTALL_DATA) ./files/wpad_acl.json $(1)/usr/share/acl.d
+	$(INSTALL_DATA) ./files/wpad.json $(1)/etc/capabilities
 endef
 
 define Package/hostapd/install
diff --git a/package/network/services/hostapd/files/hostapd.sh b/package/network/services/hostapd/files/hostapd.sh
index 41b04e6029..781a34028a 100644
--- a/package/network/services/hostapd/files/hostapd.sh
+++ b/package/network/services/hostapd/files/hostapd.sh
@@ -1365,6 +1365,7 @@ wpa_supplicant_run() {
 	_wpa_supplicant_common "$ifname"
 
 	ubus wait_for wpa_supplicant
+	local supplicant_pid=$(ubus call wpa_supplicant getpid | jsonfilter -l 1 -e @.pid)
 	ubus call wpa_supplicant config_add "{ \
 		\"driver\": \"${_w_driver:-wext}\", \"ctrl\": \"$_rpath\", \
 		\"iface\": \"$ifname\", \"config\": \"$_config\" \
@@ -1376,7 +1377,6 @@ wpa_supplicant_run() {
 
 	[ "$ret" != 0 ] && wireless_setup_vif_failed WPA_SUPPLICANT_FAILED
 
-	local supplicant_pid=$(ubus call service list '{"name": "wpad"}' | jsonfilter -l 1 -e "@['wpad'].instances['supplicant'].pid")
 	wireless_add_process "$supplicant_pid" "/usr/sbin/wpa_supplicant" 1
 
 	return $ret
diff --git a/package/network/services/hostapd/files/wpad.init b/package/network/services/hostapd/files/wpad.init
index 3198e9801f..6c60d539a2 100644
--- a/package/network/services/hostapd/files/wpad.init
+++ b/package/network/services/hostapd/files/wpad.init
@@ -9,17 +9,33 @@ NAME=wpad
 start_service() {
 	if [ -x "/usr/sbin/hostapd" ]; then
 		mkdir -p /var/run/hostapd
+		chown network:network /var/run/hostapd
 		procd_open_instance hostapd
 		procd_set_param command /usr/sbin/hostapd -s -g /var/run/hostapd/global
 		procd_set_param respawn
+		[ -x /sbin/ujail -a -e /etc/capabilities/wpad.json ] && {
+			procd_add_jail netifd
+			procd_set_param capabilities /etc/capabilities/wpad.json
+			procd_set_param user network
+			procd_set_param group network
+			procd_set_param no_new_privs 1
+		}
 		procd_close_instance
 	fi
 
 	if [ -x "/usr/sbin/wpa_supplicant" ]; then
 		mkdir -p /var/run/wpa_supplicant
+		chown network:network /var/run/wpa_supplicant
 		procd_open_instance supplicant
 		procd_set_param command /usr/sbin/wpa_supplicant -n -s -g /var/run/wpa_supplicant/global
 		procd_set_param respawn
+		[ -x /sbin/ujail -a -e /etc/capabilities/wpad.json ] && {
+			procd_add_jail netifd
+			procd_set_param capabilities /etc/capabilities/wpad.json
+			procd_set_param user network
+			procd_set_param group network
+			procd_set_param no_new_privs 1
+		}
 		procd_close_instance
 	fi
 }
diff --git a/package/network/services/hostapd/files/wpad.json b/package/network/services/hostapd/files/wpad.json
new file mode 100644
index 0000000000..ae3edd4fea
--- /dev/null
+++ b/package/network/services/hostapd/files/wpad.json
@@ -0,0 +1,22 @@
+{
+	"bounding": [
+		"CAP_NET_RAW",
+		"CAP_NET_ADMIN"
+	],
+	"effective": [
+		"CAP_NET_RAW",
+		"CAP_NET_ADMIN"
+	],
+	"ambient": [
+		"CAP_NET_RAW",
+		"CAP_NET_ADMIN"
+	],
+	"permitted": [
+		"CAP_NET_RAW",
+		"CAP_NET_ADMIN"
+	],
+	"inheritable": [
+		"CAP_NET_RAW",
+		"CAP_NET_ADMIN"
+	]
+}
diff --git a/package/network/services/hostapd/files/wpad_acl.json b/package/network/services/hostapd/files/wpad_acl.json
new file mode 100644
index 0000000000..c77ccd8ea0
--- /dev/null
+++ b/package/network/services/hostapd/files/wpad_acl.json
@@ -0,0 +1,10 @@
+{
+	"user": "network",
+	"access": {
+		"service": {
+			"methods": [ "event" ]
+		}
+	},
+	"publish": [ "hostapd", "hostapd.*", "wpa_supplicant", "wpa_supplicant.*" ],
+	"send": [ "bss.*", "wps_credentials" ]
+}
diff --git a/package/network/services/hostapd/src/src/ap/ubus.c b/package/network/services/hostapd/src/src/ap/ubus.c
index 8546d2ce69..e59db00bd3 100644
--- a/package/network/services/hostapd/src/src/ap/ubus.c
+++ b/package/network/services/hostapd/src/src/ap/ubus.c
@@ -690,6 +690,21 @@ hostapd_config_remove(struct ubus_context *ctx, struct ubus_object *obj,
 	return UBUS_STATUS_OK;
 }
 
+static int
+hostapd_getpid(struct ubus_context *ctx, struct ubus_object *obj,
+	       struct ubus_request_data *req, const char *method,
+	       struct blob_attr *msg)
+{
+
+	blob_buf_init(&b, 0);
+
+	blobmsg_add_u32(&b, "pid", getpid());
+
+	ubus_send_reply(ctx, req, b.head);
+
+	return UBUS_STATUS_OK;
+}
+
 enum {
 	CSA_FREQ,
 	CSA_BCN_COUNT,
@@ -1363,6 +1378,7 @@ void hostapd_ubus_free_bss(struct hostapd_data *hapd)
 static const struct ubus_method daemon_methods[] = {
 	UBUS_METHOD("config_add", hostapd_config_add, config_add_policy),
 	UBUS_METHOD("config_remove", hostapd_config_remove, config_remove_policy),
+	UBUS_METHOD_NOARG("getpid", hostapd_getpid),
 };
 
 static struct ubus_object_type daemon_object_type =
diff --git a/package/network/services/hostapd/src/wpa_supplicant/ubus.c b/package/network/services/hostapd/src/wpa_supplicant/ubus.c
index 4bb92a7b66..f9fa1645d7 100644
--- a/package/network/services/hostapd/src/wpa_supplicant/ubus.c
+++ b/package/network/services/hostapd/src/wpa_supplicant/ubus.c
@@ -311,9 +311,25 @@ wpas_config_remove(struct ubus_context *ctx, struct ubus_object *obj,
 	return UBUS_STATUS_OK;
 }
 
+static int
+wpas_getpid(struct ubus_context *ctx, struct ubus_object *obj,
+	    struct ubus_request_data *req, const char *method,
+	    struct blob_attr *msg)
+{
+
+	blob_buf_init(&b, 0);
+
+	blobmsg_add_u32(&b, "pid", getpid());
+
+	ubus_send_reply(ctx, req, b.head);
+
+	return UBUS_STATUS_OK;
+}
+
 static const struct ubus_method wpas_daemon_methods[] = {
 	UBUS_METHOD("config_add", wpas_config_add, wpas_config_add_policy),
 	UBUS_METHOD("config_remove", wpas_config_remove, wpas_config_remove_policy),
+	UBUS_METHOD_NOARG("getpid", wpas_getpid),
 };
 
 static struct ubus_object_type wpas_daemon_object_type =
-- 
2.29.2




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