2 * esp_decrypt.c : IPSec ESP decrypt node
4 * Copyright (c) 2015 Cisco and/or its affiliates.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 #include <vnet/vnet.h>
19 #include <vnet/api_errno.h>
20 #include <vnet/ip/ip.h>
22 #include <vnet/ipsec/ipsec.h>
23 #include <vnet/ipsec/esp.h>
24 #include <vnet/ipsec/ipsec_io.h>
25 #include <vnet/ipsec/ipsec_tun.h>
27 #define foreach_esp_decrypt_next \
28 _(DROP, "error-drop") \
29 _(IP4_INPUT, "ip4-input-no-checksum") \
30 _(IP6_INPUT, "ip6-input") \
33 #define _(v, s) ESP_DECRYPT_NEXT_##v,
36 foreach_esp_decrypt_next
42 #define foreach_esp_decrypt_error \
43 _(RX_PKTS, "ESP pkts received") \
44 _(DECRYPTION_FAILED, "ESP decryption failed") \
45 _(INTEG_ERROR, "Integrity check failed") \
46 _(CRYPTO_ENGINE_ERROR, "crypto engine error (packet dropped)") \
47 _(REPLAY, "SA replayed packet") \
48 _(RUNT, "undersized packet") \
49 _(CHAINED_BUFFER, "chained buffers (packet dropped)") \
50 _(OVERSIZED_HEADER, "buffer with oversized header (dropped)") \
51 _(NO_TAIL_SPACE, "no enough buffer tail space (dropped)") \
52 _(TUN_NO_PROTO, "no tunnel protocol") \
57 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
58 foreach_esp_decrypt_error
61 } esp_decrypt_error_t;
63 static char *esp_decrypt_error_strings[] = {
64 #define _(sym,string) string,
65 foreach_esp_decrypt_error
74 ipsec_crypto_alg_t crypto_alg;
75 ipsec_integ_alg_t integ_alg;
76 } esp_decrypt_trace_t;
78 /* packet trace format function */
80 format_esp_decrypt_trace (u8 * s, va_list * args)
82 CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
83 CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
84 esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
88 "esp: crypto %U integrity %U pkt-seq %d sa-seq %u sa-seq-hi %u",
89 format_ipsec_crypto_alg, t->crypto_alg, format_ipsec_integ_alg,
90 t->integ_alg, t->seq, t->sa_seq, t->sa_seq_hi);
102 ipsec_sa_flags_t flags;
112 } esp_decrypt_packet_data_t;
114 STATIC_ASSERT_SIZEOF (esp_decrypt_packet_data_t, 3 * sizeof (u64));
116 #define ESP_ENCRYPT_PD_F_FD_TRANSPORT (1 << 2)
119 esp_decrypt_inline (vlib_main_t * vm,
120 vlib_node_runtime_t * node, vlib_frame_t * from_frame,
121 int is_ip6, int is_tun)
123 ipsec_main_t *im = &ipsec_main;
124 u32 thread_index = vm->thread_index;
125 u16 buffer_data_size = vlib_buffer_get_default_data_size (vm);
127 ipsec_per_thread_data_t *ptd = vec_elt_at_index (im->ptd, thread_index);
128 u32 *from = vlib_frame_vector_args (from_frame);
129 u32 n, n_left = from_frame->n_vectors;
130 vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;
131 u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
132 esp_decrypt_packet_data_t pkt_data[VLIB_FRAME_SIZE], *pd = pkt_data;
133 esp_decrypt_packet_data_t cpd = { };
134 u32 current_sa_index = ~0, current_sa_bytes = 0, current_sa_pkts = 0;
135 const u8 esp_sz = sizeof (esp_header_t);
138 vlib_get_buffers (vm, from, b, n_left);
139 vec_reset_length (ptd->crypto_ops);
140 vec_reset_length (ptd->integ_ops);
141 clib_memset_u16 (nexts, -1, n_left);
150 vlib_prefetch_buffer_header (b[2], LOAD);
151 p = vlib_buffer_get_current (b[1]);
152 CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
153 p -= CLIB_CACHE_LINE_BYTES;
154 CLIB_PREFETCH (p, CLIB_CACHE_LINE_BYTES, LOAD);
157 if (vlib_buffer_chain_linearize (vm, b[0]) != 1)
159 b[0]->error = node->errors[ESP_DECRYPT_ERROR_CHAINED_BUFFER];
160 next[0] = ESP_DECRYPT_NEXT_DROP;
164 if (vnet_buffer (b[0])->ipsec.sad_index != current_sa_index)
167 vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
171 current_sa_bytes = current_sa_pkts = 0;
173 current_sa_index = vnet_buffer (b[0])->ipsec.sad_index;
174 sa0 = pool_elt_at_index (im->sad, current_sa_index);
175 cpd.icv_sz = sa0->integ_icv_size;
176 cpd.iv_sz = sa0->crypto_iv_size;
177 cpd.flags = sa0->flags;
178 cpd.sa_index = current_sa_index;
181 if (PREDICT_FALSE (~0 == sa0->decrypt_thread_index))
183 /* this is the first packet to use this SA, claim the SA
184 * for this thread. this could happen simultaneously on
186 clib_atomic_cmp_and_swap (&sa0->decrypt_thread_index, ~0,
187 ipsec_sa_assign_thread (thread_index));
190 if (PREDICT_TRUE (thread_index != sa0->decrypt_thread_index))
192 next[0] = ESP_DECRYPT_NEXT_HANDOFF;
196 /* store packet data for next round for easier prefetch */
197 pd->sa_data = cpd.sa_data;
198 pd->current_data = b[0]->current_data;
199 pd->current_length = b[0]->current_length;
200 pd->hdr_sz = pd->current_data - vnet_buffer (b[0])->l3_hdr_offset;
201 payload = b[0]->data + pd->current_data;
202 pd->seq = clib_host_to_net_u32 (((esp_header_t *) payload)->seq);
204 /* we need 4 extra bytes for HMAC calculation when ESN are used */
205 if (ipsec_sa_is_set_USE_ESN (sa0) && pd->icv_sz &&
206 (pd->current_data + pd->current_length + 4 > buffer_data_size))
208 b[0]->error = node->errors[ESP_DECRYPT_ERROR_NO_TAIL_SPACE];
209 next[0] = ESP_DECRYPT_NEXT_DROP;
213 /* anti-reply check */
214 if (ipsec_sa_anti_replay_check (sa0, pd->seq))
216 b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
217 next[0] = ESP_DECRYPT_NEXT_DROP;
221 if (pd->current_length < cpd.icv_sz + esp_sz + cpd.iv_sz)
223 b[0]->error = node->errors[ESP_DECRYPT_ERROR_RUNT];
224 next[0] = ESP_DECRYPT_NEXT_DROP;
228 len = pd->current_length - cpd.icv_sz;
229 current_sa_pkts += 1;
230 current_sa_bytes += pd->current_length;
232 if (PREDICT_TRUE (sa0->integ_op_id != VNET_CRYPTO_OP_NONE))
234 vnet_crypto_op_t *op;
235 vec_add2_aligned (ptd->integ_ops, op, 1, CLIB_CACHE_LINE_BYTES);
237 vnet_crypto_op_init (op, sa0->integ_op_id);
238 op->key_index = sa0->integ_key_index;
240 op->flags = VNET_CRYPTO_OP_FLAG_HMAC_CHECK;
241 op->user_data = b - bufs;
242 op->digest = payload + len;
243 op->digest_len = cpd.icv_sz;
245 if (ipsec_sa_is_set_USE_ESN (sa0))
247 /* shift ICV by 4 bytes to insert ESN */
248 u32 seq_hi = clib_host_to_net_u32 (sa0->seq_hi);
249 u8 tmp[ESP_MAX_ICV_SIZE], sz = sizeof (sa0->seq_hi);
250 clib_memcpy_fast (tmp, payload + len, ESP_MAX_ICV_SIZE);
251 clib_memcpy_fast (payload + len, &seq_hi, sz);
252 clib_memcpy_fast (payload + len + sz, tmp, ESP_MAX_ICV_SIZE);
261 if (sa0->crypto_enc_op_id != VNET_CRYPTO_OP_NONE)
263 vnet_crypto_op_t *op;
264 vec_add2_aligned (ptd->crypto_ops, op, 1, CLIB_CACHE_LINE_BYTES);
265 vnet_crypto_op_init (op, sa0->crypto_dec_op_id);
266 op->key_index = sa0->crypto_key_index;
269 if (ipsec_sa_is_set_IS_AEAD (sa0))
276 * construct the AAD and the nonce (Salt || IV) in a scratch
277 * space in front of the IP header.
279 scratch = payload - esp_sz;
280 esp0 = (esp_header_t *) (scratch);
282 scratch -= (sizeof (*aad) + pd->hdr_sz);
285 esp_aad_fill (op, esp0, sa0);
288 * we don't need to refer to the ESP header anymore so we
289 * can overwrite it with the salt and use the IV where it is
290 * to form the nonce = (Salt + IV)
292 op->iv -= sizeof (sa0->salt);
293 clib_memcpy_fast (op->iv, &sa0->salt, sizeof (sa0->salt));
295 op->tag = payload + len;
298 op->src = op->dst = payload += cpd.iv_sz;
299 op->len = len - cpd.iv_sz;
300 op->user_data = b - bufs;
311 vlib_increment_combined_counter (&ipsec_sa_counters, thread_index,
312 current_sa_index, current_sa_pkts,
315 if ((n = vec_len (ptd->integ_ops)))
317 vnet_crypto_op_t *op = ptd->integ_ops;
318 n -= vnet_crypto_process_ops (vm, op, n);
321 ASSERT (op - ptd->integ_ops < vec_len (ptd->integ_ops));
322 if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
324 u32 err, bi = op->user_data;
325 if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
326 err = ESP_DECRYPT_ERROR_INTEG_ERROR;
328 err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;
329 bufs[bi]->error = node->errors[err];
330 nexts[bi] = ESP_DECRYPT_NEXT_DROP;
336 if ((n = vec_len (ptd->crypto_ops)))
338 vnet_crypto_op_t *op = ptd->crypto_ops;
339 n -= vnet_crypto_process_ops (vm, op, n);
342 ASSERT (op - ptd->crypto_ops < vec_len (ptd->crypto_ops));
343 if (op->status != VNET_CRYPTO_OP_STATUS_COMPLETED)
349 if (op->status == VNET_CRYPTO_OP_STATUS_FAIL_BAD_HMAC)
350 err = ESP_DECRYPT_ERROR_DECRYPTION_FAILED;
352 err = ESP_DECRYPT_ERROR_CRYPTO_ENGINE_ERROR;
354 bufs[bi]->error = node->errors[err];
355 nexts[bi] = ESP_DECRYPT_NEXT_DROP;
362 /* Post decryption ronud - adjust packet data start and length and next
365 n_left = from_frame->n_vectors;
372 const u8 tun_flags = IPSEC_SA_FLAG_IS_TUNNEL |
373 IPSEC_SA_FLAG_IS_TUNNEL_V6;
377 void *data = b[1]->data + pd[1].current_data;
379 /* buffer metadata */
380 vlib_prefetch_buffer_header (b[1], LOAD);
383 CLIB_PREFETCH (data + pd[1].current_length - pd[1].icv_sz - 2,
384 CLIB_CACHE_LINE_BYTES, LOAD);
387 CLIB_PREFETCH (data - CLIB_CACHE_LINE_BYTES,
388 CLIB_CACHE_LINE_BYTES * 2, LOAD);
391 if (next[0] < ESP_DECRYPT_N_NEXT)
394 sa0 = vec_elt_at_index (im->sad, pd->sa_index);
397 * redo the anti-reply check
398 * in this frame say we have sequence numbers, s, s+1, s+1, s+1
399 * and s and s+1 are in the window. When we did the anti-replay
400 * check above we did so against the state of the window (W),
401 * after packet s-1. So each of the packets in the sequence will be
403 * This time s will be cheked against Ws-1, s+1 chceked against Ws
404 * (i.e. the window state is updated/advnaced)
405 * so this time the successive s+! packet will be dropped.
406 * This is a consequence of batching the decrypts. If the
407 * check-dcrypt-advance process was done for each packet it would
408 * be fine. But we batch the decrypts because it's much more efficient
409 * to do so in SW and if we offload to HW and the process is async.
411 * You're probably thinking, but this means an attacker can send the
412 * above sequence and cause VPP to perform decrpyts that will fail,
413 * and that's true. But if the attacker can determine s (a valid
414 * sequence number in the window) which is non-trivial, it can generate
415 * a sequence s, s+1, s+2, s+3, ... s+n and nothing will prevent any
416 * implementation, sequential or batching, from decrypting these.
418 if (ipsec_sa_anti_replay_check (sa0, pd->seq))
420 b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
421 next[0] = ESP_DECRYPT_NEXT_DROP;
425 ipsec_sa_anti_replay_advance (sa0, pd->seq);
427 esp_footer_t *f = (esp_footer_t *) (b[0]->data + pd->current_data +
428 pd->current_length - sizeof (*f) -
430 u16 adv = pd->iv_sz + esp_sz;
431 u16 tail = sizeof (esp_footer_t) + f->pad_length + pd->icv_sz;
433 if ((pd->flags & tun_flags) == 0 && !is_tun) /* transport mode */
435 u8 udp_sz = (is_ip6 == 0 && pd->flags & IPSEC_SA_FLAG_UDP_ENCAP) ?
436 sizeof (udp_header_t) : 0;
437 u16 ip_hdr_sz = pd->hdr_sz - udp_sz;
438 u8 *old_ip = b[0]->data + pd->current_data - ip_hdr_sz - udp_sz;
439 u8 *ip = old_ip + adv + udp_sz;
441 if (is_ip6 && ip_hdr_sz > 64)
442 memmove (ip, old_ip, ip_hdr_sz);
444 clib_memcpy_le64 (ip, old_ip, ip_hdr_sz);
446 b[0]->current_data = pd->current_data + adv - ip_hdr_sz;
447 b[0]->current_length = pd->current_length + ip_hdr_sz - tail - adv;
451 ip6_header_t *ip6 = (ip6_header_t *) ip;
452 u16 len = clib_net_to_host_u16 (ip6->payload_length);
454 ip6->payload_length = clib_host_to_net_u16 (len);
455 ip6->protocol = f->next_header;
456 next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
460 ip4_header_t *ip4 = (ip4_header_t *) ip;
461 ip_csum_t sum = ip4->checksum;
462 u16 len = clib_net_to_host_u16 (ip4->length);
463 len = clib_host_to_net_u16 (len - adv - tail - udp_sz);
464 sum = ip_csum_update (sum, ip4->protocol, f->next_header,
465 ip4_header_t, protocol);
466 sum = ip_csum_update (sum, ip4->length, len,
467 ip4_header_t, length);
468 ip4->checksum = ip_csum_fold (sum);
469 ip4->protocol = f->next_header;
471 next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
476 if (PREDICT_TRUE (f->next_header == IP_PROTOCOL_IP_IN_IP))
478 next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
479 b[0]->current_data = pd->current_data + adv;
480 b[0]->current_length = pd->current_length - adv - tail;
482 else if (f->next_header == IP_PROTOCOL_IPV6)
484 next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
485 b[0]->current_data = pd->current_data + adv;
486 b[0]->current_length = pd->current_length - adv - tail;
490 next[0] = ESP_DECRYPT_NEXT_DROP;
491 b[0]->error = node->errors[ESP_DECRYPT_ERROR_DECRYPTION_FAILED];
496 if (ipsec_sa_is_set_IS_PROTECT (sa0))
499 * Check that the reveal IP header matches that
500 * of the tunnel we are protecting
502 const ipsec_tun_protect_t *itp;
505 ipsec_tun_protect_get (vnet_buffer (b[0])->
506 ipsec.protect_index);
507 if (PREDICT_TRUE (f->next_header == IP_PROTOCOL_IP_IN_IP))
509 const ip4_header_t *ip4;
511 ip4 = vlib_buffer_get_current (b[0]);
513 if (!ip46_address_is_equal_v4 (&itp->itp_tun.src,
514 &ip4->dst_address) ||
515 !ip46_address_is_equal_v4 (&itp->itp_tun.dst,
518 next[0] = ESP_DECRYPT_NEXT_DROP;
520 node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
523 else if (f->next_header == IP_PROTOCOL_IPV6)
525 const ip6_header_t *ip6;
527 ip6 = vlib_buffer_get_current (b[0]);
529 if (!ip46_address_is_equal_v6 (&itp->itp_tun.src,
530 &ip6->dst_address) ||
531 !ip46_address_is_equal_v6 (&itp->itp_tun.dst,
534 next[0] = ESP_DECRYPT_NEXT_DROP;
536 node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
544 if (PREDICT_FALSE (b[0]->flags & VLIB_BUFFER_IS_TRACED))
546 esp_decrypt_trace_t *tr;
547 tr = vlib_add_trace (vm, node, b[0], sizeof (*tr));
548 sa0 = pool_elt_at_index (im->sad,
549 vnet_buffer (b[0])->ipsec.sad_index);
550 tr->crypto_alg = sa0->crypto_alg;
551 tr->integ_alg = sa0->integ_alg;
553 tr->sa_seq = sa0->last_seq;
554 tr->sa_seq_hi = sa0->seq_hi;
564 n_left = from_frame->n_vectors;
565 vlib_node_increment_counter (vm, node->node_index,
566 ESP_DECRYPT_ERROR_RX_PKTS, n_left);
568 vlib_buffer_enqueue_to_next (vm, node, from, nexts, n_left);
574 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
575 vlib_node_runtime_t * node,
576 vlib_frame_t * from_frame)
578 return esp_decrypt_inline (vm, node, from_frame, 0, 0);
581 VLIB_NODE_FN (esp4_decrypt_tun_node) (vlib_main_t * vm,
582 vlib_node_runtime_t * node,
583 vlib_frame_t * from_frame)
585 return esp_decrypt_inline (vm, node, from_frame, 0, 1);
588 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
589 vlib_node_runtime_t * node,
590 vlib_frame_t * from_frame)
592 return esp_decrypt_inline (vm, node, from_frame, 1, 0);
595 VLIB_NODE_FN (esp6_decrypt_tun_node) (vlib_main_t * vm,
596 vlib_node_runtime_t * node,
597 vlib_frame_t * from_frame)
599 return esp_decrypt_inline (vm, node, from_frame, 1, 1);
603 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
604 .name = "esp4-decrypt",
605 .vector_size = sizeof (u32),
606 .format_trace = format_esp_decrypt_trace,
607 .type = VLIB_NODE_TYPE_INTERNAL,
609 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
610 .error_strings = esp_decrypt_error_strings,
612 .n_next_nodes = ESP_DECRYPT_N_NEXT,
614 [ESP_DECRYPT_NEXT_DROP] = "ip4-drop",
615 [ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
616 [ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
617 [ESP_DECRYPT_NEXT_HANDOFF] = "esp4-decrypt-handoff",
621 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
622 .name = "esp6-decrypt",
623 .vector_size = sizeof (u32),
624 .format_trace = format_esp_decrypt_trace,
625 .type = VLIB_NODE_TYPE_INTERNAL,
627 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
628 .error_strings = esp_decrypt_error_strings,
630 .n_next_nodes = ESP_DECRYPT_N_NEXT,
632 [ESP_DECRYPT_NEXT_DROP] = "ip6-drop",
633 [ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
634 [ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
635 [ESP_DECRYPT_NEXT_HANDOFF]= "esp6-decrypt-handoff",
639 VLIB_REGISTER_NODE (esp4_decrypt_tun_node) = {
640 .name = "esp4-decrypt-tun",
641 .vector_size = sizeof (u32),
642 .format_trace = format_esp_decrypt_trace,
643 .type = VLIB_NODE_TYPE_INTERNAL,
644 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
645 .error_strings = esp_decrypt_error_strings,
646 .n_next_nodes = ESP_DECRYPT_N_NEXT,
648 [ESP_DECRYPT_NEXT_DROP] = "ip4-drop",
649 [ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
650 [ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
651 [ESP_DECRYPT_NEXT_HANDOFF] = "esp4-decrypt-handoff",
655 VLIB_REGISTER_NODE (esp6_decrypt_tun_node) = {
656 .name = "esp6-decrypt-tun",
657 .vector_size = sizeof (u32),
658 .format_trace = format_esp_decrypt_trace,
659 .type = VLIB_NODE_TYPE_INTERNAL,
660 .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
661 .error_strings = esp_decrypt_error_strings,
662 .n_next_nodes = ESP_DECRYPT_N_NEXT,
664 [ESP_DECRYPT_NEXT_DROP] = "ip6-drop",
665 [ESP_DECRYPT_NEXT_IP4_INPUT] = "ip4-input-no-checksum",
666 [ESP_DECRYPT_NEXT_IP6_INPUT] = "ip6-input",
667 [ESP_DECRYPT_NEXT_HANDOFF]= "esp6-decrypt-handoff",
673 * fd.io coding-style-patch-verification: ON
676 * eval: (c-set-style "gnu")