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