struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
- /* No way to verify the MIC if the hardware stripped it */
- if (status->flag & RX_FLAG_MMIC_STRIPPED)
+ /*
+ * it makes no sense to check for MIC errors on anything other
+ * than data frames.
+ */
+ if (!ieee80211_is_data_present(hdr->frame_control))
return RX_CONTINUE;
+ /*
+ * No way to verify the MIC if the hardware stripped it or
+ * the IV with the key index. In this case we have solely rely
+ * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
+ * MIC failure report.
+ */
+ if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
+ if (status->flag & RX_FLAG_MMIC_ERROR)
+ goto mic_fail;
+
+ if (!(status->flag & RX_FLAG_IV_STRIPPED))
+ goto update_iv;
+
+ return RX_CONTINUE;
+ }
+
+ /*
+ * Some hardware seems to generate Michael MIC failure reports; even
+ * though, the frame was not encrypted with TKIP and therefore has no
+ * MIC. Ignore the flag them to avoid triggering countermeasures.
+ */
if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
- !ieee80211_has_protected(hdr->frame_control) ||
- !ieee80211_is_data_present(hdr->frame_control))
+ !(status->flag & RX_FLAG_DECRYPTED))
return RX_CONTINUE;
+ if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
+ /*
+ * APs with pairwise keys should never receive Michael MIC
+ * errors for non-zero keyidx because these are reserved for
+ * group keys and only the AP is sending real multicast
+ * frames in the BSS. (
+ */
+ return RX_DROP_UNUSABLE;
+ }
+
+ if (status->flag & RX_FLAG_MMIC_ERROR)
+ goto mic_fail;
+
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (skb->len < hdrlen + MICHAEL_MIC_LEN)
return RX_DROP_UNUSABLE;
data = skb->data + hdrlen;
data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
-
key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
michael_mic(key, hdr, data, data_len, mic);
- if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) {
- if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
- return RX_DROP_UNUSABLE;
-
- mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
- (void *) skb->data, NULL,
- GFP_ATOMIC);
- return RX_DROP_UNUSABLE;
- }
+ if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
+ goto mic_fail;
/* remove Michael MIC from payload */
skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
+update_iv:
/* update IV in key information to be able to detect replays */
rx->key->u.tkip.rx[rx->queue].iv32 = rx->tkip_iv32;
rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
return RX_CONTINUE;
+
+mic_fail:
+ /*
+ * In some cases the key can be unset - e.g. a multicast packet, in
+ * a driver that supports HW encryption. Send up the key idx only if
+ * the key is set.
+ */
+ mac80211_ev_michael_mic_failure(rx->sdata,
+ rx->key ? rx->key->conf.keyidx : -1,
+ (void *) skb->data, NULL, GFP_ATOMIC);
+ return RX_DROP_UNUSABLE;
}