Skip to content

Commit 7ec7c4a

Browse files
Ard Biesheuveljmberg-intel
Ard Biesheuvel
authored and
jmberg-intel
committed
mac80211: port CCMP to cryptoapi's CCM driver
Use the generic CCM aead chaining mode driver rather than a local implementation that sits right on top of the core AES cipher. This allows the use of accelerated implementations of either CCM as a whole or the CTR mode which it encapsulates. Signed-off-by: Ard Biesheuvel <[email protected]> Signed-off-by: Johannes Berg <[email protected]>
1 parent fa1fb9c commit 7ec7c4a

File tree

5 files changed

+84
-146
lines changed

5 files changed

+84
-146
lines changed

‎net/mac80211/Kconfig

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,7 @@ config MAC80211
44
select CRYPTO
55
select CRYPTO_ARC4
66
select CRYPTO_AES
7+
select CRYPTO_CCM
78
select CRC32
89
select AVERAGE
910
---help---

‎net/mac80211/aes_ccm.c

Lines changed: 56 additions & 113 deletions
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,8 @@
22
* Copyright 2003-2004, Instant802 Networks, Inc.
33
* Copyright 2005-2006, Devicescape Software, Inc.
44
*
5+
* Rewrite: Copyright (C) 2013 Linaro Ltd <[email protected]>
6+
*
57
* This program is free software; you can redistribute it and/or modify
68
* it under the terms of the GNU General Public License version 2 as
79
* published by the Free Software Foundation.
@@ -17,134 +19,75 @@
1719
#include "key.h"
1820
#include "aes_ccm.h"
1921

20-
static void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *scratch, u8 *a)
22+
void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
23+
u8 *data, size_t data_len, u8 *mic)
2124
{
22-
int i;
23-
u8 *b_0, *aad, *b, *s_0;
24-
25-
b_0 = scratch + 3 * AES_BLOCK_SIZE;
26-
aad = scratch + 4 * AES_BLOCK_SIZE;
27-
b = scratch;
28-
s_0 = scratch + AES_BLOCK_SIZE;
29-
30-
crypto_cipher_encrypt_one(tfm, b, b_0);
25+
struct scatterlist assoc, pt, ct[2];
26+
struct {
27+
struct aead_request req;
28+
u8 priv[crypto_aead_reqsize(tfm)];
29+
} aead_req;
3130

32-
/* Extra Authenticate-only data (always two AES blocks) */
33-
for (i = 0; i < AES_BLOCK_SIZE; i++)
34-
aad[i] ^= b[i];
35-
crypto_cipher_encrypt_one(tfm, b, aad);
31+
memset(&aead_req, 0, sizeof(aead_req));
3632

37-
aad += AES_BLOCK_SIZE;
33+
sg_init_one(&pt, data, data_len);
34+
sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
35+
sg_init_table(ct, 2);
36+
sg_set_buf(&ct[0], data, data_len);
37+
sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
3838

39-
for (i = 0; i < AES_BLOCK_SIZE; i++)
40-
aad[i] ^= b[i];
41-
crypto_cipher_encrypt_one(tfm, a, aad);
39+
aead_request_set_tfm(&aead_req.req, tfm);
40+
aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
41+
aead_request_set_crypt(&aead_req.req, &pt, ct, data_len, b_0);
4242

43-
/* Mask out bits from auth-only-b_0 */
44-
b_0[0] &= 0x07;
45-
46-
/* S_0 is used to encrypt T (= MIC) */
47-
b_0[14] = 0;
48-
b_0[15] = 0;
49-
crypto_cipher_encrypt_one(tfm, s_0, b_0);
43+
crypto_aead_encrypt(&aead_req.req);
5044
}
5145

52-
53-
void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
54-
u8 *data, size_t data_len,
55-
u8 *cdata, u8 *mic)
46+
int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
47+
u8 *data, size_t data_len, u8 *mic)
5648
{
57-
int i, j, last_len, num_blocks;
58-
u8 *pos, *cpos, *b, *s_0, *e, *b_0;
59-
60-
b = scratch;
61-
s_0 = scratch + AES_BLOCK_SIZE;
62-
e = scratch + 2 * AES_BLOCK_SIZE;
63-
b_0 = scratch + 3 * AES_BLOCK_SIZE;
64-
65-
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE);
66-
last_len = data_len % AES_BLOCK_SIZE;
67-
aes_ccm_prepare(tfm, scratch, b);
68-
69-
/* Process payload blocks */
70-
pos = data;
71-
cpos = cdata;
72-
for (j = 1; j <= num_blocks; j++) {
73-
int blen = (j == num_blocks && last_len) ?
74-
last_len : AES_BLOCK_SIZE;
75-
76-
/* Authentication followed by encryption */
77-
for (i = 0; i < blen; i++)
78-
b[i] ^= pos[i];
79-
crypto_cipher_encrypt_one(tfm, b, b);
80-
81-
b_0[14] = (j >> 8) & 0xff;
82-
b_0[15] = j & 0xff;
83-
crypto_cipher_encrypt_one(tfm, e, b_0);
84-
for (i = 0; i < blen; i++)
85-
*cpos++ = *pos++ ^ e[i];
86-
}
87-
88-
for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++)
89-
mic[i] = b[i] ^ s_0[i];
49+
struct scatterlist assoc, pt, ct[2];
50+
struct {
51+
struct aead_request req;
52+
u8 priv[crypto_aead_reqsize(tfm)];
53+
} aead_req;
54+
55+
memset(&aead_req, 0, sizeof(aead_req));
56+
57+
sg_init_one(&pt, data, data_len);
58+
sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
59+
sg_init_table(ct, 2);
60+
sg_set_buf(&ct[0], data, data_len);
61+
sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
62+
63+
aead_request_set_tfm(&aead_req.req, tfm);
64+
aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
65+
aead_request_set_crypt(&aead_req.req, ct, &pt,
66+
data_len + IEEE80211_CCMP_MIC_LEN, b_0);
67+
68+
return crypto_aead_decrypt(&aead_req.req);
9069
}
9170

92-
93-
int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
94-
u8 *cdata, size_t data_len, u8 *mic, u8 *data)
71+
struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[])
9572
{
96-
int i, j, last_len, num_blocks;
97-
u8 *pos, *cpos, *b, *s_0, *a, *b_0;
98-
99-
b = scratch;
100-
s_0 = scratch + AES_BLOCK_SIZE;
101-
a = scratch + 2 * AES_BLOCK_SIZE;
102-
b_0 = scratch + 3 * AES_BLOCK_SIZE;
103-
104-
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE);
105-
last_len = data_len % AES_BLOCK_SIZE;
106-
aes_ccm_prepare(tfm, scratch, a);
107-
108-
/* Process payload blocks */
109-
cpos = cdata;
110-
pos = data;
111-
for (j = 1; j <= num_blocks; j++) {
112-
int blen = (j == num_blocks && last_len) ?
113-
last_len : AES_BLOCK_SIZE;
114-
115-
/* Decryption followed by authentication */
116-
b_0[14] = (j >> 8) & 0xff;
117-
b_0[15] = j & 0xff;
118-
crypto_cipher_encrypt_one(tfm, b, b_0);
119-
for (i = 0; i < blen; i++) {
120-
*pos = *cpos++ ^ b[i];
121-
a[i] ^= *pos++;
122-
}
123-
crypto_cipher_encrypt_one(tfm, a, a);
124-
}
125-
126-
for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++) {
127-
if ((mic[i] ^ s_0[i]) != a[i])
128-
return -1;
129-
}
130-
131-
return 0;
132-
}
73+
struct crypto_aead *tfm;
74+
int err;
13375

76+
tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
77+
if (IS_ERR(tfm))
78+
return tfm;
13479

135-
struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[])
136-
{
137-
struct crypto_cipher *tfm;
80+
err = crypto_aead_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
81+
if (!err)
82+
err = crypto_aead_setauthsize(tfm, IEEE80211_CCMP_MIC_LEN);
83+
if (!err)
84+
return tfm;
13885

139-
tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
140-
if (!IS_ERR(tfm))
141-
crypto_cipher_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
142-
143-
return tfm;
86+
crypto_free_aead(tfm);
87+
return ERR_PTR(err);
14488
}
14589

146-
147-
void ieee80211_aes_key_free(struct crypto_cipher *tfm)
90+
void ieee80211_aes_key_free(struct crypto_aead *tfm)
14891
{
149-
crypto_free_cipher(tfm);
92+
crypto_free_aead(tfm);
15093
}

‎net/mac80211/aes_ccm.h

Lines changed: 6 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -12,13 +12,11 @@
1212

1313
#include <linux/crypto.h>
1414

15-
struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]);
16-
void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
17-
u8 *data, size_t data_len,
18-
u8 *cdata, u8 *mic);
19-
int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
20-
u8 *cdata, size_t data_len,
21-
u8 *mic, u8 *data);
22-
void ieee80211_aes_key_free(struct crypto_cipher *tfm);
15+
struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[]);
16+
void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
17+
u8 *data, size_t data_len, u8 *mic);
18+
int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
19+
u8 *data, size_t data_len, u8 *mic);
20+
void ieee80211_aes_key_free(struct crypto_aead *tfm);
2321

2422
#endif /* AES_CCM_H */

‎net/mac80211/key.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -83,7 +83,7 @@ struct ieee80211_key {
8383
* Management frames.
8484
*/
8585
u8 rx_pn[IEEE80211_NUM_TIDS + 1][IEEE80211_CCMP_PN_LEN];
86-
struct crypto_cipher *tfm;
86+
struct crypto_aead *tfm;
8787
u32 replays; /* dot11RSNAStatsCCMPReplays */
8888
} ccmp;
8989
struct {

‎net/mac80211/wpa.c

Lines changed: 20 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -301,22 +301,16 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
301301
}
302302

303303

304-
static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
304+
static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
305305
int encrypted)
306306
{
307307
__le16 mask_fc;
308308
int a4_included, mgmt;
309309
u8 qos_tid;
310-
u8 *b_0, *aad;
311-
u16 data_len, len_a;
310+
u16 len_a;
312311
unsigned int hdrlen;
313312
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
314313

315-
memset(scratch, 0, 6 * AES_BLOCK_SIZE);
316-
317-
b_0 = scratch + 3 * AES_BLOCK_SIZE;
318-
aad = scratch + 4 * AES_BLOCK_SIZE;
319-
320314
/*
321315
* Mask FC: zero subtype b4 b5 b6 (if not mgmt)
322316
* Retry, PwrMgt, MoreData; set Protected
@@ -338,20 +332,21 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
338332
else
339333
qos_tid = 0;
340334

341-
data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN;
342-
if (encrypted)
343-
data_len -= IEEE80211_CCMP_MIC_LEN;
335+
/* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
336+
* mode authentication are not allowed to collide, yet both are derived
337+
* from this vector b_0. We only set L := 1 here to indicate that the
338+
* data size can be represented in (L+1) bytes. The CCM layer will take
339+
* care of storing the data length in the top (L+1) bytes and setting
340+
* and clearing the other bits as is required to derive the two IVs.
341+
*/
342+
b_0[0] = 0x1;
344343

345-
/* First block, b_0 */
346-
b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
347344
/* Nonce: Nonce Flags | A2 | PN
348345
* Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
349346
*/
350347
b_0[1] = qos_tid | (mgmt << 4);
351348
memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
352349
memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
353-
/* l(m) */
354-
put_unaligned_be16(data_len, &b_0[14]);
355350

356351
/* AAD (extra authenticate-only data) / masked 802.11 header
357352
* FC | A1 | A2 | A3 | SC | [A4] | [QC] */
@@ -407,7 +402,8 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
407402
u8 *pos;
408403
u8 pn[6];
409404
u64 pn64;
410-
u8 scratch[6 * AES_BLOCK_SIZE];
405+
u8 aad[2 * AES_BLOCK_SIZE];
406+
u8 b_0[AES_BLOCK_SIZE];
411407

412408
if (info->control.hw_key &&
413409
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
@@ -460,9 +456,9 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
460456
return 0;
461457

462458
pos += IEEE80211_CCMP_HDR_LEN;
463-
ccmp_special_blocks(skb, pn, scratch, 0);
464-
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
465-
pos, skb_put(skb, IEEE80211_CCMP_MIC_LEN));
459+
ccmp_special_blocks(skb, pn, b_0, aad, 0);
460+
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
461+
skb_put(skb, IEEE80211_CCMP_MIC_LEN));
466462

467463
return 0;
468464
}
@@ -525,16 +521,16 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
525521
}
526522

527523
if (!(status->flag & RX_FLAG_DECRYPTED)) {
528-
u8 scratch[6 * AES_BLOCK_SIZE];
524+
u8 aad[2 * AES_BLOCK_SIZE];
525+
u8 b_0[AES_BLOCK_SIZE];
529526
/* hardware didn't decrypt/verify MIC */
530-
ccmp_special_blocks(skb, pn, scratch, 1);
527+
ccmp_special_blocks(skb, pn, b_0, aad, 1);
531528

532529
if (ieee80211_aes_ccm_decrypt(
533-
key->u.ccmp.tfm, scratch,
530+
key->u.ccmp.tfm, b_0, aad,
534531
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
535532
data_len,
536-
skb->data + skb->len - IEEE80211_CCMP_MIC_LEN,
537-
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN))
533+
skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
538534
return RX_DROP_UNUSABLE;
539535
}
540536

0 commit comments

Comments
 (0)