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mac80211: port CCMP to cryptoapi's CCM driver

Browse source 
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 <ard.biesheuvel@linaro.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Ard Biesheuvel 2013-10-10 09:55:20 +02:00 • committed by Johannes Berg
commit 7ec7c4a9a6
5 changed files with 80 additions and 142 deletions
Download patch file Download diff file Expand all files Collapse all files

1
net/mac80211/Kconfig
View file

@ -4,6 +4,7 @@ config MAC80211
select CRYPTO select CRYPTO
select CRYPTO_ARC4 select CRYPTO_ARC4
select CRYPTO_AES select CRYPTO_AES
select CRYPTO_CCM
select CRC32 select CRC32
select AVERAGE select AVERAGE
---help--- ---help---

163
net/mac80211/aes_ccm.c
View file

@ -2,6 +2,8 @@
* Copyright 2003-2004, Instant802 Networks, Inc. * Copyright 2003-2004, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc. * Copyright 2005-2006, Devicescape Software, Inc.
* *
* Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify * 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 * it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. * published by the Free Software Foundation.
@ -17,134 +19,75 @@
#include "key.h" #include "key.h"
#include "aes_ccm.h" #include "aes_ccm.h"
static void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *scratch, u8 *a) void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
u8 *data, size_t data_len, u8 *mic)
{ {
int i; struct scatterlist assoc, pt, ct[2];
u8 *b_0, *aad, *b, *s_0; struct {
struct aead_request req;
u8 priv[crypto_aead_reqsize(tfm)];
} aead_req;
b_0 = scratch + 3 * AES_BLOCK_SIZE; memset(&aead_req, 0, sizeof(aead_req));
aad = scratch + 4 * AES_BLOCK_SIZE;
b = scratch;
s_0 = scratch + AES_BLOCK_SIZE;
crypto_cipher_encrypt_one(tfm, b, b_0); sg_init_one(&pt, data, data_len);
sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
sg_init_table(ct, 2);
sg_set_buf(&ct[0], data, data_len);
sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
/* Extra Authenticate-only data (always two AES blocks) */ aead_request_set_tfm(&aead_req.req, tfm);
for (i = 0; i < AES_BLOCK_SIZE; i++) aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
aad[i] ^= b[i]; aead_request_set_crypt(&aead_req.req, &pt, ct, data_len, b_0);
crypto_cipher_encrypt_one(tfm, b, aad);
aad += AES_BLOCK_SIZE; crypto_aead_encrypt(&aead_req.req);
for (i = 0; i < AES_BLOCK_SIZE; i++)
aad[i] ^= b[i];
crypto_cipher_encrypt_one(tfm, a, aad);
/* Mask out bits from auth-only-b_0 */
b_0[0] &= 0x07;
/* S_0 is used to encrypt T (= MIC) */
b_0[14] = 0;
b_0[15] = 0;
crypto_cipher_encrypt_one(tfm, s_0, b_0);
} }
int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch, u8 *data, size_t data_len, u8 *mic)
u8 *data, size_t data_len,
u8 *cdata, u8 *mic)
{ {
int i, j, last_len, num_blocks; struct scatterlist assoc, pt, ct[2];
u8 *pos, *cpos, *b, *s_0, *e, *b_0; struct {
struct aead_request req;
u8 priv[crypto_aead_reqsize(tfm)];
} aead_req;
b = scratch; memset(&aead_req, 0, sizeof(aead_req));
s_0 = scratch + AES_BLOCK_SIZE;
e = scratch + 2 * AES_BLOCK_SIZE;
b_0 = scratch + 3 * AES_BLOCK_SIZE;
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE); sg_init_one(&pt, data, data_len);
last_len = data_len % AES_BLOCK_SIZE; sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
aes_ccm_prepare(tfm, scratch, b); sg_init_table(ct, 2);
sg_set_buf(&ct[0], data, data_len);
sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
/* Process payload blocks */ aead_request_set_tfm(&aead_req.req, tfm);
pos = data; aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
cpos = cdata; aead_request_set_crypt(&aead_req.req, ct, &pt,
for (j = 1; j <= num_blocks; j++) { data_len + IEEE80211_CCMP_MIC_LEN, b_0);
int blen = (j == num_blocks && last_len) ?
last_len : AES_BLOCK_SIZE;
/* Authentication followed by encryption */ return crypto_aead_decrypt(&aead_req.req);
for (i = 0; i < blen; i++)
b[i] ^= pos[i];
crypto_cipher_encrypt_one(tfm, b, b);
b_0[14] = (j >> 8) & 0xff;
b_0[15] = j & 0xff;
crypto_cipher_encrypt_one(tfm, e, b_0);
for (i = 0; i < blen; i++)
*cpos++ = *pos++ ^ e[i];
}
for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++)
mic[i] = b[i] ^ s_0[i];
} }
struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[])
int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
u8 *cdata, size_t data_len, u8 *mic, u8 *data)
{ {
int i, j, last_len, num_blocks; struct crypto_aead *tfm;
u8 *pos, *cpos, *b, *s_0, *a, *b_0; int err;
b = scratch;
s_0 = scratch + AES_BLOCK_SIZE;
a = scratch + 2 * AES_BLOCK_SIZE;
b_0 = scratch + 3 * AES_BLOCK_SIZE;
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE);
last_len = data_len % AES_BLOCK_SIZE;
aes_ccm_prepare(tfm, scratch, a);
/* Process payload blocks */
cpos = cdata;
pos = data;
for (j = 1; j <= num_blocks; j++) {
int blen = (j == num_blocks && last_len) ?
last_len : AES_BLOCK_SIZE;
/* Decryption followed by authentication */
b_0[14] = (j >> 8) & 0xff;
b_0[15] = j & 0xff;
crypto_cipher_encrypt_one(tfm, b, b_0);
for (i = 0; i < blen; i++) {
*pos = *cpos++ ^ b[i];
a[i] ^= *pos++;
}
crypto_cipher_encrypt_one(tfm, a, a);
}
for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++) {
if ((mic[i] ^ s_0[i]) != a[i])
return -1;
}
return 0;
}
struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[])
{
struct crypto_cipher *tfm;
tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
if (!IS_ERR(tfm))
crypto_cipher_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
return tfm; return tfm;
err = crypto_aead_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
if (!err)
err = crypto_aead_setauthsize(tfm, IEEE80211_CCMP_MIC_LEN);
if (!err)
return tfm;
crypto_free_aead(tfm);
return ERR_PTR(err);
} }
void ieee80211_aes_key_free(struct crypto_aead *tfm)
void ieee80211_aes_key_free(struct crypto_cipher *tfm)
{ {
crypto_free_cipher(tfm); crypto_free_aead(tfm);
} }

14
net/mac80211/aes_ccm.h
View file

@ -12,13 +12,11 @@
#include <linux/crypto.h> #include <linux/crypto.h>
struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]); struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[]);
void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch, void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
u8 *data, size_t data_len, u8 *data, size_t data_len, u8 *mic);
u8 *cdata, u8 *mic); int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch, u8 *data, size_t data_len, u8 *mic);
u8 *cdata, size_t data_len, void ieee80211_aes_key_free(struct crypto_aead *tfm);
u8 *mic, u8 *data);
void ieee80211_aes_key_free(struct crypto_cipher *tfm);
#endif /* AES_CCM_H */ #endif /* AES_CCM_H */

2
net/mac80211/key.h
View file

@ -83,7 +83,7 @@ struct ieee80211_key {
* Management frames. * Management frames.
*/ */
u8 rx_pn[IEEE80211_NUM_TIDS + 1][IEEE80211_CCMP_PN_LEN]; u8 rx_pn[IEEE80211_NUM_TIDS + 1][IEEE80211_CCMP_PN_LEN];
struct crypto_cipher *tfm; struct crypto_aead *tfm;
u32 replays; /* dot11RSNAStatsCCMPReplays */ u32 replays; /* dot11RSNAStatsCCMPReplays */
} ccmp; } ccmp;
struct { struct {

44
net/mac80211/wpa.c
View file

@ -301,22 +301,16 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
} }
static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
int encrypted) int encrypted)
{ {
__le16 mask_fc; __le16 mask_fc;
int a4_included, mgmt; int a4_included, mgmt;
u8 qos_tid; u8 qos_tid;
u8 *b_0, *aad; u16 len_a;
u16 data_len, len_a;
unsigned int hdrlen; unsigned int hdrlen;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 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) * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
* Retry, PwrMgt, MoreData; set Protected * Retry, PwrMgt, MoreData; set Protected
@ -338,20 +332,21 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
else else
qos_tid = 0; qos_tid = 0;
data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN; /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
if (encrypted) * mode authentication are not allowed to collide, yet both are derived
data_len -= IEEE80211_CCMP_MIC_LEN; * from this vector b_0. We only set L := 1 here to indicate that the
* data size can be represented in (L+1) bytes. The CCM layer will take
* care of storing the data length in the top (L+1) bytes and setting
* and clearing the other bits as is required to derive the two IVs.
*/
b_0[0] = 0x1;
/* First block, b_0 */
b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
/* Nonce: Nonce Flags | A2 | PN /* Nonce: Nonce Flags | A2 | PN
* Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
*/ */
b_0[1] = qos_tid | (mgmt << 4); b_0[1] = qos_tid | (mgmt << 4);
memcpy(&b_0[2], hdr->addr2, ETH_ALEN); memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN); memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
/* l(m) */
put_unaligned_be16(data_len, &b_0[14]);
/* AAD (extra authenticate-only data) / masked 802.11 header /* AAD (extra authenticate-only data) / masked 802.11 header
* FC | A1 | A2 | A3 | SC | [A4] | [QC] */ * 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)
u8 *pos; u8 *pos;
u8 pn[6]; u8 pn[6];
u64 pn64; u64 pn64;
u8 scratch[6 * AES_BLOCK_SIZE]; u8 aad[2 * AES_BLOCK_SIZE];
u8 b_0[AES_BLOCK_SIZE];
if (info->control.hw_key && if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) && !(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)
return 0; return 0;
pos += IEEE80211_CCMP_HDR_LEN; pos += IEEE80211_CCMP_HDR_LEN;
ccmp_special_blocks(skb, pn, scratch, 0); ccmp_special_blocks(skb, pn, b_0, aad, 0);
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len, ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
pos, skb_put(skb, IEEE80211_CCMP_MIC_LEN)); skb_put(skb, IEEE80211_CCMP_MIC_LEN));
return 0; return 0;
} }
@ -525,16 +521,16 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
} }
if (!(status->flag & RX_FLAG_DECRYPTED)) { if (!(status->flag & RX_FLAG_DECRYPTED)) {
u8 scratch[6 * AES_BLOCK_SIZE]; u8 aad[2 * AES_BLOCK_SIZE];
u8 b_0[AES_BLOCK_SIZE];
/* hardware didn't decrypt/verify MIC */ /* hardware didn't decrypt/verify MIC */
ccmp_special_blocks(skb, pn, scratch, 1); ccmp_special_blocks(skb, pn, b_0, aad, 1);
if (ieee80211_aes_ccm_decrypt( if (ieee80211_aes_ccm_decrypt(
key->u.ccmp.tfm, scratch, key->u.ccmp.tfm, b_0, aad,
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN, skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
data_len, data_len,
skb->data + skb->len - IEEE80211_CCMP_MIC_LEN, skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN))
return RX_DROP_UNUSABLE; return RX_DROP_UNUSABLE;
} }