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 static uword
 116 esp_decrypt_node_fn (vlib_main_t * vm,
 117                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 118 {
 119   u32 n_left_from, *from, next_index, *to_next;
 120   ipsec_main_t *im = &ipsec_main;
 121   ipsec_proto_main_t *em = &ipsec_proto_main;
 122   u32 *recycle = 0;
 123   from = vlib_frame_vector_args (from_frame);
 124   n_left_from = from_frame->n_vectors;
 125   u32 thread_index = vlib_get_thread_index ();
 126
 127   ipsec_alloc_empty_buffers (vm, im);
 128
 129   u32 *empty_buffers = im->empty_buffers[thread_index];
 130
 131   if (PREDICT_FALSE (vec_len (empty_buffers) < n_left_from))
 132     {
 133       vlib_node_increment_counter (vm, esp_decrypt_node.index,
 134                                    ESP_DECRYPT_ERROR_NO_BUFFER, n_left_from);
 135       goto free_buffers_and_exit;
 136     }
 137
 138   next_index = node->cached_next_index;
 139
 140   while (n_left_from > 0)
 141     {
 142       u32 n_left_to_next;
 143
 144       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
 145
 146       while (n_left_from > 0 && n_left_to_next > 0)
 147         {
 148           u32 i_bi0, o_bi0 = (u32) ~ 0, next0;
 149           vlib_buffer_t *i_b0;
 150           vlib_buffer_t *o_b0 = 0;
 151           esp_header_t *esp0;
 152           ipsec_sa_t *sa0;
 153           u32 sa_index0 = ~0;
 154           u32 seq;
 155           ip4_header_t *ih4 = 0, *oh4 = 0;
 156           ip6_header_t *ih6 = 0, *oh6 = 0;
 157           u8 tunnel_mode = 1;
 158           u8 transport_ip6 = 0;
 159
 160
 161           i_bi0 = from[0];
 162           from += 1;
 163           n_left_from -= 1;
 164           n_left_to_next -= 1;
 165
 166           next0 = ESP_DECRYPT_NEXT_DROP;
 167
 168           i_b0 = vlib_get_buffer (vm, i_bi0);
 169           esp0 = vlib_buffer_get_current (i_b0);
 170
 171           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 172           sa0 = pool_elt_at_index (im->sad, sa_index0);
 173
 174           seq = clib_host_to_net_u32 (esp0->seq);
 175
 176           /* anti-replay check */
 177           if (sa0->use_anti_replay)
 178             {
 179               int rv = 0;
 180
 181               if (PREDICT_TRUE (sa0->use_esn))
 182                 rv = esp_replay_check_esn (sa0, seq);
 183               else
 184                 rv = esp_replay_check (sa0, seq);
 185
 186               if (PREDICT_FALSE (rv))
 187                 {
 188                   clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
 189                   vlib_node_increment_counter (vm, esp_decrypt_node.index,
 190                                                ESP_DECRYPT_ERROR_REPLAY, 1);
 191                   o_bi0 = i_bi0;
 192                   to_next[0] = o_bi0;
 193                   to_next += 1;
 194                   goto trace;
 195                 }
 196             }
 197
 198           sa0->total_data_size += i_b0->current_length;
 199
 200           if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 201             {
 202               u8 sig[64];
 203               int icv_size =
 204                 em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 205               memset (sig, 0, sizeof (sig));
 206               u8 *icv =
 207                 vlib_buffer_get_current (i_b0) + i_b0->current_length -
 208                 icv_size;
 209               i_b0->current_length -= icv_size;
 210
 211               hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
 212                          (u8 *) esp0, i_b0->current_length, sig, sa0->use_esn,
 213                          sa0->seq_hi);
 214
 215               if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 216                 {
 217                   vlib_node_increment_counter (vm, esp_decrypt_node.index,
 218                                                ESP_DECRYPT_ERROR_INTEG_ERROR,
 219                                                1);
 220                   o_bi0 = i_bi0;
 221                   to_next[0] = o_bi0;
 222                   to_next += 1;
 223                   goto trace;
 224                 }
 225             }
 226
 227           if (PREDICT_TRUE (sa0->use_anti_replay))
 228             {
 229               if (PREDICT_TRUE (sa0->use_esn))
 230                 esp_replay_advance_esn (sa0, seq);
 231               else
 232                 esp_replay_advance (sa0, seq);
 233             }
 234
 235           /* grab free buffer */
 236           uword last_empty_buffer = vec_len (empty_buffers) - 1;
 237           o_bi0 = empty_buffers[last_empty_buffer];
 238           to_next[0] = o_bi0;
 239           to_next += 1;
 240           o_b0 = vlib_get_buffer (vm, o_bi0);
 241           vlib_prefetch_buffer_with_index (vm,
 242                                            empty_buffers[last_empty_buffer -
 243                                                          1], STORE);
 244           _vec_len (empty_buffers) = last_empty_buffer;
 245
 246           /* add old buffer to the recycle list */
 247           vec_add1 (recycle, i_bi0);
 248
 249           if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 250                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 251               (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 252                sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 253             {
 254               const int BLOCK_SIZE =
 255                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
 256               const int IV_SIZE =
 257                 em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 258               esp_footer_t *f0;
 259               u8 ip_hdr_size = 0;
 260
 261               int blocks =
 262                 (i_b0->current_length - sizeof (esp_header_t) -
 263                  IV_SIZE) / BLOCK_SIZE;
 264
 265               o_b0->current_data = sizeof (ethernet_header_t);
 266
 267               /* transport mode */
 268               if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 269                 {
 270                   tunnel_mode = 0;
 271                   ih4 =
 272                     (ip4_header_t *) (i_b0->data +
 273                                       sizeof (ethernet_header_t));
 274                   if (PREDICT_TRUE
 275                       ((ih4->ip_version_and_header_length & 0xF0) != 0x40))
 276                     {
 277                       if (PREDICT_TRUE
 278                           ((ih4->ip_version_and_header_length & 0xF0) ==
 279                            0x60))
 280                         {
 281                           transport_ip6 = 1;
 282                           ip_hdr_size = sizeof (ip6_header_t);
 283                           ih6 =
 284                             (ip6_header_t *) (i_b0->data +
 285                                               sizeof (ethernet_header_t));
 286                           oh6 = vlib_buffer_get_current (o_b0);
 287                         }
 288                       else
 289                         {
 290                           vlib_node_increment_counter (vm,
 291                                                        esp_decrypt_node.index,
 292                                                        ESP_DECRYPT_ERROR_NOT_IP,
 293                                                        1);
 294                           o_b0 = 0;
 295                           goto trace;
 296                         }
 297                     }
 298                   else
 299                     {
 300                       oh4 = vlib_buffer_get_current (o_b0);
 301                       ip_hdr_size = sizeof (ip4_header_t);
 302                     }
 303                 }
 304
 305               esp_decrypt_cbc (sa0->crypto_alg,
 306                                esp0->data + IV_SIZE,
 307                                (u8 *) vlib_buffer_get_current (o_b0) +
 308                                ip_hdr_size, BLOCK_SIZE * blocks,
 309                                sa0->crypto_key, esp0->data);
 310
 311               o_b0->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 312               o_b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 313               f0 =
 314                 (esp_footer_t *) ((u8 *) vlib_buffer_get_current (o_b0) +
 315                                   o_b0->current_length);
 316               o_b0->current_length -= f0->pad_length;
 317
 318               /* tunnel mode */
 319               if (PREDICT_TRUE (tunnel_mode))
 320                 {
 321                   if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 322                     {
 323                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 324                       oh4 = vlib_buffer_get_current (o_b0);
 325                     }
 326                   else if (f0->next_header == IP_PROTOCOL_IPV6)
 327                     next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 328                   else
 329                     {
 330                       clib_warning ("next header: 0x%x", f0->next_header);
 331                       vlib_node_increment_counter (vm, esp_decrypt_node.index,
 332                                                    ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 333                                                    1);
 334                       o_b0 = 0;
 335                       goto trace;
 336                     }
 337                 }
 338               /* transport mode */
 339               else
 340                 {
 341                   if (PREDICT_FALSE (transport_ip6))
 342                     {
 343                       next0 = ESP_DECRYPT_NEXT_IP6_INPUT;
 344                       oh6->ip_version_traffic_class_and_flow_label =
 345                         ih6->ip_version_traffic_class_and_flow_label;
 346                       oh6->protocol = f0->next_header;
 347                       oh6->hop_limit = ih6->hop_limit;
 348                       oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 349                       oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 350                       oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 351                       oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 352                       oh6->payload_length =
 353                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 354                                               (vm,
 355                                                o_b0) - sizeof (ip6_header_t));
 356                     }
 357                   else
 358                     {
 359                       next0 = ESP_DECRYPT_NEXT_IP4_INPUT;
 360                       oh4->ip_version_and_header_length = 0x45;
 361                       oh4->tos = ih4->tos;
 362                       oh4->fragment_id = 0;
 363                       oh4->flags_and_fragment_offset = 0;
 364                       oh4->ttl = ih4->ttl;
 365                       oh4->protocol = f0->next_header;
 366                       oh4->src_address.as_u32 = ih4->src_address.as_u32;
 367                       oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 368                       oh4->length =
 369                         clib_host_to_net_u16 (vlib_buffer_length_in_chain
 370                                               (vm, o_b0));
 371                       oh4->checksum = ip4_header_checksum (oh4);
 372                     }
 373                 }
 374
 375               /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 376               if (PREDICT_FALSE
 377                   ((vnet_buffer (i_b0)->ipsec.flags) &
 378                    IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 379                 next0 = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 380
 381               vnet_buffer (o_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 382               vnet_buffer (o_b0)->sw_if_index[VLIB_RX] =
 383                 vnet_buffer (i_b0)->sw_if_index[VLIB_RX];
 384             }
 385
 386         trace:
 387           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 388             {
 389               if (o_b0)
 390                 {
 391                   o_b0->flags |= VLIB_BUFFER_IS_TRACED;
 392                   o_b0->trace_index = i_b0->trace_index;
 393                   esp_decrypt_trace_t *tr =
 394                     vlib_add_trace (vm, node, o_b0, sizeof (*tr));
 395                   tr->crypto_alg = sa0->crypto_alg;
 396                   tr->integ_alg = sa0->integ_alg;
 397                 }
 398             }
 399
 400           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 401                                            n_left_to_next, o_bi0, next0);
 402         }
 403       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 404     }
 405   vlib_node_increment_counter (vm, esp_decrypt_node.index,
 406                                ESP_DECRYPT_ERROR_RX_PKTS,
 407                                from_frame->n_vectors);
 408
 409 free_buffers_and_exit:
 410   if (recycle)
 411     vlib_buffer_free (vm, recycle, vec_len (recycle));
 412   vec_free (recycle);
 413   return from_frame->n_vectors;
 414 }
 415
 416
 417 /* *INDENT-OFF* */
 418 VLIB_REGISTER_NODE (esp_decrypt_node) = {
 419   .function = esp_decrypt_node_fn,
 420   .name = "esp-decrypt",
 421   .vector_size = sizeof (u32),
 422   .format_trace = format_esp_decrypt_trace,
 423   .type = VLIB_NODE_TYPE_INTERNAL,
 424
 425   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 426   .error_strings = esp_decrypt_error_strings,
 427
 428   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 429   .next_nodes = {
 430 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 431     foreach_esp_decrypt_next
 432 #undef _
 433   },
 434 };
 435 /* *INDENT-ON* */
 436
 437 VLIB_NODE_FUNCTION_MULTIARCH (esp_decrypt_node, esp_decrypt_node_fn)
 438 /*
 439  * fd.io coding-style-patch-verification: ON
 440  *
 441  * Local Variables:
 442  * eval: (c-set-style "gnu")
 443  * End:
 444  */