src/vnet/ipsec/ah_decrypt.c

   1 /*
   2  * ah_decrypt.c : IPSec AH 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/ah.h>
  25
  26 #define foreach_ah_decrypt_next \
  27   _ (DROP, "error-drop")        \
  28   _ (IP4_INPUT, "ip4-input")    \
  29   _ (IP6_INPUT, "ip6-input")    \
  30   _ (IPSEC_GRE_INPUT, "ipsec-gre-input")
  31
  32 #define _(v, s) AH_DECRYPT_NEXT_##v,
  33 typedef enum
  34 {
  35   foreach_ah_decrypt_next
  36 #undef _
  37     AH_DECRYPT_N_NEXT,
  38 } ah_decrypt_next_t;
  39
  40 #define foreach_ah_decrypt_error                \
  41   _ (RX_PKTS, "AH pkts received")               \
  42   _ (DECRYPTION_FAILED, "AH decryption failed") \
  43   _ (INTEG_ERROR, "Integrity check failed")     \
  44   _ (REPLAY, "SA replayed packet")
  45
  46 typedef enum
  47 {
  48 #define _(sym,str) AH_DECRYPT_ERROR_##sym,
  49   foreach_ah_decrypt_error
  50 #undef _
  51     AH_DECRYPT_N_ERROR,
  52 } ah_decrypt_error_t;
  53
  54 static char *ah_decrypt_error_strings[] = {
  55 #define _(sym,string) string,
  56   foreach_ah_decrypt_error
  57 #undef _
  58 };
  59
  60 typedef struct
  61 {
  62   ipsec_integ_alg_t integ_alg;
  63 } ah_decrypt_trace_t;
  64
  65 /* packet trace format function */
  66 static u8 *
  67 format_ah_decrypt_trace (u8 * s, va_list * args)
  68 {
  69   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  70   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  71   ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *);
  72
  73   s = format (s, "ah: integrity %U", format_ipsec_integ_alg, t->integ_alg);
  74   return s;
  75 }
  76
  77 always_inline uword
  78 ah_decrypt_inline (vlib_main_t * vm,
  79                    vlib_node_runtime_t * node, vlib_frame_t * from_frame,
  80                    int is_ip6)
  81 {
  82   u32 n_left_from, *from, next_index, *to_next;
  83   ipsec_main_t *im = &ipsec_main;
  84   ipsec_proto_main_t *em = &ipsec_proto_main;
  85   from = vlib_frame_vector_args (from_frame);
  86   n_left_from = from_frame->n_vectors;
  87   int icv_size = 0;
  88
  89   next_index = node->cached_next_index;
  90
  91   while (n_left_from > 0)
  92     {
  93       u32 n_left_to_next;
  94
  95       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  96
  97       while (n_left_from > 0 && n_left_to_next > 0)
  98         {
  99           u32 i_bi0;
 100           u32 next0;
 101           vlib_buffer_t *i_b0;
 102           ah_header_t *ah0;
 103           ipsec_sa_t *sa0;
 104           u32 sa_index0 = ~0;
 105           u32 seq;
 106           ip4_header_t *ih4 = 0, *oh4 = 0;
 107           ip6_header_t *ih6 = 0, *oh6 = 0;
 108           u8 ip_hdr_size = 0;
 109           u8 tos = 0;
 110           u8 ttl = 0;
 111           u32 ip_version_traffic_class_and_flow_label = 0;
 112           u8 hop_limit = 0;
 113           u8 nexthdr = 0;
 114           u8 icv_padding_len = 0;
 115
 116
 117           i_bi0 = from[0];
 118           from += 1;
 119           n_left_from -= 1;
 120           n_left_to_next -= 1;
 121
 122           next0 = AH_DECRYPT_NEXT_DROP;
 123
 124           i_b0 = vlib_get_buffer (vm, i_bi0);
 125           to_next[0] = i_bi0;
 126           to_next += 1;
 127           ih4 = vlib_buffer_get_current (i_b0);
 128           ih6 = vlib_buffer_get_current (i_b0);
 129           sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index;
 130           sa0 = pool_elt_at_index (im->sad, sa_index0);
 131
 132           if (is_ip6)
 133             {
 134               ip6_ext_header_t *prev = NULL;
 135               ip6_ext_header_find_t (ih6, prev, ah0, IP_PROTOCOL_IPSEC_AH);
 136               ip_hdr_size = sizeof (ip6_header_t);
 137               ASSERT ((u8 *) ah0 - (u8 *) ih6 == ip_hdr_size);
 138             }
 139           else
 140             {
 141               ip_hdr_size = ip4_header_bytes (ih4);
 142               ah0 = (ah_header_t *) ((u8 *) ih4 + ip_hdr_size);
 143             }
 144
 145           seq = clib_host_to_net_u32 (ah0->seq_no);
 146           /* anti-replay check */
 147           //TODO UT remaining
 148           if (sa0->use_anti_replay)
 149             {
 150               int rv = 0;
 151
 152               if (PREDICT_TRUE (sa0->use_esn))
 153                 rv = esp_replay_check_esn (sa0, seq);
 154               else
 155                 rv = esp_replay_check (sa0, seq);
 156
 157               if (PREDICT_FALSE (rv))
 158                 {
 159                   clib_warning ("anti-replay SPI %u seq %u", sa0->spi, seq);
 160                   if (is_ip6)
 161                     vlib_node_increment_counter (vm,
 162                                                  ah6_decrypt_node.index,
 163                                                  AH_DECRYPT_ERROR_REPLAY, 1);
 164                   else
 165                     vlib_node_increment_counter (vm,
 166                                                  ah4_decrypt_node.index,
 167                                                  AH_DECRYPT_ERROR_REPLAY, 1);
 168                   to_next[0] = i_bi0;
 169                   to_next += 1;
 170                   goto trace;
 171                 }
 172             }
 173
 174
 175           sa0->total_data_size += i_b0->current_length;
 176           icv_size =
 177             em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size;
 178           if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE))
 179             {
 180               u8 sig[64];
 181               u8 digest[64];
 182               clib_memset (sig, 0, sizeof (sig));
 183               clib_memset (digest, 0, sizeof (digest));
 184               u8 *icv = ah0->auth_data;
 185               memcpy (digest, icv, icv_size);
 186               clib_memset (icv, 0, icv_size);
 187
 188               if (is_ip6)
 189                 {
 190                   ip_version_traffic_class_and_flow_label =
 191                     ih6->ip_version_traffic_class_and_flow_label;
 192                   hop_limit = ih6->hop_limit;
 193                   ih6->ip_version_traffic_class_and_flow_label = 0x60;
 194                   ih6->hop_limit = 0;
 195                   nexthdr = ah0->nexthdr;
 196                   icv_padding_len =
 197                     ah_calc_icv_padding_len (icv_size, 1 /* is_ipv6 */ );
 198                 }
 199               else
 200                 {
 201                   tos = ih4->tos;
 202                   ttl = ih4->ttl;
 203                   ih4->tos = 0;
 204                   ih4->ttl = 0;
 205                   ih4->checksum = 0;
 206                   ih4->flags_and_fragment_offset = 0;
 207                   icv_padding_len =
 208                     ah_calc_icv_padding_len (icv_size, 0 /* is_ipv6 */ );
 209                 }
 210               hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len,
 211                          (u8 *) ih4, i_b0->current_length, sig, sa0->use_esn,
 212                          sa0->seq_hi);
 213
 214               if (PREDICT_FALSE (memcmp (digest, sig, icv_size)))
 215                 {
 216                   if (is_ip6)
 217                     vlib_node_increment_counter (vm,
 218                                                  ah6_decrypt_node.index,
 219                                                  AH_DECRYPT_ERROR_INTEG_ERROR,
 220                                                  1);
 221                   else
 222                     vlib_node_increment_counter (vm,
 223                                                  ah4_decrypt_node.index,
 224                                                  AH_DECRYPT_ERROR_INTEG_ERROR,
 225                                                  1);
 226                   to_next[0] = i_bi0;
 227                   to_next += 1;
 228                   goto trace;
 229                 }
 230
 231               //TODO UT remaining
 232               if (PREDICT_TRUE (sa0->use_anti_replay))
 233                 {
 234                   if (PREDICT_TRUE (sa0->use_esn))
 235                     esp_replay_advance_esn (sa0, seq);
 236                   else
 237                     esp_replay_advance (sa0, seq);
 238                 }
 239
 240             }
 241
 242           vlib_buffer_advance (i_b0,
 243                                ip_hdr_size + sizeof (ah_header_t) + icv_size +
 244                                icv_padding_len);
 245           i_b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
 246
 247           if (PREDICT_TRUE (sa0->is_tunnel))
 248             {                   /* tunnel mode */
 249               if (PREDICT_TRUE (ah0->nexthdr == IP_PROTOCOL_IP_IN_IP))
 250                 next0 = AH_DECRYPT_NEXT_IP4_INPUT;
 251               else if (ah0->nexthdr == IP_PROTOCOL_IPV6)
 252                 next0 = AH_DECRYPT_NEXT_IP6_INPUT;
 253               else
 254                 {
 255                   clib_warning ("next header: 0x%x", ah0->nexthdr);
 256                   if (is_ip6)
 257                     vlib_node_increment_counter (vm,
 258                                                  ah6_decrypt_node.index,
 259                                                  AH_DECRYPT_ERROR_DECRYPTION_FAILED,
 260                                                  1);
 261                   else
 262                     vlib_node_increment_counter (vm,
 263                                                  ah4_decrypt_node.index,
 264                                                  AH_DECRYPT_ERROR_DECRYPTION_FAILED,
 265                                                  1);
 266                   goto trace;
 267                 }
 268             }
 269           else
 270             {                   /* transport mode */
 271               if (is_ip6)
 272                 {
 273                   vlib_buffer_advance (i_b0, -sizeof (ip6_header_t));
 274                   oh6 = vlib_buffer_get_current (i_b0);
 275                   memmove (oh6, ih6, sizeof (ip6_header_t));
 276
 277                   next0 = AH_DECRYPT_NEXT_IP6_INPUT;
 278                   oh6->protocol = nexthdr;
 279                   oh6->hop_limit = hop_limit;
 280                   oh6->ip_version_traffic_class_and_flow_label =
 281                     ip_version_traffic_class_and_flow_label;
 282                   oh6->payload_length =
 283                     clib_host_to_net_u16 (vlib_buffer_length_in_chain
 284                                           (vm, i_b0) - sizeof (ip6_header_t));
 285                 }
 286               else
 287                 {
 288                   vlib_buffer_advance (i_b0, -sizeof (ip4_header_t));
 289                   oh4 = vlib_buffer_get_current (i_b0);
 290                   memmove (oh4, ih4, sizeof (ip4_header_t));
 291
 292                   next0 = AH_DECRYPT_NEXT_IP4_INPUT;
 293                   oh4->ip_version_and_header_length = 0x45;
 294                   oh4->fragment_id = 0;
 295                   oh4->flags_and_fragment_offset = 0;
 296                   oh4->protocol = ah0->nexthdr;
 297                   oh4->length =
 298                     clib_host_to_net_u16 (vlib_buffer_length_in_chain
 299                                           (vm, i_b0));
 300                   oh4->ttl = ttl;
 301                   oh4->tos = tos;
 302                   oh4->checksum = ip4_header_checksum (oh4);
 303                 }
 304             }
 305
 306           /* for IPSec-GRE tunnel next node is ipsec-gre-input */
 307           if (PREDICT_FALSE
 308               ((vnet_buffer (i_b0)->ipsec.flags) &
 309                IPSEC_FLAG_IPSEC_GRE_TUNNEL))
 310             next0 = AH_DECRYPT_NEXT_IPSEC_GRE_INPUT;
 311
 312
 313           vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 314         trace:
 315           if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED))
 316             {
 317               i_b0->flags |= VLIB_BUFFER_IS_TRACED;
 318               ah_decrypt_trace_t *tr =
 319                 vlib_add_trace (vm, node, i_b0, sizeof (*tr));
 320               tr->integ_alg = sa0->integ_alg;
 321             }
 322           vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 323                                            n_left_to_next, i_bi0, next0);
 324         }
 325       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
 326     }
 327   if (is_ip6)
 328     vlib_node_increment_counter (vm, ah6_decrypt_node.index,
 329                                  AH_DECRYPT_ERROR_RX_PKTS,
 330                                  from_frame->n_vectors);
 331   else
 332     vlib_node_increment_counter (vm, ah4_decrypt_node.index,
 333                                  AH_DECRYPT_ERROR_RX_PKTS,
 334                                  from_frame->n_vectors);
 335
 336   return from_frame->n_vectors;
 337 }
 338
 339 static uword
 340 ah4_decrypt_node_fn (vlib_main_t * vm,
 341                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 342 {
 343   return ah_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ );
 344 }
 345
 346 /* *INDENT-OFF* */
 347 VLIB_REGISTER_NODE (ah4_decrypt_node) = {
 348   .function = ah4_decrypt_node_fn,
 349   .name = "ah4-decrypt",
 350   .vector_size = sizeof (u32),
 351   .format_trace = format_ah_decrypt_trace,
 352   .type = VLIB_NODE_TYPE_INTERNAL,
 353
 354   .n_errors = ARRAY_LEN(ah_decrypt_error_strings),
 355   .error_strings = ah_decrypt_error_strings,
 356
 357   .n_next_nodes = AH_DECRYPT_N_NEXT,
 358   .next_nodes = {
 359 #define _(s,n) [AH_DECRYPT_NEXT_##s] = n,
 360     foreach_ah_decrypt_next
 361 #undef _
 362   },
 363 };
 364 /* *INDENT-ON* */
 365
 366 VLIB_NODE_FUNCTION_MULTIARCH (ah4_decrypt_node, ah4_decrypt_node_fn);
 367
 368 static uword
 369 ah6_decrypt_node_fn (vlib_main_t * vm,
 370                      vlib_node_runtime_t * node, vlib_frame_t * from_frame)
 371 {
 372   return ah_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ );
 373 }
 374
 375 /* *INDENT-OFF* */
 376 VLIB_REGISTER_NODE (ah6_decrypt_node) = {
 377   .function = ah6_decrypt_node_fn,
 378   .name = "ah6-decrypt",
 379   .vector_size = sizeof (u32),
 380   .format_trace = format_ah_decrypt_trace,
 381   .type = VLIB_NODE_TYPE_INTERNAL,
 382
 383   .n_errors = ARRAY_LEN(ah_decrypt_error_strings),
 384   .error_strings = ah_decrypt_error_strings,
 385
 386   .n_next_nodes = AH_DECRYPT_N_NEXT,
 387   .next_nodes = {
 388 #define _(s,n) [AH_DECRYPT_NEXT_##s] = n,
 389     foreach_ah_decrypt_next
 390 #undef _
 391   },
 392 };
 393 /* *INDENT-ON* */
 394
 395 VLIB_NODE_FUNCTION_MULTIARCH (ah6_decrypt_node, ah6_decrypt_node_fn);
 396 /*
 397  * fd.io coding-style-patch-verification: ON
 398  *
 399  * Local Variables:
 400  * eval: (c-set-style "gnu")
 401  * End:
 402  */