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