Merge tag 'mac80211-for-net-2021-04-08.2' of git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211

Johannes berg says:

====================
Various small fixes:
 * S1G beacon validation
 * potential leak in nl80211
 * fast-RX confusion with 4-addr mode
 * erroneous WARN_ON that userspace can trigger
 * wrong time units in virt_wifi
 * rfkill userspace API breakage
 * TXQ AC confusing that led to traffic stopped forever
 * connection monitoring time after/before confusion
 * netlink beacon head validation buffer overrun
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

9 files changed, 99 insertions, 30 deletions

diff --git a/drivers/net/wireless/virt_wifi.c b/drivers/net/wireless/virt_wifi.c
index c878097f0dda..1df959532c7d 100644
--- a/drivers/net/wireless/virt_wifi.c
+++ b/drivers/net/wireless/virt_wifi.c
@@ -12,6 +12,7 @@
 #include <net/cfg80211.h>
 #include <net/rtnetlink.h>
 #include <linux/etherdevice.h>
+#include <linux/math64.h>
 #include <linux/module.h>
 
 static struct wiphy *common_wiphy;
@@ -168,11 +169,11 @@ static void virt_wifi_scan_result(struct work_struct *work)
 			     scan_result.work);
 	struct wiphy *wiphy = priv_to_wiphy(priv);
 	struct cfg80211_scan_info scan_info = { .aborted = false };
+	u64 tsf = div_u64(ktime_get_boottime_ns(), 1000);
 
 	informed_bss = cfg80211_inform_bss(wiphy, &channel_5ghz,
 					   CFG80211_BSS_FTYPE_PRESP,
-					   fake_router_bssid,
-					   ktime_get_boottime_ns(),
+					   fake_router_bssid, tsf,
 					   WLAN_CAPABILITY_ESS, 0,
 					   (void *)&ssid, sizeof(ssid),
 					   DBM_TO_MBM(-50), GFP_KERNEL);
diff --git a/include/uapi/linux/rfkill.h b/include/uapi/linux/rfkill.h
index 03e8af87b364..9b77cfc42efa 100644
--- a/include/uapi/linux/rfkill.h
+++ b/include/uapi/linux/rfkill.h
@@ -86,34 +86,90 @@ enum rfkill_hard_block_reasons {
  * @op: operation code
  * @hard: hard state (0/1)
  * @soft: soft state (0/1)
+ *
+ * Structure used for userspace communication on /dev/rfkill,
+ * used for events from the kernel and control to the kernel.
+ */
+struct rfkill_event {
+	__u32 idx;
+	__u8  type;
+	__u8  op;
+	__u8  soft;
+	__u8  hard;
+} __attribute__((packed));
+
+/**
+ * struct rfkill_event_ext - events for userspace on /dev/rfkill
+ * @idx: index of dev rfkill
+ * @type: type of the rfkill struct
+ * @op: operation code
+ * @hard: hard state (0/1)
+ * @soft: soft state (0/1)
  * @hard_block_reasons: valid if hard is set. One or several reasons from
  *	&enum rfkill_hard_block_reasons.
  *
  * Structure used for userspace communication on /dev/rfkill,
  * used for events from the kernel and control to the kernel.
+ *
+ * See the extensibility docs below.
  */
-struct rfkill_event {
+struct rfkill_event_ext {
 	__u32 idx;
 	__u8  type;
 	__u8  op;
 	__u8  soft;
 	__u8  hard;
+
+	/*
+	 * older kernels will accept/send only up to this point,
+	 * and if extended further up to any chunk marked below
+	 */
+
 	__u8  hard_block_reasons;
 } __attribute__((packed));
 
-/*
- * We are planning to be backward and forward compatible with changes
- * to the event struct, by adding new, optional, members at the end.
- * When reading an event (whether the kernel from userspace or vice
- * versa) we need to accept anything that's at least as large as the
- * version 1 event size, but might be able to accept other sizes in
- * the future.
+/**
+ * DOC: Extensibility
+ *
+ * Originally, we had planned to allow backward and forward compatible
+ * changes by just adding fields at the end of the structure that are
+ * then not reported on older kernels on read(), and not written to by
+ * older kernels on write(), with the kernel reporting the size it did
+ * accept as the result.
+ *
+ * This would have allowed userspace to detect on read() and write()
+ * which kernel structure version it was dealing with, and if was just
+ * recompiled it would have gotten the new fields, but obviously not
+ * accessed them, but things should've continued to work.
+ *
+ * Unfortunately, while actually exercising this mechanism to add the
+ * hard block reasons field, we found that userspace (notably systemd)
+ * did all kinds of fun things not in line with this scheme:
+ *
+ * 1. treat the (expected) short writes as an error;
+ * 2. ask to read sizeof(struct rfkill_event) but then compare the
+ *    actual return value to RFKILL_EVENT_SIZE_V1 and treat any
+ *    mismatch as an error.
+ *
+ * As a consequence, just recompiling with a new struct version caused
+ * things to no longer work correctly on old and new kernels.
+ *
+ * Hence, we've rolled back &struct rfkill_event to the original version
+ * and added &struct rfkill_event_ext. This effectively reverts to the
+ * old behaviour for all userspace, unless it explicitly opts in to the
+ * rules outlined here by using the new &struct rfkill_event_ext.
+ *
+ * Userspace using &struct rfkill_event_ext must adhere to the following
+ * rules
  *
- * One exception is the kernel -- we already have two event sizes in
- * that we've made the 'hard' member optional since our only option
- * is to ignore it anyway.
+ * 1. accept short writes, optionally using them to detect that it's
+ *    running on an older kernel;
+ * 2. accept short reads, knowing that this means it's running on an
+ *    older kernel;
+ * 3. treat reads that are as long as requested as acceptable, not
+ *    checking against RFKILL_EVENT_SIZE_V1 or such.
  */
-#define RFKILL_EVENT_SIZE_V1	8
+#define RFKILL_EVENT_SIZE_V1	sizeof(struct rfkill_event)
 
 /* ioctl for turning off rfkill-input (if present) */
 #define RFKILL_IOC_MAGIC	'R'
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 68a0de02b561..860bc35383d5 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1788,8 +1788,10 @@ static int ieee80211_change_station(struct wiphy *wiphy,
 		}
 
 		if (sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
-		    sta->sdata->u.vlan.sta)
+		    sta->sdata->u.vlan.sta) {
+			ieee80211_clear_fast_rx(sta);
 			RCU_INIT_POINTER(sta->sdata->u.vlan.sta, NULL);
+		}
 
 		if (test_sta_flag(sta, WLAN_STA_AUTHORIZED))
 			ieee80211_vif_dec_num_mcast(sta->sdata);
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ce4e3855fec1..96f487fc0071 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -4707,7 +4707,10 @@ static void ieee80211_sta_conn_mon_timer(struct timer_list *t)
 		timeout = sta->rx_stats.last_rx;
 	timeout += IEEE80211_CONNECTION_IDLE_TIME;
 
-	if (time_is_before_jiffies(timeout)) {
+	/* If timeout is after now, then update timer to fire at
+	 * the later date, but do not actually probe at this time.
+	 */
+	if (time_is_after_jiffies(timeout)) {
 		mod_timer(&ifmgd->conn_mon_timer, round_jiffies_up(timeout));
 		return;
 	}
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 5d06de61047a..3b3bcefbf657 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -3573,7 +3573,7 @@ begin:
 	    test_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags))
 		goto out;
 
-	if (vif->txqs_stopped[ieee80211_ac_from_tid(txq->tid)]) {
+	if (vif->txqs_stopped[txq->ac]) {
 		set_bit(IEEE80211_TXQ_STOP_NETIF_TX, &txqi->flags);
 		goto out;
 	}
diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 68d6ef9e59fc..ac15a944573f 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -69,7 +69,7 @@ struct rfkill {
 
 struct rfkill_int_event {
 	struct list_head	list;
-	struct rfkill_event	ev;
+	struct rfkill_event_ext	ev;
 };
 
 struct rfkill_data {
@@ -253,7 +253,8 @@ static void rfkill_global_led_trigger_unregister(void)
 }
 #endif /* CONFIG_RFKILL_LEDS */
 
-static void rfkill_fill_event(struct rfkill_event *ev, struct rfkill *rfkill,
+static void rfkill_fill_event(struct rfkill_event_ext *ev,
+			      struct rfkill *rfkill,
 			      enum rfkill_operation op)
 {
 	unsigned long flags;
@@ -1237,7 +1238,7 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *pos)
 {
 	struct rfkill *rfkill;
-	struct rfkill_event ev;
+	struct rfkill_event_ext ev;
 	int ret;
 
 	/* we don't need the 'hard' variable but accept it */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 034af85f79d8..b1df42e4f1eb 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5,7 +5,7 @@
  * Copyright 2006-2010	Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
  * Copyright 2015-2017	Intel Deutschland GmbH
- * Copyright (C) 2018-2020 Intel Corporation
+ * Copyright (C) 2018-2021 Intel Corporation
  */
 
 #include <linux/if.h>
@@ -229,9 +229,13 @@ static int validate_beacon_head(const struct nlattr *attr,
 	unsigned int len = nla_len(attr);
 	const struct element *elem;
 	const struct ieee80211_mgmt *mgmt = (void *)data;
-	bool s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
 	unsigned int fixedlen, hdrlen;
+	bool s1g_bcn;
 
+	if (len < offsetofend(typeof(*mgmt), frame_control))
+		goto err;
+
+	s1g_bcn = ieee80211_is_s1g_beacon(mgmt->frame_control);
 	if (s1g_bcn) {
 		fixedlen = offsetof(struct ieee80211_ext,
 				    u.s1g_beacon.variable);
@@ -5485,7 +5489,7 @@ static int nl80211_start_ap(struct sk_buff *skb, struct genl_info *info)
 			rdev, info->attrs[NL80211_ATTR_UNSOL_BCAST_PROBE_RESP],
 			&params);
 		if (err)
-			return err;
+			goto out;
 	}
 
 	nl80211_calculate_ap_params(&params);
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 019952d4fc7d..758eb7d2a706 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -2352,14 +2352,16 @@ cfg80211_inform_single_bss_frame_data(struct wiphy *wiphy,
 		return NULL;
 
 	if (ext) {
-		struct ieee80211_s1g_bcn_compat_ie *compat;
-		u8 *ie;
+		const struct ieee80211_s1g_bcn_compat_ie *compat;
+		const struct element *elem;
 
-		ie = (void *)cfg80211_find_ie(WLAN_EID_S1G_BCN_COMPAT,
-					      variable, ielen);
-		if (!ie)
+		elem = cfg80211_find_elem(WLAN_EID_S1G_BCN_COMPAT,
+					  variable, ielen);
+		if (!elem)
+			return NULL;
+		if (elem->datalen < sizeof(*compat))
 			return NULL;
-		compat = (void *)(ie + 2);
+		compat = (void *)elem->data;
 		bssid = ext->u.s1g_beacon.sa;
 		capability = le16_to_cpu(compat->compat_info);
 		beacon_int = le16_to_cpu(compat->beacon_int);
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 07756ca5e3b5..08a70b4f090c 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -529,7 +529,7 @@ static int cfg80211_sme_connect(struct wireless_dev *wdev,
 		cfg80211_sme_free(wdev);
 	}
 
-	if (WARN_ON(wdev->conn))
+	if (wdev->conn)
 		return -EINPROGRESS;
 
 	wdev->conn = kzalloc(sizeof(*wdev->conn), GFP_KERNEL);