linux-kernel - [PATCH 4.19 58/93] mac80211: Reject malformed SSID elements

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20191027203303.292196375@linuxfoundation.org>
Date:   Sun, 27 Oct 2019 22:01:10 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        Nicolas Waisman <nico@...mle.com>,
        Will Deacon <will@...nel.org>,
        Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH 4.19 58/93] mac80211: Reject malformed SSID elements

From: Will Deacon <will@...nel.org>

commit 4152561f5da3fca92af7179dd538ea89e248f9d0 upstream.

Although this shouldn't occur in practice, it's a good idea to bounds
check the length field of the SSID element prior to using it for things
like allocations or memcpy operations.

Cc: <stable@...r.kernel.org>
Cc: Kees Cook <keescook@...omium.org>
Reported-by: Nicolas Waisman <nico@...mle.com>
Signed-off-by: Will Deacon <will@...nel.org>
Link: https://lore.kernel.org/r/20191004095132.15777-1-will@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 net/mac80211/mlme.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2554,7 +2554,8 @@ struct sk_buff *ieee80211_ap_probereq_ge
 
 	rcu_read_lock();
 	ssid = ieee80211_bss_get_ie(cbss, WLAN_EID_SSID);
-	if (WARN_ON_ONCE(ssid == NULL))
+	if (WARN_ONCE(!ssid || ssid[1] > IEEE80211_MAX_SSID_LEN,
+		      "invalid SSID element (len=%d)", ssid ? ssid[1] : -1))
 		ssid_len = 0;
 	else
 		ssid_len = ssid[1];
@@ -5039,7 +5040,7 @@ int ieee80211_mgd_assoc(struct ieee80211
 
 	rcu_read_lock();
 	ssidie = ieee80211_bss_get_ie(req->bss, WLAN_EID_SSID);
-	if (!ssidie) {
+	if (!ssidie || ssidie[1] > sizeof(assoc_data->ssid)) {
 		rcu_read_unlock();
 		kfree(assoc_data);
 		return -EINVAL;