FAILED: patch "[PATCH] nl80211: correctly check NL80211_ATTR_REG_ALPHA2 size" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6624bb34b4eb19f715db9908cca00122748765d7 Mon Sep 17 00:00:00 2001
From: Johannes Berg <[email protected]>
Date: Mon, 11 Apr 2022 11:42:03 +0200
Subject: [PATCH] nl80211: correctly check NL80211_ATTR_REG_ALPHA2 size

We need this to be at least two bytes, so we can access alpha2[0] and alpha2[1]. It may be three in case some userspace used NUL-termination since it was NLA_STRING (and we also push it out with NUL-termination).

index ee1c2b6b6971..21e808fcb676 100644
@@ -528,7 +528,8 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 				   .len = IEEE80211_MAX_MESH_ID_LEN },
 	[NL80211_ATTR_MPATH_NEXT_HOP] = NLA_POLICY_ETH_ADDR_COMPAT,
 
-	[NL80211_ATTR_REG_ALPHA2] = { .type = NLA_STRING, .len = 2 },
+	/* allow 3 for NUL-termination, we used to declare this NLA_STRING */
+	[NL80211_ATTR_REG_ALPHA2] = NLA_POLICY_RANGE(NLA_BINARY, 2, 3),
 	[NL80211_ATTR_REG_RULES] = { .type = NLA_NESTED },
 
 	[NL80211_ATTR_BSS_CTS_PROT] = { .type = NLA_U8 },