1 /* Copyright (c) 2018, Mellanox Technologies All rights reserved.
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:
9 * Redistribution and use in source and binary forms, with or
10 * without modification, are permitted provided that the following
13 * - Redistributions of source code must retain the above
14 * copyright notice, this list of conditions and the following
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.
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
33 #include <crypto/aead.h>
34 #include <crypto/scatterwalk.h>
35 #include <net/ip6_checksum.h>
37 static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk)
39 struct scatterlist *src = walk->sg;
40 int diff = walk->offset - src->offset;
42 sg_set_page(sg, sg_page(src),
43 src->length - diff, walk->offset);
45 scatterwalk_crypto_chain(sg, sg_next(src), 2);
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)
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];
60 len = min_t(int, *in_len, ARRAY_SIZE(buf));
62 scatterwalk_copychunks(buf, in, len, 0);
63 scatterwalk_copychunks(buf, out, len, 1);
69 scatterwalk_pagedone(in, 0, 1);
70 scatterwalk_pagedone(out, 1, 1);
72 len = buf[4] | (buf[3] << 8);
73 len -= TLS_CIPHER_AES_GCM_128_IV_SIZE;
75 tls_make_aad(aad, len - TLS_CIPHER_AES_GCM_128_TAG_SIZE,
76 (char *)&rcd_sn, sizeof(rcd_sn), buf[0]);
78 memcpy(iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, buf + TLS_HEADER_SIZE,
79 TLS_CIPHER_AES_GCM_128_IV_SIZE);
81 sg_init_table(sg_in, ARRAY_SIZE(sg_in));
82 sg_init_table(sg_out, ARRAY_SIZE(sg_out));
83 sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE);
84 sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE);
85 chain_to_walk(sg_in + 1, in);
86 chain_to_walk(sg_out + 1, out);
90 *in_len += TLS_CIPHER_AES_GCM_128_TAG_SIZE;
91 /* the input buffer doesn't contain the entire record.
92 * trim len accordingly. The resulting authentication tag
93 * will contain garbage, but we don't care, so we won't
94 * include any of it in the output skb
95 * Note that we assume the output buffer length
96 * is larger then input buffer length + tag size
105 scatterwalk_copychunks(NULL, in, len, 2);
106 scatterwalk_pagedone(in, 0, 1);
107 scatterwalk_copychunks(NULL, out, len, 2);
108 scatterwalk_pagedone(out, 1, 1);
111 len -= TLS_CIPHER_AES_GCM_128_TAG_SIZE;
112 aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv);
114 rc = crypto_aead_encrypt(aead_req);
119 static void tls_init_aead_request(struct aead_request *aead_req,
120 struct crypto_aead *aead)
122 aead_request_set_tfm(aead_req, aead);
123 aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
126 static struct aead_request *tls_alloc_aead_request(struct crypto_aead *aead,
129 unsigned int req_size = sizeof(struct aead_request) +
130 crypto_aead_reqsize(aead);
131 struct aead_request *aead_req;
133 aead_req = kzalloc(req_size, flags);
135 tls_init_aead_request(aead_req, aead);
139 static int tls_enc_records(struct aead_request *aead_req,
140 struct crypto_aead *aead, struct scatterlist *sg_in,
141 struct scatterlist *sg_out, char *aad, char *iv,
144 struct scatter_walk out, in;
147 scatterwalk_start(&in, sg_in);
148 scatterwalk_start(&out, sg_out);
151 rc = tls_enc_record(aead_req, aead, aad, iv,
152 cpu_to_be64(rcd_sn), &in, &out, &len);
155 } while (rc == 0 && len);
157 scatterwalk_done(&in, 0, 0);
158 scatterwalk_done(&out, 1, 0);
163 /* Can't use icsk->icsk_af_ops->send_check here because the ip addresses
164 * might have been changed by NAT.
166 static void update_chksum(struct sk_buff *skb, int headln)
168 struct tcphdr *th = tcp_hdr(skb);
169 int datalen = skb->len - headln;
170 const struct ipv6hdr *ipv6h;
171 const struct iphdr *iph;
173 /* We only changed the payload so if we are using partial we don't
174 * need to update anything.
176 if (likely(skb->ip_summed == CHECKSUM_PARTIAL))
179 skb->ip_summed = CHECKSUM_PARTIAL;
180 skb->csum_start = skb_transport_header(skb) - skb->head;
181 skb->csum_offset = offsetof(struct tcphdr, check);
183 if (skb->sk->sk_family == AF_INET6) {
184 ipv6h = ipv6_hdr(skb);
185 th->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
186 datalen, IPPROTO_TCP, 0);
189 th->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen,
194 static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln)
196 skb_copy_header(nskb, skb);
198 skb_put(nskb, skb->len);
199 memcpy(nskb->data, skb->data, headln);
200 update_chksum(nskb, headln);
202 nskb->destructor = skb->destructor;
204 skb->destructor = NULL;
206 refcount_add(nskb->truesize - skb->truesize,
207 &nskb->sk->sk_wmem_alloc);
210 /* This function may be called after the user socket is already
211 * closed so make sure we don't use anything freed during
212 * tls_sk_proto_close here
215 static int fill_sg_in(struct scatterlist *sg_in,
217 struct tls_offload_context_tx *ctx,
222 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
223 int payload_len = skb->len - tcp_payload_offset;
224 u32 tcp_seq = ntohl(tcp_hdr(skb)->seq);
225 struct tls_record_info *record;
230 spin_lock_irqsave(&ctx->lock, flags);
231 record = tls_get_record(ctx, tcp_seq, rcd_sn);
233 spin_unlock_irqrestore(&ctx->lock, flags);
234 WARN(1, "Record not found for seq %u\n", tcp_seq);
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);
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.
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 retranmit a packet that doesn't contain
251 * already acked payload.
253 if (!is_start_marker)
258 remaining = *sync_size;
259 for (i = 0; remaining > 0; i++) {
260 skb_frag_t *frag = &record->frags[i];
262 __skb_frag_ref(frag);
263 sg_set_page(sg_in + i, skb_frag_page(frag),
264 skb_frag_size(frag), frag->page_offset);
266 remaining -= skb_frag_size(frag);
269 sg_in[i].length += remaining;
273 spin_unlock_irqrestore(&ctx->lock, flags);
274 if (skb_to_sgvec(skb, &sg_in[i], tcp_payload_offset, payload_len) < 0)
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,
288 sg_set_buf(&sg_out[0], dummy_buf, sync_size);
289 sg_set_buf(&sg_out[1], nskb->data + tcp_payload_offset, payload_len);
290 /* Add room for authentication tag produced by crypto */
291 dummy_buf += sync_size;
292 sg_set_buf(&sg_out[2], dummy_buf, TLS_CIPHER_AES_GCM_128_TAG_SIZE);
295 static struct sk_buff *tls_enc_skb(struct tls_context *tls_ctx,
296 struct scatterlist sg_out[3],
297 struct scatterlist *sg_in,
299 s32 sync_size, u64 rcd_sn)
301 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
302 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
303 int payload_len = skb->len - tcp_payload_offset;
304 void *buf, *iv, *aad, *dummy_buf;
305 struct aead_request *aead_req;
306 struct sk_buff *nskb = NULL;
309 aead_req = tls_alloc_aead_request(ctx->aead_send, GFP_ATOMIC);
313 buf_len = TLS_CIPHER_AES_GCM_128_SALT_SIZE +
314 TLS_CIPHER_AES_GCM_128_IV_SIZE +
317 TLS_CIPHER_AES_GCM_128_TAG_SIZE;
318 buf = kmalloc(buf_len, GFP_ATOMIC);
323 memcpy(iv, tls_ctx->crypto_send.aes_gcm_128.salt,
324 TLS_CIPHER_AES_GCM_128_SALT_SIZE);
325 aad = buf + TLS_CIPHER_AES_GCM_128_SALT_SIZE +
326 TLS_CIPHER_AES_GCM_128_IV_SIZE;
327 dummy_buf = aad + TLS_AAD_SPACE_SIZE;
329 nskb = alloc_skb(skb_headroom(skb) + skb->len, GFP_ATOMIC);
333 skb_reserve(nskb, skb_headroom(skb));
335 fill_sg_out(sg_out, buf, tls_ctx, nskb, tcp_payload_offset,
336 payload_len, sync_size, dummy_buf);
338 if (tls_enc_records(aead_req, ctx->aead_send, sg_in, sg_out, aad, iv,
339 rcd_sn, sync_size + payload_len) < 0)
342 complete_skb(nskb, skb, tcp_payload_offset);
344 /* validate_xmit_skb_list assumes that if the skb wasn't segmented
345 * nskb->prev will point to the skb itself
360 static struct sk_buff *tls_sw_fallback(struct sock *sk, struct sk_buff *skb)
362 int tcp_payload_offset = skb_transport_offset(skb) + tcp_hdrlen(skb);
363 struct tls_context *tls_ctx = tls_get_ctx(sk);
364 struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
365 int payload_len = skb->len - tcp_payload_offset;
366 struct scatterlist *sg_in, sg_out[3];
367 struct sk_buff *nskb = NULL;
368 int sg_in_max_elements;
374 * MAX_SKB_FRAGS in tls_record_info
375 * MAX_SKB_FRAGS + 1 in SKB head and frags.
377 sg_in_max_elements = 2 * MAX_SKB_FRAGS + 1;
382 sg_in = kmalloc_array(sg_in_max_elements, sizeof(*sg_in), GFP_ATOMIC);
386 sg_init_table(sg_in, sg_in_max_elements);
387 sg_init_table(sg_out, ARRAY_SIZE(sg_out));
389 if (fill_sg_in(sg_in, skb, ctx, &rcd_sn, &sync_size, &resync_sgs)) {
390 /* bypass packets before kernel TLS socket option was set */
391 if (sync_size < 0 && payload_len <= -sync_size)
396 nskb = tls_enc_skb(tls_ctx, sg_out, sg_in, skb, sync_size, rcd_sn);
400 put_page(sg_page(&sg_in[--resync_sgs]));
407 struct sk_buff *tls_validate_xmit_skb(struct sock *sk,
408 struct net_device *dev,
411 if (dev == tls_get_ctx(sk)->netdev)
414 return tls_sw_fallback(sk, skb);
416 EXPORT_SYMBOL_GPL(tls_validate_xmit_skb);
418 int tls_sw_fallback_init(struct sock *sk,
419 struct tls_offload_context_tx *offload_ctx,
420 struct tls_crypto_info *crypto_info)
425 offload_ctx->aead_send =
426 crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
427 if (IS_ERR(offload_ctx->aead_send)) {
428 rc = PTR_ERR(offload_ctx->aead_send);
429 pr_err_ratelimited("crypto_alloc_aead failed rc=%d\n", rc);
430 offload_ctx->aead_send = NULL;
434 key = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->key;
436 rc = crypto_aead_setkey(offload_ctx->aead_send, key,
437 TLS_CIPHER_AES_GCM_128_KEY_SIZE);
441 rc = crypto_aead_setauthsize(offload_ctx->aead_send,
442 TLS_CIPHER_AES_GCM_128_TAG_SIZE);
448 crypto_free_aead(offload_ctx->aead_send);