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authorXin Long <lucien.xin@gmail.com>2021-05-03 04:41:20 +0800
committerDavid S. Miller <davem@davemloft.net>2021-05-03 13:32:12 -0700
commitf282df0391267fb2b263da1cc3233aa6fb81defc (patch)
tree2a53a0dcf0b9f4340a9f5e80e95274335037fd00 /net
parenta52445ae5a3a4cbfa6380583eea2abf997ae45d1 (diff)
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 <marcelo.leitner@gmail.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/sm_statefuns.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index 5fc3f3a331f8..fd1e319eda00 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -1953,7 +1953,8 @@ static enum sctp_disposition sctp_sf_do_dupcook_b(
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());
/* Update the content of current association. */