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 static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk) 38 { 39 struct scatterlist *src = walk->sg; 40 int diff = walk->offset - src->offset; 41 42 sg_set_page(sg, sg_page(src), 43 src->length - diff, walk->offset); 44 45 scatterwalk_crypto_chain(sg, sg_next(src), 2); 46 } 47 48 static int tls_enc_record(struct aead_request *aead_req, 49 struct crypto_aead *aead, char *aad, 50 char *iv, __be64 rcd_sn, 51 struct scatter_walk *in, 52 struct scatter_walk *out, int *in_len, 53 struct tls_prot_info *prot) 54 { 55 unsigned char buf[TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE]; 56 struct scatterlist sg_in[3]; 57 struct scatterlist sg_out[3]; 58 u16 len; 59 int rc; 60 61 len = min_t(int, *in_len, ARRAY_SIZE(buf)); 62 63 scatterwalk_copychunks(buf, in, len, 0); 64 scatterwalk_copychunks(buf, out, len, 1); 65 66 *in_len -= len; 67 if (!*in_len) 68 return 0; 69 70 scatterwalk_pagedone(in, 0, 1); 71 scatterwalk_pagedone(out, 1, 1); 72 73 len = buf[4] | (buf[3] << 8); 74 len -= TLS_CIPHER_AES_GCM_128_IV_SIZE; 75 76 tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE, 77 (char *)&rcd_sn, buf[0], prot); 78 79 memcpy(iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, buf + TLS_HEADER_SIZE, 80 TLS_CIPHER_AES_GCM_128_IV_SIZE); 81 82 sg_init_table(sg_in, ARRAY_SIZE(sg_in)); 83 sg_init_table(sg_out, ARRAY_SIZE(sg_out)); 84 sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE); 85 sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE); 86 chain_to_walk(sg_in + 1, in); 87 chain_to_walk(sg_out + 1, out); 88 89 *in_len -= len; 90 if (*in_len < 0) { 91 *in_len += TLS_CIPHER_AES_GCM_128_TAG_SIZE; 92 /* the input buffer doesn't contain the entire record. 93 * trim len accordingly. The resulting authentication tag 94 * will contain garbage, but we don't care, so we won't 95 * include any of it in the output skb 96 * Note that we assume the output buffer length 97 * is larger then input buffer length + tag size 98 */ 99 if (*in_len < 0) 100 len += *in_len; 101 102 *in_len = 0; 103 } 104 105 if (*in_len) { 106 scatterwalk_copychunks(NULL, in, len, 2); 107 scatterwalk_pagedone(in, 0, 1); 108 scatterwalk_copychunks(NULL, out, len, 2); 109 scatterwalk_pagedone(out, 1, 1); 110 } 111 112 len -= TLS_CIPHER_AES_GCM_128_TAG_SIZE; 113 aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv); 114 115 rc = crypto_aead_encrypt(aead_req); 116 117 return rc; 118 } 119 120 static void tls_init_aead_request(struct aead_request *aead_req, 121 struct crypto_aead *aead) 122 { 123 aead_request_set_tfm(aead_req, aead); 124 aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE); 125 } 126 127 static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead, 128 gfp_t flags) 129 { 130 unsigned int req_size = sizeof(struct aead_request) + 131 crypto_aead_reqsize(aead); 132 struct aead_request *aead_req; 133 134 aead_req = kzalloc(req_size, flags); 135 if (aead_req) 136 tls_init_aead_request(aead_req, aead); 137 return aead_req; 138 } 139 140 static int tls_enc_records(struct aead_request *aead_req, 141 struct crypto_aead *aead, struct scatterlist *sg_in, 142 struct scatterlist *sg_out, char *aad, char *iv, 143 u64 rcd_sn, int len, struct tls_prot_info *prot) 144 { 145 struct scatter_walk out, in; 146 int rc; 147 148 scatterwalk_start(&in, sg_in); 149 scatterwalk_start(&out, sg_out); 150 151 do { 152 rc = tls_enc_record(aead_req, aead, aad, iv, 153 cpu_to_be64(rcd_sn), &in, &out, &len, prot); 154 rcd_sn++; 155 156 } while (rc == 0 && len); 157 158 scatterwalk_done(&in, 0, 0); 159 scatterwalk_done(&out, 1, 0); 160 161 return rc; 162 } 163 164 /* Can't use icsk->icsk_af_ops->send_check here because the ip addresses 165 * might have been changed by NAT. 166 */ 167 static void update_chksum(struct sk_buff *skb, int headln) 168 { 169 struct tcphdr *th = tcp_hdr(skb); 170 int datalen = skb->len - headln; 171 const struct ipv6hdr *ipv6h; 172 const struct iphdr *iph; 173 174 /* We only changed the payload so if we are using partial we don't 175 * need to update anything. 176 */ 177 if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) 178 return; 179 180 skb->ip_summed = CHECKSUM_PARTIAL; 181 skb->csum_start = skb_transport_header(skb) - skb->head; 182 skb->csum_offset = offsetof(struct tcphdr, check); 183 184 if (skb->sk->sk_family == AF_INET6) { 185 ipv6h = ipv6_hdr(skb); 186 th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, 187 datalen, IPPROTO_TCP, 0); 188 } else { 189 iph = ip_hdr(skb); 190 th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen, 191 IPPROTO_TCP, 0); 192 } 193 } 194 195 static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln) 196 { 197 struct sock *sk = skb->sk; 198 int delta; 199 200 skb_copy_header(nskb, skb); 201 202 skb_put(nskb, skb->len); 203 memcpy(nskb->data, skb->data, headln); 204 205 nskb->destructor = skb->destructor; 206 nskb->sk = sk; 207 skb->destructor = NULL; 208 skb->sk = NULL; 209 210 update_chksum(nskb, headln); 211 212 /* sock_efree means skb must gone through skb_orphan_partial() */ 213 if (nskb->destructor == sock_efree) 214 return; 215 216 delta = nskb->truesize - skb->truesize; 217 if (likely(delta < 0)) 218 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); 219 else if (delta) 220 refcount_add(delta, &sk->sk_wmem_alloc); 221 } 222 223 /* This function may be called after the user socket is already 224 * closed so make sure we don't use anything freed during 225 * tls_sk_proto_close here 226 */ 227 228 static int fill_sg_in(struct scatterlist *sg_in, 229 struct sk_buff *skb, 230 struct tls_offload_context_tx *ctx, 231 u64 *rcd_sn, 232 s32 *sync_size, 233 int *resync_sgs) 234 { 235 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 236 int payload_len = skb->len - tcp_payload_offset; 237 u32 tcp_seq = ntohl(tcp_hdr(skb)->seq); 238 struct tls_record_info *record; 239 unsigned long flags; 240 int remaining; 241 int i; 242 243 spin_lock_irqsave(&ctx->lock, flags); 244 record = tls_get_record(ctx, tcp_seq, rcd_sn); 245 if (!record) { 246 spin_unlock_irqrestore(&ctx->lock, flags); 247 return -EINVAL; 248 } 249 250 *sync_size = tcp_seq - tls_record_start_seq(record); 251 if (*sync_size < 0) { 252 int is_start_marker = tls_record_is_start_marker(record); 253 254 spin_unlock_irqrestore(&ctx->lock, flags); 255 /* This should only occur if the relevant record was 256 * already acked. In that case it should be ok 257 * to drop the packet and avoid retransmission. 258 * 259 * There is a corner case where the packet contains 260 * both an acked and a non-acked record. 261 * We currently don't handle that case and rely 262 * on TCP to retranmit a packet that doesn't contain 263 * already acked payload. 264 */ 265 if (!is_start_marker) 266 *sync_size = 0; 267 return -EINVAL; 268 } 269 270 remaining = *sync_size; 271 for (i = 0; remaining > 0; i++) { 272 skb_frag_t *frag = &record->frags[i]; 273 274 __skb_frag_ref(frag); 275 sg_set_page(sg_in + i, skb_frag_page(frag), 276 skb_frag_size(frag), skb_frag_off(frag)); 277 278 remaining -= skb_frag_size(frag); 279 280 if (remaining < 0) 281 sg_in[i].length += remaining; 282 } 283 *resync_sgs = i; 284 285 spin_unlock_irqrestore(&ctx->lock, flags); 286 if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0) 287 return -EINVAL; 288 289 return 0; 290 } 291 292 static void fill_sg_out(struct scatterlist sg_out[3], void *buf, 293 struct tls_context *tls_ctx, 294 struct sk_buff *nskb, 295 int tcp_payload_offset, 296 int payload_len, 297 int sync_size, 298 void *dummy_buf) 299 { 300 sg_set_buf(&sg_out[0], dummy_buf, sync_size); 301 sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len); 302 /* Add room for authentication tag produced by crypto */ 303 dummy_buf += sync_size; 304 sg_set_buf(&sg_out[2], dummy_buf, TLS_CIPHER_AES_GCM_128_TAG_SIZE); 305 } 306 307 static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx, 308 struct scatterlist sg_out[3], 309 struct scatterlist *sg_in, 310 struct sk_buff *skb, 311 s32 sync_size, u64 rcd_sn) 312 { 313 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 314 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 315 int payload_len = skb->len - tcp_payload_offset; 316 void *buf, *iv, *aad, *dummy_buf; 317 struct aead_request *aead_req; 318 struct sk_buff *nskb = NULL; 319 int buf_len; 320 321 aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC); 322 if (!aead_req) 323 return NULL; 324 325 buf_len = TLS_CIPHER_AES_GCM_128_SALT_SIZE + 326 TLS_CIPHER_AES_GCM_128_IV_SIZE + 327 TLS_AAD_SPACE_SIZE + 328 sync_size + 329 TLS_CIPHER_AES_GCM_128_TAG_SIZE; 330 buf = kmalloc(buf_len, GFP_ATOMIC); 331 if (!buf) 332 goto free_req; 333 334 iv = buf; 335 memcpy(iv, tls_ctx->crypto_send.aes_gcm_128.salt, 336 TLS_CIPHER_AES_GCM_128_SALT_SIZE); 337 aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE + 338 TLS_CIPHER_AES_GCM_128_IV_SIZE; 339 dummy_buf = aad + TLS_AAD_SPACE_SIZE; 340 341 nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC); 342 if (!nskb) 343 goto free_buf; 344 345 skb_reserve(nskb, skb_headroom(skb)); 346 347 fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset, 348 payload_len, sync_size, dummy_buf); 349 350 if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv, 351 rcd_sn, sync_size + payload_len, 352 &tls_ctx->prot_info) < 0) 353 goto free_nskb; 354 355 complete_skb(nskb, skb, tcp_payload_offset); 356 357 /* validate_xmit_skb_list assumes that if the skb wasn't segmented 358 * nskb->prev will point to the skb itself 359 */ 360 nskb->prev = nskb; 361 362 free_buf: 363 kfree(buf); 364 free_req: 365 kfree(aead_req); 366 return nskb; 367 free_nskb: 368 kfree_skb(nskb); 369 nskb = NULL; 370 goto free_buf; 371 } 372 373 static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb) 374 { 375 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 376 struct tls_context *tls_ctx = tls_get_ctx(sk); 377 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 378 int payload_len = skb->len - tcp_payload_offset; 379 struct scatterlist *sg_in, sg_out[3]; 380 struct sk_buff *nskb = NULL; 381 int sg_in_max_elements; 382 int resync_sgs = 0; 383 s32 sync_size = 0; 384 u64 rcd_sn; 385 386 /* worst case is: 387 * MAX_SKB_FRAGS in tls_record_info 388 * MAX_SKB_FRAGS + 1 in SKB head and frags. 389 */ 390 sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1; 391 392 if (!payload_len) 393 return skb; 394 395 sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC); 396 if (!sg_in) 397 goto free_orig; 398 399 sg_init_table(sg_in, sg_in_max_elements); 400 sg_init_table(sg_out, ARRAY_SIZE(sg_out)); 401 402 if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) { 403 /* bypass packets before kernel TLS socket option was set */ 404 if (sync_size < 0 && payload_len <= -sync_size) 405 nskb = skb_get(skb); 406 goto put_sg; 407 } 408 409 nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn); 410 411 put_sg: 412 while (resync_sgs) 413 put_page(sg_page(&sg_in[--resync_sgs])); 414 kfree(sg_in); 415 free_orig: 416 if (nskb) 417 consume_skb(skb); 418 else 419 kfree_skb(skb); 420 return nskb; 421 } 422 423 struct sk_buff *tls_validate_xmit_skb(struct sock *sk, 424 struct net_device *dev, 425 struct sk_buff *skb) 426 { 427 if (dev == tls_get_ctx(sk)->netdev || netif_is_bond_master(dev)) 428 return skb; 429 430 return tls_sw_fallback(sk, skb); 431 } 432 EXPORT_SYMBOL_GPL(tls_validate_xmit_skb); 433 434 struct sk_buff *tls_validate_xmit_skb_sw(struct sock *sk, 435 struct net_device *dev, 436 struct sk_buff *skb) 437 { 438 return tls_sw_fallback(sk, skb); 439 } 440 441 struct sk_buff *tls_encrypt_skb(struct sk_buff *skb) 442 { 443 return tls_sw_fallback(skb->sk, skb); 444 } 445 EXPORT_SYMBOL_GPL(tls_encrypt_skb); 446 447 int tls_sw_fallback_init(struct sock *sk, 448 struct tls_offload_context_tx *offload_ctx, 449 struct tls_crypto_info *crypto_info) 450 { 451 const u8 *key; 452 int rc; 453 454 offload_ctx->aead_send = 455 crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); 456 if (IS_ERR(offload_ctx->aead_send)) { 457 rc = PTR_ERR(offload_ctx->aead_send); 458 pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc); 459 offload_ctx->aead_send = NULL; 460 goto err_out; 461 } 462 463 key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key; 464 465 rc = crypto_aead_setkey(offload_ctx->aead_send, key, 466 TLS_CIPHER_AES_GCM_128_KEY_SIZE); 467 if (rc) 468 goto free_aead; 469 470 rc = crypto_aead_setauthsize(offload_ctx->aead_send, 471 TLS_CIPHER_AES_GCM_128_TAG_SIZE); 472 if (rc) 473 goto free_aead; 474 475 return 0; 476 free_aead: 477 crypto_free_aead(offload_ctx->aead_send); 478 err_out: 479 return rc; 480 } 481