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 (vlib_main_t * vm, ipsec_crypto_alg_t alg,
  86                  u8 * in, u8 * out, size_t in_len, u8 * key, u8 * iv)
  87 {
  88   ipsec_main_t *im = &ipsec_main;
  89   ipsec_main_crypto_alg_t *a;
  90   vnet_crypto_op_t _op, *op = &_op;
  91
  92   ASSERT (alg < IPSEC_CRYPTO_N_ALG);
  93
  94   a = &im->crypto_algs[alg];
  95
  96   if (PREDICT_FALSE (a->dec_op_type == VNET_CRYPTO_OP_NONE))
  97     return;
  98
  99   op->op = a->dec_op_type;
 100   op->iv = iv;
 101   op->src = in;
 102   op->dst = out;
 103   op->len = in_len;
 104   op->key = key;
 105
 106   vnet_crypto_process_ops (vm, op, 1);
 107 }
 108
 109 always_inline uword
 110 esp_decrypt_inline (vlib_main_t * vm,
 111                     vlib_node_runtime_t * node, vlib_frame_t * from_frame,
 112                     int is_ip6)
 113 {
 114   ipsec_main_t *im = &ipsec_main;
 115   u32 *from = vlib_frame_vector_args (from_frame);
 116   u32 n_left_from = from_frame->n_vectors;
 117   u32 new_bufs[VLIB_FRAME_SIZE];
 118   vlib_buffer_t *i_bufs[VLIB_FRAME_SIZE], **ib = i_bufs;
 119   vlib_buffer_t *o_bufs[VLIB_FRAME_SIZE], **ob = o_bufs;
 120   u16 nexts[VLIB_FRAME_SIZE], *next = nexts;
 121   u32 n_alloc, thread_index = vm->thread_index;
 122
 123   n_alloc = vlib_buffer_alloc (vm, new_bufs, n_left_from);
 124   if (n_alloc != n_left_from)
 125     {
 126       vlib_node_increment_counter (vm, node->node_index,
 127                                    ESP_DECRYPT_ERROR_NO_BUFFER,
 128                                    n_left_from - n_alloc);
 129       if (n_alloc == 0)
 130         goto done;
 131       n_left_from = n_alloc;
 132     }
 133
 134   vlib_get_buffers (vm, from, ib, n_left_from);
 135   vlib_get_buffers (vm, new_bufs, ob, n_left_from);
 136
 137   while (n_left_from > 0)
 138     {
 139       esp_header_t *esp0;
 140       ipsec_sa_t *sa0;
 141       u32 sa_index0 = ~0;
 142       u32 seq;
 143       ip4_header_t *ih4 = 0, *oh4 = 0;
 144       ip6_header_t *ih6 = 0, *oh6 = 0;
 145       u8 tunnel_mode = 1;
 146
 147       next[0] = ESP_DECRYPT_NEXT_DROP;
 148
 149       esp0 = vlib_buffer_get_current (ib[0]);
 150       sa_index0 = vnet_buffer (ib[0])->ipsec.sad_index;
 151       sa0 = pool_elt_at_index (im->sad, sa_index0);
 152       seq = clib_host_to_net_u32 (esp0->seq);
 153
 154       /* anti-replay check */
 155       if (sa0->use_anti_replay)
 156         {
 157           int rv = 0;
 158
 159           if (PREDICT_TRUE (sa0->use_esn))
 160             rv = esp_replay_check_esn (sa0, seq);
 161           else
 162             rv = esp_replay_check (sa0, seq);
 163
 164           if (PREDICT_FALSE (rv))
 165             {
 166               u32 tmp, off = n_alloc - n_left_from;
 167               /* send original packet to drop node */
 168               tmp = from[off];
 169               from[off] = new_bufs[off];
 170               new_bufs[off] = tmp;
 171               ib[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
 172               next[0] = ESP_DECRYPT_NEXT_DROP;
 173               goto trace;
 174             }
 175         }
 176
 177       vlib_increment_combined_counter
 178         (&ipsec_sa_counters, thread_index, sa_index0,
 179          1, ib[0]->current_length);
 180
 181       if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 182         {
 183           u8 sig[64];
 184           int icv_size = im->integ_algs[sa0->integ_alg].trunc_size;
 185           clib_memset (sig, 0, sizeof (sig));
 186           u8 *icv = vlib_buffer_get_current (ib[0]) + ib[0]->current_length -
 187             icv_size;
 188           ib[0]->current_length -= icv_size;
 189
 190           hmac_calc (vm, sa0->integ_alg, sa0->integ_key.data,
 191                      sa0->integ_key.len, (u8 *) esp0,
 192                      ib[0]->current_length, sig, sa0->use_esn, sa0->seq_hi);
 193
 194           if (PREDICT_FALSE (memcmp (icv, sig, icv_size)))
 195             {
 196               u32 tmp, off = n_alloc - n_left_from;
 197               /* send original packet to drop node */
 198               tmp = from[off];
 199               from[off] = new_bufs[off];
 200               new_bufs[off] = tmp;
 201               ib[0]->error = node->errors[ESP_DECRYPT_ERROR_INTEG_ERROR];
 202               next[0] = ESP_DECRYPT_NEXT_DROP;
 203               goto trace;
 204             }
 205         }
 206
 207       if (PREDICT_TRUE (sa0->use_anti_replay))
 208         {
 209           if (PREDICT_TRUE (sa0->use_esn))
 210             esp_replay_advance_esn (sa0, seq);
 211           else
 212             esp_replay_advance (sa0, seq);
 213         }
 214
 215       if ((sa0->crypto_alg >= IPSEC_CRYPTO_ALG_AES_CBC_128 &&
 216            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_AES_CBC_256) ||
 217           (sa0->crypto_alg >= IPSEC_CRYPTO_ALG_DES_CBC &&
 218            sa0->crypto_alg <= IPSEC_CRYPTO_ALG_3DES_CBC))
 219         {
 220           const int BLOCK_SIZE = im->crypto_algs[sa0->crypto_alg].block_size;
 221           const int IV_SIZE = im->crypto_algs[sa0->crypto_alg].iv_size;
 222           esp_footer_t *f0;
 223           u8 ip_hdr_size = 0;
 224
 225           int blocks =
 226             (ib[0]->current_length - sizeof (esp_header_t) -
 227              IV_SIZE) / BLOCK_SIZE;
 228
 229           ob[0]->current_data = sizeof (ethernet_header_t);
 230
 231           /* transport mode */
 232           if (PREDICT_FALSE (!sa0->is_tunnel && !sa0->is_tunnel_ip6))
 233             {
 234               tunnel_mode = 0;
 235
 236               if (is_ip6)
 237                 {
 238                   ip_hdr_size = sizeof (ip6_header_t);
 239                   ih6 = (ip6_header_t *) ((u8 *) esp0 - ip_hdr_size);
 240                   oh6 = vlib_buffer_get_current (ob[0]);
 241                 }
 242               else
 243                 {
 244                   ip_hdr_size = sizeof (ip4_header_t);
 245                   if (sa0->udp_encap)
 246                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size -
 247                                             sizeof (udp_header_t));
 248                   else
 249                     ih4 = (ip4_header_t *) ((u8 *) esp0 - ip_hdr_size);
 250                   oh4 = vlib_buffer_get_current (ob[0]);
 251                 }
 252             }
 253
 254           esp_decrypt_cbc (vm, sa0->crypto_alg,
 255                            esp0->data + IV_SIZE,
 256                            (u8 *) vlib_buffer_get_current (ob[0]) +
 257                            ip_hdr_size, BLOCK_SIZE * blocks,
 258                            sa0->crypto_key.data, esp0->data);
 259
 260           ob[0]->current_length = (blocks * BLOCK_SIZE) - 2 + ip_hdr_size;
 261           ob[0]->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 262           f0 = (esp_footer_t *) ((u8 *) vlib_buffer_get_current (ob[0]) +
 263                                  ob[0]->current_length);
 264           ob[0]->current_length -= f0->pad_length;
 265
 266           /* tunnel mode */
 267           if (PREDICT_TRUE (tunnel_mode))
 268             {
 269               if (PREDICT_TRUE (f0->next_header == IP_PROTOCOL_IP_IN_IP))
 270                 {
 271                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 272                   oh4 = vlib_buffer_get_current (ob[0]);
 273                 }
 274               else if (f0->next_header == IP_PROTOCOL_IPV6)
 275                 next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 276               else
 277                 {
 278                   vlib_node_increment_counter (vm, node->node_index,
 279                                                ESP_DECRYPT_ERROR_DECRYPTION_FAILED,
 280                                                1);
 281                   ob[0] = 0;
 282                   goto trace;
 283                 }
 284             }
 285           /* transport mode */
 286           else
 287             {
 288               u32 len = vlib_buffer_length_in_chain (vm, ob[0]);
 289               if (is_ip6)
 290                 {
 291                   next[0] = ESP_DECRYPT_NEXT_IP6_INPUT;
 292                   oh6->ip_version_traffic_class_and_flow_label =
 293                     ih6->ip_version_traffic_class_and_flow_label;
 294                   oh6->protocol = f0->next_header;
 295                   oh6->hop_limit = ih6->hop_limit;
 296                   oh6->src_address.as_u64[0] = ih6->src_address.as_u64[0];
 297                   oh6->src_address.as_u64[1] = ih6->src_address.as_u64[1];
 298                   oh6->dst_address.as_u64[0] = ih6->dst_address.as_u64[0];
 299                   oh6->dst_address.as_u64[1] = ih6->dst_address.as_u64[1];
 300                   len -= sizeof (ip6_header_t);
 301                   oh6->payload_length = clib_host_to_net_u16 (len);
 302                 }
 303               else
 304                 {
 305                   next[0] = ESP_DECRYPT_NEXT_IP4_INPUT;
 306                   oh4->ip_version_and_header_length = 0x45;
 307                   oh4->tos = ih4->tos;
 308                   oh4->fragment_id = 0;
 309                   oh4->flags_and_fragment_offset = 0;
 310                   oh4->ttl = ih4->ttl;
 311                   oh4->protocol = f0->next_header;
 312                   oh4->src_address.as_u32 = ih4->src_address.as_u32;
 313                   oh4->dst_address.as_u32 = ih4->dst_address.as_u32;
 314                   oh4->length = clib_host_to_net_u16 (len);
 315                   oh4->checksum = ip4_header_checksum (oh4);
 316                 }
 317             }
 318
 319           /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 320           if (PREDICT_FALSE
 321               ((vnet_buffer (ib[0])->ipsec.flags) &
 322                IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 323             next[0] = ESP_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 324
 325           vnet_buffer (ob[0])->sw_if_index[VLIB_TX] = (u32) ~ 0;
 326           vnet_buffer (ob[0])->sw_if_index[VLIB_RX] =
 327             vnet_buffer (ib[0])->sw_if_index[VLIB_RX];
 328         }
 329
 330     trace:
 331       if (PREDICT_FALSE (ib[0]->flags & VLIB_BUFFER_IS_TRACED))
 332         {
 333           if (ob[0])
 334             {
 335               ob[0]->flags |= VLIB_BUFFER_IS_TRACED;
 336               ob[0]->trace_index = ib[0]->trace_index;
 337               esp_decrypt_trace_t *tr =
 338                 vlib_add_trace (vm, node, ob[0], sizeof (*tr));
 339               tr->crypto_alg = sa0->crypto_alg;
 340               tr->integ_alg = sa0->integ_alg;
 341             }
 342         }
 343
 344       /* next */
 345       n_left_from -= 1;
 346       ib += 1;
 347       ob += 1;
 348       next += 1;
 349     }
 350
 351   vlib_node_increment_counter (vm, node->node_index,
 352                                ESP_DECRYPT_ERROR_RX_PKTS, n_alloc);
 353
 354   vlib_buffer_enqueue_to_next (vm, node, new_bufs, nexts, n_alloc);
 355 done:
 356   vlib_buffer_free (vm, from, from_frame->n_vectors);
 357   return n_alloc;
 358 }
 359
 360 VLIB_NODE_FN (esp4_decrypt_node) (vlib_main_t * vm,
 361                                   vlib_node_runtime_t * node,
 362                                   vlib_frame_t * from_frame)
 363 {
 364   return esp_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 365 }
 366
 367 /* *INDENT-OFF* */
 368 VLIB_REGISTER_NODE (esp4_decrypt_node) = {
 369   .name = "esp4-decrypt",
 370   .vector_size = sizeof (u32),
 371   .format_trace = format_esp_decrypt_trace,
 372   .type = VLIB_NODE_TYPE_INTERNAL,
 373
 374   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 375   .error_strings = esp_decrypt_error_strings,
 376
 377   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 378   .next_nodes = {
 379 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 380     foreach_esp_decrypt_next
 381 #undef _
 382   },
 383 };
 384 /* *INDENT-ON* */
 385
 386 VLIB_NODE_FN (esp6_decrypt_node) (vlib_main_t * vm,
 387                                   vlib_node_runtime_t * node,
 388                                   vlib_frame_t * from_frame)
 389 {
 390   return esp_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 391 }
 392
 393 /* *INDENT-OFF* */
 394 VLIB_REGISTER_NODE (esp6_decrypt_node) = {
 395   .name = "esp6-decrypt",
 396   .vector_size = sizeof (u32),
 397   .format_trace = format_esp_decrypt_trace,
 398   .type = VLIB_NODE_TYPE_INTERNAL,
 399
 400   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
 401   .error_strings = esp_decrypt_error_strings,
 402
 403   .n_next_nodes = ESP_DECRYPT_N_NEXT,
 404   .next_nodes = {
 405 #define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
 406     foreach_esp_decrypt_next
 407 #undef _
 408   },
 409 };
 410 /* *INDENT-ON* */
 411
 412 /*
 413  * fd.io coding-style-patch-verification: ON
 414  *
 415  * Local Variables:
 416  * eval: (c-set-style "gnu")
 417  * End:
 418  */