Commit | Line | Data |
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21042e41 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
b453872c | 2 | /* |
274bfb8d | 3 | * lib80211 crypt: host-based CCMP encryption implementation for lib80211 |
b453872c | 4 | * |
85d32e7b | 5 | * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi> |
274bfb8d | 6 | * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com> |
b453872c JG |
7 | */ |
8 | ||
172589cc | 9 | #include <linux/kernel.h> |
f12cc209 | 10 | #include <linux/err.h> |
b453872c JG |
11 | #include <linux/module.h> |
12 | #include <linux/init.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/random.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/netdevice.h> | |
17 | #include <linux/if_ether.h> | |
18 | #include <linux/if_arp.h> | |
19 | #include <asm/string.h> | |
20 | #include <linux/wireless.h> | |
21 | ||
274bfb8d | 22 | #include <linux/ieee80211.h> |
b453872c | 23 | |
b453872c | 24 | #include <linux/crypto.h> |
a11e2f85 | 25 | #include <crypto/aead.h> |
b453872c | 26 | |
274bfb8d JL |
27 | #include <net/lib80211.h> |
28 | ||
b453872c JG |
29 | MODULE_AUTHOR("Jouni Malinen"); |
30 | MODULE_DESCRIPTION("Host AP crypt: CCMP"); | |
31 | MODULE_LICENSE("GPL"); | |
32 | ||
33 | #define AES_BLOCK_LEN 16 | |
34 | #define CCMP_HDR_LEN 8 | |
35 | #define CCMP_MIC_LEN 8 | |
36 | #define CCMP_TK_LEN 16 | |
37 | #define CCMP_PN_LEN 6 | |
38 | ||
274bfb8d | 39 | struct lib80211_ccmp_data { |
b453872c JG |
40 | u8 key[CCMP_TK_LEN]; |
41 | int key_set; | |
42 | ||
43 | u8 tx_pn[CCMP_PN_LEN]; | |
44 | u8 rx_pn[CCMP_PN_LEN]; | |
45 | ||
46 | u32 dot11RSNAStatsCCMPFormatErrors; | |
47 | u32 dot11RSNAStatsCCMPReplays; | |
48 | u32 dot11RSNAStatsCCMPDecryptErrors; | |
49 | ||
50 | int key_idx; | |
51 | ||
a11e2f85 | 52 | struct crypto_aead *tfm; |
b453872c JG |
53 | |
54 | /* scratch buffers for virt_to_page() (crypto API) */ | |
a11e2f85 AB |
55 | u8 tx_aad[2 * AES_BLOCK_LEN]; |
56 | u8 rx_aad[2 * AES_BLOCK_LEN]; | |
b453872c JG |
57 | }; |
58 | ||
274bfb8d | 59 | static void *lib80211_ccmp_init(int key_idx) |
b453872c | 60 | { |
274bfb8d | 61 | struct lib80211_ccmp_data *priv; |
b453872c | 62 | |
0da974f4 | 63 | priv = kzalloc(sizeof(*priv), GFP_ATOMIC); |
b453872c JG |
64 | if (priv == NULL) |
65 | goto fail; | |
b453872c JG |
66 | priv->key_idx = key_idx; |
67 | ||
a11e2f85 | 68 | priv->tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC); |
f12cc209 | 69 | if (IS_ERR(priv->tfm)) { |
f12cc209 | 70 | priv->tfm = NULL; |
b453872c JG |
71 | goto fail; |
72 | } | |
73 | ||
74 | return priv; | |
75 | ||
0edd5b44 | 76 | fail: |
b453872c JG |
77 | if (priv) { |
78 | if (priv->tfm) | |
a11e2f85 | 79 | crypto_free_aead(priv->tfm); |
b453872c JG |
80 | kfree(priv); |
81 | } | |
82 | ||
83 | return NULL; | |
84 | } | |
85 | ||
274bfb8d | 86 | static void lib80211_ccmp_deinit(void *priv) |
b453872c | 87 | { |
274bfb8d | 88 | struct lib80211_ccmp_data *_priv = priv; |
b453872c | 89 | if (_priv && _priv->tfm) |
a11e2f85 | 90 | crypto_free_aead(_priv->tfm); |
b453872c JG |
91 | kfree(priv); |
92 | } | |
93 | ||
a11e2f85 AB |
94 | static int ccmp_init_iv_and_aad(const struct ieee80211_hdr *hdr, |
95 | const u8 *pn, u8 *iv, u8 *aad) | |
b453872c JG |
96 | { |
97 | u8 *pos, qc = 0; | |
98 | size_t aad_len; | |
b453872c | 99 | int a4_included, qc_included; |
b453872c | 100 | |
274bfb8d JL |
101 | a4_included = ieee80211_has_a4(hdr->frame_control); |
102 | qc_included = ieee80211_is_data_qos(hdr->frame_control); | |
103 | ||
b453872c JG |
104 | aad_len = 22; |
105 | if (a4_included) | |
106 | aad_len += 6; | |
107 | if (qc_included) { | |
0edd5b44 | 108 | pos = (u8 *) & hdr->addr4; |
b453872c JG |
109 | if (a4_included) |
110 | pos += 6; | |
111 | qc = *pos & 0x0f; | |
112 | aad_len += 2; | |
113 | } | |
114 | ||
a11e2f85 AB |
115 | /* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC |
116 | * mode authentication are not allowed to collide, yet both are derived | |
117 | * from the same vector. We only set L := 1 here to indicate that the | |
118 | * data size can be represented in (L+1) bytes. The CCM layer will take | |
119 | * care of storing the data length in the top (L+1) bytes and setting | |
120 | * and clearing the other bits as is required to derive the two IVs. | |
121 | */ | |
122 | iv[0] = 0x1; | |
123 | ||
124 | /* Nonce: QC | A2 | PN */ | |
125 | iv[1] = qc; | |
126 | memcpy(iv + 2, hdr->addr2, ETH_ALEN); | |
127 | memcpy(iv + 8, pn, CCMP_PN_LEN); | |
b453872c JG |
128 | |
129 | /* AAD: | |
130 | * FC with bits 4..6 and 11..13 masked to zero; 14 is always one | |
131 | * A1 | A2 | A3 | |
132 | * SC with bits 4..15 (seq#) masked to zero | |
133 | * A4 (if present) | |
134 | * QC (if present) | |
135 | */ | |
136 | pos = (u8 *) hdr; | |
a11e2f85 AB |
137 | aad[0] = pos[0] & 0x8f; |
138 | aad[1] = pos[1] & 0xc7; | |
2aec9099 | 139 | memcpy(aad + 2, &hdr->addrs, 3 * ETH_ALEN); |
274bfb8d | 140 | pos = (u8 *) & hdr->seq_ctrl; |
a11e2f85 AB |
141 | aad[20] = pos[0] & 0x0f; |
142 | aad[21] = 0; /* all bits masked */ | |
143 | memset(aad + 22, 0, 8); | |
b453872c | 144 | if (a4_included) |
a11e2f85 | 145 | memcpy(aad + 22, hdr->addr4, ETH_ALEN); |
b453872c | 146 | if (qc_included) { |
a11e2f85 | 147 | aad[a4_included ? 28 : 22] = qc; |
b453872c JG |
148 | /* rest of QC masked */ |
149 | } | |
a11e2f85 | 150 | return aad_len; |
b453872c JG |
151 | } |
152 | ||
274bfb8d | 153 | static int lib80211_ccmp_hdr(struct sk_buff *skb, int hdr_len, |
9184d934 | 154 | u8 *aeskey, int keylen, void *priv) |
b453872c | 155 | { |
274bfb8d | 156 | struct lib80211_ccmp_data *key = priv; |
31b59eae JK |
157 | int i; |
158 | u8 *pos; | |
b453872c | 159 | |
31b59eae | 160 | if (skb_headroom(skb) < CCMP_HDR_LEN || skb->len < hdr_len) |
b453872c JG |
161 | return -1; |
162 | ||
9184d934 ZY |
163 | if (aeskey != NULL && keylen >= CCMP_TK_LEN) |
164 | memcpy(aeskey, key->key, CCMP_TK_LEN); | |
165 | ||
b453872c JG |
166 | pos = skb_push(skb, CCMP_HDR_LEN); |
167 | memmove(pos, pos + CCMP_HDR_LEN, hdr_len); | |
168 | pos += hdr_len; | |
b453872c JG |
169 | |
170 | i = CCMP_PN_LEN - 1; | |
171 | while (i >= 0) { | |
172 | key->tx_pn[i]++; | |
173 | if (key->tx_pn[i] != 0) | |
174 | break; | |
175 | i--; | |
176 | } | |
177 | ||
178 | *pos++ = key->tx_pn[5]; | |
179 | *pos++ = key->tx_pn[4]; | |
180 | *pos++ = 0; | |
0edd5b44 | 181 | *pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */ ; |
b453872c JG |
182 | *pos++ = key->tx_pn[3]; |
183 | *pos++ = key->tx_pn[2]; | |
184 | *pos++ = key->tx_pn[1]; | |
185 | *pos++ = key->tx_pn[0]; | |
186 | ||
31b59eae JK |
187 | return CCMP_HDR_LEN; |
188 | } | |
189 | ||
274bfb8d | 190 | static int lib80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv) |
31b59eae | 191 | { |
274bfb8d | 192 | struct lib80211_ccmp_data *key = priv; |
274bfb8d | 193 | struct ieee80211_hdr *hdr; |
a11e2f85 AB |
194 | struct aead_request *req; |
195 | struct scatterlist sg[2]; | |
196 | u8 *aad = key->tx_aad; | |
197 | u8 iv[AES_BLOCK_LEN]; | |
198 | int len, data_len, aad_len; | |
199 | int ret; | |
31b59eae JK |
200 | |
201 | if (skb_tailroom(skb) < CCMP_MIC_LEN || skb->len < hdr_len) | |
202 | return -1; | |
203 | ||
204 | data_len = skb->len - hdr_len; | |
274bfb8d | 205 | len = lib80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv); |
31b59eae JK |
206 | if (len < 0) |
207 | return -1; | |
208 | ||
a11e2f85 AB |
209 | req = aead_request_alloc(key->tfm, GFP_ATOMIC); |
210 | if (!req) | |
211 | return -ENOMEM; | |
212 | ||
274bfb8d | 213 | hdr = (struct ieee80211_hdr *)skb->data; |
a11e2f85 | 214 | aad_len = ccmp_init_iv_and_aad(hdr, key->tx_pn, iv, aad); |
b453872c | 215 | |
a11e2f85 | 216 | skb_put(skb, CCMP_MIC_LEN); |
b453872c | 217 | |
a11e2f85 AB |
218 | sg_init_table(sg, 2); |
219 | sg_set_buf(&sg[0], aad, aad_len); | |
220 | sg_set_buf(&sg[1], skb->data + hdr_len + CCMP_HDR_LEN, | |
221 | data_len + CCMP_MIC_LEN); | |
222 | ||
223 | aead_request_set_callback(req, 0, NULL, NULL); | |
224 | aead_request_set_ad(req, aad_len); | |
225 | aead_request_set_crypt(req, sg, sg, data_len, iv); | |
226 | ||
227 | ret = crypto_aead_encrypt(req); | |
228 | aead_request_free(req); | |
229 | ||
230 | return ret; | |
b453872c JG |
231 | } |
232 | ||
b4328d87 ZY |
233 | /* |
234 | * deal with seq counter wrapping correctly. | |
235 | * refer to timer_after() for jiffies wrapping handling | |
236 | */ | |
237 | static inline int ccmp_replay_check(u8 *pn_n, u8 *pn_o) | |
238 | { | |
239 | u32 iv32_n, iv16_n; | |
240 | u32 iv32_o, iv16_o; | |
241 | ||
242 | iv32_n = (pn_n[0] << 24) | (pn_n[1] << 16) | (pn_n[2] << 8) | pn_n[3]; | |
243 | iv16_n = (pn_n[4] << 8) | pn_n[5]; | |
244 | ||
245 | iv32_o = (pn_o[0] << 24) | (pn_o[1] << 16) | (pn_o[2] << 8) | pn_o[3]; | |
246 | iv16_o = (pn_o[4] << 8) | pn_o[5]; | |
247 | ||
248 | if ((s32)iv32_n - (s32)iv32_o < 0 || | |
249 | (iv32_n == iv32_o && iv16_n <= iv16_o)) | |
250 | return 1; | |
251 | return 0; | |
252 | } | |
253 | ||
274bfb8d | 254 | static int lib80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv) |
b453872c | 255 | { |
274bfb8d | 256 | struct lib80211_ccmp_data *key = priv; |
b453872c | 257 | u8 keyidx, *pos; |
274bfb8d | 258 | struct ieee80211_hdr *hdr; |
a11e2f85 AB |
259 | struct aead_request *req; |
260 | struct scatterlist sg[2]; | |
261 | u8 *aad = key->rx_aad; | |
262 | u8 iv[AES_BLOCK_LEN]; | |
b453872c | 263 | u8 pn[6]; |
a11e2f85 AB |
264 | int aad_len, ret; |
265 | size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN; | |
b453872c JG |
266 | |
267 | if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) { | |
268 | key->dot11RSNAStatsCCMPFormatErrors++; | |
269 | return -1; | |
270 | } | |
271 | ||
274bfb8d | 272 | hdr = (struct ieee80211_hdr *)skb->data; |
b453872c JG |
273 | pos = skb->data + hdr_len; |
274 | keyidx = pos[3]; | |
275 | if (!(keyidx & (1 << 5))) { | |
e87cc472 JP |
276 | net_dbg_ratelimited("CCMP: received packet without ExtIV flag from %pM\n", |
277 | hdr->addr2); | |
b453872c JG |
278 | key->dot11RSNAStatsCCMPFormatErrors++; |
279 | return -2; | |
280 | } | |
281 | keyidx >>= 6; | |
282 | if (key->key_idx != keyidx) { | |
996bf99c JB |
283 | net_dbg_ratelimited("CCMP: RX tkey->key_idx=%d frame keyidx=%d\n", |
284 | key->key_idx, keyidx); | |
b453872c JG |
285 | return -6; |
286 | } | |
287 | if (!key->key_set) { | |
e87cc472 JP |
288 | net_dbg_ratelimited("CCMP: received packet from %pM with keyid=%d that does not have a configured key\n", |
289 | hdr->addr2, keyidx); | |
b453872c JG |
290 | return -3; |
291 | } | |
292 | ||
293 | pn[0] = pos[7]; | |
294 | pn[1] = pos[6]; | |
295 | pn[2] = pos[5]; | |
296 | pn[3] = pos[4]; | |
297 | pn[4] = pos[1]; | |
298 | pn[5] = pos[0]; | |
299 | pos += 8; | |
300 | ||
b4328d87 | 301 | if (ccmp_replay_check(pn, key->rx_pn)) { |
6f16bf3b | 302 | #ifdef CONFIG_LIB80211_DEBUG |
e87cc472 JP |
303 | net_dbg_ratelimited("CCMP: replay detected: STA=%pM previous PN %02x%02x%02x%02x%02x%02x received PN %02x%02x%02x%02x%02x%02x\n", |
304 | hdr->addr2, | |
305 | key->rx_pn[0], key->rx_pn[1], key->rx_pn[2], | |
306 | key->rx_pn[3], key->rx_pn[4], key->rx_pn[5], | |
307 | pn[0], pn[1], pn[2], pn[3], pn[4], pn[5]); | |
6f16bf3b | 308 | #endif |
b453872c JG |
309 | key->dot11RSNAStatsCCMPReplays++; |
310 | return -4; | |
311 | } | |
312 | ||
a11e2f85 AB |
313 | req = aead_request_alloc(key->tfm, GFP_ATOMIC); |
314 | if (!req) | |
315 | return -ENOMEM; | |
b453872c | 316 | |
a11e2f85 AB |
317 | aad_len = ccmp_init_iv_and_aad(hdr, pn, iv, aad); |
318 | ||
319 | sg_init_table(sg, 2); | |
320 | sg_set_buf(&sg[0], aad, aad_len); | |
321 | sg_set_buf(&sg[1], pos, data_len); | |
322 | ||
323 | aead_request_set_callback(req, 0, NULL, NULL); | |
324 | aead_request_set_ad(req, aad_len); | |
325 | aead_request_set_crypt(req, sg, sg, data_len, iv); | |
326 | ||
327 | ret = crypto_aead_decrypt(req); | |
328 | aead_request_free(req); | |
329 | ||
330 | if (ret) { | |
331 | net_dbg_ratelimited("CCMP: decrypt failed: STA=%pM (%d)\n", | |
332 | hdr->addr2, ret); | |
b453872c JG |
333 | key->dot11RSNAStatsCCMPDecryptErrors++; |
334 | return -5; | |
335 | } | |
336 | ||
337 | memcpy(key->rx_pn, pn, CCMP_PN_LEN); | |
338 | ||
339 | /* Remove hdr and MIC */ | |
340 | memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len); | |
341 | skb_pull(skb, CCMP_HDR_LEN); | |
342 | skb_trim(skb, skb->len - CCMP_MIC_LEN); | |
343 | ||
344 | return keyidx; | |
345 | } | |
346 | ||
274bfb8d | 347 | static int lib80211_ccmp_set_key(void *key, int len, u8 * seq, void *priv) |
b453872c | 348 | { |
274bfb8d | 349 | struct lib80211_ccmp_data *data = priv; |
b453872c | 350 | int keyidx; |
a11e2f85 | 351 | struct crypto_aead *tfm = data->tfm; |
b453872c JG |
352 | |
353 | keyidx = data->key_idx; | |
354 | memset(data, 0, sizeof(*data)); | |
355 | data->key_idx = keyidx; | |
356 | data->tfm = tfm; | |
357 | if (len == CCMP_TK_LEN) { | |
358 | memcpy(data->key, key, CCMP_TK_LEN); | |
359 | data->key_set = 1; | |
360 | if (seq) { | |
361 | data->rx_pn[0] = seq[5]; | |
362 | data->rx_pn[1] = seq[4]; | |
363 | data->rx_pn[2] = seq[3]; | |
364 | data->rx_pn[3] = seq[2]; | |
365 | data->rx_pn[4] = seq[1]; | |
366 | data->rx_pn[5] = seq[0]; | |
367 | } | |
a11e2f85 AB |
368 | if (crypto_aead_setauthsize(data->tfm, CCMP_MIC_LEN) || |
369 | crypto_aead_setkey(data->tfm, data->key, CCMP_TK_LEN)) | |
370 | return -1; | |
b453872c JG |
371 | } else if (len == 0) |
372 | data->key_set = 0; | |
373 | else | |
374 | return -1; | |
375 | ||
376 | return 0; | |
377 | } | |
378 | ||
274bfb8d | 379 | static int lib80211_ccmp_get_key(void *key, int len, u8 * seq, void *priv) |
b453872c | 380 | { |
274bfb8d | 381 | struct lib80211_ccmp_data *data = priv; |
b453872c JG |
382 | |
383 | if (len < CCMP_TK_LEN) | |
384 | return -1; | |
385 | ||
386 | if (!data->key_set) | |
387 | return 0; | |
388 | memcpy(key, data->key, CCMP_TK_LEN); | |
389 | ||
390 | if (seq) { | |
391 | seq[0] = data->tx_pn[5]; | |
392 | seq[1] = data->tx_pn[4]; | |
393 | seq[2] = data->tx_pn[3]; | |
394 | seq[3] = data->tx_pn[2]; | |
395 | seq[4] = data->tx_pn[1]; | |
396 | seq[5] = data->tx_pn[0]; | |
397 | } | |
398 | ||
399 | return CCMP_TK_LEN; | |
400 | } | |
401 | ||
6bbefe86 | 402 | static void lib80211_ccmp_print_stats(struct seq_file *m, void *priv) |
b453872c | 403 | { |
274bfb8d | 404 | struct lib80211_ccmp_data *ccmp = priv; |
0795af57 | 405 | |
6bbefe86 DH |
406 | seq_printf(m, |
407 | "key[%d] alg=CCMP key_set=%d " | |
408 | "tx_pn=%02x%02x%02x%02x%02x%02x " | |
409 | "rx_pn=%02x%02x%02x%02x%02x%02x " | |
410 | "format_errors=%d replays=%d decrypt_errors=%d\n", | |
411 | ccmp->key_idx, ccmp->key_set, | |
412 | ccmp->tx_pn[0], ccmp->tx_pn[1], ccmp->tx_pn[2], | |
413 | ccmp->tx_pn[3], ccmp->tx_pn[4], ccmp->tx_pn[5], | |
414 | ccmp->rx_pn[0], ccmp->rx_pn[1], ccmp->rx_pn[2], | |
415 | ccmp->rx_pn[3], ccmp->rx_pn[4], ccmp->rx_pn[5], | |
416 | ccmp->dot11RSNAStatsCCMPFormatErrors, | |
417 | ccmp->dot11RSNAStatsCCMPReplays, | |
418 | ccmp->dot11RSNAStatsCCMPDecryptErrors); | |
b453872c JG |
419 | } |
420 | ||
274bfb8d | 421 | static struct lib80211_crypto_ops lib80211_crypt_ccmp = { |
74079fdc | 422 | .name = "CCMP", |
274bfb8d JL |
423 | .init = lib80211_ccmp_init, |
424 | .deinit = lib80211_ccmp_deinit, | |
274bfb8d JL |
425 | .encrypt_mpdu = lib80211_ccmp_encrypt, |
426 | .decrypt_mpdu = lib80211_ccmp_decrypt, | |
74079fdc JK |
427 | .encrypt_msdu = NULL, |
428 | .decrypt_msdu = NULL, | |
274bfb8d JL |
429 | .set_key = lib80211_ccmp_set_key, |
430 | .get_key = lib80211_ccmp_get_key, | |
431 | .print_stats = lib80211_ccmp_print_stats, | |
1264fc04 JK |
432 | .extra_mpdu_prefix_len = CCMP_HDR_LEN, |
433 | .extra_mpdu_postfix_len = CCMP_MIC_LEN, | |
74079fdc | 434 | .owner = THIS_MODULE, |
b453872c JG |
435 | }; |
436 | ||
274bfb8d | 437 | static int __init lib80211_crypto_ccmp_init(void) |
b453872c | 438 | { |
274bfb8d | 439 | return lib80211_register_crypto_ops(&lib80211_crypt_ccmp); |
b453872c JG |
440 | } |
441 | ||
274bfb8d | 442 | static void __exit lib80211_crypto_ccmp_exit(void) |
b453872c | 443 | { |
274bfb8d | 444 | lib80211_unregister_crypto_ops(&lib80211_crypt_ccmp); |
b453872c JG |
445 | } |
446 | ||
274bfb8d JL |
447 | module_init(lib80211_crypto_ccmp_init); |
448 | module_exit(lib80211_crypto_ccmp_exit); |