Merge tag 'wireless-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless

Johannes Berg says:

====================
More wireless fixes for 6.1

This has only the fixes for the scan parsing issues.

* tag 'wireless-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/wireless/wireless:
  wifi: cfg80211: update hidden BSSes to avoid WARN_ON
  wifi: mac80211: fix crash in beacon protection for P2P-device
  wifi: mac80211_hwsim: avoid mac80211 warning on bad rate
  wifi: cfg80211: avoid nontransmitted BSS list corruption
  wifi: cfg80211: fix BSS refcounting bugs
  wifi: cfg80211: ensure length byte is present before access
  wifi: mac80211: fix MBSSID parsing use-after-free
  wifi: cfg80211/mac80211: reject bad MBSSID elements
  wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans()
====================

Link: https://lore.kernel.org/r/20221013100522.46346-1-johannes@sipsolutions.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

4 files changed, 82 insertions, 47 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4e1d4c339f2d..a842f2e1c230 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1709,6 +1709,14 @@ struct ieee802_11_elems {
 
 	/* whether a parse error occurred while retrieving these elements */
 	bool parse_error;
+
+	/*
+	 * scratch buffer that can be used for various element parsing related
+	 * tasks, e.g., element de-fragmentation etc.
+	 */
+	size_t scratch_len;
+	u8 *scratch_pos;
+	u8 scratch[];
 };
 
 static inline struct ieee80211_local *hw_to_local(
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 589521717c35..f99416d2e144 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1978,10 +1978,11 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 
 		if (mmie_keyidx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS ||
 		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS +
-		    NUM_DEFAULT_BEACON_KEYS) {
-			cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
-						     skb->data,
-						     skb->len);
+				   NUM_DEFAULT_BEACON_KEYS) {
+			if (rx->sdata->dev)
+				cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
+							     skb->data,
+							     skb->len);
 			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
 		}
 
@@ -2131,7 +2132,8 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 	/* either the frame has been decrypted or will be dropped */
 	status->flag |= RX_FLAG_DECRYPTED;
 
-	if (unlikely(ieee80211_is_beacon(fc) && result == RX_DROP_UNUSABLE))
+	if (unlikely(ieee80211_is_beacon(fc) && result == RX_DROP_UNUSABLE &&
+		     rx->sdata->dev))
 		cfg80211_rx_unprot_mlme_mgmt(rx->sdata->dev,
 					     skb->data, skb->len);
 
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 1e929b82deef..b512cb37aafb 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1445,6 +1445,8 @@ static size_t ieee802_11_find_bssid_profile(const u8 *start, size_t len,
 	for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, start, len) {
 		if (elem->datalen < 2)
 			continue;
+		if (elem->data[0] < 1 || elem->data[0] > 8)
+			continue;
 
 		for_each_element(sub, elem->data + 1, elem->datalen - 1) {
 			u8 new_bssid[ETH_ALEN];
@@ -1504,24 +1506,26 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 	const struct element *non_inherit = NULL;
 	u8 *nontransmitted_profile;
 	int nontransmitted_profile_len = 0;
+	size_t scratch_len = params->len;
 
-	elems = kzalloc(sizeof(*elems), GFP_ATOMIC);
+	elems = kzalloc(sizeof(*elems) + scratch_len, GFP_ATOMIC);
 	if (!elems)
 		return NULL;
 	elems->ie_start = params->start;
 	elems->total_len = params->len;
-
-	nontransmitted_profile = kmalloc(params->len, GFP_ATOMIC);
-	if (nontransmitted_profile) {
-		nontransmitted_profile_len =
-			ieee802_11_find_bssid_profile(params->start, params->len,
-						      elems, params->bss,
-						      nontransmitted_profile);
-		non_inherit =
-			cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
-					       nontransmitted_profile,
-					       nontransmitted_profile_len);
-	}
+	elems->scratch_len = scratch_len;
+	elems->scratch_pos = elems->scratch;
+
+	nontransmitted_profile = elems->scratch_pos;
+	nontransmitted_profile_len =
+		ieee802_11_find_bssid_profile(params->start, params->len,
+					      elems, params->bss,
+					      nontransmitted_profile);
+	elems->scratch_pos += nontransmitted_profile_len;
+	elems->scratch_len -= nontransmitted_profile_len;
+	non_inherit = cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE,
+					     nontransmitted_profile,
+					     nontransmitted_profile_len);
 
 	elems->crc = _ieee802_11_parse_elems_full(params, elems, non_inherit);
 
@@ -1555,8 +1559,6 @@ ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params)
 	    offsetofend(struct ieee80211_bssid_index, dtim_count))
 		elems->dtim_count = elems->bssid_index->dtim_count;
 
-	kfree(nontransmitted_profile);
-
 	return elems;
 }
 
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 5382fc2003db..806a5f1330ff 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -143,18 +143,12 @@ static inline void bss_ref_get(struct cfg80211_registered_device *rdev,
 	lockdep_assert_held(&rdev->bss_lock);
 
 	bss->refcount++;
-	if (bss->pub.hidden_beacon_bss) {
-		bss = container_of(bss->pub.hidden_beacon_bss,
-				   struct cfg80211_internal_bss,
-				   pub);
-		bss->refcount++;
-	}
-	if (bss->pub.transmitted_bss) {
-		bss = container_of(bss->pub.transmitted_bss,
-				   struct cfg80211_internal_bss,
-				   pub);
-		bss->refcount++;
-	}
+
+	if (bss->pub.hidden_beacon_bss)
+		bss_from_pub(bss->pub.hidden_beacon_bss)->refcount++;
+
+	if (bss->pub.transmitted_bss)
+		bss_from_pub(bss->pub.transmitted_bss)->refcount++;
 }
 
 static inline void bss_ref_put(struct cfg80211_registered_device *rdev,
@@ -304,7 +298,8 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 	tmp_old = cfg80211_find_ie(WLAN_EID_SSID, ie, ielen);
 	tmp_old = (tmp_old) ? tmp_old + tmp_old[1] + 2 : ie;
 
-	while (tmp_old + tmp_old[1] + 2 - ie <= ielen) {
+	while (tmp_old + 2 - ie <= ielen &&
+	       tmp_old + tmp_old[1] + 2 - ie <= ielen) {
 		if (tmp_old[0] == 0) {
 			tmp_old++;
 			continue;
@@ -364,7 +359,8 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 	 * copied to new ie, skip ssid, capability, bssid-index ie
 	 */
 	tmp_new = sub_copy;
-	while (tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {
+	while (tmp_new + 2 - sub_copy <= subie_len &&
+	       tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {
 		if (!(tmp_new[0] == WLAN_EID_NON_TX_BSSID_CAP ||
 		      tmp_new[0] == WLAN_EID_SSID)) {
 			memcpy(pos, tmp_new, tmp_new[1] + 2);
@@ -427,6 +423,15 @@ cfg80211_add_nontrans_list(struct cfg80211_bss *trans_bss,
 
 	rcu_read_unlock();
 
+	/*
+	 * This is a bit weird - it's not on the list, but already on another
+	 * one! The only way that could happen is if there's some BSSID/SSID
+	 * shared by multiple APs in their multi-BSSID profiles, potentially
+	 * with hidden SSID mixed in ... ignore it.
+	 */
+	if (!list_empty(&nontrans_bss->nontrans_list))
+		return -EINVAL;
+
 	/* add to the list */
 	list_add_tail(&nontrans_bss->nontrans_list, &trans_bss->nontrans_list);
 	return 0;
@@ -1602,6 +1607,23 @@ struct cfg80211_non_tx_bss {
 	u8 bssid_index;
 };
 
+static void cfg80211_update_hidden_bsses(struct cfg80211_internal_bss *known,
+					 const struct cfg80211_bss_ies *new_ies,
+					 const struct cfg80211_bss_ies *old_ies)
+{
+	struct cfg80211_internal_bss *bss;
+
+	/* Assign beacon IEs to all sub entries */
+	list_for_each_entry(bss, &known->hidden_list, hidden_list) {
+		const struct cfg80211_bss_ies *ies;
+
+		ies = rcu_access_pointer(bss->pub.beacon_ies);
+		WARN_ON(ies != old_ies);
+
+		rcu_assign_pointer(bss->pub.beacon_ies, new_ies);
+	}
+}
+
 static bool
 cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
 			  struct cfg80211_internal_bss *known,
@@ -1625,7 +1647,6 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
 			kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
 	} else if (rcu_access_pointer(new->pub.beacon_ies)) {
 		const struct cfg80211_bss_ies *old;
-		struct cfg80211_internal_bss *bss;
 
 		if (known->pub.hidden_beacon_bss &&
 		    !list_empty(&known->hidden_list)) {
@@ -1653,16 +1674,7 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
 		if (old == rcu_access_pointer(known->pub.ies))
 			rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies);
 
-		/* Assign beacon IEs to all sub entries */
-		list_for_each_entry(bss, &known->hidden_list, hidden_list) {
-			const struct cfg80211_bss_ies *ies;
-
-			ies = rcu_access_pointer(bss->pub.beacon_ies);
-			WARN_ON(ies != old);
-
-			rcu_assign_pointer(bss->pub.beacon_ies,
-					   new->pub.beacon_ies);
-		}
+		cfg80211_update_hidden_bsses(known, new->pub.beacon_ies, old);
 
 		if (old)
 			kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
@@ -1739,6 +1751,8 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
 		new->refcount = 1;
 		INIT_LIST_HEAD(&new->hidden_list);
 		INIT_LIST_HEAD(&new->pub.nontrans_list);
+		/* we'll set this later if it was non-NULL */
+		new->pub.transmitted_bss = NULL;
 
 		if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
 			hidden = rb_find_bss(rdev, tmp, BSS_CMP_HIDE_ZLEN);
@@ -2021,10 +2035,15 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy,
 		spin_lock_bh(&rdev->bss_lock);
 		if (cfg80211_add_nontrans_list(non_tx_data->tx_bss,
 					       &res->pub)) {
-			if (__cfg80211_unlink_bss(rdev, res))
+			if (__cfg80211_unlink_bss(rdev, res)) {
 				rdev->bss_generation++;
+				res = NULL;
+			}
 		}
 		spin_unlock_bh(&rdev->bss_lock);
+
+		if (!res)
+			return NULL;
 	}
 
 	trace_cfg80211_return_bss(&res->pub);
@@ -2143,6 +2162,8 @@ static void cfg80211_parse_mbssid_data(struct wiphy *wiphy,
 	for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, ie, ielen) {
 		if (elem->datalen < 4)
 			continue;
+		if (elem->data[0] < 1 || (int)elem->data[0] > 8)
+			continue;
 		for_each_element(sub, elem->data + 1, elem->datalen - 1) {
 			u8 profile_len;
 
@@ -2279,7 +2300,7 @@ cfg80211_update_notlisted_nontrans(struct wiphy *wiphy,
 	size_t new_ie_len;
 	struct cfg80211_bss_ies *new_ies;
 	const struct cfg80211_bss_ies *old;
-	u8 cpy_len;
+	size_t cpy_len;
 
 	lockdep_assert_held(&wiphy_to_rdev(wiphy)->bss_lock);
 
@@ -2346,6 +2367,8 @@ cfg80211_update_notlisted_nontrans(struct wiphy *wiphy,
 	} else {
 		old = rcu_access_pointer(nontrans_bss->beacon_ies);
 		rcu_assign_pointer(nontrans_bss->beacon_ies, new_ies);
+		cfg80211_update_hidden_bsses(bss_from_pub(nontrans_bss),
+					     new_ies, old);
 		rcu_assign_pointer(nontrans_bss->ies, new_ies);
 		if (old)
 			kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);