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.data,
 210                          sa0->integ_key.len, (u8 *) esp0,
 211                          i_b0->current_length, sig, sa0->use_esn,
 212                          sa0->seq_hi);
 213
 214               if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 215                 {
 216                   vlib_node_increment_counter (vm, node->node_index,
 217                                                ESP_DECRYPT_ERROR_INTEG_ERROR,
 218                                                1);
 219                   o_bi0 = i_bi0;
 220                   to_next[0] = o_bi0;
 221                   to_next += 1;
 222                   goto trace;
 223                 }
 224             }
 225
 226           if (PREDICT_TRUE (sa0->use_anti_replay))
 227             {
 228               if (PREDICT_TRUE (sa0->use_esn))
 229                 esp_replay_advance_esn (sa0, seq);
 230               else
 231                 esp_replay_advance (sa0, seq);
 232             }
 233
 234           /* grab free buffer */
 235           uword last_empty_buffer = vec_len (empty_buffers) - 1;
 236           o_bi0 = empty_buffers[last_empty_buffer];
 237           to_next[0] = o_bi0;
 238           to_next += 1;
 239           o_b0 = vlib_get_buffer (vm, o_bi0);
 240           vlib_prefetch_buffer_with_index (vm,
 241                                            empty_buffers[last_empty_buffer -
 242                                                          1], STORE);
 243           _vec_len (empty_buffers) = last_empty_buffer;
 244
 245           /* add old buffer to the recycle list */
 246           vec_add1 (recycle, i_bi0);
 247
 248           if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 249                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 250               (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 251                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 252             {
 253               const int BLOCK_SIZE =
 254                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
 255               const int IV_SIZE =
 256                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 257               esp_footer_t *f0;
 258               u8 ip_hdr_size = 0;
 259
 260               int blocks =
 261                 (i_b0->current_length - sizeof (esp_header_t) -
 262                  IV_SIZE) / BLOCK_SIZE;
 263
 264               o_b0->current_data = sizeof (ethernet_header_t);
 265
 266               /* transport mode */
 267               if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 268                 {
 269                   tunnel_mode = 0;
 270
 271                   if (is_ip6)
 272                     {
 273                       ih6 =
 274                         (ip6_header_t *) ((u8 *) esp0 -
 275                                           sizeof (ip6_header_t));
 276                       ip_hdr_size = sizeof (ip6_header_t);
 277                       oh6 = vlib_buffer_get_current (o_b0);
 278                     }
 279                   else
 280                     {
 281                       if (sa0->udp_encap)
 282                         {
 283                           ih4 =
 284                             (ip4_header_t *) ((u8 *) esp0 -
 285                                               sizeof (udp_header_t) -
 286                                               sizeof (ip4_header_t));
 287                         }
 288                       else
 289                         {
 290                           ih4 =
 291                             (ip4_header_t *) ((u8 *) esp0 -
 292                                               sizeof (ip4_header_t));
 293                         }
 294                       oh4 = vlib_buffer_get_current (o_b0);
 295                       ip_hdr_size = sizeof (ip4_header_t);
 296                     }
 297                 }
 298
 299               esp_decrypt_cbc (sa0->crypto_alg,
 300                                esp0->data + IV_SIZE,
 301                                (u8 *) vlib_buffer_get_current (o_b0) +
 302                                ip_hdr_size, BLOCK_SIZE * blocks,
 303                                sa0->crypto_key.data, esp0->data);
 304
 305               o_b0->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 306               o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 307               f0 =
 308                 (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
 309                                   o_b0->current_length);
 310               o_b0->current_length -= f0->pad_length;
 311
 312               /* tunnel mode */
 313               if (PREDICT_TRUE (tunnel_mode))
 314                 {
 315                   if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 316                     {
 317                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 318                       oh4 = vlib_buffer_get_current (o_b0);
 319                     }
 320                   else if (f0->next_header == IP_PROTOCOL_IPV6)
 321                     next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 322                   else
 323                     {
 324                       vlib_node_increment_counter (vm, node->node_index,
 325                                                    ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 326                                                    1);
 327                       o_b0 = 0;
 328                       goto trace;
 329                     }
 330                 }
 331               /* transport mode */
 332               else
 333                 {
 334                   if (is_ip6)
 335                     {
 336                       next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 337                       oh6->ip_version_traffic_class_and_flow_label =
 338                         ih6->ip_version_traffic_class_and_flow_label;
 339                       oh6->protocol = f0->next_header;
 340                       oh6->hop_limit = ih6->hop_limit;
 341                       oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 342                       oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 343                       oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 344                       oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 345                       oh6->payload_length =
 346                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 347                                               (vm,
 348                                                o_b0) - sizeof (ip6_header_t));
 349                     }
 350                   else
 351                     {
 352                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 353                       oh4->ip_version_and_header_length = 0x45;
 354                       oh4->tos = ih4->tos;
 355                       oh4->fragment_id = 0;
 356                       oh4->flags_and_fragment_offset = 0;
 357                       oh4->ttl = ih4->ttl;
 358                       oh4->protocol = f0->next_header;
 359                       oh4->src_address.as_u32 = ih4->src_address.as_u32;
 360                       oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 361                       oh4->length =
 362                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 363                                               (vm, o_b0));
 364                       oh4->checksum = ip4_header_checksum (oh4);
 365                     }
 366                 }
 367
 368               /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 369               if (PREDICT_FALSE
 370                   ((vnet_buffer (i_b0)->ipsec.flags) &
 371                    IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 372                 next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 373
 374               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 375               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 376                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 377             }
 378
 379         trace:
 380           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 381             {
 382               if (o_b0)
 383                 {
 384                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 385                   o_b0->trace_index = i_b0->trace_index;
 386                   esp_decrypt_trace_t *tr =
 387                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 388                   tr->crypto_alg = sa0->crypto_alg;
 389                   tr->integ_alg = sa0->integ_alg;
 390                 }
 391             }
 392
 393           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 394                                            n_left_to_next, o_bi0, next0);
 395         }
 396       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 397     }
 398   vlib_node_increment_counter (vm, node->node_index,
 399                                ESP_DECRYPT_ERROR_RX_PKTS,
 400                                from_frame->n_vectors);
 401
 402
 403 free_buffers_and_exit:
 404   if (recycle)
 405     vlib_buffer_free (vm, recycle, vec_len (recycle));
 406   vec_free (recycle);
 407   return from_frame->n_vectors;
 408 }
 409
 410 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
 411                                   vlib_node_runtime_t * node,
 412                                   vlib_frame_t * from_frame)
 413 {
 414   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 415 }
 416
 417 /* *INDENT-OFF* */
 418 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 419   .name = "esp4-decrypt",
 420   .vector_size = sizeof (u32),
 421   .format_trace = format_esp_decrypt_trace,
 422   .type = VLIB_NODE_TYPE_INTERNAL,
 423
 424   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 425   .error_strings = esp_decrypt_error_strings,
 426
 427   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 428   .next_nodes = {
 429 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 430     foreach_esp_decrypt_next
 431 #undef _
 432   },
 433 };
 434 /* *INDENT-ON* */
 435
 436 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
 437                                   vlib_node_runtime_t * node,
 438                                   vlib_frame_t * from_frame)
 439 {
 440   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 441 }
 442
 443 /* *INDENT-OFF* */
 444 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 445   .name = "esp6-decrypt",
 446   .vector_size = sizeof (u32),
 447   .format_trace = format_esp_decrypt_trace,
 448   .type = VLIB_NODE_TYPE_INTERNAL,
 449
 450   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 451   .error_strings = esp_decrypt_error_strings,
 452
 453   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 454   .next_nodes = {
 455 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 456     foreach_esp_decrypt_next
 457 #undef _
 458   },
 459 };
 460 /* *INDENT-ON* */
 461
 462 /*
 463  * fd.io coding-style-patch-verification: ON
 464  *
 465  * Local Variables:
 466  * eval: (c-set-style "gnu")
 467  * End:
 468  */