wifi: cfg80211: fix u8 overflow in cfg80211_update_notlisted_nontrans()

commit aebe9f4639 upstream.

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: 0b8fb8235b ("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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Berg 2022-09-28 21:56:15 +02:00 committed by Greg Kroah-Hartman
parent 398e30b670
commit 9a8ef20305

View file

@ -2238,7 +2238,7 @@ 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);