src/vnet/ipsec/esp_decrypt.c

   1 /*
   2  * esp_decrypt.c : IPSec ESP decrypt node
   3  *
   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:
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  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.
  16  */
  17
  18 #include <vnet/vnet.h>
  19 #include <vnet/api_errno.h>
  20 #include <vnet/ip/ip.h>
  21
  22 #include <vnet/ipsec/ipsec.h>
  23 #include <vnet/ipsec/esp.h>
  24
  25 #define foreach_esp_decrypt_next                \
  26 _(DROP, "error-drop")                           \
  27 _(IP4_INPUT, "ip4-input")                       \
  28 _(IP6_INPUT, "ip6-input")                       \
  29 _(IPSEC_GRE_INPUT, "ipsec-gre-input")
  30
  31 #define _(v, s) ESP_DECRYPT_NEXT_##v,
  32 typedef enum
  33 {
  34   foreach_esp_decrypt_next
  35 #undef _
  36     ESP_DECRYPT_N_NEXT,
  37 } esp_decrypt_next_t;
  38
  39
  40 #define foreach_esp_decrypt_error                   \
  41  _(RX_PKTS, "ESP pkts received")                    \
  42  _(NO_BUFFER, "No buffer (packed dropped)")         \
  43  _(DECRYPTION_FAILED, "ESP decryption failed")      \
  44  _(INTEG_ERROR, "Integrity check failed")           \
  45  _(REPLAY, "SA replayed packet")                    \
  46  _(NOT_IP, "Not IP packet (dropped)")
  47
  48
  49 typedef enum
  50 {
  51 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
  52   foreach_esp_decrypt_error
  53 #undef _
  54     ESP_DECRYPT_N_ERROR,
  55 } esp_decrypt_error_t;
  56
  57 static char *esp_decrypt_error_strings[] = {
  58 #define _(sym,string) string,
  59   foreach_esp_decrypt_error
  60 #undef _
  61 };
  62
  63 typedef struct
  64 {
  65   ipsec_crypto_alg_t crypto_alg;
  66   ipsec_integ_alg_t integ_alg;
  67 } esp_decrypt_trace_t;
  68
  69 /* packet trace format function */
  70 static u8 *
  71 format_esp_decrypt_trace (u8 * s, va_list * args)
  72 {
  73   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  74   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  75   esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
  76
  77   s = format (s, "esp: crypto %U integrity %U",
  78               format_ipsec_crypto_alg, t->crypto_alg,
  79               format_ipsec_integ_alg, t->integ_alg);
  80   return s;
  81 }
  82
  83 always_inline void
  84 esp_decrypt_cbc (ipsec_crypto_alg_t alg,
  85                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  86 {
  87   ipsec_proto_main_t *em = &ipsec_proto_main;
  88   u32 thread_index = vlib_get_thread_index ();
  89 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
  90   EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].decrypt_ctx;
  91 #else
  92   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].decrypt_ctx);
  93 #endif
  94   const EVP_CIPHER *cipher = NULL;
  95   int out_len;
  96
  97   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
  98
  99   if (PREDICT_FALSE (em->ipsec_proto_main_crypto_algs[alg].type == 0))
 100     return;
 101
 102   if (PREDICT_FALSE
 103       (alg != em->per_thread_data[thread_index].last_decrypt_alg))
 104     {
 105       cipher = em->ipsec_proto_main_crypto_algs[alg].type;
 106       em->per_thread_data[thread_index].last_decrypt_alg = alg;
 107     }
 108
 109   EVP_DecryptInit_ex (ctx, cipher, NULL, key, iv);
 110
 111   EVP_DecryptUpdate (ctx, out, &out_len, in, in_len);
 112   EVP_DecryptFinal_ex (ctx, out + out_len, &out_len);
 113 }
 114
 115 always_inline uword
 116 esp_decrypt_inline (vlib_main_t * vm,
 117                     vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 118                     int is_ip6)
 119 {
 120   u32 n_left_from, *from, next_index, *to_next;
 121   ipsec_main_t *im = &ipsec_main;
 122   ipsec_proto_main_t *em = &ipsec_proto_main;
 123   u32 *recycle = 0;
 124   from = vlib_frame_vector_args (from_frame);
 125   n_left_from = from_frame->n_vectors;
 126   u32 thread_index = vlib_get_thread_index ();
 127
 128   ipsec_alloc_empty_buffers (vm, im);
 129
 130   u32 *empty_buffers = im->empty_buffers[thread_index];
 131
 132   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 133     {
 134       if (is_ip6)
 135         vlib_node_increment_counter (vm, esp6_decrypt_node.index,
 136                                      ESP_DECRYPT_ERROR_NO_BUFFER,
 137                                      n_left_from);
 138       else
 139         vlib_node_increment_counter (vm, esp4_decrypt_node.index,
 140                                      ESP_DECRYPT_ERROR_NO_BUFFER,
 141                                      n_left_from);
 142       goto free_buffers_and_exit;
 143     }
 144
 145   next_index = node->cached_next_index;
 146
 147   while (n_left_from > 0)
 148     {
 149       u32 n_left_to_next;
 150
 151       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 152
 153       while (n_left_from > 0 && n_left_to_next > 0)
 154         {
 155           u32 i_bi0, o_bi0 = (u32) ~ 0, next0;
 156           vlib_buffer_t *i_b0;
 157           vlib_buffer_t *o_b0 = 0;
 158           esp_header_t *esp0;
 159           ipsec_sa_t *sa0;
 160           u32 sa_index0 = ~0;
 161           u32 seq;
 162           ip4_header_t *ih4 = 0, *oh4 = 0;
 163           ip6_header_t *ih6 = 0, *oh6 = 0;
 164           u8 tunnel_mode = 1;
 165
 166           i_bi0 = from[0];
 167           from += 1;
 168           n_left_from -= 1;
 169           n_left_to_next -= 1;
 170
 171           next0 = ESP_DECRYPT_NEXT_DROP;
 172
 173           i_b0 = vlib_get_buffer (vm, i_bi0);
 174           esp0 = vlib_buffer_get_current (i_b0);
 175
 176           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 177           sa0 = pool_elt_at_index (im->sad, sa_index0);
 178
 179           seq = clib_host_to_net_u32 (esp0->seq);
 180
 181           /* anti-replay check */
 182           if (sa0->use_anti_replay)
 183             {
 184               int rv = 0;
 185
 186               if (PREDICT_TRUE (sa0->use_esn))
 187                 rv = esp_replay_check_esn (sa0, seq);
 188               else
 189                 rv = esp_replay_check (sa0, seq);
 190
 191               if (PREDICT_FALSE (rv))
 192                 {
 193                   clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
 194                   if (is_ip6)
 195                     vlib_node_increment_counter (vm,
 196                                                  esp6_decrypt_node.index,
 197                                                  ESP_DECRYPT_ERROR_REPLAY, 1);
 198                   else
 199                     vlib_node_increment_counter (vm,
 200                                                  esp4_decrypt_node.index,
 201                                                  ESP_DECRYPT_ERROR_REPLAY, 1);
 202                   o_bi0 = i_bi0;
 203                   to_next[0] = o_bi0;
 204                   to_next += 1;
 205                   goto trace;
 206                 }
 207             }
 208
 209           sa0->total_data_size += i_b0->current_length;
 210
 211           if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 212             {
 213               u8 sig[64];
 214               int icv_size =
 215                 em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 216               clib_memset (sig, 0, sizeof (sig));
 217               u8 *icv =
 218                 vlib_buffer_get_current (i_b0) + i_b0->current_length -
 219                 icv_size;
 220               i_b0->current_length -= icv_size;
 221
 222               hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
 223                          (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
 224                          sa0->seq_hi);
 225
 226               if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 227                 {
 228                   if (is_ip6)
 229                     vlib_node_increment_counter (vm,
 230                                                  esp6_decrypt_node.index,
 231                                                  ESP_DECRYPT_ERROR_INTEG_ERROR,
 232                                                  1);
 233                   else
 234                     vlib_node_increment_counter (vm,
 235                                                  esp4_decrypt_node.index,
 236                                                  ESP_DECRYPT_ERROR_INTEG_ERROR,
 237                                                  1);
 238                   o_bi0 = i_bi0;
 239                   to_next[0] = o_bi0;
 240                   to_next += 1;
 241                   goto trace;
 242                 }
 243             }
 244
 245           if (PREDICT_TRUE (sa0->use_anti_replay))
 246             {
 247               if (PREDICT_TRUE (sa0->use_esn))
 248                 esp_replay_advance_esn (sa0, seq);
 249               else
 250                 esp_replay_advance (sa0, seq);
 251             }
 252
 253           /* grab free buffer */
 254           uword last_empty_buffer = vec_len (empty_buffers) - 1;
 255           o_bi0 = empty_buffers[last_empty_buffer];
 256           to_next[0] = o_bi0;
 257           to_next += 1;
 258           o_b0 = vlib_get_buffer (vm, o_bi0);
 259           vlib_prefetch_buffer_with_index (vm,
 260                                            empty_buffers[last_empty_buffer -
 261                                                          1], STORE);
 262           _vec_len (empty_buffers) = last_empty_buffer;
 263
 264           /* add old buffer to the recycle list */
 265           vec_add1 (recycle, i_bi0);
 266
 267           if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 268                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 269               (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 270                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 271             {
 272               const int BLOCK_SIZE =
 273                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
 274               const int IV_SIZE =
 275                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 276               esp_footer_t *f0;
 277               u8 ip_hdr_size = 0;
 278
 279               int blocks =
 280                 (i_b0->current_length - sizeof (esp_header_t) -
 281                  IV_SIZE) / BLOCK_SIZE;
 282
 283               o_b0->current_data = sizeof (ethernet_header_t);
 284
 285               /* transport mode */
 286               if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 287                 {
 288                   tunnel_mode = 0;
 289
 290                   if (is_ip6)
 291                     {
 292                       ih6 =
 293                         (ip6_header_t *) ((u8 *) esp0 -
 294                                           sizeof (ip6_header_t));
 295                       ip_hdr_size = sizeof (ip6_header_t);
 296                       oh6 = vlib_buffer_get_current (o_b0);
 297                     }
 298                   else
 299                     {
 300                       ih4 =
 301                         (ip4_header_t *) ((u8 *) esp0 -
 302                                           sizeof (ip4_header_t));
 303                       oh4 = vlib_buffer_get_current (o_b0);
 304                       ip_hdr_size = sizeof (ip4_header_t);
 305                     }
 306                 }
 307
 308               esp_decrypt_cbc (sa0->crypto_alg,
 309                                esp0->data + IV_SIZE,
 310                                (u8 *) vlib_buffer_get_current (o_b0) +
 311                                ip_hdr_size, BLOCK_SIZE * blocks,
 312                                sa0->crypto_key, esp0->data);
 313
 314               o_b0->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 315               o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 316               f0 =
 317                 (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
 318                                   o_b0->current_length);
 319               o_b0->current_length -= f0->pad_length;
 320
 321               /* tunnel mode */
 322               if (PREDICT_TRUE (tunnel_mode))
 323                 {
 324                   if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 325                     {
 326                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 327                       oh4 = vlib_buffer_get_current (o_b0);
 328                     }
 329                   else if (f0->next_header == IP_PROTOCOL_IPV6)
 330                     next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 331                   else
 332                     {
 333                       clib_warning ("next header: 0x%x", f0->next_header);
 334                       if (is_ip6)
 335                         vlib_node_increment_counter (vm,
 336                                                      esp6_decrypt_node.index,
 337                                                      ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 338                                                      1);
 339                       else
 340                         vlib_node_increment_counter (vm,
 341                                                      esp4_decrypt_node.index,
 342                                                      ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 343                                                      1);
 344                       o_b0 = 0;
 345                       goto trace;
 346                     }
 347                 }
 348               /* transport mode */
 349               else
 350                 {
 351                   if (is_ip6)
 352                     {
 353                       next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 354                       oh6->ip_version_traffic_class_and_flow_label =
 355                         ih6->ip_version_traffic_class_and_flow_label;
 356                       oh6->protocol = f0->next_header;
 357                       oh6->hop_limit = ih6->hop_limit;
 358                       oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 359                       oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 360                       oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 361                       oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 362                       oh6->payload_length =
 363                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 364                                               (vm,
 365                                                o_b0) - sizeof (ip6_header_t));
 366                     }
 367                   else
 368                     {
 369                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 370                       oh4->ip_version_and_header_length = 0x45;
 371                       oh4->tos = ih4->tos;
 372                       oh4->fragment_id = 0;
 373                       oh4->flags_and_fragment_offset = 0;
 374                       oh4->ttl = ih4->ttl;
 375                       oh4->protocol = f0->next_header;
 376                       oh4->src_address.as_u32 = ih4->src_address.as_u32;
 377                       oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 378                       oh4->length =
 379                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 380                                               (vm, o_b0));
 381                       oh4->checksum = ip4_header_checksum (oh4);
 382                     }
 383                 }
 384
 385               /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 386               if (PREDICT_FALSE
 387                   ((vnet_buffer (i_b0)->ipsec.flags) &
 388                    IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 389                 next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 390
 391               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 392               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 393                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 394             }
 395
 396         trace:
 397           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 398             {
 399               if (o_b0)
 400                 {
 401                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 402                   o_b0->trace_index = i_b0->trace_index;
 403                   esp_decrypt_trace_t *tr =
 404                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 405                   tr->crypto_alg = sa0->crypto_alg;
 406                   tr->integ_alg = sa0->integ_alg;
 407                 }
 408             }
 409
 410           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 411                                            n_left_to_next, o_bi0, next0);
 412         }
 413       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 414     }
 415   if (is_ip6)
 416     vlib_node_increment_counter (vm, esp6_decrypt_node.index,
 417                                  ESP_DECRYPT_ERROR_RX_PKTS,
 418                                  from_frame->n_vectors);
 419   else
 420     vlib_node_increment_counter (vm, esp4_decrypt_node.index,
 421                                  ESP_DECRYPT_ERROR_RX_PKTS,
 422                                  from_frame->n_vectors);
 423
 424
 425 free_buffers_and_exit:
 426   if (recycle)
 427     vlib_buffer_free (vm, recycle, vec_len (recycle));
 428   vec_free (recycle);
 429   return from_frame->n_vectors;
 430 }
 431
 432 static uword
 433 esp4_decrypt_node_fn (vlib_main_t * vm,
 434                       vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 435 {
 436   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 437 }
 438
 439 /* *INDENT-OFF* */
 440 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 441   .function = esp4_decrypt_node_fn,
 442   .name = "esp4-decrypt",
 443   .vector_size = sizeof (u32),
 444   .format_trace = format_esp_decrypt_trace,
 445   .type = VLIB_NODE_TYPE_INTERNAL,
 446
 447   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 448   .error_strings = esp_decrypt_error_strings,
 449
 450   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 451   .next_nodes = {
 452 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 453     foreach_esp_decrypt_next
 454 #undef _
 455   },
 456 };
 457 /* *INDENT-ON* */
 458
 459 VLIB_NODE_FUNCTION_MULTIARCH (esp4_decrypt_node, esp4_decrypt_node_fn);
 460
 461 static uword
 462 esp6_decrypt_node_fn (vlib_main_t * vm,
 463                       vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 464 {
 465   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 466 }
 467
 468 /* *INDENT-OFF* */
 469 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 470   .function = esp6_decrypt_node_fn,
 471   .name = "esp6-decrypt",
 472   .vector_size = sizeof (u32),
 473   .format_trace = format_esp_decrypt_trace,
 474   .type = VLIB_NODE_TYPE_INTERNAL,
 475
 476   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 477   .error_strings = esp_decrypt_error_strings,
 478
 479   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 480   .next_nodes = {
 481 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 482     foreach_esp_decrypt_next
 483 #undef _
 484   },
 485 };
 486 /* *INDENT-ON* */
 487
 488 VLIB_NODE_FUNCTION_MULTIARCH (esp6_decrypt_node, esp6_decrypt_node_fn);
 489 /*
 490  * fd.io coding-style-patch-verification: ON
 491  *
 492  * Local Variables:
 493  * eval: (c-set-style "gnu")
 494  * End:
 495  */