From: Johannes Berg Date: Wed, 28 Sep 2022 19:56:15 +0000 (+0200) Subject: wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=aebe9f4639b13a1f4e9a6b42cdd2e38c617b442d;p=linux.git wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans() 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 Tested-by: Soenke Huster Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in scanning") Reviewed-by: Kees Cook Signed-off-by: Johannes Berg --- diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 5382fc2003db4..62f8c10412ad3 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);