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e8f69799 IL |
1 | /* Copyright (c) 2018, Mellanox Technologies All rights reserved. |
2 | * | |
3 | * This software is available to you under a choice of one of two | |
4 | * licenses. You may choose to be licensed under the terms of the GNU | |
5 | * General Public License (GPL) Version 2, available from the file | |
6 | * COPYING in the main directory of this source tree, or the | |
7 | * OpenIB.org BSD license below: | |
8 | * | |
9 | * Redistribution and use in source and binary forms, with or | |
10 | * without modification, are permitted provided that the following | |
11 | * conditions are met: | |
12 | * | |
13 | * - Redistributions of source code must retain the above | |
14 | * copyright notice, this list of conditions and the following | |
15 | * disclaimer. | |
16 | * | |
17 | * - Redistributions in binary form must reproduce the above | |
18 | * copyright notice, this list of conditions and the following | |
19 | * disclaimer in the documentation and/or other materials | |
20 | * provided with the distribution. | |
21 | * | |
22 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | |
23 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF | |
24 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
25 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS | |
26 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN | |
27 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
28 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
29 | * SOFTWARE. | |
30 | */ | |
31 | ||
32 | #include <net/tls.h> | |
33 | #include <crypto/aead.h> | |
34 | #include <crypto/scatterwalk.h> | |
35 | #include <net/ip6_checksum.h> | |
36 | ||
37 | static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk) | |
38 | { | |
39 | struct scatterlist *src = walk->sg; | |
40 | int diff = walk->offset - src->offset; | |
41 | ||
42 | sg_set_page(sg, sg_page(src), | |
43 | src->length - diff, walk->offset); | |
44 | ||
45 | scatterwalk_crypto_chain(sg, sg_next(src), 0, 2); | |
46 | } | |
47 | ||
48 | static int tls_enc_record(struct aead_request *aead_req, | |
49 | struct crypto_aead *aead, char *aad, | |
50 | char *iv, __be64 rcd_sn, | |
51 | struct scatter_walk *in, | |
52 | struct scatter_walk *out, int *in_len) | |
53 | { | |
54 | unsigned char buf[TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE]; | |
55 | struct scatterlist sg_in[3]; | |
56 | struct scatterlist sg_out[3]; | |
57 | u16 len; | |
58 | int rc; | |
59 | ||
60 | len = min_t(int, *in_len, ARRAY_SIZE(buf)); | |
61 | ||
62 | scatterwalk_copychunks(buf, in, len, 0); | |
63 | scatterwalk_copychunks(buf, out, len, 1); | |
64 | ||
65 | *in_len -= len; | |
66 | if (!*in_len) | |
67 | return 0; | |
68 | ||
69 | scatterwalk_pagedone(in, 0, 1); | |
70 | scatterwalk_pagedone(out, 1, 1); | |
71 | ||
72 | len = buf[4] | (buf[3] << 8); | |
73 | len -= TLS_CIPHER_AES_GCM_128_IV_SIZE; | |
74 | ||
75 | tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE, | |
76 | (char *)&rcd_sn, sizeof(rcd_sn), buf[0]); | |
77 | ||
78 | memcpy(iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, buf + TLS_HEADER_SIZE, | |
79 | TLS_CIPHER_AES_GCM_128_IV_SIZE); | |
80 | ||
81 | sg_init_table(sg_in, ARRAY_SIZE(sg_in)); | |
82 | sg_init_table(sg_out, ARRAY_SIZE(sg_out)); | |
83 | sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE); | |
84 | sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE); | |
85 | chain_to_walk(sg_in + 1, in); | |
86 | chain_to_walk(sg_out + 1, out); | |
87 | ||
88 | *in_len -= len; | |
89 | if (*in_len < 0) { | |
90 | *in_len += TLS_CIPHER_AES_GCM_128_TAG_SIZE; | |
91 | /* the input buffer doesn't contain the entire record. | |
92 | * trim len accordingly. The resulting authentication tag | |
93 | * will contain garbage, but we don't care, so we won't | |
94 | * include any of it in the output skb | |
95 | * Note that we assume the output buffer length | |
96 | * is larger then input buffer length + tag size | |
97 | */ | |
98 | if (*in_len < 0) | |
99 | len += *in_len; | |
100 | ||
101 | *in_len = 0; | |
102 | } | |
103 | ||
104 | if (*in_len) { | |
105 | scatterwalk_copychunks(NULL, in, len, 2); | |
106 | scatterwalk_pagedone(in, 0, 1); | |
107 | scatterwalk_copychunks(NULL, out, len, 2); | |
108 | scatterwalk_pagedone(out, 1, 1); | |
109 | } | |
110 | ||
111 | len -= TLS_CIPHER_AES_GCM_128_TAG_SIZE; | |
112 | aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv); | |
113 | ||
114 | rc = crypto_aead_encrypt(aead_req); | |
115 | ||
116 | return rc; | |
117 | } | |
118 | ||
119 | static void tls_init_aead_request(struct aead_request *aead_req, | |
120 | struct crypto_aead *aead) | |
121 | { | |
122 | aead_request_set_tfm(aead_req, aead); | |
123 | aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE); | |
124 | } | |
125 | ||
126 | static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead, | |
127 | gfp_t flags) | |
128 | { | |
129 | unsigned int req_size = sizeof(struct aead_request) + | |
130 | crypto_aead_reqsize(aead); | |
131 | struct aead_request *aead_req; | |
132 | ||
133 | aead_req = kzalloc(req_size, flags); | |
134 | if (aead_req) | |
135 | tls_init_aead_request(aead_req, aead); | |
136 | return aead_req; | |
137 | } | |
138 | ||
139 | static int tls_enc_records(struct aead_request *aead_req, | |
140 | struct crypto_aead *aead, struct scatterlist *sg_in, | |
141 | struct scatterlist *sg_out, char *aad, char *iv, | |
142 | u64 rcd_sn, int len) | |
143 | { | |
144 | struct scatter_walk out, in; | |
145 | int rc; | |
146 | ||
147 | scatterwalk_start(&in, sg_in); | |
148 | scatterwalk_start(&out, sg_out); | |
149 | ||
150 | do { | |
151 | rc = tls_enc_record(aead_req, aead, aad, iv, | |
152 | cpu_to_be64(rcd_sn), &in, &out, &len); | |
153 | rcd_sn++; | |
154 | ||
155 | } while (rc == 0 && len); | |
156 | ||
157 | scatterwalk_done(&in, 0, 0); | |
158 | scatterwalk_done(&out, 1, 0); | |
159 | ||
160 | return rc; | |
161 | } | |
162 | ||
163 | /* Can't use icsk->icsk_af_ops->send_check here because the ip addresses | |
164 | * might have been changed by NAT. | |
165 | */ | |
166 | static void update_chksum(struct sk_buff *skb, int headln) | |
167 | { | |
168 | struct tcphdr *th = tcp_hdr(skb); | |
169 | int datalen = skb->len - headln; | |
170 | const struct ipv6hdr *ipv6h; | |
171 | const struct iphdr *iph; | |
172 | ||
173 | /* We only changed the payload so if we are using partial we don't | |
174 | * need to update anything. | |
175 | */ | |
176 | if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) | |
177 | return; | |
178 | ||
179 | skb->ip_summed = CHECKSUM_PARTIAL; | |
180 | skb->csum_start = skb_transport_header(skb) - skb->head; | |
181 | skb->csum_offset = offsetof(struct tcphdr, check); | |
182 | ||
183 | if (skb->sk->sk_family == AF_INET6) { | |
184 | ipv6h = ipv6_hdr(skb); | |
185 | th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, | |
186 | datalen, IPPROTO_TCP, 0); | |
187 | } else { | |
188 | iph = ip_hdr(skb); | |
189 | th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen, | |
190 | IPPROTO_TCP, 0); | |
191 | } | |
192 | } | |
193 | ||
194 | static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln) | |
195 | { | |
196 | skb_copy_header(nskb, skb); | |
197 | ||
198 | skb_put(nskb, skb->len); | |
199 | memcpy(nskb->data, skb->data, headln); | |
200 | update_chksum(nskb, headln); | |
201 | ||
202 | nskb->destructor = skb->destructor; | |
203 | nskb->sk = skb->sk; | |
204 | skb->destructor = NULL; | |
205 | skb->sk = NULL; | |
206 | refcount_add(nskb->truesize - skb->truesize, | |
207 | &nskb->sk->sk_wmem_alloc); | |
208 | } | |
209 | ||
210 | /* This function may be called after the user socket is already | |
211 | * closed so make sure we don't use anything freed during | |
212 | * tls_sk_proto_close here | |
213 | */ | |
214 | ||
215 | static int fill_sg_in(struct scatterlist *sg_in, | |
216 | struct sk_buff *skb, | |
d80a1b9d | 217 | struct tls_offload_context_tx *ctx, |
e8f69799 IL |
218 | u64 *rcd_sn, |
219 | s32 *sync_size, | |
220 | int *resync_sgs) | |
221 | { | |
222 | int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); | |
223 | int payload_len = skb->len - tcp_payload_offset; | |
224 | u32 tcp_seq = ntohl(tcp_hdr(skb)->seq); | |
225 | struct tls_record_info *record; | |
226 | unsigned long flags; | |
227 | int remaining; | |
228 | int i; | |
229 | ||
230 | spin_lock_irqsave(&ctx->lock, flags); | |
231 | record = tls_get_record(ctx, tcp_seq, rcd_sn); | |
232 | if (!record) { | |
233 | spin_unlock_irqrestore(&ctx->lock, flags); | |
234 | WARN(1, "Record not found for seq %u\n", tcp_seq); | |
235 | return -EINVAL; | |
236 | } | |
237 | ||
238 | *sync_size = tcp_seq - tls_record_start_seq(record); | |
239 | if (*sync_size < 0) { | |
240 | int is_start_marker = tls_record_is_start_marker(record); | |
241 | ||
242 | spin_unlock_irqrestore(&ctx->lock, flags); | |
243 | /* This should only occur if the relevant record was | |
244 | * already acked. In that case it should be ok | |
245 | * to drop the packet and avoid retransmission. | |
246 | * | |
247 | * There is a corner case where the packet contains | |
248 | * both an acked and a non-acked record. | |
249 | * We currently don't handle that case and rely | |
250 | * on TCP to retranmit a packet that doesn't contain | |
251 | * already acked payload. | |
252 | */ | |
253 | if (!is_start_marker) | |
254 | *sync_size = 0; | |
255 | return -EINVAL; | |
256 | } | |
257 | ||
258 | remaining = *sync_size; | |
259 | for (i = 0; remaining > 0; i++) { | |
260 | skb_frag_t *frag = &record->frags[i]; | |
261 | ||
262 | __skb_frag_ref(frag); | |
263 | sg_set_page(sg_in + i, skb_frag_page(frag), | |
264 | skb_frag_size(frag), frag->page_offset); | |
265 | ||
266 | remaining -= skb_frag_size(frag); | |
267 | ||
268 | if (remaining < 0) | |
269 | sg_in[i].length += remaining; | |
270 | } | |
271 | *resync_sgs = i; | |
272 | ||
273 | spin_unlock_irqrestore(&ctx->lock, flags); | |
274 | if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0) | |
275 | return -EINVAL; | |
276 | ||
277 | return 0; | |
278 | } | |
279 | ||
280 | static void fill_sg_out(struct scatterlist sg_out[3], void *buf, | |
281 | struct tls_context *tls_ctx, | |
282 | struct sk_buff *nskb, | |
283 | int tcp_payload_offset, | |
284 | int payload_len, | |
285 | int sync_size, | |
286 | void *dummy_buf) | |
287 | { | |
288 | sg_set_buf(&sg_out[0], dummy_buf, sync_size); | |
289 | sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len); | |
290 | /* Add room for authentication tag produced by crypto */ | |
291 | dummy_buf += sync_size; | |
292 | sg_set_buf(&sg_out[2], dummy_buf, TLS_CIPHER_AES_GCM_128_TAG_SIZE); | |
293 | } | |
294 | ||
295 | static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx, | |
296 | struct scatterlist sg_out[3], | |
297 | struct scatterlist *sg_in, | |
298 | struct sk_buff *skb, | |
299 | s32 sync_size, u64 rcd_sn) | |
300 | { | |
301 | int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); | |
d80a1b9d | 302 | struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); |
e8f69799 IL |
303 | int payload_len = skb->len - tcp_payload_offset; |
304 | void *buf, *iv, *aad, *dummy_buf; | |
305 | struct aead_request *aead_req; | |
306 | struct sk_buff *nskb = NULL; | |
307 | int buf_len; | |
308 | ||
309 | aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC); | |
310 | if (!aead_req) | |
311 | return NULL; | |
312 | ||
313 | buf_len = TLS_CIPHER_AES_GCM_128_SALT_SIZE + | |
314 | TLS_CIPHER_AES_GCM_128_IV_SIZE + | |
315 | TLS_AAD_SPACE_SIZE + | |
316 | sync_size + | |
317 | TLS_CIPHER_AES_GCM_128_TAG_SIZE; | |
318 | buf = kmalloc(buf_len, GFP_ATOMIC); | |
319 | if (!buf) | |
320 | goto free_req; | |
321 | ||
322 | iv = buf; | |
323 | memcpy(iv, tls_ctx->crypto_send_aes_gcm_128.salt, | |
324 | TLS_CIPHER_AES_GCM_128_SALT_SIZE); | |
325 | aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE + | |
326 | TLS_CIPHER_AES_GCM_128_IV_SIZE; | |
327 | dummy_buf = aad + TLS_AAD_SPACE_SIZE; | |
328 | ||
329 | nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC); | |
330 | if (!nskb) | |
331 | goto free_buf; | |
332 | ||
333 | skb_reserve(nskb, skb_headroom(skb)); | |
334 | ||
335 | fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset, | |
336 | payload_len, sync_size, dummy_buf); | |
337 | ||
338 | if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv, | |
339 | rcd_sn, sync_size + payload_len) < 0) | |
340 | goto free_nskb; | |
341 | ||
342 | complete_skb(nskb, skb, tcp_payload_offset); | |
343 | ||
344 | /* validate_xmit_skb_list assumes that if the skb wasn't segmented | |
345 | * nskb->prev will point to the skb itself | |
346 | */ | |
347 | nskb->prev = nskb; | |
348 | ||
349 | free_buf: | |
350 | kfree(buf); | |
351 | free_req: | |
352 | kfree(aead_req); | |
353 | return nskb; | |
354 | free_nskb: | |
355 | kfree_skb(nskb); | |
356 | nskb = NULL; | |
357 | goto free_buf; | |
358 | } | |
359 | ||
360 | static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb) | |
361 | { | |
362 | int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); | |
363 | struct tls_context *tls_ctx = tls_get_ctx(sk); | |
d80a1b9d | 364 | struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); |
e8f69799 IL |
365 | int payload_len = skb->len - tcp_payload_offset; |
366 | struct scatterlist *sg_in, sg_out[3]; | |
367 | struct sk_buff *nskb = NULL; | |
368 | int sg_in_max_elements; | |
369 | int resync_sgs = 0; | |
370 | s32 sync_size = 0; | |
371 | u64 rcd_sn; | |
372 | ||
373 | /* worst case is: | |
374 | * MAX_SKB_FRAGS in tls_record_info | |
375 | * MAX_SKB_FRAGS + 1 in SKB head and frags. | |
376 | */ | |
377 | sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1; | |
378 | ||
379 | if (!payload_len) | |
380 | return skb; | |
381 | ||
382 | sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC); | |
383 | if (!sg_in) | |
384 | goto free_orig; | |
385 | ||
386 | sg_init_table(sg_in, sg_in_max_elements); | |
387 | sg_init_table(sg_out, ARRAY_SIZE(sg_out)); | |
388 | ||
389 | if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) { | |
390 | /* bypass packets before kernel TLS socket option was set */ | |
391 | if (sync_size < 0 && payload_len <= -sync_size) | |
392 | nskb = skb_get(skb); | |
393 | goto put_sg; | |
394 | } | |
395 | ||
396 | nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn); | |
397 | ||
398 | put_sg: | |
399 | while (resync_sgs) | |
400 | put_page(sg_page(&sg_in[--resync_sgs])); | |
401 | kfree(sg_in); | |
402 | free_orig: | |
403 | kfree_skb(skb); | |
404 | return nskb; | |
405 | } | |
406 | ||
407 | struct sk_buff *tls_validate_xmit_skb(struct sock *sk, | |
408 | struct net_device *dev, | |
409 | struct sk_buff *skb) | |
410 | { | |
411 | if (dev == tls_get_ctx(sk)->netdev) | |
412 | return skb; | |
413 | ||
414 | return tls_sw_fallback(sk, skb); | |
415 | } | |
4799ac81 | 416 | EXPORT_SYMBOL_GPL(tls_validate_xmit_skb); |
e8f69799 IL |
417 | |
418 | int tls_sw_fallback_init(struct sock *sk, | |
d80a1b9d | 419 | struct tls_offload_context_tx *offload_ctx, |
e8f69799 IL |
420 | struct tls_crypto_info *crypto_info) |
421 | { | |
422 | const u8 *key; | |
423 | int rc; | |
424 | ||
425 | offload_ctx->aead_send = | |
426 | crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); | |
427 | if (IS_ERR(offload_ctx->aead_send)) { | |
428 | rc = PTR_ERR(offload_ctx->aead_send); | |
429 | pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc); | |
430 | offload_ctx->aead_send = NULL; | |
431 | goto err_out; | |
432 | } | |
433 | ||
434 | key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key; | |
435 | ||
436 | rc = crypto_aead_setkey(offload_ctx->aead_send, key, | |
437 | TLS_CIPHER_AES_GCM_128_KEY_SIZE); | |
438 | if (rc) | |
439 | goto free_aead; | |
440 | ||
441 | rc = crypto_aead_setauthsize(offload_ctx->aead_send, | |
442 | TLS_CIPHER_AES_GCM_128_TAG_SIZE); | |
443 | if (rc) | |
444 | goto free_aead; | |
445 | ||
446 | return 0; | |
447 | free_aead: | |
448 | crypto_free_aead(offload_ctx->aead_send); | |
449 | err_out: | |
450 | return rc; | |
451 | } |