[Dovecot] imap-login hanging when firewall blocks ssl handshaking

[Erik A Johnson]

FYI, the tcpdump I sent previously was with one of our previously-discussed patches in place:

    if (!proxy->client_proxy && net_geterror(proxy->fd_ssl) == EBADF) {

I'm attaching that dump again (as tcpdump_output_witholdpatch_headeronly.txt), as well as a dump without any of the patches (tcpdump_output_withoutpatches_headeronly.txt) in case there is any difference.

On December 4, 2012 6:18:23 AM PST, Ben Morrow <ben at morrow.me.uk> wrote:
> At 12PM +0000 on  4/12/12 Ben Morrow wrote:
>> Well, it looks to me as though xnu/bsd/kern/uipc_socket.c:soreceive will
>> indeed return ENOTCONN for a socket which was once successfully
>> connected but has now been disconnected. This happens when the socket is
>> in the DEFUNCT state, which is a state that doesn't exist in FreeBSD;
>> it's not completely clear but I suspect firewalls may be able to put
>> arbitrary sockets into that state.
> 
> Investigating a little further, it should be possible to test for this
> situation directly. Assuming I'm correct about what's going on here,
> this should be both cleaner and safer than mucking about looking for
> ENOTCONN and guessing about what's happening.
> 
> Erik, does this make the problem go away? I left out the
> proxy->client_proxy test, since AFAICT this is just as likely to happen
> on a client socket.
> 
> Ben
> 
> #ifdef SO_ISDEFUNCT
> +                if (getsockopt(proxy->fd_ssl, SOL_SOCKET, SO_ISDEFUNCT,
> +                    (void *)&err, sizeof(err)) == 0 && err) {
> +                        errstr = t_strdup_printf(
> +                            "%s: socket is defunct", func_name);
> +                        break;
> +                }
> +#endif

Nope, SO_ISDEFUNCT isn't defined.


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