From: Xin Long lucien.xin@gmail.com
[ Upstream commit f282df0391267fb2b263da1cc3233aa6fb81defc ]
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 marcelo.leitner@gmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/sm_statefuns.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index a9a72f7e0cd7..a9ba6f2bb8c8 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -1851,7 +1851,8 @@ static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net, sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_ESTABLISHED)); - 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());
repl = sctp_make_cookie_ack(new_asoc, chunk);