diff options
| -rw-r--r-- | include/linux/ieee80211.h | 10 | ||||
| -rw-r--r-- | net/mac80211/Makefile | 1 | ||||
| -rw-r--r-- | net/mac80211/aes_cmac.c | 135 | ||||
| -rw-r--r-- | net/mac80211/aes_cmac.h | 19 | ||||
| -rw-r--r-- | net/mac80211/ieee80211_i.h | 2 | ||||
| -rw-r--r-- | net/mac80211/key.h | 10 | ||||
| -rw-r--r-- | net/mac80211/wpa.c | 125 | ||||
| -rw-r--r-- | net/mac80211/wpa.h | 5 |
8 files changed, 306 insertions, 1 deletions
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index d516589..cceb9e8 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -655,6 +655,15 @@ struct ieee80211_mgmt { #define IEEE80211_MIN_ACTION_SIZE offsetof(struct ieee80211_mgmt, u.action.u) +/* Management MIC information element (IEEE 802.11w) */ +struct ieee80211_mmie { + u8 element_id; + u8 length; + __le16 key_id; + u8 sequence_number[6]; + u8 mic[8]; +} __attribute__ ((packed)); + /* Control frames */ struct ieee80211_rts { __le16 frame_control; @@ -1018,6 +1027,7 @@ enum ieee80211_eid { WLAN_EID_HT_INFORMATION = 61, /* 802.11i */ WLAN_EID_RSN = 48, + WLAN_EID_MMIE = 76 /* 802.11w */, WLAN_EID_WPA = 221, WLAN_EID_GENERIC = 221, WLAN_EID_VENDOR_SPECIFIC = 221, diff --git a/net/mac80211/Makefile b/net/mac80211/Makefile index 7d4971a..5c6fadf 100644 --- a/net/mac80211/Makefile +++ b/net/mac80211/Makefile @@ -15,6 +15,7 @@ mac80211-y := \ michael.o \ tkip.o \ aes_ccm.o \ + aes_cmac.o \ cfg.o \ rx.o \ spectmgmt.o \ diff --git a/net/mac80211/aes_cmac.c b/net/mac80211/aes_cmac.c new file mode 100644 index 0000000..3d097b3 --- /dev/null +++ b/net/mac80211/aes_cmac.c @@ -0,0 +1,135 @@ +/* + * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP + * 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/kernel.h> +#include <linux/types.h> +#include <linux/crypto.h> +#include <linux/err.h> + +#include <net/mac80211.h> +#include "key.h" +#include "aes_cmac.h" + +#define AES_BLOCK_SIZE 16 +#define AES_CMAC_KEY_LEN 16 +#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */ +#define AAD_LEN 20 + + +static void gf_mulx(u8 *pad) +{ + int i, carry; + + carry = pad[0] & 0x80; + for (i = 0; i < AES_BLOCK_SIZE - 1; i++) + pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7); + pad[AES_BLOCK_SIZE - 1] <<= 1; + if (carry) + pad[AES_BLOCK_SIZE - 1] ^= 0x87; +} + + +static void aes_128_cmac_vector(struct crypto_cipher *tfm, u8 *scratch, + size_t num_elem, + const u8 *addr[], const size_t *len, u8 *mac) +{ + u8 *cbc, *pad; + const u8 *pos, *end; + size_t i, e, left, total_len; + + cbc = scratch; + pad = scratch + AES_BLOCK_SIZE; + + memset(cbc, 0, AES_BLOCK_SIZE); + + total_len = 0; + for (e = 0; e < num_elem; e++) + total_len += len[e]; + left = total_len; + + e = 0; + pos = addr[0]; + end = pos + len[0]; + + while (left >= AES_BLOCK_SIZE) { + for (i = 0; i < AES_BLOCK_SIZE; i++) { + cbc[i] ^= *pos++; + if (pos >= end) { + e++; + pos = addr[e]; + end = pos + len[e]; + } + } + if (left > AES_BLOCK_SIZE) + crypto_cipher_encrypt_one(tfm, cbc, cbc); + left -= AES_BLOCK_SIZE; + } + + memset(pad, 0, AES_BLOCK_SIZE); + crypto_cipher_encrypt_one(tfm, pad, pad); + gf_mulx(pad); + + if (left || total_len == 0) { + for (i = 0; i < left; i++) { + cbc[i] ^= *pos++; + if (pos >= end) { + e++; + pos = addr[e]; + end = pos + len[e]; + } + } + cbc[left] ^= 0x80; + gf_mulx(pad); + } + + for (i = 0; i < AES_BLOCK_SIZE; i++) + pad[i] ^= cbc[i]; + crypto_cipher_encrypt_one(tfm, pad, pad); + memcpy(mac, pad, CMAC_TLEN); +} + + +void ieee80211_aes_cmac(struct crypto_cipher *tfm, u8 *scratch, const u8 *aad, + const u8 *data, size_t data_len, u8 *mic) +{ + const u8 *addr[3]; + size_t len[3]; + u8 zero[CMAC_TLEN]; + + memset(zero, 0, CMAC_TLEN); + addr[0] = aad; + len[0] = AAD_LEN; + addr[1] = data; + len[1] = data_len - CMAC_TLEN; + addr[2] = zero; + len[2] = CMAC_TLEN; + + aes_128_cmac_vector(tfm, scratch, 3, addr, len, mic); +} + + +struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[]) +{ + struct crypto_cipher *tfm; + + tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) + return NULL; + + crypto_cipher_setkey(tfm, key, AES_CMAC_KEY_LEN); + + return tfm; +} + + +void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm) +{ + if (tfm) + crypto_free_cipher(tfm); +} diff --git a/net/mac80211/aes_cmac.h b/net/mac80211/aes_cmac.h new file mode 100644 index 0000000..0eb9a48 --- /dev/null +++ b/net/mac80211/aes_cmac.h @@ -0,0 +1,19 @@ +/* + * 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. + */ + +#ifndef AES_CMAC_H +#define AES_CMAC_H + +#include <linux/crypto.h> + +struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[]); +void ieee80211_aes_cmac(struct crypto_cipher *tfm, u8 *scratch, const u8 *aad, + const u8 *data, size_t data_len, u8 *mic); +void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm); + +#endif /* AES_CMAC_H */ diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index b5f86cb..20af92a 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -43,7 +43,7 @@ struct ieee80211_local; /* Required encryption head and tailroom */ #define IEEE80211_ENCRYPT_HEADROOM 8 -#define IEEE80211_ENCRYPT_TAILROOM 12 +#define IEEE80211_ENCRYPT_TAILROOM 18 /* IEEE 802.11 (Ch. 9.5 Defragmentation) requires support for concurrent * reception of at least three fragmented frames. This limit can be increased diff --git a/net/mac80211/key.h b/net/mac80211/key.h index 425816e..73ac28c 100644 --- a/net/mac80211/key.h +++ b/net/mac80211/key.h @@ -96,6 +96,16 @@ struct ieee80211_key { u8 tx_crypto_buf[6 * AES_BLOCK_LEN]; u8 rx_crypto_buf[6 * AES_BLOCK_LEN]; } ccmp; + struct { + u8 tx_pn[6]; + u8 rx_pn[6]; + struct crypto_cipher *tfm; + u32 replays; /* dot11RSNAStatsCMACReplays */ + u32 icverrors; /* dot11RSNAStatsCMACICVErrors */ + /* scratch buffers for virt_to_page() (crypto API) */ + u8 tx_crypto_buf[2 * AES_BLOCK_LEN]; + u8 rx_crypto_buf[2 * AES_BLOCK_LEN]; + } aes_cmac; } u; /* number of times this key has been used */ diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index aff46ad..53e11e6 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -1,5 +1,6 @@ /* * 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 @@ -19,6 +20,7 @@ #include "michael.h" #include "tkip.h" #include "aes_ccm.h" +#include "aes_cmac.h" #include "wpa.h" ieee80211_tx_result @@ -491,3 +493,126 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx) 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_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 = tx->skb; + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + struct ieee80211_key *key = tx->key; + struct ieee80211_mmie *mmie; + u8 *pn, aad[20]; + int i; + + if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { + /* hwaccel */ + info->control.hw_key = &tx->key->conf; + return 0; + } + + 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 */ + pn = key->u.aes_cmac.tx_pn; + + for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) { + pn[i]++; + if (pn[i]) + break; + } + bip_ipn_swap(mmie->sequence_number, pn); + + bip_aad(skb, aad); + + /* + * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64) + */ + ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf, + 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_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; + + if ((rx->status->flag & RX_FLAG_DECRYPTED) && + (rx->status->flag & RX_FLAG_IV_STRIPPED)) + return RX_CONTINUE; + + 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 (!(rx->status->flag & RX_FLAG_DECRYPTED)) { + /* hardware didn't decrypt/verify MIC */ + bip_aad(skb, aad); + ieee80211_aes_cmac(key->u.aes_cmac.tfm, + key->u.aes_cmac.rx_crypto_buf, 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; +} diff --git a/net/mac80211/wpa.h b/net/mac80211/wpa.h index d42d221..baba060 100644 --- a/net/mac80211/wpa.h +++ b/net/mac80211/wpa.h @@ -28,4 +28,9 @@ ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx); ieee80211_rx_result ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx); +ieee80211_tx_result +ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx); +ieee80211_rx_result +ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx); + #endif /* WPA_H */ |