On Fri, Oct 04, 2019 at 10:51:31AM +0100, Will Deacon wrote: > 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: <[email protected]> > Cc: Johannes Berg <[email protected]> > Cc: Kees Cook <[email protected]> > Reported-by: Nicolas Waisman <[email protected]> > Signed-off-by: Will Deacon <[email protected]>
Reviewed-by: Kees Cook <[email protected]> -Kees > --- > 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 26a2f49208b6..54dd8849d1cc 100644 > --- a/net/mac80211/mlme.c > +++ b/net/mac80211/mlme.c > @@ -2633,7 +2633,8 @@ 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]; > @@ -5233,7 +5234,7 @@ 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; > -- > 2.23.0.581.g78d2f28ef7-goog > -- Kees Cook
