From 24ca6289203266875c35d018ab01b872e302a6d6 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 4 Oct 2019 10:51:31 +0100 Subject: [PATCH] mac80211: Reject malformed SSID elements 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: Cc: Kees Cook Reported-by: Nicolas Waisman Signed-off-by: Will Deacon Link: https://lore.kernel.org/r/20191004095132.15777-1-will@kernel.org Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/mlme.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index b5c0624..5c9dcaf 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -2554,7 +2554,8 @@ struct sk_buff *ieee80211_ap_probereq_get(struct ieee80211_hw *hw, 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_sub_if_data *sdata, 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; -- 2.7.4