This patchset adds support for running 802.11 authentication mechanisms (e.g. 802.1X, 4-Way Handshake, etc) over NL80211 instead of putting them onto the network device. This has the advantage of fixing several long-standing race conditions that result from userspace operating on multiple transports in order to manage a 802.11 connection (e.g. NL80211 and wireless netdev, wlan0, etc). For example, userspace would sometimes see 4-Way handshake packets before NL80211 signaled that the connection has been established. Leading to ugly hacks or having the STA wait for retransmissions from the AP. This also provides a way to mitigate a particularly nasty race condition where the encryption key could be set prior to the 4-way handshake packet 4/4 being sent. This would result in the packet being sent encrypted and discarded by the peer. The mitigation strategy for this race is for userspace to explicitly tell the kernel that a particular EAPoL packet should not be encrypted. To make this possible this patchset introduces a new NL80211 command and several new attributes. A userspace that is capable of processing EAPoL packets over NL80211 includes a new NL80211_ATTR_CONTROL_PORT_OVER_NL80211 attribute in its NL80211_CMD_ASSOCIATE or NL80211_CMD_CONNECT requests being sent to the kernel. The previously added NL80211_ATTR_SOCKET_OWNER attribute must also be included. The latter is used by the kernel to send NL80211_CMD_CONTROL_PORT_FRAME notifications back to userspace via a netlink unicast. If the NL80211_ATTR_CONTROL_PORT_OVER_NL80211 attribute is not specified, then legacy behavior is kept and control port packets continue to flow over the network interface. If control port over nl80211 transport is requested, then control port packets are intercepted just prior to being handed to the network device and sent over netlink via the NL80211_CMD_CONTROL_PORT_FRAME notification. NL80211_ATTR_CONTROL_PORT_ETHERTYPE and NL80211_ATTR_MAC are included to specify the control port frame protocol and source address respectively. If the control port frame was received unencrypted then NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT flag is also included. NL80211_ATTR_FRAME attribute contains the raw control port frame with all transport layer headers stripped (e.g. this would be the raw EAPoL frame). Userspace can reply to control port frames either via legacy methods (by sending frames to the network device) or via NL80211_CMD_CONTROL_PORT_FRAME request. Userspace would included NL80211_ATTR_FRAME with the raw control port frame as well as NL80211_Attr_MAC and NL80211_ATTR_CONTROL_PORT_ETHERTYPE attributes to specify the destination address and protocol respectively. This allows Pre-Authentication (protocol 0x88c7) frames to be sent via this mechanism as well. Finally, NL80211_ATTR_CONTROL_PORT_NO_ENCRYPT flag can be included to tell the driver to send the frame unencrypted, e.g. for 4-Way handshake 4/4 frames. The proposed patchset has been tested in a mac80211_hwsim based environment with hostapd and iwd. ChangeLog v5 - Johannes' main comment was that we're not handling interface types other than STATION inside tx_control_port (patch 2). This patch was modified to support all interface types that seemed relevant. - Since tx_control_port relies on wdev->conn_owner_nlportid being set, SOCKET_OWNER support was added to JOIN_IBSS, JOIN_MESH and START_AP - SOCKET_OWNER auto-destruction logic was updated to support interface types other than STATION/P2P_CLIENT - Last patch was modified to support control_port_over_nl80211 for mac80211 based AP mode. It also copies necessary bits for AP_VLAN interfaces. This version has been tested on both STATION and AP mode interfaces with SOCKET_OWNER & CONTROL_PORT_OVER_NL80211 attributes provided to CMD_CONNECT and CMD_START_AP. TODO: - It is unclear to me how AP_VLAN and AP interfaces should synchronize on conn_owner_nlportid. This is required for tx_control_port to work. - JOIN_IBSS & JOIN_MESH don't seem to support control_port_ethertype or control_port_no_encrypt. Should struct cfg80211_crypto_settings parsed inside nl80211_crypto_settings be added to ibss_params or mesh_config/mesh_setup? v4 - Reordered the patches to make sure that: when CONTROL_PORT_OVER_NL80211 is provided by userspace, nl80211 checks that both EXT_FEATURE bit is set and the tx_control_port is present in rdev ops. - Fixed up various issues Johannes found in his review v3 - Added ETH_P_PREAUTH to if_ether.h - Moved NL80211 feature bit from wiphy features to ext features - Addressed various comments from Johannes v2 - Added WIPHY_FLAG_CONTROL_PORT_OVER_NL80211 flag. This is a capability flag used by the drivers, e.g. that the driver supports control port over nl80211 capability. This capability is now checked when CONTROL_PORT_OVER_NL80211 is requested. - mac80211 rx path now forwards Pre-Authentication frames over NL80211 as well, if requested. Tweaked the signature of cfg80211_rx_control_port. - TX path reworked completely. tx_control_port method has been introduced to cfg80211_ops. An implementation of tx_control_port for mac80211 was added. Denis Kenzior (9): nl80211: Add CMD_CONTROL_PORT_FRAME API nl80211: Implement TX of control port frames nl80211: Add CONTROL_PORT_OVER_NL80211 attribute cfg80211: Support all iftypes in autodisconnect_wk nl80211: Add SOCKET_OWNER support to JOIN_IBSS nl80211: Add SOCKET_OWNER support to JOIN_MESH nl80211: Add SOCKET_OWNER support to START_AP mac80211: Add support for tx_control_port mac80211: Send control port frames over nl80211 include/net/cfg80211.h | 34 +++++++++ include/uapi/linux/nl80211.h | 36 +++++++++- net/mac80211/cfg.c | 5 ++ net/mac80211/ieee80211_i.h | 4 ++ net/mac80211/iface.c | 2 + net/mac80211/main.c | 2 + net/mac80211/mlme.c | 2 + net/mac80211/rx.c | 33 +++++++-- net/mac80211/tx.c | 46 +++++++++++++ net/wireless/ap.c | 1 + net/wireless/ibss.c | 1 + net/wireless/mesh.c | 1 + net/wireless/nl80211.c | 161 ++++++++++++++++++++++++++++++++++++++++++- net/wireless/rdev-ops.h | 15 ++++ net/wireless/sme.c | 43 +++++++++--- net/wireless/trace.h | 47 +++++++++++++ 16 files changed, 414 insertions(+), 19 deletions(-) -- 2.13.5
