FAILED: patch "[PATCH] nl80211: correctly check NL80211_ATTR_REG_ALPHA2 size" failed to apply to 4.19-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.19-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 <stable@vger.kernel.org>.

thanks,

greg k-h

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

From 6624bb34b4eb19f715db9908cca00122748765d7 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
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).

Cc: stable@vger.kernel.org
Reported-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220411114201.fd4a31f06541.Ie7ff4be2cf348d8cc28ed0d626fc54becf7ea799@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index ee1c2b6b6971..21e808fcb676 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -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 },