sctp: fix a SCTP_MIB_CURRESTAB leak in sctp_sf_do_dupcook_b
Normally SCTP_MIB_CURRESTAB is always incremented once asoc enter into
ESTABLISHED from the state < ESTABLISHED and decremented when the asoc
is being deleted.
However, in sctp_sf_do_dupcook_b(), the asoc's state can be changed to
ESTABLISHED from the state >= ESTABLISHED where it shouldn't increment
SCTP_MIB_CURRESTAB. Otherwise, one asoc may increment MIB_CURRESTAB
multiple times but only decrement once at the end.
I was able to reproduce it by using scapy to do the 4-way shakehands,
after that I replayed the COOKIE-ECHO chunk with 'peer_vtag' field
changed to different values, and SCTP_MIB_CURRESTAB was incremented
multiple times and never went back to 0 even when the asoc was freed.
This patch is to fix it by only incrementing SCTP_MIB_CURRESTAB when
the state < ESTABLISHED in sctp_sf_do_dupcook_b().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Marcelo Ricardo Leitner <firstname.lastname@example.org>
Signed-off-by: Xin Long <email@example.com>
Signed-off-by: David S. Miller <firstname.lastname@example.org>
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 5fc3f3a..fd1e319 100644
@@ -1953,7 +1953,8 @@
- SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
+ if (asoc->state < SCTP_STATE_ESTABLISHED)
+ SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
/* Update the content of current association. */