From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	syzbot+cc867e537e4bd36f69bb@syzkaller.appspotmail.com,
	Deepanshu Kartikey <kartikey406@gmail.com>,
	Johannes Berg <johannes.berg@intel.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 0448/1102] wifi: cfg80211: validate IEs in cfg80211_wext_siwgenie()
Date: Thu, 17 Sep 2026 16:06:31 +0100
Message-ID: <20260917151550.929813279@linuxfoundation.org>
In-Reply-To: <20260917151539.408551884@linuxfoundation.org>
References: <20260917151539.408551884@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Deepanshu Kartikey <kartikey406@gmail.com>

[ Upstream commit a2f5286ca4f304d3fd469f01b96b518608912a5c ]

The KASAN allocation trace shows that a malformed IE buffer is
stored via SIOCSIWGENIE (cfg80211_wext_siwgenie()) without any
validation. The crash trace shows that a subsequent SIOCSIWESSID
triggers a connection attempt which calls cfg80211_sme_get_conn_ies()
to process the stored IE buffer, causing:

 - An out-of-bounds read in skip_ie() which reads ies[pos+1]
   (the length byte) past the end of the 1-byte buffer.

 - An integer underflow in the memcpy size argument when offs
   returned by ieee80211_ie_split() exceeds ies_len, causing
   unsigned subtraction to wrap to SIZE_MAX and triggering a
   fortify panic.

Fix this by validating the IE buffer in cfg80211_wext_siwgenie()
before storing it.

Reported-by: syzbot+cc867e537e4bd36f69bb@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cc867e537e4bd36f69bb
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Link: https://patch.msgid.link/20260725142028.32560-1-kartikey406@gmail.com
[drop unnecessary ie_len check, update commit message]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/wireless/wext-sme.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index 573b6b15a446e..b5914f3658db4 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -319,6 +319,15 @@ int cfg80211_wext_siwgenie(struct net_device *dev,
 		return 0;
 
 	if (ie_len) {
+		const struct element *elem;
+
+		for_each_element(elem, extra, ie_len) {
+			/* nothing */
+		}
+
+		if (!for_each_element_completed(elem, extra, ie_len))
+			return -EINVAL;
+
 		ie = kmemdup(extra, ie_len, GFP_KERNEL);
 		if (!ie)
 			return -ENOMEM;
-- 
2.53.0