1 // SPDX-License-Identifier: GPL-2.0
2 /* Host AP crypt: host-based CCMP encryption implementation for Host AP driver
4 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/slab.h>
10 #include <linux/random.h>
11 #include <linux/skbuff.h>
12 #include <linux/netdevice.h>
13 #include <linux/if_ether.h>
14 #include <linux/if_arp.h>
15 #include <linux/string.h>
16 #include <linux/wireless.h>
19 #include <linux/crypto.h>
21 #include <linux/scatterlist.h>
23 #define AES_BLOCK_LEN 16
24 #define CCMP_HDR_LEN 8
25 #define CCMP_MIC_LEN 8
26 #define CCMP_TK_LEN 16
29 struct rtllib_ccmp_data {
33 u8 tx_pn[CCMP_PN_LEN];
34 u8 rx_pn[CCMP_PN_LEN];
36 u32 dot11RSNAStatsCCMPFormatErrors;
37 u32 dot11RSNAStatsCCMPReplays;
38 u32 dot11RSNAStatsCCMPDecryptErrors;
42 struct crypto_tfm *tfm;
44 /* scratch buffers for virt_to_page() (crypto API) */
45 u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],
46 tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];
47 u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];
50 static void rtllib_ccmp_aes_encrypt(struct crypto_tfm *tfm,
51 const u8 pt[16], u8 ct[16])
53 crypto_cipher_encrypt_one((void *)tfm, ct, pt);
56 static void *rtllib_ccmp_init(int key_idx)
58 struct rtllib_ccmp_data *priv;
60 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
63 priv->key_idx = key_idx;
65 priv->tfm = (void *)crypto_alloc_cipher("aes", 0, 0);
66 if (IS_ERR(priv->tfm)) {
67 pr_debug("Could not allocate crypto API aes\n");
76 crypto_free_cipher((void *)priv->tfm);
84 static void rtllib_ccmp_deinit(void *priv)
86 struct rtllib_ccmp_data *_priv = priv;
88 if (_priv && _priv->tfm)
89 crypto_free_cipher((void *)_priv->tfm);
94 static inline void xor_block(u8 *b, u8 *a, size_t len)
98 for (i = 0; i < len; i++)
104 static void ccmp_init_blocks(struct crypto_tfm *tfm,
105 struct rtllib_hdr_4addr *hdr,
106 u8 *pn, size_t dlen, u8 *b0, u8 *auth,
112 int a4_included, qc_included;
113 u8 aad[2 * AES_BLOCK_LEN];
115 fc = le16_to_cpu(hdr->frame_ctl);
116 a4_included = ((fc & (RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS)) ==
117 (RTLLIB_FCTL_TODS | RTLLIB_FCTL_FROMDS));
119 qc_included = ((WLAN_FC_GET_TYPE(fc) == RTLLIB_FTYPE_DATA) &&
120 (WLAN_FC_GET_STYPE(fc) & 0x80));
125 pos = (u8 *) &hdr->addr4;
131 /* CCM Initial Block:
132 * Flag (Include authentication header, M=3 (8-octet MIC),
133 * L=1 (2-octet Dlen))
134 * Nonce: 0x00 | A2 | PN
139 memcpy(b0 + 2, hdr->addr2, ETH_ALEN);
140 memcpy(b0 + 8, pn, CCMP_PN_LEN);
141 b0[14] = (dlen >> 8) & 0xff;
142 b0[15] = dlen & 0xff;
145 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
147 * SC with bits 4..15 (seq#) masked to zero
152 aad[0] = 0; /* aad_len >> 8 */
153 aad[1] = aad_len & 0xff;
154 aad[2] = pos[0] & 0x8f;
155 aad[3] = pos[1] & 0xc7;
156 memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);
157 pos = (u8 *) &hdr->seq_ctl;
158 aad[22] = pos[0] & 0x0f;
159 aad[23] = 0; /* all bits masked */
160 memset(aad + 24, 0, 8);
162 memcpy(aad + 24, hdr->addr4, ETH_ALEN);
164 aad[a4_included ? 30 : 24] = qc;
165 /* rest of QC masked */
168 /* Start with the first block and AAD */
169 rtllib_ccmp_aes_encrypt(tfm, b0, auth);
170 xor_block(auth, aad, AES_BLOCK_LEN);
171 rtllib_ccmp_aes_encrypt(tfm, auth, auth);
172 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
173 rtllib_ccmp_aes_encrypt(tfm, auth, auth);
176 rtllib_ccmp_aes_encrypt(tfm, b0, s0);
181 static int rtllib_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
183 struct rtllib_ccmp_data *key = priv;
186 struct rtllib_hdr_4addr *hdr;
187 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
189 if (skb_headroom(skb) < CCMP_HDR_LEN ||
190 skb_tailroom(skb) < CCMP_MIC_LEN ||
194 data_len = skb->len - hdr_len;
195 pos = skb_push(skb, CCMP_HDR_LEN);
196 memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
202 if (key->tx_pn[i] != 0)
207 *pos++ = key->tx_pn[5];
208 *pos++ = key->tx_pn[4];
210 *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */;
211 *pos++ = key->tx_pn[3];
212 *pos++ = key->tx_pn[2];
213 *pos++ = key->tx_pn[1];
214 *pos++ = key->tx_pn[0];
217 hdr = (struct rtllib_hdr_4addr *) skb->data;
218 if (!tcb_desc->bHwSec) {
219 int blocks, last, len;
226 mic = skb_put(skb, CCMP_MIC_LEN);
228 ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len,
231 blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
232 last = data_len % AES_BLOCK_LEN;
234 for (i = 1; i <= blocks; i++) {
235 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
237 xor_block(b, pos, len);
238 rtllib_ccmp_aes_encrypt(key->tfm, b, b);
239 /* Encryption, with counter */
240 b0[14] = (i >> 8) & 0xff;
242 rtllib_ccmp_aes_encrypt(key->tfm, b0, e);
243 xor_block(pos, e, len);
247 for (i = 0; i < CCMP_MIC_LEN; i++)
248 mic[i] = b[i] ^ s0[i];
254 static int rtllib_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
256 struct rtllib_ccmp_data *key = priv;
258 struct rtllib_hdr_4addr *hdr;
259 struct cb_desc *tcb_desc = (struct cb_desc *)(skb->cb +
263 if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
264 key->dot11RSNAStatsCCMPFormatErrors++;
268 hdr = (struct rtllib_hdr_4addr *) skb->data;
269 pos = skb->data + hdr_len;
271 if (!(keyidx & (1 << 5))) {
272 if (net_ratelimit()) {
273 pr_debug("CCMP: received packet without ExtIV flag from %pM\n",
276 key->dot11RSNAStatsCCMPFormatErrors++;
280 if (key->key_idx != keyidx) {
281 pr_debug("CCMP: RX tkey->key_idx=%d frame keyidx=%d priv=%p\n",
282 key->key_idx, keyidx, priv);
286 if (net_ratelimit()) {
287 pr_debug("CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
300 if (memcmp(pn, key->rx_pn, CCMP_PN_LEN) <= 0) {
301 key->dot11RSNAStatsCCMPReplays++;
304 if (!tcb_desc->bHwSec) {
305 size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN -
307 u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;
311 int i, blocks, last, len;
314 ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);
315 xor_block(mic, b, CCMP_MIC_LEN);
317 blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
318 last = data_len % AES_BLOCK_LEN;
320 for (i = 1; i <= blocks; i++) {
321 len = (i == blocks && last) ? last : AES_BLOCK_LEN;
322 /* Decrypt, with counter */
323 b0[14] = (i >> 8) & 0xff;
325 rtllib_ccmp_aes_encrypt(key->tfm, b0, b);
326 xor_block(pos, b, len);
328 xor_block(a, pos, len);
329 rtllib_ccmp_aes_encrypt(key->tfm, a, a);
333 if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {
334 if (net_ratelimit()) {
335 pr_debug("CCMP: decrypt failed: STA= %pM\n",
338 key->dot11RSNAStatsCCMPDecryptErrors++;
342 memcpy(key->rx_pn, pn, CCMP_PN_LEN);
344 /* Remove hdr and MIC */
345 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
346 skb_pull(skb, CCMP_HDR_LEN);
347 skb_trim(skb, skb->len - CCMP_MIC_LEN);
353 static int rtllib_ccmp_set_key(void *key, int len, u8 *seq, void *priv)
355 struct rtllib_ccmp_data *data = priv;
357 struct crypto_tfm *tfm = data->tfm;
359 keyidx = data->key_idx;
360 memset(data, 0, sizeof(*data));
361 data->key_idx = keyidx;
363 if (len == CCMP_TK_LEN) {
364 memcpy(data->key, key, CCMP_TK_LEN);
367 data->rx_pn[0] = seq[5];
368 data->rx_pn[1] = seq[4];
369 data->rx_pn[2] = seq[3];
370 data->rx_pn[3] = seq[2];
371 data->rx_pn[4] = seq[1];
372 data->rx_pn[5] = seq[0];
374 crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);
375 } else if (len == 0) {
385 static int rtllib_ccmp_get_key(void *key, int len, u8 *seq, void *priv)
387 struct rtllib_ccmp_data *data = priv;
389 if (len < CCMP_TK_LEN)
394 memcpy(key, data->key, CCMP_TK_LEN);
397 seq[0] = data->tx_pn[5];
398 seq[1] = data->tx_pn[4];
399 seq[2] = data->tx_pn[3];
400 seq[3] = data->tx_pn[2];
401 seq[4] = data->tx_pn[1];
402 seq[5] = data->tx_pn[0];
409 static void rtllib_ccmp_print_stats(struct seq_file *m, void *priv)
411 struct rtllib_ccmp_data *ccmp = priv;
414 "key[%d] alg=CCMP key_set=%d tx_pn=%pM rx_pn=%pM format_errors=%d replays=%d decrypt_errors=%d\n",
415 ccmp->key_idx, ccmp->key_set,
416 ccmp->tx_pn, ccmp->rx_pn,
417 ccmp->dot11RSNAStatsCCMPFormatErrors,
418 ccmp->dot11RSNAStatsCCMPReplays,
419 ccmp->dot11RSNAStatsCCMPDecryptErrors);
422 static struct lib80211_crypto_ops rtllib_crypt_ccmp = {
424 .init = rtllib_ccmp_init,
425 .deinit = rtllib_ccmp_deinit,
426 .encrypt_mpdu = rtllib_ccmp_encrypt,
427 .decrypt_mpdu = rtllib_ccmp_decrypt,
428 .encrypt_msdu = NULL,
429 .decrypt_msdu = NULL,
430 .set_key = rtllib_ccmp_set_key,
431 .get_key = rtllib_ccmp_get_key,
432 .print_stats = rtllib_ccmp_print_stats,
433 .extra_mpdu_prefix_len = CCMP_HDR_LEN,
434 .extra_mpdu_postfix_len = CCMP_MIC_LEN,
435 .owner = THIS_MODULE,
439 static int __init rtllib_crypto_ccmp_init(void)
441 return lib80211_register_crypto_ops(&rtllib_crypt_ccmp);
445 static void __exit rtllib_crypto_ccmp_exit(void)
447 lib80211_unregister_crypto_ops(&rtllib_crypt_ccmp);
450 module_init(rtllib_crypto_ccmp_init);
451 module_exit(rtllib_crypto_ccmp_exit);
453 MODULE_LICENSE("GPL");