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