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 #include <linux/skbuff_ref.h>
37
38 #include "tls.h"
39
40 static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk)
41 {
42 struct scatterlist *src = walk->sg;
43 int diff = walk->offset - src->offset;
44
45 sg_set_page(sg, sg_page(src),
46 src->length - diff, walk->offset);
47
48 scatterwalk_crypto_chain(sg, sg_next(src), 2);
49 }
50
51 static int tls_enc_record(struct aead_request *aead_req,
52 struct crypto_aead *aead, char *aad,
53 char *iv, __be64 rcd_sn,
54 struct scatter_walk *in,
55 struct scatter_walk *out, int *in_len,
56 struct tls_prot_info *prot)
57 {
58 unsigned char buf[TLS_HEADER_SIZE + TLS_MAX_IV_SIZE];
59 const struct tls_cipher_desc *cipher_desc;
60 struct scatterlist sg_in[3];
61 struct scatterlist sg_out[3];
62 unsigned int buf_size;
63 u16 len;
64 int rc;
65
66 cipher_desc = get_cipher_desc(prot->cipher_type);
67 DEBUG_NET_WARN_ON_ONCE(!cipher_desc || !cipher_desc->offloadable);
68
69 buf_size = TLS_HEADER_SIZE + cipher_desc->iv;
70 len = min_t(int, *in_len, buf_size);
71
72 scatterwalk_copychunks(buf, in, len, 0);
73 scatterwalk_copychunks(buf, out, len, 1);
74
75 *in_len -= len;
76 if (!*in_len)
77 return 0;
78
79 scatterwalk_pagedone(in, 0, 1);
80 scatterwalk_pagedone(out, 1, 1);
81
82 len = buf[4] | (buf[3] << 8);
83 len -= cipher_desc->iv;
84
85 tls_make_aad(aad, len - cipher_desc->tag, (char *)&rcd_sn, buf[0], prot);
86
87 memcpy(iv + cipher_desc->salt, buf + TLS_HEADER_SIZE, cipher_desc->iv);
88
89 sg_init_table(sg_in, ARRAY_SIZE(sg_in));
90 sg_init_table(sg_out, ARRAY_SIZE(sg_out));
91 sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE);
92 sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE);
93 chain_to_walk(sg_in + 1, in);
94 chain_to_walk(sg_out + 1, out);
95
96 *in_len -= len;
97 if (*in_len < 0) {
98 *in_len += cipher_desc->tag;
99 /* the input buffer doesn't contain the entire record.
100 * trim len accordingly. The resulting authentication tag
101 * will contain garbage, but we don't care, so we won't
102 * include any of it in the output skb
103 * Note that we assume the output buffer length
104 * is larger then input buffer length + tag size
105 */
106 if (*in_len < 0)
107 len += *in_len;
108
109 *in_len = 0;
110 }
111
112 if (*in_len) {
113 scatterwalk_copychunks(NULL, in, len, 2);
114 scatterwalk_pagedone(in, 0, 1);
115 scatterwalk_copychunks(NULL, out, len, 2);
116 scatterwalk_pagedone(out, 1, 1);
117 }
118
119 len -= cipher_desc->tag;
120 aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv);
121
122 rc = crypto_aead_encrypt(aead_req);
123
124 return rc;
125 }
126
127 static void tls_init_aead_request(struct aead_request *aead_req,
128 struct crypto_aead *aead)
129 {
130 aead_request_set_tfm(aead_req, aead);
131 aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
132 }
133
134 static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead,
135 gfp_t flags)
136 {
137 unsigned int req_size = sizeof(struct aead_request) +
138 crypto_aead_reqsize(aead);
139 struct aead_request *aead_req;
140
141 aead_req = kzalloc(req_size, flags);
142 if (aead_req)
143 tls_init_aead_request(aead_req, aead);
144 return aead_req;
145 }
146
147 static int tls_enc_records(struct aead_request *aead_req,
148 struct crypto_aead *aead, struct scatterlist *sg_in,
149 struct scatterlist *sg_out, char *aad, char *iv,
150 u64 rcd_sn, int len, struct tls_prot_info *prot)
151 {
152 struct scatter_walk out, in;
153 int rc;
154
155 scatterwalk_start(&in, sg_in);
156 scatterwalk_start(&out, sg_out);
157
158 do {
159 rc = tls_enc_record(aead_req, aead, aad, iv,
160 cpu_to_be64(rcd_sn), &in, &out, &len, prot);
161 rcd_sn++;
162
163 } while (rc == 0 && len);
164
165 scatterwalk_done(&in, 0, 0);
166 scatterwalk_done(&out, 1, 0);
167
168 return rc;
169 }
170
171 /* Can't use icsk->icsk_af_ops->send_check here because the ip addresses
172 * might have been changed by NAT.
173 */
174 static void update_chksum(struct sk_buff *skb, int headln)
175 {
176 struct tcphdr *th = tcp_hdr(skb);
177 int datalen = skb->len - headln;
178 const struct ipv6hdr *ipv6h;
179 const struct iphdr *iph;
180
181 /* We only changed the payload so if we are using partial we don't
182 * need to update anything.
183 */
184 if (likely(skb->ip_summed == CHECKSUM_PARTIAL))
185 return;
186
187 skb->ip_summed = CHECKSUM_PARTIAL;
188 skb->csum_start = skb_transport_header(skb) - skb->head;
189 skb->csum_offset = offsetof(struct tcphdr, check);
190
191 if (skb->sk->sk_family == AF_INET6) {
192 ipv6h = ipv6_hdr(skb);
193 th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
194 datalen, IPPROTO_TCP, 0);
195 } else {
196 iph = ip_hdr(skb);
197 th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen,
198 IPPROTO_TCP, 0);
199 }
200 }
201
202 static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln)
203 {
204 struct sock *sk = skb->sk;
205 int delta;
206
207 skb_copy_header(nskb, skb);
208
209 skb_put(nskb, skb->len);
210 memcpy(nskb->data, skb->data, headln);
211
212 nskb->destructor = skb->destructor;
213 nskb->sk = sk;
214 skb->destructor = NULL;
215 skb->sk = NULL;
216
217 update_chksum(nskb, headln);
218
219 /* sock_efree means skb must gone through skb_orphan_partial() */
220 if (nskb->destructor == sock_efree)
221 return;
222
223 delta = nskb->truesize - skb->truesize;
224 if (likely(delta < 0))
225 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc));
226 else if (delta)
227 refcount_add(delta, &sk->sk_wmem_alloc);
228 }
229
230 /* This function may be called after the user socket is already
231 * closed so make sure we don't use anything freed during
232 * tls_sk_proto_close here
233 */
234
235 static int fill_sg_in(struct scatterlist *sg_in,
236 struct sk_buff *skb,
237 struct tls_offload_context_tx *ctx,
238 u64 *rcd_sn,
239 s32 *sync_size,
240 int *resync_sgs)
241 {
242 int tcp_payload_offset = skb_tcp_all_headers(skb);
243 int payload_len = skb->len - tcp_payload_offset;
244 u32 tcp_seq = ntohl(tcp_hdr(skb)->seq);
245 struct tls_record_info *record;
246 unsigned long flags;
247 int remaining;
248 int i;
249
250 spin_lock_irqsave(&ctx->lock, flags);
251 record = tls_get_record(ctx, tcp_seq, rcd_sn);
252 if (!record) {
253 spin_unlock_irqrestore(&ctx->lock, flags);
254 return -EINVAL;
255 }
256
257 *sync_size = tcp_seq - tls_record_start_seq(record);
258 if (*sync_size < 0) {
259 int is_start_marker = tls_record_is_start_marker(record);
260
261 spin_unlock_irqrestore(&ctx->lock, flags);
262 /* This should only occur if the relevant record was
263 * already acked. In that case it should be ok
264 * to drop the packet and avoid retransmission.
265 *
266 * There is a corner case where the packet contains
267 * both an acked and a non-acked record.
268 * We currently don't handle that case and rely
269 * on TCP to retransmit a packet that doesn't contain
270 * already acked payload.
271 */
272 if (!is_start_marker)
273 *sync_size = 0;
274 return -EINVAL;
275 }
276
277 remaining = *sync_size;
278 for (i = 0; remaining > 0; i++) {
279 skb_frag_t *frag = &record->frags[i];
280
281 __skb_frag_ref(frag);
282 sg_set_page(sg_in + i, skb_frag_page(frag),
283 skb_frag_size(frag), skb_frag_off(frag));
284
285 remaining -= skb_frag_size(frag);
286
287 if (remaining < 0)
288 sg_in[i].length += remaining;
289 }
290 *resync_sgs = i;
291
292 spin_unlock_irqrestore(&ctx->lock, flags);
293 if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0)
294 return -EINVAL;
295
296 return 0;
297 }
298
299 static void fill_sg_out(struct scatterlist sg_out[3], void *buf,
300 struct tls_context *tls_ctx,
301 struct sk_buff *nskb,
302 int tcp_payload_offset,
303 int payload_len,
304 int sync_size,
305 void *dummy_buf)
306 {
307 const struct tls_cipher_desc *cipher_desc =
308 get_cipher_desc(tls_ctx->crypto_send.info.cipher_type);
309
310 sg_set_buf(&sg_out[0], dummy_buf, sync_size);
311 sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len);
312 /* Add room for authentication tag produced by crypto */
313 dummy_buf += sync_size;
314 sg_set_buf(&sg_out[2], dummy_buf, cipher_desc->tag);
315 }
316
317 static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx,
318 struct scatterlist sg_out[3],
319 struct scatterlist *sg_in,
320 struct sk_buff *skb,
321 s32 sync_size, u64 rcd_sn)
322 {
323 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
324 int tcp_payload_offset = skb_tcp_all_headers(skb);
325 int payload_len = skb->len - tcp_payload_offset;
326 const struct tls_cipher_desc *cipher_desc;
327 void *buf, *iv, *aad, *dummy_buf, *salt;
328 struct aead_request *aead_req;
329 struct sk_buff *nskb = NULL;
330 int buf_len;
331
332 aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC);
333 if (!aead_req)
334 return NULL;
335
336 cipher_desc = get_cipher_desc(tls_ctx->crypto_send.info.cipher_type);
337 DEBUG_NET_WARN_ON_ONCE(!cipher_desc || !cipher_desc->offloadable);
338
339 buf_len = cipher_desc->salt + cipher_desc->iv + TLS_AAD_SPACE_SIZE +
340 sync_size + cipher_desc->tag;
341 buf = kmalloc(buf_len, GFP_ATOMIC);
342 if (!buf)
343 goto free_req;
344
345 iv = buf;
346 salt = crypto_info_salt(&tls_ctx->crypto_send.info, cipher_desc);
347 memcpy(iv, salt, cipher_desc->salt);
348 aad = buf + cipher_desc->salt + cipher_desc->iv;
349 dummy_buf = aad + TLS_AAD_SPACE_SIZE;
350
351 nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC);
352 if (!nskb)
353 goto free_buf;
354
355 skb_reserve(nskb, skb_headroom(skb));
356
357 fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset,
358 payload_len, sync_size, dummy_buf);
359
360 if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv,
361 rcd_sn, sync_size + payload_len,
362 &tls_ctx->prot_info) < 0)
363 goto free_nskb;
364
365 complete_skb(nskb, skb, tcp_payload_offset);
366
367 /* validate_xmit_skb_list assumes that if the skb wasn't segmented
368 * nskb->prev will point to the skb itself
369 */
370 nskb->prev = nskb;
371
372 free_buf:
373 kfree(buf);
374 free_req:
375 kfree(aead_req);
376 return nskb;
377 free_nskb:
378 kfree_skb(nskb);
379 nskb = NULL;
380 goto free_buf;
381 }
382
383 static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb)
384 {
385 int tcp_payload_offset = skb_tcp_all_headers(skb);
386 struct tls_context *tls_ctx = tls_get_ctx(sk);
387 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
388 int payload_len = skb->len - tcp_payload_offset;
389 struct scatterlist *sg_in, sg_out[3];
390 struct sk_buff *nskb = NULL;
391 int sg_in_max_elements;
392 int resync_sgs = 0;
393 s32 sync_size = 0;
394 u64 rcd_sn;
395
396 /* worst case is:
397 * MAX_SKB_FRAGS in tls_record_info
398 * MAX_SKB_FRAGS + 1 in SKB head and frags.
399 */
400 sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1;
401
402 if (!payload_len)
403 return skb;
404
405 sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC);
406 if (!sg_in)
407 goto free_orig;
408
409 sg_init_table(sg_in, sg_in_max_elements);
410 sg_init_table(sg_out, ARRAY_SIZE(sg_out));
411
412 if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) {
413 /* bypass packets before kernel TLS socket option was set */
414 if (sync_size < 0 && payload_len <= -sync_size)
415 nskb = skb_get(skb);
416 goto put_sg;
417 }
418
419 nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn);
420
421 put_sg:
422 while (resync_sgs)
423 put_page(sg_page(&sg_in[--resync_sgs]));
424 kfree(sg_in);
425 free_orig:
426 if (nskb)
427 consume_skb(skb);
428 else
429 kfree_skb(skb);
430 return nskb;
431 }
432
433 struct sk_buff *tls_validate_xmit_skb(struct sock *sk,
434 struct net_device *dev,
435 struct sk_buff *skb)
436 {
437 if (dev == rcu_dereference_bh(tls_get_ctx(sk)->netdev) ||
438 netif_is_bond_master(dev))
439 return skb;
440
441 return tls_sw_fallback(sk, skb);
442 }
443 EXPORT_SYMBOL_GPL(tls_validate_xmit_skb);
444
445 struct sk_buff *tls_validate_xmit_skb_sw(struct sock *sk,
446 struct net_device *dev,
447 struct sk_buff *skb)
448 {
449 return tls_sw_fallback(sk, skb);
450 }
451
452 struct sk_buff *tls_encrypt_skb(struct sk_buff *skb)
453 {
454 return tls_sw_fallback(skb->sk, skb);
455 }
456 EXPORT_SYMBOL_GPL(tls_encrypt_skb);
457
458 int tls_sw_fallback_init(struct sock *sk,
459 struct tls_offload_context_tx *offload_ctx,
460 struct tls_crypto_info *crypto_info)
461 {
462 const struct tls_cipher_desc *cipher_desc;
463 int rc;
464
465 cipher_desc = get_cipher_desc(crypto_info->cipher_type);
466 if (!cipher_desc || !cipher_desc->offloadable)
467 return -EINVAL;
468
469 offload_ctx->aead_send =
470 crypto_alloc_aead(cipher_desc->cipher_name, 0, CRYPTO_ALG_ASYNC);
471 if (IS_ERR(offload_ctx->aead_send)) {
472 rc = PTR_ERR(offload_ctx->aead_send);
473 pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc);
474 offload_ctx->aead_send = NULL;
475 goto err_out;
476 }
477
478 rc = crypto_aead_setkey(offload_ctx->aead_send,
479 crypto_info_key(crypto_info, cipher_desc),
480 cipher_desc->key);
481 if (rc)
482 goto free_aead;
483
484 rc = crypto_aead_setauthsize(offload_ctx->aead_send, cipher_desc->tag);
485 if (rc)
486 goto free_aead;
487
488 return 0;
489 free_aead:
490 crypto_free_aead(offload_ctx->aead_send);
491 err_out:
492 return rc;
493 }
494
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