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 + MAX_IV_SIZE]; 58 const struct tls_cipher_size_desc *cipher_sz; 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 switch (prot->cipher_type) { 66 case TLS_CIPHER_AES_GCM_128: 67 case TLS_CIPHER_AES_GCM_256: 68 break; 69 default: 70 return -EINVAL; 71 } 72 cipher_sz = &tls_cipher_size_desc[prot->cipher_type]; 73 74 buf_size = TLS_HEADER_SIZE + cipher_sz->iv; 75 len = min_t(int, *in_len, buf_size); 76 77 scatterwalk_copychunks(buf, in, len, 0); 78 scatterwalk_copychunks(buf, out, len, 1); 79 80 *in_len -= len; 81 if (!*in_len) 82 return 0; 83 84 scatterwalk_pagedone(in, 0, 1); 85 scatterwalk_pagedone(out, 1, 1); 86 87 len = buf[4] | (buf[3] << 8); 88 len -= cipher_sz->iv; 89 90 tls_make_aad(aad, len - cipher_sz->tag, (char *)&rcd_sn, buf[0], prot); 91 92 memcpy(iv + cipher_sz->salt, buf + TLS_HEADER_SIZE, cipher_sz->iv); 93 94 sg_init_table(sg_in, ARRAY_SIZE(sg_in)); 95 sg_init_table(sg_out, ARRAY_SIZE(sg_out)); 96 sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE); 97 sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE); 98 chain_to_walk(sg_in + 1, in); 99 chain_to_walk(sg_out + 1, out); 100 101 *in_len -= len; 102 if (*in_len < 0) { 103 *in_len += cipher_sz->tag; 104 /* the input buffer doesn't contain the entire record. 105 * trim len accordingly. The resulting authentication tag 106 * will contain garbage, but we don't care, so we won't 107 * include any of it in the output skb 108 * Note that we assume the output buffer length 109 * is larger then input buffer length + tag size 110 */ 111 if (*in_len < 0) 112 len += *in_len; 113 114 *in_len = 0; 115 } 116 117 if (*in_len) { 118 scatterwalk_copychunks(NULL, in, len, 2); 119 scatterwalk_pagedone(in, 0, 1); 120 scatterwalk_copychunks(NULL, out, len, 2); 121 scatterwalk_pagedone(out, 1, 1); 122 } 123 124 len -= cipher_sz->tag; 125 aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv); 126 127 rc = crypto_aead_encrypt(aead_req); 128 129 return rc; 130 } 131 132 static void tls_init_aead_request(struct aead_request *aead_req, 133 struct crypto_aead *aead) 134 { 135 aead_request_set_tfm(aead_req, aead); 136 aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE); 137 } 138 139 static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead, 140 gfp_t flags) 141 { 142 unsigned int req_size = sizeof(struct aead_request) + 143 crypto_aead_reqsize(aead); 144 struct aead_request *aead_req; 145 146 aead_req = kzalloc(req_size, flags); 147 if (aead_req) 148 tls_init_aead_request(aead_req, aead); 149 return aead_req; 150 } 151 152 static int tls_enc_records(struct aead_request *aead_req, 153 struct crypto_aead *aead, struct scatterlist *sg_in, 154 struct scatterlist *sg_out, char *aad, char *iv, 155 u64 rcd_sn, int len, struct tls_prot_info *prot) 156 { 157 struct scatter_walk out, in; 158 int rc; 159 160 scatterwalk_start(&in, sg_in); 161 scatterwalk_start(&out, sg_out); 162 163 do { 164 rc = tls_enc_record(aead_req, aead, aad, iv, 165 cpu_to_be64(rcd_sn), &in, &out, &len, prot); 166 rcd_sn++; 167 168 } while (rc == 0 && len); 169 170 scatterwalk_done(&in, 0, 0); 171 scatterwalk_done(&out, 1, 0); 172 173 return rc; 174 } 175 176 /* Can't use icsk->icsk_af_ops->send_check here because the ip addresses 177 * might have been changed by NAT. 178 */ 179 static void update_chksum(struct sk_buff *skb, int headln) 180 { 181 struct tcphdr *th = tcp_hdr(skb); 182 int datalen = skb->len - headln; 183 const struct ipv6hdr *ipv6h; 184 const struct iphdr *iph; 185 186 /* We only changed the payload so if we are using partial we don't 187 * need to update anything. 188 */ 189 if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) 190 return; 191 192 skb->ip_summed = CHECKSUM_PARTIAL; 193 skb->csum_start = skb_transport_header(skb) - skb->head; 194 skb->csum_offset = offsetof(struct tcphdr, check); 195 196 if (skb->sk->sk_family == AF_INET6) { 197 ipv6h = ipv6_hdr(skb); 198 th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, 199 datalen, IPPROTO_TCP, 0); 200 } else { 201 iph = ip_hdr(skb); 202 th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen, 203 IPPROTO_TCP, 0); 204 } 205 } 206 207 static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln) 208 { 209 struct sock *sk = skb->sk; 210 int delta; 211 212 skb_copy_header(nskb, skb); 213 214 skb_put(nskb, skb->len); 215 memcpy(nskb->data, skb->data, headln); 216 217 nskb->destructor = skb->destructor; 218 nskb->sk = sk; 219 skb->destructor = NULL; 220 skb->sk = NULL; 221 222 update_chksum(nskb, headln); 223 224 /* sock_efree means skb must gone through skb_orphan_partial() */ 225 if (nskb->destructor == sock_efree) 226 return; 227 228 delta = nskb->truesize - skb->truesize; 229 if (likely(delta < 0)) 230 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); 231 else if (delta) 232 refcount_add(delta, &sk->sk_wmem_alloc); 233 } 234 235 /* This function may be called after the user socket is already 236 * closed so make sure we don't use anything freed during 237 * tls_sk_proto_close here 238 */ 239 240 static int fill_sg_in(struct scatterlist *sg_in, 241 struct sk_buff *skb, 242 struct tls_offload_context_tx *ctx, 243 u64 *rcd_sn, 244 s32 *sync_size, 245 int *resync_sgs) 246 { 247 int tcp_payload_offset = skb_tcp_all_headers(skb); 248 int payload_len = skb->len - tcp_payload_offset; 249 u32 tcp_seq = ntohl(tcp_hdr(skb)->seq); 250 struct tls_record_info *record; 251 unsigned long flags; 252 int remaining; 253 int i; 254 255 spin_lock_irqsave(&ctx->lock, flags); 256 record = tls_get_record(ctx, tcp_seq, rcd_sn); 257 if (!record) { 258 spin_unlock_irqrestore(&ctx->lock, flags); 259 return -EINVAL; 260 } 261 262 *sync_size = tcp_seq - tls_record_start_seq(record); 263 if (*sync_size < 0) { 264 int is_start_marker = tls_record_is_start_marker(record); 265 266 spin_unlock_irqrestore(&ctx->lock, flags); 267 /* This should only occur if the relevant record was 268 * already acked. In that case it should be ok 269 * to drop the packet and avoid retransmission. 270 * 271 * There is a corner case where the packet contains 272 * both an acked and a non-acked record. 273 * We currently don't handle that case and rely 274 * on TCP to retransmit a packet that doesn't contain 275 * already acked payload. 276 */ 277 if (!is_start_marker) 278 *sync_size = 0; 279 return -EINVAL; 280 } 281 282 remaining = *sync_size; 283 for (i = 0; remaining > 0; i++) { 284 skb_frag_t *frag = &record->frags[i]; 285 286 __skb_frag_ref(frag); 287 sg_set_page(sg_in + i, skb_frag_page(frag), 288 skb_frag_size(frag), skb_frag_off(frag)); 289 290 remaining -= skb_frag_size(frag); 291 292 if (remaining < 0) 293 sg_in[i].length += remaining; 294 } 295 *resync_sgs = i; 296 297 spin_unlock_irqrestore(&ctx->lock, flags); 298 if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0) 299 return -EINVAL; 300 301 return 0; 302 } 303 304 static void fill_sg_out(struct scatterlist sg_out[3], void *buf, 305 struct tls_context *tls_ctx, 306 struct sk_buff *nskb, 307 int tcp_payload_offset, 308 int payload_len, 309 int sync_size, 310 void *dummy_buf) 311 { 312 const struct tls_cipher_size_desc *cipher_sz = 313 &tls_cipher_size_desc[tls_ctx->crypto_send.info.cipher_type]; 314 315 sg_set_buf(&sg_out[0], dummy_buf, sync_size); 316 sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len); 317 /* Add room for authentication tag produced by crypto */ 318 dummy_buf += sync_size; 319 sg_set_buf(&sg_out[2], dummy_buf, cipher_sz->tag); 320 } 321 322 static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx, 323 struct scatterlist sg_out[3], 324 struct scatterlist *sg_in, 325 struct sk_buff *skb, 326 s32 sync_size, u64 rcd_sn) 327 { 328 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 329 int tcp_payload_offset = skb_tcp_all_headers(skb); 330 int payload_len = skb->len - tcp_payload_offset; 331 const struct tls_cipher_size_desc *cipher_sz; 332 void *buf, *iv, *aad, *dummy_buf, *salt; 333 struct aead_request *aead_req; 334 struct sk_buff *nskb = NULL; 335 int buf_len; 336 337 aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC); 338 if (!aead_req) 339 return NULL; 340 341 switch (tls_ctx->crypto_send.info.cipher_type) { 342 case TLS_CIPHER_AES_GCM_128: 343 salt = tls_ctx->crypto_send.aes_gcm_128.salt; 344 break; 345 case TLS_CIPHER_AES_GCM_256: 346 salt = tls_ctx->crypto_send.aes_gcm_256.salt; 347 break; 348 default: 349 goto free_req; 350 } 351 cipher_sz = &tls_cipher_size_desc[tls_ctx->crypto_send.info.cipher_type]; 352 buf_len = cipher_sz->salt + cipher_sz->iv + TLS_AAD_SPACE_SIZE + 353 sync_size + cipher_sz->tag; 354 buf = kmalloc(buf_len, GFP_ATOMIC); 355 if (!buf) 356 goto free_req; 357 358 iv = buf; 359 memcpy(iv, salt, cipher_sz->salt); 360 aad = buf + cipher_sz->salt + cipher_sz->iv; 361 dummy_buf = aad + TLS_AAD_SPACE_SIZE; 362 363 nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC); 364 if (!nskb) 365 goto free_buf; 366 367 skb_reserve(nskb, skb_headroom(skb)); 368 369 fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset, 370 payload_len, sync_size, dummy_buf); 371 372 if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv, 373 rcd_sn, sync_size + payload_len, 374 &tls_ctx->prot_info) < 0) 375 goto free_nskb; 376 377 complete_skb(nskb, skb, tcp_payload_offset); 378 379 /* validate_xmit_skb_list assumes that if the skb wasn't segmented 380 * nskb->prev will point to the skb itself 381 */ 382 nskb->prev = nskb; 383 384 free_buf: 385 kfree(buf); 386 free_req: 387 kfree(aead_req); 388 return nskb; 389 free_nskb: 390 kfree_skb(nskb); 391 nskb = NULL; 392 goto free_buf; 393 } 394 395 static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb) 396 { 397 int tcp_payload_offset = skb_tcp_all_headers(skb); 398 struct tls_context *tls_ctx = tls_get_ctx(sk); 399 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 400 int payload_len = skb->len - tcp_payload_offset; 401 struct scatterlist *sg_in, sg_out[3]; 402 struct sk_buff *nskb = NULL; 403 int sg_in_max_elements; 404 int resync_sgs = 0; 405 s32 sync_size = 0; 406 u64 rcd_sn; 407 408 /* worst case is: 409 * MAX_SKB_FRAGS in tls_record_info 410 * MAX_SKB_FRAGS + 1 in SKB head and frags. 411 */ 412 sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1; 413 414 if (!payload_len) 415 return skb; 416 417 sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC); 418 if (!sg_in) 419 goto free_orig; 420 421 sg_init_table(sg_in, sg_in_max_elements); 422 sg_init_table(sg_out, ARRAY_SIZE(sg_out)); 423 424 if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) { 425 /* bypass packets before kernel TLS socket option was set */ 426 if (sync_size < 0 && payload_len <= -sync_size) 427 nskb = skb_get(skb); 428 goto put_sg; 429 } 430 431 nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn); 432 433 put_sg: 434 while (resync_sgs) 435 put_page(sg_page(&sg_in[--resync_sgs])); 436 kfree(sg_in); 437 free_orig: 438 if (nskb) 439 consume_skb(skb); 440 else 441 kfree_skb(skb); 442 return nskb; 443 } 444 445 struct sk_buff *tls_validate_xmit_skb(struct sock *sk, 446 struct net_device *dev, 447 struct sk_buff *skb) 448 { 449 if (dev == rcu_dereference_bh(tls_get_ctx(sk)->netdev) || 450 netif_is_bond_master(dev)) 451 return skb; 452 453 return tls_sw_fallback(sk, skb); 454 } 455 EXPORT_SYMBOL_GPL(tls_validate_xmit_skb); 456 457 struct sk_buff *tls_validate_xmit_skb_sw(struct sock *sk, 458 struct net_device *dev, 459 struct sk_buff *skb) 460 { 461 return tls_sw_fallback(sk, skb); 462 } 463 464 struct sk_buff *tls_encrypt_skb(struct sk_buff *skb) 465 { 466 return tls_sw_fallback(skb->sk, skb); 467 } 468 EXPORT_SYMBOL_GPL(tls_encrypt_skb); 469 470 int tls_sw_fallback_init(struct sock *sk, 471 struct tls_offload_context_tx *offload_ctx, 472 struct tls_crypto_info *crypto_info) 473 { 474 const struct tls_cipher_size_desc *cipher_sz; 475 const u8 *key; 476 int rc; 477 478 offload_ctx->aead_send = 479 crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); 480 if (IS_ERR(offload_ctx->aead_send)) { 481 rc = PTR_ERR(offload_ctx->aead_send); 482 pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc); 483 offload_ctx->aead_send = NULL; 484 goto err_out; 485 } 486 487 switch (crypto_info->cipher_type) { 488 case TLS_CIPHER_AES_GCM_128: 489 key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key; 490 break; 491 case TLS_CIPHER_AES_GCM_256: 492 key = ((struct tls12_crypto_info_aes_gcm_256 *)crypto_info)->key; 493 break; 494 default: 495 rc = -EINVAL; 496 goto free_aead; 497 } 498 cipher_sz = &tls_cipher_size_desc[crypto_info->cipher_type]; 499 500 rc = crypto_aead_setkey(offload_ctx->aead_send, key, cipher_sz->key); 501 if (rc) 502 goto free_aead; 503 504 rc = crypto_aead_setauthsize(offload_ctx->aead_send, cipher_sz->tag); 505 if (rc) 506 goto free_aead; 507 508 return 0; 509 free_aead: 510 crypto_free_aead(offload_ctx->aead_send); 511 err_out: 512 return rc; 513 } 514