ipsec: Fix setting the hi-sequence number for decrypt

Type: fix

two problems;
 1 - just because anti-reply is not enabled doesn't mean the high sequence
number should not be used.
   - fix, there needs to be some means to detect a wrapped packet, so we
use a window size of 2^30.
 2 - The SA object was used as a scratch pad for the high-sequence
number used during decryption. That means that once the batch has been
processed the high-sequence number used is lost. This means it is not
possible to distinguish this case:
      if (seq < IPSEC_SA_ANTI_REPLAY_WINDOW_LOWER_BOUND (tl))
	{
	  ...
	  if (post_decrypt)
	    {
	      if (hi_seq_used == sa->seq_hi)
		/* the high sequence number used to succesfully decrypt this
		 * packet is the same as the last-sequnence number of the SA.
		 * that means this packet did not cause a wrap.
		 * this packet is thus out of window and should be dropped */
		return 1;
	      else
		/* The packet decrypted with a different high sequence number
		 * to the SA, that means it is the wrap packet and should be
		 * accepted */
		return 0;
	    }
  - fix: don't use the SA as a scratch pad, use the 'packet_data' - the
same place that is used as the scratch pad for the low sequence number.

other consequences:
 - An SA doesn't have seq and last_seq, it has only seq; the sequence
numnber of the last packet tx'd or rx'd.
 - there's 64bits of space available on the SA's first cache line. move
the AES CTR mode IV there.
 - test the ESN/AR combinations to catch the bugs this fixes. This
doubles the amount of tests, but without AR on they only run for 2
seconds. In the AR tests, the time taken to wait for packets that won't
arrive is dropped from 1 to 0.2 seconds thus reducing the runtime of
these tests from 10-15 to about 5 sceonds.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: Iaac78905289a272dc01930d70decd8109cf5e7a5

1 files changed, 2 insertions, 3 deletions

diff --git a/src/vnet/ipsec/ipsec_format.c b/src/vnet/ipsec/ipsec_format.c
index b67c11da1cd..5f7caab44e4 100644
--- a/src/vnet/ipsec/ipsec_format.c
+++ b/src/vnet/ipsec/ipsec_format.c
@@ -293,9 +293,8 @@ format_ipsec_sa (u8 * s, va_list * args)
   s = format (s, "\n   salt 0x%x", clib_net_to_host_u32 (sa->salt));
   s = format (s, "\n   thread-index:%d", sa->thread_index);
   s = format (s, "\n   seq %u seq-hi %u", sa->seq, sa->seq_hi);
-  s = format (s, "\n   last-seq %u last-seq-hi %u window %U",
-	      sa->last_seq, sa->last_seq_hi,
-	      format_ipsec_replay_window, sa->replay_window);
+  s = format (s, "\n   window %U", format_ipsec_replay_window,
+	      sa->replay_window);
   s = format (s, "\n   crypto alg %U",
 	      format_ipsec_crypto_alg, sa->crypto_alg);
   if (sa->crypto_alg && (flags & IPSEC_FORMAT_INSECURE))