ieee80211_rx_result ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) { u8 *data, *key = NULL, key_offset; size_t data_len; unsigned int hdrlen; u8 mic[MICHAEL_MIC_LEN]; struct sk_buff *skb = rx->skb; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; int authenticator = 1, wpa_test = 0; /* No way to verify the MIC if the hardware stripped it */ if (status->flag & RX_FLAG_MMIC_STRIPPED) return RX_CONTINUE; if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || !ieee80211_has_protected(hdr->frame_control) || !ieee80211_is_data_present(hdr->frame_control)) return RX_CONTINUE; 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; #if 0 authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */ #else authenticator = 1; #endif key_offset = authenticator ? NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY : NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY; key = &rx->key->conf.key[key_offset]; michael_mic(key, hdr, data, data_len, mic); if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) { 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; } /* remove Michael MIC from payload */ skb_trim(skb, skb->len - MICHAEL_MIC_LEN); /* 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; }
ieee80211_rx_result ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx) { u8 *data, *key = NULL; size_t data_len; unsigned int hdrlen; u8 mic[MICHAEL_MIC_LEN]; struct sk_buff *skb = rx->skb; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; /* * 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 || !(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) 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->security_idx].iv32 = rx->tkip_iv32; rx->key->u.tkip.rx[rx->security_idx].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; }