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
diff --git a/src/vnet/ipsec/ipsec_format.c b/src/vnet/ipsec/ipsec_format.c
index b67c11d..5f7caab 100644
--- a/src/vnet/ipsec/ipsec_format.c
+++ b/src/vnet/ipsec/ipsec_format.c
@@ -293,9 +293,8 @@
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))