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       vlib_node_increment_counter (vm, node->node_index,
 135                                    ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from);
 136       goto free_buffers_and_exit;
 137     }
 138
 139   next_index = node->cached_next_index;
 140
 141   while (n_left_from > 0)
 142     {
 143       u32 n_left_to_next;
 144
 145       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 146
 147       while (n_left_from > 0 && n_left_to_next > 0)
 148         {
 149           u32 i_bi0, o_bi0 = (u32) ~ 0, next0;
 150           vlib_buffer_t *i_b0;
 151           vlib_buffer_t *o_b0 = 0;
 152           esp_header_t *esp0;
 153           ipsec_sa_t *sa0;
 154           u32 sa_index0 = ~0;
 155           u32 seq;
 156           ip4_header_t *ih4 = 0, *oh4 = 0;
 157           ip6_header_t *ih6 = 0, *oh6 = 0;
 158           u8 tunnel_mode = 1;
 159
 160           i_bi0 = from[0];
 161           from += 1;
 162           n_left_from -= 1;
 163           n_left_to_next -= 1;
 164
 165           next0 = ESP_DECRYPT_NEXT_DROP;
 166
 167           i_b0 = vlib_get_buffer (vm, i_bi0);
 168           esp0 = vlib_buffer_get_current (i_b0);
 169
 170           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 171           sa0 = pool_elt_at_index (im->sad, sa_index0);
 172
 173           seq = clib_host_to_net_u32 (esp0->seq);
 174
 175           /* anti-replay check */
 176           if (sa0->use_anti_replay)
 177             {
 178               int rv = 0;
 179
 180               if (PREDICT_TRUE (sa0->use_esn))
 181                 rv = esp_replay_check_esn (sa0, seq);
 182               else
 183                 rv = esp_replay_check (sa0, seq);
 184
 185               if (PREDICT_FALSE (rv))
 186                 {
 187                   vlib_node_increment_counter (vm, node->node_index,
 188                                                ESP_DECRYPT_ERROR_REPLAY, 1);
 189                   o_bi0 = i_bi0;
 190                   to_next[0] = o_bi0;
 191                   to_next += 1;
 192                   goto trace;
 193                 }
 194             }
 195
 196           sa0->total_data_size += i_b0->current_length;
 197
 198           if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 199             {
 200               u8 sig[64];
 201               int icv_size =
 202                 em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 203               clib_memset (sig, 0, sizeof (sig));
 204               u8 *icv =
 205                 vlib_buffer_get_current (i_b0) + i_b0->current_length -
 206                 icv_size;
 207               i_b0->current_length -= icv_size;
 208
 209               hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
 210                          (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
 211                          sa0->seq_hi);
 212
 213               if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 214                 {
 215                   vlib_node_increment_counter (vm, node->node_index,
 216                                                ESP_DECRYPT_ERROR_INTEG_ERROR,
 217                                                1);
 218                   o_bi0 = i_bi0;
 219                   to_next[0] = o_bi0;
 220                   to_next += 1;
 221                   goto trace;
 222                 }
 223             }
 224
 225           if (PREDICT_TRUE (sa0->use_anti_replay))
 226             {
 227               if (PREDICT_TRUE (sa0->use_esn))
 228                 esp_replay_advance_esn (sa0, seq);
 229               else
 230                 esp_replay_advance (sa0, seq);
 231             }
 232
 233           /* grab free buffer */
 234           uword last_empty_buffer = vec_len (empty_buffers) - 1;
 235           o_bi0 = empty_buffers[last_empty_buffer];
 236           to_next[0] = o_bi0;
 237           to_next += 1;
 238           o_b0 = vlib_get_buffer (vm, o_bi0);
 239           vlib_prefetch_buffer_with_index (vm,
 240                                            empty_buffers[last_empty_buffer -
 241                                                          1], STORE);
 242           _vec_len (empty_buffers) = last_empty_buffer;
 243
 244           /* add old buffer to the recycle list */
 245           vec_add1 (recycle, i_bi0);
 246
 247           if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 248                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 249               (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 250                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 251             {
 252               const int BLOCK_SIZE =
 253                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
 254               const int IV_SIZE =
 255                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 256               esp_footer_t *f0;
 257               u8 ip_hdr_size = 0;
 258
 259               int blocks =
 260                 (i_b0->current_length - sizeof (esp_header_t) -
 261                  IV_SIZE) / BLOCK_SIZE;
 262
 263               o_b0->current_data = sizeof (ethernet_header_t);
 264
 265               /* transport mode */
 266               if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 267                 {
 268                   tunnel_mode = 0;
 269
 270                   if (is_ip6)
 271                     {
 272                       ih6 =
 273                         (ip6_header_t *) ((u8 *) esp0 -
 274                                           sizeof (ip6_header_t));
 275                       ip_hdr_size = sizeof (ip6_header_t);
 276                       oh6 = vlib_buffer_get_current (o_b0);
 277                     }
 278                   else
 279                     {
 280                       if (sa0->udp_encap)
 281                         {
 282                           ih4 =
 283                             (ip4_header_t *) ((u8 *) esp0 -
 284                                               sizeof (udp_header_t) -
 285                                               sizeof (ip4_header_t));
 286                         }
 287                       else
 288                         {
 289                           ih4 =
 290                             (ip4_header_t *) ((u8 *) esp0 -
 291                                               sizeof (ip4_header_t));
 292                         }
 293                       oh4 = vlib_buffer_get_current (o_b0);
 294                       ip_hdr_size = sizeof (ip4_header_t);
 295                     }
 296                 }
 297
 298               esp_decrypt_cbc (sa0->crypto_alg,
 299                                esp0->data + IV_SIZE,
 300                                (u8 *) vlib_buffer_get_current (o_b0) +
 301                                ip_hdr_size, BLOCK_SIZE * blocks,
 302                                sa0->crypto_key, esp0->data);
 303
 304               o_b0->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 305               o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 306               f0 =
 307                 (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
 308                                   o_b0->current_length);
 309               o_b0->current_length -= f0->pad_length;
 310
 311               /* tunnel mode */
 312               if (PREDICT_TRUE (tunnel_mode))
 313                 {
 314                   if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 315                     {
 316                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 317                       oh4 = vlib_buffer_get_current (o_b0);
 318                     }
 319                   else if (f0->next_header == IP_PROTOCOL_IPV6)
 320                     next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 321                   else
 322                     {
 323                       vlib_node_increment_counter (vm, node->node_index,
 324                                                    ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 325                                                    1);
 326                       o_b0 = 0;
 327                       goto trace;
 328                     }
 329                 }
 330               /* transport mode */
 331               else
 332                 {
 333                   if (is_ip6)
 334                     {
 335                       next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 336                       oh6->ip_version_traffic_class_and_flow_label =
 337                         ih6->ip_version_traffic_class_and_flow_label;
 338                       oh6->protocol = f0->next_header;
 339                       oh6->hop_limit = ih6->hop_limit;
 340                       oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 341                       oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 342                       oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 343                       oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 344                       oh6->payload_length =
 345                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 346                                               (vm,
 347                                                o_b0) - sizeof (ip6_header_t));
 348                     }
 349                   else
 350                     {
 351                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 352                       oh4->ip_version_and_header_length = 0x45;
 353                       oh4->tos = ih4->tos;
 354                       oh4->fragment_id = 0;
 355                       oh4->flags_and_fragment_offset = 0;
 356                       oh4->ttl = ih4->ttl;
 357                       oh4->protocol = f0->next_header;
 358                       oh4->src_address.as_u32 = ih4->src_address.as_u32;
 359                       oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 360                       oh4->length =
 361                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 362                                               (vm, o_b0));
 363                       oh4->checksum = ip4_header_checksum (oh4);
 364                     }
 365                 }
 366
 367               /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 368               if (PREDICT_FALSE
 369                   ((vnet_buffer (i_b0)->ipsec.flags) &
 370                    IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 371                 next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 372
 373               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 374               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 375                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 376             }
 377
 378         trace:
 379           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 380             {
 381               if (o_b0)
 382                 {
 383                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 384                   o_b0->trace_index = i_b0->trace_index;
 385                   esp_decrypt_trace_t *tr =
 386                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 387                   tr->crypto_alg = sa0->crypto_alg;
 388                   tr->integ_alg = sa0->integ_alg;
 389                 }
 390             }
 391
 392           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 393                                            n_left_to_next, o_bi0, next0);
 394         }
 395       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 396     }
 397   vlib_node_increment_counter (vm, node->node_index,
 398                                ESP_DECRYPT_ERROR_RX_PKTS,
 399                                from_frame->n_vectors);
 400
 401
 402 free_buffers_and_exit:
 403   if (recycle)
 404     vlib_buffer_free (vm, recycle, vec_len (recycle));
 405   vec_free (recycle);
 406   return from_frame->n_vectors;
 407 }
 408
 409 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
 410                                   vlib_node_runtime_t * node,
 411                                   vlib_frame_t * from_frame)
 412 {
 413   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 414 }
 415
 416 /* *INDENT-OFF* */
 417 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 418   .name = "esp4-decrypt",
 419   .vector_size = sizeof (u32),
 420   .format_trace = format_esp_decrypt_trace,
 421   .type = VLIB_NODE_TYPE_INTERNAL,
 422
 423   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 424   .error_strings = esp_decrypt_error_strings,
 425
 426   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 427   .next_nodes = {
 428 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 429     foreach_esp_decrypt_next
 430 #undef _
 431   },
 432 };
 433 /* *INDENT-ON* */
 434
 435 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
 436                                   vlib_node_runtime_t * node,
 437                                   vlib_frame_t * from_frame)
 438 {
 439   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 440 }
 441
 442 /* *INDENT-OFF* */
 443 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 444   .name = "esp6-decrypt",
 445   .vector_size = sizeof (u32),
 446   .format_trace = format_esp_decrypt_trace,
 447   .type = VLIB_NODE_TYPE_INTERNAL,
 448
 449   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 450   .error_strings = esp_decrypt_error_strings,
 451
 452   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 453   .next_nodes = {
 454 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 455     foreach_esp_decrypt_next
 456 #undef _
 457   },
 458 };
 459 /* *INDENT-ON* */
 460
 461 /*
 462  * fd.io coding-style-patch-verification: ON
 463  *
 464  * Local Variables:
 465  * eval: (c-set-style "gnu")
 466  * End:
 467  */