Re: [Emacs-diffs] master a066fb1: Fix use-after-close in connect_network_socket

[Ken Brown <kbrown@cornell.edu>]

On 7/21/2016 5:29 AM, Paul Eggert wrote:
> branch: master
> commit a066fb1ceee373c982214c28206108c5fba01bf7
> Author: Paul Eggert <eggert@cs.ucla.edu>
> Commit: Paul Eggert <eggert@cs.ucla.edu>
>
>     Fix use-after-close in connect_network_socket
>
>     * src/process.c (connect_network_socket): Don’t use
>     external_sock_fd after closing it.  Problem found by Coverity Scan.
> ---
>  src/process.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/src/process.c b/src/process.c
> index bdbdefa..bc2ac45 100644
> --- a/src/process.c
> +++ b/src/process.c
> @@ -3185,6 +3185,8 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
>  	      xerrno = errno;
>  	      emacs_close (s);
>  	      s = -1;
> +	      if (socket_to_use < 0)
> +		break;
>  	      continue;
>  	    }
>  	}
> @@ -3312,6 +3314,8 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
>        specpdl_ptr = specpdl + count1;
>        emacs_close (s);
>        s = -1;
> +      if (socket_to_use < 0)
> +	break;
>
>  #ifdef WINDOWSNT
>        if (xerrno == EINTR)

This commit causes two network-streams-tests failures on Cygwin:

    FAILED  echo-server-with-dns
    FAILED  echo-server-with-localhost

Did you perhaps get the condition (socket_to_use < 0) backwards?  If 
socket_to_use < 0, then it is not external_sock_fd that has been closed.

Ken