Re: [FIX] Re: connect() occasionally succeeds improperly to localhost port 1024-4999

Craig Milo Rogers (rogers@ISI.EDU)
Mon, 30 Aug 1999 11:34:31 -0700

>> This involves a trivial change to
>> ipv4/tcp_ipv4/tcp_v4_get_port() in linux-2.2.12 and linux-2.3.15.
>> In the rover loop, before the "break;", add:
>>
>> if (sk->dport == rover) goto next;
>
>I don't believe it is quite this simple, since sk->dport isn't initialized
>until after the tcp_v4_get_port call. inet_stream_connect() calls
>inet_autobind() early on. The latter immediately calls tcp_v4_get_port()
>for this type of socket. Perhaps sk->dport could be initialized at the
>beginning of inet_stream_connect()? I am not familiar enough with the
>kernel to judge the side effects of such a move.

Well, clearly I'm not so familiar with the code, either; I
should have examined the code paths more thoroughly... I'd say that
the simplest thing to do is to move the sk->dport and sk->daddr
assignments in itcp_ipv4.c up 22 lines, between the sk->rcv_saddr
assignment and the if (!sk->num) {.

I don't see inet_stream_connect() calling inet_autobind() in
linux-2.3.15/net/ipve/af_inet.c. However, inet_dgram_connect(),
inet_recvmsg(), and inet_sendmsg() all call inet_autobind(), and these
call sites also need review and possible change.

Craig Milo Rogers

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