From: Johannes Berg <johannes.berg@xxxxxxxxx>
Check that the SSID in beacons is correct, if it's not hidden
and beacon protection is enabled (otherwise there's no value).
If it doesn't match, disconnect.
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
net/mac80211/mlme.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ef3280fafbe9..df0978ce69de 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -6654,6 +6654,29 @@ ieee80211_mgd_check_cross_link_csa(struct ieee80211_sub_if_data *sdata,
}
}
+static bool ieee80211_mgd_ssid_mismatch(struct ieee80211_sub_if_data *sdata,
+ const struct ieee802_11_elems *elems)
+{
+ struct ieee80211_vif_cfg *cfg = &sdata->vif.cfg;
+ static u8 zero_ssid[IEEE80211_MAX_SSID_LEN];
+
+ if (!elems->ssid)
+ return false;
+
+ /* hidden SSID: zero length */
+ if (elems->ssid_len == 0)
+ return false;
+
+ if (elems->ssid_len != cfg->ssid_len)
+ return true;
+
+ /* hidden SSID: zeroed out */
+ if (memcmp(elems->ssid, zero_ssid, elems->ssid_len))
+ return false;
+
+ return memcmp(elems->ssid, cfg->ssid, cfg->ssid_len);
+}
+
static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
struct ieee80211_hdr *hdr, size_t len,
struct ieee80211_rx_status *rx_status)
@@ -6795,6 +6818,15 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
elems = ieee802_11_parse_elems_full(&parse_params);
if (!elems)
return;
+
+ if (rx_status->flag & RX_FLAG_DECRYPTED &&
+ ieee80211_mgd_ssid_mismatch(sdata, elems)) {
+ sdata_info(sdata, "SSID mismatch for AP %pM, disconnect\n",
+ sdata->vif.cfg.ap_addr);
+ __ieee80211_disconnect(sdata);
+ return;
+ }
+
ncrc = elems->crc;
if (ieee80211_hw_check(&local->hw, PS_NULLFUNC_STACK) &&
--
2.45.2
