| From foo@baz Thu 28 May 2020 02:29:37 PM CEST |
| From: "Jere Leppänen" <jere.leppanen@nokia.com> |
| Date: Wed, 20 May 2020 18:15:31 +0300 |
| Subject: sctp: Start shutdown on association restart if in SHUTDOWN-SENT state and socket is closed |
| |
| From: "Jere Leppänen" <jere.leppanen@nokia.com> |
| |
| [ Upstream commit d3e8e4c11870413789f029a71e72ae6e971fe678 ] |
| |
| Commit bdf6fa52f01b ("sctp: handle association restarts when the |
| socket is closed.") starts shutdown when an association is restarted, |
| if in SHUTDOWN-PENDING state and the socket is closed. However, the |
| rationale stated in that commit applies also when in SHUTDOWN-SENT |
| state - we don't want to move an association to ESTABLISHED state when |
| the socket has been closed, because that results in an association |
| that is unreachable from user space. |
| |
| The problem scenario: |
| |
| 1. Client crashes and/or restarts. |
| |
| 2. Server (using one-to-one socket) calls close(). SHUTDOWN is lost. |
| |
| 3. Client reconnects using the same addresses and ports. |
| |
| 4. Server's association is restarted. The association and the socket |
| move to ESTABLISHED state, even though the server process has |
| closed its descriptor. |
| |
| Also, after step 4 when the server process exits, some resources are |
| leaked in an attempt to release the underlying inet sock structure in |
| ESTABLISHED state: |
| |
| IPv4: Attempt to release TCP socket in state 1 00000000377288c7 |
| |
| Fix by acting the same way as in SHUTDOWN-PENDING state. That is, if |
| an association is restarted in SHUTDOWN-SENT state and the socket is |
| closed, then start shutdown and don't move the association or the |
| socket to ESTABLISHED state. |
| |
| Fixes: bdf6fa52f01b ("sctp: handle association restarts when the socket is closed.") |
| Signed-off-by: Jere Leppänen <jere.leppanen@nokia.com> |
| Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sctp/sm_statefuns.c | 9 +++++---- |
| 1 file changed, 5 insertions(+), 4 deletions(-) |
| |
| --- a/net/sctp/sm_statefuns.c |
| +++ b/net/sctp/sm_statefuns.c |
| @@ -1829,12 +1829,13 @@ static enum sctp_disposition sctp_sf_do_ |
| /* Update the content of current association. */ |
| sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); |
| sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); |
| - if (sctp_state(asoc, SHUTDOWN_PENDING) && |
| + if ((sctp_state(asoc, SHUTDOWN_PENDING) || |
| + sctp_state(asoc, SHUTDOWN_SENT)) && |
| (sctp_sstate(asoc->base.sk, CLOSING) || |
| sock_flag(asoc->base.sk, SOCK_DEAD))) { |
| - /* if were currently in SHUTDOWN_PENDING, but the socket |
| - * has been closed by user, don't transition to ESTABLISHED. |
| - * Instead trigger SHUTDOWN bundled with COOKIE_ACK. |
| + /* If the socket has been closed by user, don't |
| + * transition to ESTABLISHED. Instead trigger SHUTDOWN |
| + * bundled with COOKIE_ACK. |
| */ |
| sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); |
| return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, |