From aebe9f4639b13a1f4e9a6b42cdd2e38c617b442d Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 28 Sep 2022 21:56:15 +0200
Subject: [PATCH] wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans()
Git-commit: aebe9f4639b13a1f4e9a6b42cdd2e38c617b442d
Patch-mainline: v6.1-rc1
References: CVE-2022-41674 bsc#1203770

In the copy code of the elements, we do the following calculation
to reach the end of the MBSSID element:

	/* copy the IEs after MBSSID */
	cpy_len = mbssid[1] + 2;

This looks fine, however, cpy_len is a u8, the same as mbssid[1],
so the addition of two can overflow. In this case the subsequent
memcpy() will overflow the allocated buffer, since it copies 256
bytes too much due to the way the allocation and memcpy() sizes
are calculated.

Fix this by using size_t for the cpy_len variable.

This fixes CVE-2022-41674.

Reported-by: Soenke Huster <shuster@seemoo.tu-darmstadt.de>
Tested-by: Soenke Huster <shuster@seemoo.tu-darmstadt.de>
Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 net/wireless/scan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 5382fc2003db..62f8c10412ad 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -2279,7 +2279,7 @@ 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);
 
-- 
2.35.3