/* * Copyright 2002-2004, Instant802 Networks, Inc. * Copyright 2008, Jouni Malinen <j@w1.fi> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/netdevice.h> #include <linux/types.h> #include <linux/skbuff.h> #include <linux/compiler.h> #include <linux/ieee80211.h> #include <linux/gfp.h> #include <asm/unaligned.h> #include <net/mac80211.h> #include <crypto/aes.h> #include "ieee80211_i.h" #include "michael.h" #include "tkip.h" #include "aes_ccm.h" #include "aes_cmac.h" #include "wpa.h" ieee80211_tx_result ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx) { u8 *data, *key, *mic; size_t data_len; unsigned int hdrlen; struct ieee80211_hdr *hdr; struct sk_buff *skb = tx->skb; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); int tail; hdr = (struct ieee80211_hdr *)skb->data; if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP || skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control)) return TX_CONTINUE; hdrlen = ieee80211_hdrlen(hdr->frame_control); if (skb->len < hdrlen) return TX_DROP; data = skb->data + hdrlen; data_len = skb->len - hdrlen; if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) { /* Need to use software crypto for the test */ info->control.hw_key = NULL; } if (info->control.hw_key && (info->flags & IEEE80211_TX_CTL_DONTFRAG || tx->local->ops->set_frag_threshold) && !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) { /* hwaccel - with no need for SW-generated MMIC */ return TX_CONTINUE; } tail = MICHAEL_MIC_LEN; if (!info->control.hw_key) tail += TKIP_ICV_LEN; if (WARN_ON(skb_tailroom(skb) < tail || skb_headroom(skb) < TKIP_IV_LEN)) return TX_DROP; key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY]; mic = skb_put(skb, MICHAEL_MIC_LEN); michael_mic(key, hdr, data, data_len, mic); if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) mic[0]++; return TX_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) && rx->key) 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; if (skb_linearize(rx->skb)) return RX_DROP_UNUSABLE; hdr = (void *)skb->data; 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; } static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct ieee80211_key *key = tx->key; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); unsigned long flags; unsigned int hdrlen; int len, tail; u8 *pos; if (info->control.hw_key && !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { /* hwaccel - with no need for software-generated IV */ return 0; } hdrlen = ieee80211_hdrlen(hdr->frame_control); len = skb->len - hdrlen; if (info->control.hw_key) tail = 0; else tail = TKIP_ICV_LEN; if (WARN_ON(skb_tailroom(skb) < tail || skb_headroom(skb) < TKIP_IV_LEN)) return -1; pos = skb_push(skb, TKIP_IV_LEN); memmove(pos, pos + TKIP_IV_LEN, hdrlen); skb_set_network_header(skb, skb_network_offset(skb) + TKIP_IV_LEN); pos += hdrlen; /* the HW only needs room for the IV, but not the actual IV */ if (info->control.hw_key && (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) return 0; /* Increase IV for the frame */ spin_lock_irqsave(&key->u.tkip.txlock, flags); key->u.tkip.tx.iv16++; if (key->u.tkip.tx.iv16 == 0) key->u.tkip.tx.iv32++; pos = ieee80211_tkip_add_iv(pos, key); spin_unlock_irqrestore(&key->u.tkip.txlock, flags); /* hwaccel - with software IV */ if (info->control.hw_key) return 0; /* Add room for ICV */ skb_put(skb, TKIP_ICV_LEN); return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm, key, skb, pos, len); } ieee80211_tx_result ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx) { struct sk_buff *skb; ieee80211_tx_set_protected(tx); skb_queue_walk(&tx->skbs, skb) { if (tkip_encrypt_skb(tx, skb) < 0) return TX_DROP; } return TX_CONTINUE; } ieee80211_rx_result ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data; int hdrlen, res, hwaccel = 0; struct ieee80211_key *key = rx->key; struct sk_buff *skb = rx->skb; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); hdrlen = ieee80211_hdrlen(hdr->frame_control); if (!ieee80211_is_data(hdr->frame_control)) return RX_CONTINUE; if (!rx->sta || skb->len - hdrlen < 12) return RX_DROP_UNUSABLE; /* it may be possible to optimize this a bit more */ if (skb_linearize(rx->skb)) return RX_DROP_UNUSABLE; hdr = (void *)skb->data; /* * Let TKIP code verify IV, but skip decryption. * In the case where hardware checks the IV as well, * we don't even get here, see ieee80211_rx_h_decrypt() */ if (status->flag & RX_FLAG_DECRYPTED) hwaccel = 1; res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm, key, skb->data + hdrlen, skb->len - hdrlen, rx->sta->sta.addr, hdr->addr1, hwaccel, rx->security_idx, &rx->tkip_iv32, &rx->tkip_iv16); if (res != TKIP_DECRYPT_OK) return RX_DROP_UNUSABLE; /* Trim ICV */ skb_trim(skb, skb->len - TKIP_ICV_LEN); /* Remove IV */ memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen); skb_pull(skb, TKIP_IV_LEN); return RX_CONTINUE; } static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, int encrypted) { __le16 mask_fc; int a4_included, mgmt; u8 qos_tid; u8 *b_0, *aad; u16 data_len, len_a; unsigned int hdrlen; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; memset(scratch, 0, 6 * AES_BLOCK_SIZE); b_0 = scratch + 3 * AES_BLOCK_SIZE; aad = scratch + 4 * AES_BLOCK_SIZE; /* * Mask FC: zero subtype b4 b5 b6 (if not mgmt) * Retry, PwrMgt, MoreData; set Protected */ mgmt = ieee80211_is_mgmt(hdr->frame_control); mask_fc = hdr->frame_control; mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA); if (!mgmt) mask_fc &= ~cpu_to_le16(0x0070); mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED); hdrlen = ieee80211_hdrlen(hdr->frame_control); len_a = hdrlen - 2; a4_included = ieee80211_has_a4(hdr->frame_control); if (ieee80211_is_data_qos(hdr->frame_control)) qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK; else qos_tid = 0; data_len = skb->len - hdrlen - CCMP_HDR_LEN; if (encrypted) data_len -= CCMP_MIC_LEN; /* First block, b_0 */ b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */ /* Nonce: Nonce Flags | A2 | PN * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) */ b_0[1] = qos_tid | (mgmt << 4); memcpy(&b_0[2], hdr->addr2, ETH_ALEN); memcpy(&b_0[8], pn, CCMP_PN_LEN); /* l(m) */ put_unaligned_be16(data_len, &b_0[14]); /* AAD (extra authenticate-only data) / masked 802.11 header * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ put_unaligned_be16(len_a, &aad[0]); put_unaligned(mask_fc, (__le16 *)&aad[2]); memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); /* Mask Seq#, leave Frag# */ aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; aad[23] = 0; if (a4_included) { memcpy(&aad[24], hdr->addr4, ETH_ALEN); aad[30] = qos_tid; aad[31] = 0; } else { memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); aad[24] = qos_tid; } } static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id) { hdr[0] = pn[5]; hdr[1] = pn[4]; hdr[2] = 0; hdr[3] = 0x20 | (key_id << 6); hdr[4] = pn[3]; hdr[5] = pn[2]; hdr[6] = pn[1]; hdr[7] = pn[0]; } static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr) { pn[0] = hdr[7]; pn[1] = hdr[6]; pn[2] = hdr[5]; pn[3] = hdr[4]; pn[4] = hdr[1]; pn[5] = hdr[0]; } static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; struct ieee80211_key *key = tx->key; struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); int hdrlen, len, tail; u8 *pos; u8 pn[6]; u64 pn64; u8 scratch[6 * AES_BLOCK_SIZE]; if (info->control.hw_key && !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) { /* * hwaccel has no need for preallocated room for CCMP * header or MIC fields */ return 0; } hdrlen = ieee80211_hdrlen(hdr->frame_control); len = skb->len - hdrlen; if (info->control.hw_key) tail = 0; else tail = CCMP_MIC_LEN; if (WARN_ON(skb_tailroom(skb) < tail || skb_headroom(skb) < CCMP_HDR_LEN)) return -1; pos = skb_push(skb, CCMP_HDR_LEN); memmove(pos, pos + CCMP_HDR_LEN, hdrlen); skb_set_network_header(skb, skb_network_offset(skb) + CCMP_HDR_LEN); /* the HW only needs room for the IV, but not the actual IV */ if (info->control.hw_key && (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) return 0; hdr = (struct ieee80211_hdr *) pos; pos += hdrlen; pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn); pn[5] = pn64; pn[4] = pn64 >> 8; pn[3] = pn64 >> 16; pn[2] = pn64 >> 24; pn[1] = pn64 >> 32; pn[0] = pn64 >> 40; ccmp_pn2hdr(pos, pn, key->conf.keyidx); /* hwaccel - with software CCMP header */ if (info->control.hw_key) return 0; pos += CCMP_HDR_LEN; ccmp_special_blocks(skb, pn, scratch, 0); ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, pos, skb_put(skb, CCMP_MIC_LEN)); return 0; } ieee80211_tx_result ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx) { struct sk_buff *skb; ieee80211_tx_set_protected(tx); skb_queue_walk(&tx->skbs, skb) { if (ccmp_encrypt_skb(tx, skb) < 0) return TX_DROP; } return TX_CONTINUE; } ieee80211_rx_result ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data; int hdrlen; struct ieee80211_key *key = rx->key; struct sk_buff *skb = rx->skb; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); u8 pn[CCMP_PN_LEN]; int data_len; int queue; hdrlen = ieee80211_hdrlen(hdr->frame_control); if (!ieee80211_is_data(hdr->frame_control) && !ieee80211_is_robust_mgmt_frame(hdr)) return RX_CONTINUE; data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN; if (!rx->sta || data_len < 0) return RX_DROP_UNUSABLE; if (status->flag & RX_FLAG_DECRYPTED) { if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN)) return RX_DROP_UNUSABLE; } else { if (skb_linearize(rx->skb)) return RX_DROP_UNUSABLE; } ccmp_hdr2pn(pn, skb->data + hdrlen); queue = rx->security_idx; if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) { key->u.ccmp.replays++; return RX_DROP_UNUSABLE; } if (!(status->flag & RX_FLAG_DECRYPTED)) { u8 scratch[6 * AES_BLOCK_SIZE]; /* hardware didn't decrypt/verify MIC */ ccmp_special_blocks(skb, pn, scratch, 1); if (ieee80211_aes_ccm_decrypt( key->u.ccmp.tfm, scratch, skb->data + hdrlen + CCMP_HDR_LEN, data_len, skb->data + skb->len - CCMP_MIC_LEN, skb->data + hdrlen + CCMP_HDR_LEN)) return RX_DROP_UNUSABLE; } memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN); /* Remove CCMP header and MIC */ if (pskb_trim(skb, skb->len - CCMP_MIC_LEN)) return RX_DROP_UNUSABLE; memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen); skb_pull(skb, CCMP_HDR_LEN); return RX_CONTINUE; } static void bip_aad(struct sk_buff *skb, u8 *aad) { /* BIP AAD: FC(masked) || A1 || A2 || A3 */ /* FC type/subtype */ aad[0] = skb->data[0]; /* Mask FC Retry, PwrMgt, MoreData flags to zero */ aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6)); /* A1 || A2 || A3 */ memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN); } static inline void bip_ipn_set64(u8 *d, u64 pn) { *d++ = pn; *d++ = pn >> 8; *d++ = pn >> 16; *d++ = pn >> 24; *d++ = pn >> 32; *d = pn >> 40; } static inline void bip_ipn_swap(u8 *d, const u8 *s) { *d++ = s[5]; *d++ = s[4]; *d++ = s[3]; *d++ = s[2]; *d++ = s[1]; *d = s[0]; } ieee80211_tx_result ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx) { struct sk_buff *skb; struct ieee80211_tx_info *info; struct ieee80211_key *key = tx->key; struct ieee80211_mmie *mmie; u8 aad[20]; u64 pn64; if (WARN_ON(skb_queue_len(&tx->skbs) != 1)) return TX_DROP; skb = skb_peek(&tx->skbs); info = IEEE80211_SKB_CB(skb); if (info->control.hw_key) return TX_CONTINUE; if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie))) return TX_DROP; mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie)); mmie->element_id = WLAN_EID_MMIE; mmie->length = sizeof(*mmie) - 2; mmie->key_id = cpu_to_le16(key->conf.keyidx); /* PN = PN + 1 */ pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn); bip_ipn_set64(mmie->sequence_number, pn64); bip_aad(skb, aad); /* * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) */ ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, skb->data + 24, skb->len - 24, mmie->mic); return TX_CONTINUE; } ieee80211_rx_result ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx) { struct sk_buff *skb = rx->skb; struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); struct ieee80211_key *key = rx->key; struct ieee80211_mmie *mmie; u8 aad[20], mic[8], ipn[6]; struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; if (!ieee80211_is_mgmt(hdr->frame_control)) return RX_CONTINUE; /* management frames are already linear */ if (skb->len < 24 + sizeof(*mmie)) return RX_DROP_UNUSABLE; mmie = (struct ieee80211_mmie *) (skb->data + skb->len - sizeof(*mmie)); if (mmie->element_id != WLAN_EID_MMIE || mmie->length != sizeof(*mmie) - 2) return RX_DROP_UNUSABLE; /* Invalid MMIE */ bip_ipn_swap(ipn, mmie->sequence_number); if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) { key->u.aes_cmac.replays++; return RX_DROP_UNUSABLE; } if (!(status->flag & RX_FLAG_DECRYPTED)) { /* hardware didn't decrypt/verify MIC */ bip_aad(skb, aad); ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad, skb->data + 24, skb->len - 24, mic); if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) { key->u.aes_cmac.icverrors++; return RX_DROP_UNUSABLE; } } memcpy(key->u.aes_cmac.rx_pn, ipn, 6); /* Remove MMIE */ skb_trim(skb, skb->len - sizeof(*mmie)); return RX_CONTINUE; } ieee80211_tx_result ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx) { struct sk_buff *skb; struct ieee80211_tx_info *info = NULL; skb_queue_walk(&tx->skbs, skb) { info = IEEE80211_SKB_CB(skb); /* handle hw-only algorithm */ if (!info->control.hw_key) return TX_DROP; } ieee80211_tx_set_protected(tx); return TX_CONTINUE; }