cfg80211: support 4-way handshake offloading for WPA/WPA2-PSK

Let drivers advertise support for station-mode 4-way handshake
offloading with a new NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK flag.

Extend use of NL80211_ATTR_PMK attribute indicating it might be passed
as part of NL80211_CMD_CONNECT command, and contain the PSK (which is
the PMK, hence the name.)

The driver/device is assumed to handle the 4-way handshake by
itself in this case (including key derivations, etc.), instead
of relying on the supplicant.

This patch is somewhat based on this one (by Vladimir Kondratiev):
https://patchwork.kernel.org/patch/1309561/.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
[arend.vanspriel@broadcom.com rebase dealing with existing ATTR_PMK]
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
[reword NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK docs to indicate
that this offload might be required]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 6903335..e97ca3a 100644 (file)
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -2401,6 +2401,7 @@ enum ieee80211_sa_query_action {
 #define WLAN_MAX_KEY_LEN               32
 
 #define WLAN_PMKID_LEN                 16
+#define WLAN_PMK_LEN                   32
 
 #define WLAN_OUI_WFA                   0x506f9a
 #define WLAN_OUI_TYPE_WFA_P2P          9

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index fa25fbb..1b288ba 100644 (file)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -649,6 +649,7 @@ struct survey_info {
  * @wep_keys: static WEP keys, if not NULL points to an array of
  *     CFG80211_MAX_WEP_KEYS WEP keys
  * @wep_tx_key: key index (0..3) of the default TX static WEP key
+ * @psk: PSK (for devices supporting 4-way-handshake offload)
  */
 struct cfg80211_crypto_settings {
        u32 wpa_versions;
@@ -662,6 +663,7 @@ struct cfg80211_crypto_settings {
        bool control_port_no_encrypt;
        struct key_params *wep_keys;
        int wep_tx_key;
+       const u8 *psk;
 };
 
 /**

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index b8c44b9..f1f7da2 100644 (file)
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -173,6 +173,18 @@
  */
 
 /**
+ * DOC: WPA/WPA2 EAPOL handshake offload
+ *
+ * By setting @NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK flag drivers
+ * can indicate they support offloading EAPOL handshakes for WPA/WPA2
+ * preshared key authentication. In %NL80211_CMD_CONNECT the preshared
+ * key should be specified using %NL80211_ATTR_PMK. Drivers supporting
+ * this offload may reject the %NL80211_CMD_CONNECT when no preshared
+ * key material is provided, for example when that driver does not
+ * support setting the temporal keys through %CMD_NEW_KEY.
+ */
+
+/**
  * DOC: FILS shared key authentication offload
  *
  * FILS shared key authentication offload can be advertized by drivers by
@@ -2080,8 +2092,10 @@ enum nl80211_commands {
  *     identifying the scope of PMKSAs. This is used with
  *     @NL80211_CMD_SET_PMKSA and @NL80211_CMD_DEL_PMKSA.
  *
- * @NL80211_ATTR_PMK: PMK for the PMKSA identified by %NL80211_ATTR_PMKID.
- *     This is used with @NL80211_CMD_SET_PMKSA.
+ * @NL80211_ATTR_PMK: attribute for passing PMK key material. Used with
+ *     %NL80211_CMD_SET_PMKSA for the PMKSA identified by %NL80211_ATTR_PMKID.
+ *     For %NL80211_CMD_CONNECT it is used to provide PSK for offloading 4-way
+ *     handshake for WPA/WPA2-PSK networks.
  *
  * @NL80211_ATTR_SCHED_SCAN_MULTI: flag attribute which user-space shall use to
  *     indicate that it supports multiple active scheduled scan requests.
@@ -4852,6 +4866,9 @@ enum nl80211_feature_flags {
  *     RSSI threshold values to monitor rather than exactly one threshold.
  * @NL80211_EXT_FEATURE_FILS_SK_OFFLOAD: Driver SME supports FILS shared key
  *     authentication with %NL80211_CMD_CONNECT.
+ * @NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK: Device wants to do 4-way
+ *     handshake with PSK in station mode (PSK is passed as part of the connect
+ *     and associate commands), doing it in the host might not be supported.
  *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
@@ -4872,6 +4889,7 @@ enum nl80211_ext_feature_index {
        NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI,
        NL80211_EXT_FEATURE_CQM_RSSI_LIST,
        NL80211_EXT_FEATURE_FILS_SK_OFFLOAD,
+       NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK,
 
        /* add new features before the definition below */
        NUM_NL80211_EXT_FEATURES,

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 9eb5919..2c6863a 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -8168,6 +8168,15 @@ static int nl80211_crypto_settings(struct cfg80211_registered_device *rdev,
                memcpy(settings->akm_suites, data, len);
        }
 
+       if (info->attrs[NL80211_ATTR_PMK]) {
+               if (nla_len(info->attrs[NL80211_ATTR_PMK]) != WLAN_PMK_LEN)
+                       return -EINVAL;
+               if (!wiphy_ext_feature_isset(&rdev->wiphy,
+                                            NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_PSK))
+                       return -EINVAL;
+               settings->psk = nla_data(info->attrs[NL80211_ATTR_PMK]);
+       }
+
        return 0;
 }