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 { 54 unsigned char buf[TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE]; 55 struct scatterlist sg_in[3]; 56 struct scatterlist sg_out[3]; 57 u16 len; 58 int rc; 59 60 len = min_t(int, *in_len, ARRAY_SIZE(buf)); 61 62 scatterwalk_copychunks(buf, in, len, 0); 63 scatterwalk_copychunks(buf, out, len, 1); 64 65 *in_len -= len; 66 if (!*in_len) 67 return 0; 68 69 scatterwalk_pagedone(in, 0, 1); 70 scatterwalk_pagedone(out, 1, 1); 71 72 len = buf[4] | (buf[3] << 8); 73 len -= TLS_CIPHER_AES_GCM_128_IV_SIZE; 74 75 tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE, 76 (char *)&rcd_sn, sizeof(rcd_sn), buf[0], 77 TLS_1_2_VERSION); 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) 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); 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 delta = nskb->truesize - skb->truesize; 213 if (likely(delta < 0)) 214 WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); 215 else if (delta) 216 refcount_add(delta, &sk->sk_wmem_alloc); 217 } 218 219 /* This function may be called after the user socket is already 220 * closed so make sure we don't use anything freed during 221 * tls_sk_proto_close here 222 */ 223 224 static int fill_sg_in(struct scatterlist *sg_in, 225 struct sk_buff *skb, 226 struct tls_offload_context_tx *ctx, 227 u64 *rcd_sn, 228 s32 *sync_size, 229 int *resync_sgs) 230 { 231 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 232 int payload_len = skb->len - tcp_payload_offset; 233 u32 tcp_seq = ntohl(tcp_hdr(skb)->seq); 234 struct tls_record_info *record; 235 unsigned long flags; 236 int remaining; 237 int i; 238 239 spin_lock_irqsave(&ctx->lock, flags); 240 record = tls_get_record(ctx, tcp_seq, rcd_sn); 241 if (!record) { 242 spin_unlock_irqrestore(&ctx->lock, flags); 243 WARN(1, "Record not found for seq %u\n", tcp_seq); 244 return -EINVAL; 245 } 246 247 *sync_size = tcp_seq - tls_record_start_seq(record); 248 if (*sync_size < 0) { 249 int is_start_marker = tls_record_is_start_marker(record); 250 251 spin_unlock_irqrestore(&ctx->lock, flags); 252 /* This should only occur if the relevant record was 253 * already acked. In that case it should be ok 254 * to drop the packet and avoid retransmission. 255 * 256 * There is a corner case where the packet contains 257 * both an acked and a non-acked record. 258 * We currently don't handle that case and rely 259 * on TCP to retranmit a packet that doesn't contain 260 * already acked payload. 261 */ 262 if (!is_start_marker) 263 *sync_size = 0; 264 return -EINVAL; 265 } 266 267 remaining = *sync_size; 268 for (i = 0; remaining > 0; i++) { 269 skb_frag_t *frag = &record->frags[i]; 270 271 __skb_frag_ref(frag); 272 sg_set_page(sg_in + i, skb_frag_page(frag), 273 skb_frag_size(frag), frag->page_offset); 274 275 remaining -= skb_frag_size(frag); 276 277 if (remaining < 0) 278 sg_in[i].length += remaining; 279 } 280 *resync_sgs = i; 281 282 spin_unlock_irqrestore(&ctx->lock, flags); 283 if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0) 284 return -EINVAL; 285 286 return 0; 287 } 288 289 static void fill_sg_out(struct scatterlist sg_out[3], void *buf, 290 struct tls_context *tls_ctx, 291 struct sk_buff *nskb, 292 int tcp_payload_offset, 293 int payload_len, 294 int sync_size, 295 void *dummy_buf) 296 { 297 sg_set_buf(&sg_out[0], dummy_buf, sync_size); 298 sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len); 299 /* Add room for authentication tag produced by crypto */ 300 dummy_buf += sync_size; 301 sg_set_buf(&sg_out[2], dummy_buf, TLS_CIPHER_AES_GCM_128_TAG_SIZE); 302 } 303 304 static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx, 305 struct scatterlist sg_out[3], 306 struct scatterlist *sg_in, 307 struct sk_buff *skb, 308 s32 sync_size, u64 rcd_sn) 309 { 310 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 311 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 312 int payload_len = skb->len - tcp_payload_offset; 313 void *buf, *iv, *aad, *dummy_buf; 314 struct aead_request *aead_req; 315 struct sk_buff *nskb = NULL; 316 int buf_len; 317 318 aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC); 319 if (!aead_req) 320 return NULL; 321 322 buf_len = TLS_CIPHER_AES_GCM_128_SALT_SIZE + 323 TLS_CIPHER_AES_GCM_128_IV_SIZE + 324 TLS_AAD_SPACE_SIZE + 325 sync_size + 326 TLS_CIPHER_AES_GCM_128_TAG_SIZE; 327 buf = kmalloc(buf_len, GFP_ATOMIC); 328 if (!buf) 329 goto free_req; 330 331 iv = buf; 332 memcpy(iv, tls_ctx->crypto_send.aes_gcm_128.salt, 333 TLS_CIPHER_AES_GCM_128_SALT_SIZE); 334 aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE + 335 TLS_CIPHER_AES_GCM_128_IV_SIZE; 336 dummy_buf = aad + TLS_AAD_SPACE_SIZE; 337 338 nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC); 339 if (!nskb) 340 goto free_buf; 341 342 skb_reserve(nskb, skb_headroom(skb)); 343 344 fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset, 345 payload_len, sync_size, dummy_buf); 346 347 if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv, 348 rcd_sn, sync_size + payload_len) < 0) 349 goto free_nskb; 350 351 complete_skb(nskb, skb, tcp_payload_offset); 352 353 /* validate_xmit_skb_list assumes that if the skb wasn't segmented 354 * nskb->prev will point to the skb itself 355 */ 356 nskb->prev = nskb; 357 358 free_buf: 359 kfree(buf); 360 free_req: 361 kfree(aead_req); 362 return nskb; 363 free_nskb: 364 kfree_skb(nskb); 365 nskb = NULL; 366 goto free_buf; 367 } 368 369 static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb) 370 { 371 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb); 372 struct tls_context *tls_ctx = tls_get_ctx(sk); 373 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx); 374 int payload_len = skb->len - tcp_payload_offset; 375 struct scatterlist *sg_in, sg_out[3]; 376 struct sk_buff *nskb = NULL; 377 int sg_in_max_elements; 378 int resync_sgs = 0; 379 s32 sync_size = 0; 380 u64 rcd_sn; 381 382 /* worst case is: 383 * MAX_SKB_FRAGS in tls_record_info 384 * MAX_SKB_FRAGS + 1 in SKB head and frags. 385 */ 386 sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1; 387 388 if (!payload_len) 389 return skb; 390 391 sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC); 392 if (!sg_in) 393 goto free_orig; 394 395 sg_init_table(sg_in, sg_in_max_elements); 396 sg_init_table(sg_out, ARRAY_SIZE(sg_out)); 397 398 if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) { 399 /* bypass packets before kernel TLS socket option was set */ 400 if (sync_size < 0 && payload_len <= -sync_size) 401 nskb = skb_get(skb); 402 goto put_sg; 403 } 404 405 nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn); 406 407 put_sg: 408 while (resync_sgs) 409 put_page(sg_page(&sg_in[--resync_sgs])); 410 kfree(sg_in); 411 free_orig: 412 kfree_skb(skb); 413 return nskb; 414 } 415 416 struct sk_buff *tls_validate_xmit_skb(struct sock *sk, 417 struct net_device *dev, 418 struct sk_buff *skb) 419 { 420 if (dev == tls_get_ctx(sk)->netdev) 421 return skb; 422 423 return tls_sw_fallback(sk, skb); 424 } 425 EXPORT_SYMBOL_GPL(tls_validate_xmit_skb); 426 427 int tls_sw_fallback_init(struct sock *sk, 428 struct tls_offload_context_tx *offload_ctx, 429 struct tls_crypto_info *crypto_info) 430 { 431 const u8 *key; 432 int rc; 433 434 offload_ctx->aead_send = 435 crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); 436 if (IS_ERR(offload_ctx->aead_send)) { 437 rc = PTR_ERR(offload_ctx->aead_send); 438 pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc); 439 offload_ctx->aead_send = NULL; 440 goto err_out; 441 } 442 443 key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key; 444 445 rc = crypto_aead_setkey(offload_ctx->aead_send, key, 446 TLS_CIPHER_AES_GCM_128_KEY_SIZE); 447 if (rc) 448 goto free_aead; 449 450 rc = crypto_aead_setauthsize(offload_ctx->aead_send, 451 TLS_CIPHER_AES_GCM_128_TAG_SIZE); 452 if (rc) 453 goto free_aead; 454 455 return 0; 456 free_aead: 457 crypto_free_aead(offload_ctx->aead_send); 458 err_out: 459 return rc; 460 } 461