From 09dd08f167812a5fdb516fc98f14dbb43221432f Mon Sep 17 00:00:00 2001 From: "Bjoern A. Zeeb" Date: Wed, 6 Oct 2021 18:09:39 +0000 Subject: [PATCH] net80211: correct length check in ieee80211_ies_expand() In ieee80211_ies_expand() we are looping over Elements (also known as Information Elements or IEs). The comment suggests that we assume well-formedness of the IEs themselves. Checking the buffer length being least 2 (1 byte Element ID and 1 byte Length fields) rather than just 1 before accessing ie[1] is still good practise and can prevent and out-of-bounds read in case the input is not behaving according to the comment. Reported by: (coypu sdf.org) admbugs: 857 MFC after: 3 days Reviewed by: adrian, markj Differential Revision: https://reviews.freebsd.org/D32340 --- sys/net80211/ieee80211_node.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/net80211/ieee80211_node.c b/sys/net80211/ieee80211_node.c index d71503d2817..95bed7821d1 100644 --- a/sys/net80211/ieee80211_node.c +++ b/sys/net80211/ieee80211_node.c @@ -1133,7 +1133,7 @@ ieee80211_ies_expand(struct ieee80211_ies *ies) ie = ies->data; ielen = ies->len; - while (ielen > 0) { + while (ielen > 1) { switch (ie[0]) { case IEEE80211_ELEMID_VENDOR: if (iswpaoui(ie)) -- 2.45.0