2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 * Copyright 2008, Jouni Malinen <j@w1.fi>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/netdevice.h>
11 #include <linux/types.h>
12 #include <linux/skbuff.h>
13 #include <linux/compiler.h>
14 #include <linux/ieee80211.h>
15 #include <linux/gfp.h>
16 #include <asm/unaligned.h>
17 #include <net/mac80211.h>
18 #include <crypto/aes.h>
20 #include "ieee80211_i.h"
28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data
*tx
)
33 struct ieee80211_hdr
*hdr
;
34 struct sk_buff
*skb
= tx
->skb
;
35 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(skb
);
38 hdr
= (struct ieee80211_hdr
*)skb
->data
;
39 if (!tx
->key
|| tx
->key
->conf
.cipher
!= WLAN_CIPHER_SUITE_TKIP
||
40 skb
->len
< 24 || !ieee80211_is_data_present(hdr
->frame_control
))
43 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
44 if (skb
->len
< hdrlen
)
47 data
= skb
->data
+ hdrlen
;
48 data_len
= skb
->len
- hdrlen
;
50 if (unlikely(info
->flags
& IEEE80211_TX_INTFL_TKIP_MIC_FAILURE
)) {
51 /* Need to use software crypto for the test */
52 info
->control
.hw_key
= NULL
;
55 if (info
->control
.hw_key
&&
56 (info
->flags
& IEEE80211_TX_CTL_DONTFRAG
||
57 tx
->local
->ops
->set_frag_threshold
) &&
58 !(tx
->key
->conf
.flags
& IEEE80211_KEY_FLAG_GENERATE_MMIC
)) {
59 /* hwaccel - with no need for SW-generated MMIC */
63 tail
= MICHAEL_MIC_LEN
;
64 if (!info
->control
.hw_key
)
67 if (WARN_ON(skb_tailroom(skb
) < tail
||
68 skb_headroom(skb
) < TKIP_IV_LEN
))
71 key
= &tx
->key
->conf
.key
[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY
];
72 mic
= skb_put(skb
, MICHAEL_MIC_LEN
);
73 michael_mic(key
, hdr
, data
, data_len
, mic
);
74 if (unlikely(info
->flags
& IEEE80211_TX_INTFL_TKIP_MIC_FAILURE
))
82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data
*rx
)
84 u8
*data
, *key
= NULL
;
87 u8 mic
[MICHAEL_MIC_LEN
];
88 struct sk_buff
*skb
= rx
->skb
;
89 struct ieee80211_rx_status
*status
= IEEE80211_SKB_RXCB(skb
);
90 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*)skb
->data
;
93 * it makes no sense to check for MIC errors on anything other
96 if (!ieee80211_is_data_present(hdr
->frame_control
))
100 * No way to verify the MIC if the hardware stripped it or
101 * the IV with the key index. In this case we have solely rely
102 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
103 * MIC failure report.
105 if (status
->flag
& (RX_FLAG_MMIC_STRIPPED
| RX_FLAG_IV_STRIPPED
)) {
106 if (status
->flag
& RX_FLAG_MMIC_ERROR
)
109 if (!(status
->flag
& RX_FLAG_IV_STRIPPED
) && rx
->key
)
116 * Some hardware seems to generate Michael MIC failure reports; even
117 * though, the frame was not encrypted with TKIP and therefore has no
118 * MIC. Ignore the flag them to avoid triggering countermeasures.
120 if (!rx
->key
|| rx
->key
->conf
.cipher
!= WLAN_CIPHER_SUITE_TKIP
||
121 !(status
->flag
& RX_FLAG_DECRYPTED
))
124 if (rx
->sdata
->vif
.type
== NL80211_IFTYPE_AP
&& rx
->key
->conf
.keyidx
) {
126 * APs with pairwise keys should never receive Michael MIC
127 * errors for non-zero keyidx because these are reserved for
128 * group keys and only the AP is sending real multicast
129 * frames in the BSS. (
131 return RX_DROP_UNUSABLE
;
134 if (status
->flag
& RX_FLAG_MMIC_ERROR
)
137 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
138 if (skb
->len
< hdrlen
+ MICHAEL_MIC_LEN
)
139 return RX_DROP_UNUSABLE
;
141 data
= skb
->data
+ hdrlen
;
142 data_len
= skb
->len
- hdrlen
- MICHAEL_MIC_LEN
;
143 key
= &rx
->key
->conf
.key
[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY
];
144 michael_mic(key
, hdr
, data
, data_len
, mic
);
145 if (memcmp(mic
, data
+ data_len
, MICHAEL_MIC_LEN
) != 0)
148 /* remove Michael MIC from payload */
149 skb_trim(skb
, skb
->len
- MICHAEL_MIC_LEN
);
152 /* update IV in key information to be able to detect replays */
153 rx
->key
->u
.tkip
.rx
[rx
->security_idx
].iv32
= rx
->tkip_iv32
;
154 rx
->key
->u
.tkip
.rx
[rx
->security_idx
].iv16
= rx
->tkip_iv16
;
160 * In some cases the key can be unset - e.g. a multicast packet, in
161 * a driver that supports HW encryption. Send up the key idx only if
164 mac80211_ev_michael_mic_failure(rx
->sdata
,
165 rx
->key
? rx
->key
->conf
.keyidx
: -1,
166 (void *) skb
->data
, NULL
, GFP_ATOMIC
);
167 return RX_DROP_UNUSABLE
;
171 static int tkip_encrypt_skb(struct ieee80211_tx_data
*tx
, struct sk_buff
*skb
)
173 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) skb
->data
;
174 struct ieee80211_key
*key
= tx
->key
;
175 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(skb
);
181 if (info
->control
.hw_key
&&
182 !(info
->control
.hw_key
->flags
& IEEE80211_KEY_FLAG_GENERATE_IV
)) {
183 /* hwaccel - with no need for software-generated IV */
187 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
188 len
= skb
->len
- hdrlen
;
190 if (info
->control
.hw_key
)
195 if (WARN_ON(skb_tailroom(skb
) < tail
||
196 skb_headroom(skb
) < TKIP_IV_LEN
))
199 pos
= skb_push(skb
, TKIP_IV_LEN
);
200 memmove(pos
, pos
+ TKIP_IV_LEN
, hdrlen
);
203 /* Increase IV for the frame */
204 spin_lock_irqsave(&key
->u
.tkip
.txlock
, flags
);
205 key
->u
.tkip
.tx
.iv16
++;
206 if (key
->u
.tkip
.tx
.iv16
== 0)
207 key
->u
.tkip
.tx
.iv32
++;
208 pos
= ieee80211_tkip_add_iv(pos
, key
);
209 spin_unlock_irqrestore(&key
->u
.tkip
.txlock
, flags
);
211 /* hwaccel - with software IV */
212 if (info
->control
.hw_key
)
215 /* Add room for ICV */
216 skb_put(skb
, TKIP_ICV_LEN
);
218 return ieee80211_tkip_encrypt_data(tx
->local
->wep_tx_tfm
,
224 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data
*tx
)
228 ieee80211_tx_set_protected(tx
);
230 skb_queue_walk(&tx
->skbs
, skb
) {
231 if (tkip_encrypt_skb(tx
, skb
) < 0)
240 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data
*rx
)
242 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) rx
->skb
->data
;
243 int hdrlen
, res
, hwaccel
= 0;
244 struct ieee80211_key
*key
= rx
->key
;
245 struct sk_buff
*skb
= rx
->skb
;
246 struct ieee80211_rx_status
*status
= IEEE80211_SKB_RXCB(skb
);
248 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
250 if (!ieee80211_is_data(hdr
->frame_control
))
253 if (!rx
->sta
|| skb
->len
- hdrlen
< 12)
254 return RX_DROP_UNUSABLE
;
257 * Let TKIP code verify IV, but skip decryption.
258 * In the case where hardware checks the IV as well,
259 * we don't even get here, see ieee80211_rx_h_decrypt()
261 if (status
->flag
& RX_FLAG_DECRYPTED
)
264 res
= ieee80211_tkip_decrypt_data(rx
->local
->wep_rx_tfm
,
265 key
, skb
->data
+ hdrlen
,
266 skb
->len
- hdrlen
, rx
->sta
->sta
.addr
,
267 hdr
->addr1
, hwaccel
, rx
->security_idx
,
270 if (res
!= TKIP_DECRYPT_OK
)
271 return RX_DROP_UNUSABLE
;
274 skb_trim(skb
, skb
->len
- TKIP_ICV_LEN
);
277 memmove(skb
->data
+ TKIP_IV_LEN
, skb
->data
, hdrlen
);
278 skb_pull(skb
, TKIP_IV_LEN
);
284 static void ccmp_special_blocks(struct sk_buff
*skb
, u8
*pn
, u8
*scratch
,
288 int a4_included
, mgmt
;
293 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*)skb
->data
;
295 memset(scratch
, 0, 6 * AES_BLOCK_SIZE
);
297 b_0
= scratch
+ 3 * AES_BLOCK_SIZE
;
298 aad
= scratch
+ 4 * AES_BLOCK_SIZE
;
301 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
302 * Retry, PwrMgt, MoreData; set Protected
304 mgmt
= ieee80211_is_mgmt(hdr
->frame_control
);
305 mask_fc
= hdr
->frame_control
;
306 mask_fc
&= ~cpu_to_le16(IEEE80211_FCTL_RETRY
|
307 IEEE80211_FCTL_PM
| IEEE80211_FCTL_MOREDATA
);
309 mask_fc
&= ~cpu_to_le16(0x0070);
310 mask_fc
|= cpu_to_le16(IEEE80211_FCTL_PROTECTED
);
312 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
314 a4_included
= ieee80211_has_a4(hdr
->frame_control
);
316 if (ieee80211_is_data_qos(hdr
->frame_control
))
317 qos_tid
= *ieee80211_get_qos_ctl(hdr
) & IEEE80211_QOS_CTL_TID_MASK
;
321 data_len
= skb
->len
- hdrlen
- CCMP_HDR_LEN
;
323 data_len
-= CCMP_MIC_LEN
;
325 /* First block, b_0 */
326 b_0
[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
327 /* Nonce: Nonce Flags | A2 | PN
328 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
330 b_0
[1] = qos_tid
| (mgmt
<< 4);
331 memcpy(&b_0
[2], hdr
->addr2
, ETH_ALEN
);
332 memcpy(&b_0
[8], pn
, CCMP_PN_LEN
);
334 put_unaligned_be16(data_len
, &b_0
[14]);
336 /* AAD (extra authenticate-only data) / masked 802.11 header
337 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
338 put_unaligned_be16(len_a
, &aad
[0]);
339 put_unaligned(mask_fc
, (__le16
*)&aad
[2]);
340 memcpy(&aad
[4], &hdr
->addr1
, 3 * ETH_ALEN
);
342 /* Mask Seq#, leave Frag# */
343 aad
[22] = *((u8
*) &hdr
->seq_ctrl
) & 0x0f;
347 memcpy(&aad
[24], hdr
->addr4
, ETH_ALEN
);
351 memset(&aad
[24], 0, ETH_ALEN
+ IEEE80211_QOS_CTL_LEN
);
357 static inline void ccmp_pn2hdr(u8
*hdr
, u8
*pn
, int key_id
)
362 hdr
[3] = 0x20 | (key_id
<< 6);
370 static inline void ccmp_hdr2pn(u8
*pn
, u8
*hdr
)
381 static int ccmp_encrypt_skb(struct ieee80211_tx_data
*tx
, struct sk_buff
*skb
)
383 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) skb
->data
;
384 struct ieee80211_key
*key
= tx
->key
;
385 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(skb
);
386 int hdrlen
, len
, tail
;
390 u8 scratch
[6 * AES_BLOCK_SIZE
];
392 if (info
->control
.hw_key
&&
393 !(info
->control
.hw_key
->flags
& IEEE80211_KEY_FLAG_GENERATE_IV
) &&
394 !(info
->control
.hw_key
->flags
& IEEE80211_KEY_FLAG_PUT_IV_SPACE
)) {
396 * hwaccel has no need for preallocated room for CCMP
397 * header or MIC fields
402 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
403 len
= skb
->len
- hdrlen
;
405 if (info
->control
.hw_key
)
410 if (WARN_ON(skb_tailroom(skb
) < tail
||
411 skb_headroom(skb
) < CCMP_HDR_LEN
))
414 pos
= skb_push(skb
, CCMP_HDR_LEN
);
415 memmove(pos
, pos
+ CCMP_HDR_LEN
, hdrlen
);
417 /* the HW only needs room for the IV, but not the actual IV */
418 if (info
->control
.hw_key
&&
419 (info
->control
.hw_key
->flags
& IEEE80211_KEY_FLAG_PUT_IV_SPACE
))
422 hdr
= (struct ieee80211_hdr
*) pos
;
425 pn64
= atomic64_inc_return(&key
->u
.ccmp
.tx_pn
);
434 ccmp_pn2hdr(pos
, pn
, key
->conf
.keyidx
);
436 /* hwaccel - with software CCMP header */
437 if (info
->control
.hw_key
)
441 ccmp_special_blocks(skb
, pn
, scratch
, 0);
442 ieee80211_aes_ccm_encrypt(key
->u
.ccmp
.tfm
, scratch
, pos
, len
,
443 pos
, skb_put(skb
, CCMP_MIC_LEN
));
450 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data
*tx
)
454 ieee80211_tx_set_protected(tx
);
456 skb_queue_walk(&tx
->skbs
, skb
) {
457 if (ccmp_encrypt_skb(tx
, skb
) < 0)
466 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data
*rx
)
468 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*)rx
->skb
->data
;
470 struct ieee80211_key
*key
= rx
->key
;
471 struct sk_buff
*skb
= rx
->skb
;
472 struct ieee80211_rx_status
*status
= IEEE80211_SKB_RXCB(skb
);
477 hdrlen
= ieee80211_hdrlen(hdr
->frame_control
);
479 if (!ieee80211_is_data(hdr
->frame_control
) &&
480 !ieee80211_is_robust_mgmt_frame(hdr
))
483 data_len
= skb
->len
- hdrlen
- CCMP_HDR_LEN
- CCMP_MIC_LEN
;
484 if (!rx
->sta
|| data_len
< 0)
485 return RX_DROP_UNUSABLE
;
487 ccmp_hdr2pn(pn
, skb
->data
+ hdrlen
);
489 queue
= rx
->security_idx
;
491 if (memcmp(pn
, key
->u
.ccmp
.rx_pn
[queue
], CCMP_PN_LEN
) <= 0) {
492 key
->u
.ccmp
.replays
++;
493 return RX_DROP_UNUSABLE
;
496 if (!(status
->flag
& RX_FLAG_DECRYPTED
)) {
497 u8 scratch
[6 * AES_BLOCK_SIZE
];
498 /* hardware didn't decrypt/verify MIC */
499 ccmp_special_blocks(skb
, pn
, scratch
, 1);
501 if (ieee80211_aes_ccm_decrypt(
502 key
->u
.ccmp
.tfm
, scratch
,
503 skb
->data
+ hdrlen
+ CCMP_HDR_LEN
, data_len
,
504 skb
->data
+ skb
->len
- CCMP_MIC_LEN
,
505 skb
->data
+ hdrlen
+ CCMP_HDR_LEN
))
506 return RX_DROP_UNUSABLE
;
509 memcpy(key
->u
.ccmp
.rx_pn
[queue
], pn
, CCMP_PN_LEN
);
511 /* Remove CCMP header and MIC */
512 skb_trim(skb
, skb
->len
- CCMP_MIC_LEN
);
513 memmove(skb
->data
+ CCMP_HDR_LEN
, skb
->data
, hdrlen
);
514 skb_pull(skb
, CCMP_HDR_LEN
);
520 static void bip_aad(struct sk_buff
*skb
, u8
*aad
)
522 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
524 /* FC type/subtype */
525 aad
[0] = skb
->data
[0];
526 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
527 aad
[1] = skb
->data
[1] & ~(BIT(4) | BIT(5) | BIT(6));
529 memcpy(aad
+ 2, skb
->data
+ 4, 3 * ETH_ALEN
);
533 static inline void bip_ipn_set64(u8
*d
, u64 pn
)
543 static inline void bip_ipn_swap(u8
*d
, const u8
*s
)
555 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data
*tx
)
558 struct ieee80211_tx_info
*info
;
559 struct ieee80211_key
*key
= tx
->key
;
560 struct ieee80211_mmie
*mmie
;
564 if (WARN_ON(skb_queue_len(&tx
->skbs
) != 1))
567 skb
= skb_peek(&tx
->skbs
);
569 info
= IEEE80211_SKB_CB(skb
);
571 if (info
->control
.hw_key
)
574 if (WARN_ON(skb_tailroom(skb
) < sizeof(*mmie
)))
577 mmie
= (struct ieee80211_mmie
*) skb_put(skb
, sizeof(*mmie
));
578 mmie
->element_id
= WLAN_EID_MMIE
;
579 mmie
->length
= sizeof(*mmie
) - 2;
580 mmie
->key_id
= cpu_to_le16(key
->conf
.keyidx
);
583 pn64
= atomic64_inc_return(&key
->u
.aes_cmac
.tx_pn
);
585 bip_ipn_set64(mmie
->sequence_number
, pn64
);
590 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
592 ieee80211_aes_cmac(key
->u
.aes_cmac
.tfm
, aad
,
593 skb
->data
+ 24, skb
->len
- 24, mmie
->mic
);
600 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data
*rx
)
602 struct sk_buff
*skb
= rx
->skb
;
603 struct ieee80211_rx_status
*status
= IEEE80211_SKB_RXCB(skb
);
604 struct ieee80211_key
*key
= rx
->key
;
605 struct ieee80211_mmie
*mmie
;
606 u8 aad
[20], mic
[8], ipn
[6];
607 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) skb
->data
;
609 if (!ieee80211_is_mgmt(hdr
->frame_control
))
612 if (skb
->len
< 24 + sizeof(*mmie
))
613 return RX_DROP_UNUSABLE
;
615 mmie
= (struct ieee80211_mmie
*)
616 (skb
->data
+ skb
->len
- sizeof(*mmie
));
617 if (mmie
->element_id
!= WLAN_EID_MMIE
||
618 mmie
->length
!= sizeof(*mmie
) - 2)
619 return RX_DROP_UNUSABLE
; /* Invalid MMIE */
621 bip_ipn_swap(ipn
, mmie
->sequence_number
);
623 if (memcmp(ipn
, key
->u
.aes_cmac
.rx_pn
, 6) <= 0) {
624 key
->u
.aes_cmac
.replays
++;
625 return RX_DROP_UNUSABLE
;
628 if (!(status
->flag
& RX_FLAG_DECRYPTED
)) {
629 /* hardware didn't decrypt/verify MIC */
631 ieee80211_aes_cmac(key
->u
.aes_cmac
.tfm
, aad
,
632 skb
->data
+ 24, skb
->len
- 24, mic
);
633 if (memcmp(mic
, mmie
->mic
, sizeof(mmie
->mic
)) != 0) {
634 key
->u
.aes_cmac
.icverrors
++;
635 return RX_DROP_UNUSABLE
;
639 memcpy(key
->u
.aes_cmac
.rx_pn
, ipn
, 6);
642 skb_trim(skb
, skb
->len
- sizeof(*mmie
));
648 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data
*tx
)
651 struct ieee80211_tx_info
*info
= NULL
;
653 skb_queue_walk(&tx
->skbs
, skb
) {
654 info
= IEEE80211_SKB_CB(skb
);
656 /* handle hw-only algorithm */
657 if (!info
->control
.hw_key
)
661 ieee80211_tx_set_protected(tx
);