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wifi: mac80211: check SSID in beacon

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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@intel.com>
Link: https://patch.msgid.link/20240612143809.8b24a3d26a3d.I3e3ef31dbd2ec606be74d502a9d00dd9514c6885@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg 2024-06-12 14:38:10 +02:00
parent 0b2d9d9aec
commit 9cc88678db
1 changed files with 32 additions and 0 deletions
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32
net/mac80211/mlme.c
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@ -6667,6 +6667,29 @@ handle:
}
}
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)
@ -6808,6 +6831,15 @@ 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) &&