X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Fipsec%2Fesp_decrypt.c;h=cddda1f8e544b4fc219b4f9bc6d43882c1166f0f;hb=12989b538881f9681f078cf1485c51df1251877a;hp=c2b9bf4dc0cf3e8edb1129e5f230b243b2bdc649;hpb=6afaae156a9ab9de79474367d8873407f3b12a71;p=vpp.git

diff --git a/src/vnet/ipsec/esp_decrypt.c b/src/vnet/ipsec/esp_decrypt.c
index c2b9bf4dc0c..cddda1f8e54 100644
--- a/src/vnet/ipsec/esp_decrypt.c
+++ b/src/vnet/ipsec/esp_decrypt.c
@@ -47,7 +47,8 @@ typedef enum
  _(RUNT, "undersized packet")                                   \
  _(CHAINED_BUFFER, "chained buffers (packet dropped)")          \
  _(OVERSIZED_HEADER, "buffer with oversized header (dropped)")  \
- _(NO_TAIL_SPACE, "no enough buffer tail space (dropped)")
+ _(NO_TAIL_SPACE, "no enough buffer tail space (dropped)")      \
+ _(TUN_NO_PROTO, "no tunnel protocol")                          \
 
 
 typedef enum
@@ -376,6 +377,35 @@ esp_decrypt_inline (vlib_main_t * vm,
 
       sa0 = vec_elt_at_index (im->sad, pd->sa_index);
 
+      /*
+       * redo the anti-reply check
+       * in this frame say we have sequence numbers, s, s+1, s+1, s+1
+       * and s and s+1 are in the window. When we did the anti-replay
+       * check above we did so against the state of the window (W),
+       * after packet s-1. So each of the packets in the sequence will be
+       * accepted.
+       * This time s will be cheked against Ws-1, s+1 chceked against Ws
+       * (i.e. the window state is updated/advnaced)
+       * so this time the successive s+! packet will be dropped.
+       * This is a consequence of batching the decrypts. If the
+       * check-dcrypt-advance process was done for each packet it would
+       * be fine. But we batch the decrypts because it's much more efficient
+       * to do so in SW and if we offload to HW and the process is async.
+       *
+       * You're probably thinking, but this means an attacker can send the
+       * above sequence and cause VPP to perform decrpyts that will fail,
+       * and that's true. But if the attacker can determine s (a valid
+       * sequence number in the window) which is non-trivial, it can generate
+       * a sequence s, s+1, s+2, s+3, ... s+n and nothing will prevent any
+       * implementation, sequential or batching, from decrypting these.
+       */
+      if (ipsec_sa_anti_replay_check (sa0, pd->seq))
+	{
+	  b[0]->error = node->errors[ESP_DECRYPT_ERROR_REPLAY];
+	  next[0] = ESP_DECRYPT_NEXT_DROP;
+	  goto trace;
+	}
+
       ipsec_sa_anti_replay_advance (sa0, pd->seq);
 
       esp_footer_t *f = (esp_footer_t *) (b[0]->data + pd->current_data +
@@ -468,8 +498,11 @@ esp_decrypt_inline (vlib_main_t * vm,
 						     &ip4->dst_address) ||
 			  !ip46_address_is_equal_v4 (&itp->itp_tun.dst,
 						     &ip4->src_address))
-			next[0] = ESP_DECRYPT_NEXT_DROP;
-
+			{
+			  next[0] = ESP_DECRYPT_NEXT_DROP;
+			  b[0]->error =
+			    node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
+			}
 		    }
 		  else if (f->next_header == IP_PROTOCOL_IPV6)
 		    {
@@ -481,7 +514,11 @@ esp_decrypt_inline (vlib_main_t * vm,
 						     &ip6->dst_address) ||
 			  !ip46_address_is_equal_v6 (&itp->itp_tun.dst,
 						     &ip6->src_address))
-			next[0] = ESP_DECRYPT_NEXT_DROP;
+			{
+			  next[0] = ESP_DECRYPT_NEXT_DROP;
+			  b[0]->error =
+			    node->errors[ESP_DECRYPT_ERROR_TUN_NO_PROTO];
+			}
 		    }
 		}
 	    }
@@ -586,16 +623,9 @@ VLIB_REGISTER_NODE (esp4_decrypt_tun_node) = {
   .vector_size = sizeof (u32),
   .format_trace = format_esp_decrypt_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
-
   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
   .error_strings = esp_decrypt_error_strings,
-
-  .n_next_nodes = ESP_DECRYPT_N_NEXT,
-  .next_nodes = {
-#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
-    foreach_esp_decrypt_next
-#undef _
-  },
+  .sibling_of = "esp4-decrypt",
 };
 
 VLIB_REGISTER_NODE (esp6_decrypt_tun_node) = {
@@ -603,16 +633,9 @@ VLIB_REGISTER_NODE (esp6_decrypt_tun_node) = {
   .vector_size = sizeof (u32),
   .format_trace = format_esp_decrypt_trace,
   .type = VLIB_NODE_TYPE_INTERNAL,
-
   .n_errors = ARRAY_LEN(esp_decrypt_error_strings),
   .error_strings = esp_decrypt_error_strings,
-
-  .n_next_nodes = ESP_DECRYPT_N_NEXT,
-  .next_nodes = {
-#define _(s,n) [ESP_DECRYPT_NEXT_##s] = n,
-    foreach_esp_decrypt_next
-#undef _
-  },
+  .sibling_of = "esp6-decrypt",
 };
 /* *INDENT-ON* */