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 #include <vnet/ipsec/ipsec_io.h>
  25
  26 #define foreach_esp_decrypt_next                \
  27 _(DROP, "error-drop")                           \
  28 _(IP4_INPUT, "ip4-input-no-checksum")           \
  29 _(IP6_INPUT, "ip6-input")                       \
  30 _(IPSEC_GRE_INPUT, "ipsec-gre-input")
  31
  32 #define _(v, s) ESP_DECRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_esp_decrypt_next
  36 #undef _
  37     ESP_DECRYPT_N_NEXT,
  38 } esp_decrypt_next_t;
  39
  40
  41 #define foreach_esp_decrypt_error                   \
  42  _(RX_PKTS, "ESP pkts received")                    \
  43  _(NO_BUFFER, "No buffer (packed dropped)")         \
  44  _(DECRYPTION_FAILED, "ESP decryption failed")      \
  45  _(INTEG_ERROR, "Integrity check failed")           \
  46  _(REPLAY, "SA replayed packet")                    \
  47  _(NOT_IP, "Not IP packet (dropped)")
  48
  49
  50 typedef enum
  51 {
  52 #define _(sym,str) ESP_DECRYPT_ERROR_##sym,
  53   foreach_esp_decrypt_error
  54 #undef _
  55     ESP_DECRYPT_N_ERROR,
  56 } esp_decrypt_error_t;
  57
  58 static char *esp_decrypt_error_strings[] = {
  59 #define _(sym,string) string,
  60   foreach_esp_decrypt_error
  61 #undef _
  62 };
  63
  64 typedef struct
  65 {
  66   ipsec_crypto_alg_t crypto_alg;
  67   ipsec_integ_alg_t integ_alg;
  68 } esp_decrypt_trace_t;
  69
  70 /* packet trace format function */
  71 static u8 *
  72 format_esp_decrypt_trace (u8 * s, va_list * args)
  73 {
  74   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  75   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  76   esp_decrypt_trace_t *t = va_arg (*args, esp_decrypt_trace_t *);
  77
  78   s = format (s, "esp: crypto %U integrity %U",
  79               format_ipsec_crypto_alg, t->crypto_alg,
  80               format_ipsec_integ_alg, t->integ_alg);
  81   return s;
  82 }
  83
  84 always_inline void
  85 esp_decrypt_cbc (ipsec_crypto_alg_t alg,
  86                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  87 {
  88   ipsec_proto_main_t *em = &ipsec_proto_main;
  89   u32 thread_index = vlib_get_thread_index ();
  90 #if OPENSSL_VERSION_NUMBER >= 0x10100000L
  91   EVP_CIPHER_CTX *ctx = em->per_thread_data[thread_index].decrypt_ctx;
  92 #else
  93   EVP_CIPHER_CTX *ctx = &(em->per_thread_data[thread_index].decrypt_ctx);
  94 #endif
  95   const EVP_CIPHER *cipher = NULL;
  96   int out_len;
  97
  98   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
  99
 100   if (PREDICT_FALSE (em->ipsec_proto_main_crypto_algs[alg].type == 0))
 101     return;
 102
 103   if (PREDICT_FALSE
 104       (alg != em->per_thread_data[thread_index].last_decrypt_alg))
 105     {
 106       cipher = em->ipsec_proto_main_crypto_algs[alg].type;
 107       em->per_thread_data[thread_index].last_decrypt_alg = alg;
 108     }
 109
 110   EVP_DecryptInit_ex (ctx, cipher, NULL, key, iv);
 111
 112   EVP_DecryptUpdate (ctx, out, &out_len, in, in_len);
 113   EVP_DecryptFinal_ex (ctx, out + out_len, &out_len);
 114 }
 115
 116 always_inline uword
 117 esp_decrypt_inline (vlib_main_t * vm,
 118                     vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 119                     int is_ip6)
 120 {
 121   ipsec_main_t *im = &ipsec_main;
 122   ipsec_proto_main_t *em = &ipsec_proto_main;
 123   u32 *from = vlib_frame_vector_args (from_frame);
 124   u32 n_left_from = from_frame->n_vectors;
 125   u32 new_bufs[VLIB_FRAME_SIZE];
 126   vlib_buffer_t *i_bufs[VLIB_FRAME_SIZE], **ib = i_bufs;
 127   vlib_buffer_t *o_bufs[VLIB_FRAME_SIZE], **ob = o_bufs;
 128   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 129   u32 n_alloc, thread_index = vm->thread_index;
 130
 131   n_alloc = vlib_buffer_alloc (vm, new_bufs, n_left_from);
 132   if (n_alloc != n_left_from)
 133     {
 134       vlib_node_increment_counter (vm, node->node_index,
 135                                    ESP_DECRYPT_ERROR_NO_BUFFER,
 136                                    n_left_from - n_alloc);
 137       if (n_alloc == 0)
 138         goto done;
 139       n_left_from = n_alloc;
 140     }
 141
 142   vlib_get_buffers (vm, from, ib, n_left_from);
 143   vlib_get_buffers (vm, new_bufs, ob, n_left_from);
 144
 145   while (n_left_from > 0)
 146     {
 147       esp_header_t *esp0;
 148       ipsec_sa_t *sa0;
 149       u32 sa_index0 = ~0;
 150       u32 seq;
 151       ip4_header_t *ih4 = 0, *oh4 = 0;
 152       ip6_header_t *ih6 = 0, *oh6 = 0;
 153       u8 tunnel_mode = 1;
 154
 155       next[0] = ESP_DECRYPT_NEXT_DROP;
 156
 157       esp0 = vlib_buffer_get_current (ib[0]);
 158       sa_index0 = vnet_buffer (ib[0])->ipsec.sad_index;
 159       sa0 = pool_elt_at_index (im->sad, sa_index0);
 160       seq = clib_host_to_net_u32 (esp0->seq);
 161
 162       /* anti-replay check */
 163       if (sa0->use_anti_replay)
 164         {
 165           int rv = 0;
 166
 167           if (PREDICT_TRUE (sa0->use_esn))
 168             rv = esp_replay_check_esn (sa0, seq);
 169           else
 170             rv = esp_replay_check (sa0, seq);
 171
 172           if (PREDICT_FALSE (rv))
 173             {
 174               u32 tmp, off = n_alloc - n_left_from;
 175               /* send original packet to drop node */
 176               tmp = from[off];
 177               from[off] = new_bufs[off];
 178               new_bufs[off] = tmp;
 179               ib[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
 180               next[0] = ESP_DECRYPT_NEXT_DROP;
 181               goto trace;
 182             }
 183         }
 184
 185       vlib_increment_combined_counter
 186         (&ipsec_sa_counters, thread_index, sa_index0,
 187          1, ib[0]->current_length);
 188
 189       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 190         {
 191           u8 sig[64];
 192           int icv_size =
 193             em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 194           clib_memset (sig, 0, sizeof (sig));
 195           u8 *icv =
 196             vlib_buffer_get_current (ib[0]) + ib[0]->current_length -
 197             icv_size;
 198           ib[0]->current_length -= icv_size;
 199
 200           hmac_calc (sa0->integ_alg, sa0->integ_key.data,
 201                      sa0->integ_key.len, (u8 *) esp0,
 202                      ib[0]->current_length, sig, sa0->use_esn, sa0->seq_hi);
 203
 204           if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 205             {
 206               u32 tmp, off = n_alloc - n_left_from;
 207               /* send original packet to drop node */
 208               tmp = from[off];
 209               from[off] = new_bufs[off];
 210               new_bufs[off] = tmp;
 211               ib[0]->error = node->errors[ESP_DECRYPT_ERROR_INTEG_ERROR];
 212               next[0] = ESP_DECRYPT_NEXT_DROP;
 213               goto trace;
 214             }
 215         }
 216
 217       if (PREDICT_TRUE (sa0->use_anti_replay))
 218         {
 219           if (PREDICT_TRUE (sa0->use_esn))
 220             esp_replay_advance_esn (sa0, seq);
 221           else
 222             esp_replay_advance (sa0, seq);
 223         }
 224
 225       if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 226            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 227           (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 228            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 229         {
 230           const int BLOCK_SIZE =
 231             em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].block_size;;
 232           const int IV_SIZE =
 233             em->ipsec_proto_main_crypto_algs[sa0->crypto_alg].iv_size;
 234           esp_footer_t *f0;
 235           u8 ip_hdr_size = 0;
 236
 237           int blocks =
 238             (ib[0]->current_length - sizeof (esp_header_t) -
 239              IV_SIZE) / BLOCK_SIZE;
 240
 241           ob[0]->current_data = sizeof (ethernet_header_t);
 242
 243           /* transport mode */
 244           if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 245             {
 246               tunnel_mode = 0;
 247
 248               if (is_ip6)
 249                 {
 250                   ip_hdr_size = sizeof (ip6_header_t);
 251                   ih6 = (ip6_header_t *) ((u8 *) esp0 - ip_hdr_size);
 252                   oh6 = vlib_buffer_get_current (ob[0]);
 253                 }
 254               else
 255                 {
 256                   ip_hdr_size = sizeof (ip4_header_t);
 257                   if (sa0->udp_encap)
 258                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size -
 259                                             sizeof (udp_header_t));
 260                   else
 261                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size);
 262                   oh4 = vlib_buffer_get_current (ob[0]);
 263                 }
 264             }
 265
 266           esp_decrypt_cbc (sa0->crypto_alg,
 267                            esp0->data + IV_SIZE,
 268                            (u8 *) vlib_buffer_get_current (ob[0]) +
 269                            ip_hdr_size, BLOCK_SIZE * blocks,
 270                            sa0->crypto_key.data, esp0->data);
 271
 272           ob[0]->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 273           ob[0]->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 274           f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (ob[0]) +
 275                                  ob[0]->current_length);
 276           ob[0]->current_length -= f0->pad_length;
 277
 278           /* tunnel mode */
 279           if (PREDICT_TRUE (tunnel_mode))
 280             {
 281               if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 282                 {
 283                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 284                   oh4 = vlib_buffer_get_current (ob[0]);
 285                 }
 286               else if (f0->next_header == IP_PROTOCOL_IPV6)
 287                 next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 288               else
 289                 {
 290                   vlib_node_increment_counter (vm, node->node_index,
 291                                                ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 292                                                1);
 293                   ob[0] = 0;
 294                   goto trace;
 295                 }
 296             }
 297           /* transport mode */
 298           else
 299             {
 300               u32 len = vlib_buffer_length_in_chain (vm, ob[0]);
 301               if (is_ip6)
 302                 {
 303                   next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 304                   oh6->ip_version_traffic_class_and_flow_label =
 305                     ih6->ip_version_traffic_class_and_flow_label;
 306                   oh6->protocol = f0->next_header;
 307                   oh6->hop_limit = ih6->hop_limit;
 308                   oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 309                   oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 310                   oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 311                   oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 312                   len -= sizeof (ip6_header_t);
 313                   oh6->payload_length = clib_host_to_net_u16 (len);
 314                 }
 315               else
 316                 {
 317                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 318                   oh4->ip_version_and_header_length = 0x45;
 319                   oh4->tos = ih4->tos;
 320                   oh4->fragment_id = 0;
 321                   oh4->flags_and_fragment_offset = 0;
 322                   oh4->ttl = ih4->ttl;
 323                   oh4->protocol = f0->next_header;
 324                   oh4->src_address.as_u32 = ih4->src_address.as_u32;
 325                   oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 326                   oh4->length = clib_host_to_net_u16 (len);
 327                   oh4->checksum = ip4_header_checksum (oh4);
 328                 }
 329             }
 330
 331           /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 332           if (PREDICT_FALSE
 333               ((vnet_buffer (ib[0])->ipsec.flags) &
 334                IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 335             next[0] = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 336
 337           vnet_buffer (ob[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
 338           vnet_buffer (ob[0])->sw_if_index[VLIB_RX] =
 339             vnet_buffer (ib[0])->sw_if_index[VLIB_RX];
 340         }
 341
 342     trace:
 343       if (PREDICT_FALSE (ib[0]->flags & VLIB_BUFFER_IS_TRACED))
 344         {
 345           if (ob[0])
 346             {
 347               ob[0]->flags |= VLIB_BUFFER_IS_TRACED;
 348               ob[0]->trace_index = ib[0]->trace_index;
 349               esp_decrypt_trace_t *tr =
 350                 vlib_add_trace (vm, node, ob[0], sizeof (*tr));
 351               tr->crypto_alg = sa0->crypto_alg;
 352               tr->integ_alg = sa0->integ_alg;
 353             }
 354         }
 355
 356       /* next */
 357       n_left_from -= 1;
 358       ib += 1;
 359       ob += 1;
 360       next += 1;
 361     }
 362
 363   vlib_node_increment_counter (vm, node->node_index,
 364                                ESP_DECRYPT_ERROR_RX_PKTS, n_alloc);
 365
 366   vlib_buffer_enqueue_to_next (vm, node, new_bufs, nexts, n_alloc);
 367 done:
 368   vlib_buffer_free (vm, from, from_frame->n_vectors);
 369   return n_alloc;
 370 }
 371
 372 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
 373                                   vlib_node_runtime_t * node,
 374                                   vlib_frame_t * from_frame)
 375 {
 376   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 377 }
 378
 379 /* *INDENT-OFF* */
 380 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 381   .name = "esp4-decrypt",
 382   .vector_size = sizeof (u32),
 383   .format_trace = format_esp_decrypt_trace,
 384   .type = VLIB_NODE_TYPE_INTERNAL,
 385
 386   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 387   .error_strings = esp_decrypt_error_strings,
 388
 389   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 390   .next_nodes = {
 391 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 392     foreach_esp_decrypt_next
 393 #undef _
 394   },
 395 };
 396 /* *INDENT-ON* */
 397
 398 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
 399                                   vlib_node_runtime_t * node,
 400                                   vlib_frame_t * from_frame)
 401 {
 402   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 403 }
 404
 405 /* *INDENT-OFF* */
 406 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 407   .name = "esp6-decrypt",
 408   .vector_size = sizeof (u32),
 409   .format_trace = format_esp_decrypt_trace,
 410   .type = VLIB_NODE_TYPE_INTERNAL,
 411
 412   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 413   .error_strings = esp_decrypt_error_strings,
 414
 415   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 416   .next_nodes = {
 417 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 418     foreach_esp_decrypt_next
 419 #undef _
 420   },
 421 };
 422 /* *INDENT-ON* */
 423
 424 /*
 425  * fd.io coding-style-patch-verification: ON
 426  *
 427  * Local Variables:
 428  * eval: (c-set-style "gnu")
 429  * End:
 430  */