Hi Taj,

thanks a lot!
Your patch is in 'screen-v4' branch now:
https://git.savannah.gnu.org/cgit/screen.git/patch/?id=ae27fef9fb9dfe2517f1c333dec848f4df278120

Cheers,
Alex

comment #7:

> Hi Alexander,
>
> I just confirmed that the bug is still present in `screen-v4`, and have generated a new patch that I verified fixes the issue.
>

> diff --git a/src/screen.c b/src/screen.c
> index 7dcb9af..f4e6258 100644
> --- a/src/screen.c
> +++ b/src/screen.c
> @@ -1185,20 +1185,25 @@ int main(int ac, char** av)
>        else
>          exit(9 + (fo || oth ? 1 : 0) + fo);
>      }
>      if (fo == 0)
>        Panic(0, "No Sockets found in %s.\n", SockPath);
>      Msg(0, "%d Socket%s in %s.", fo, fo > 1 ? "s" : "", SockPath);
>      eexit(0);
>    }
>    signal(SIG_BYE, AttacherFinit);      /* prevent races */
>    if (cmdflag) {
> +#ifdef MULTIUSER
> +    if (multi)
> +      real_uid = multi_uid;
> +#endif
> +
>      /* attach_tty is not mandatory */
>      SetTtyname(false, &st);
>      if (!*av)
>        Panic(0, "Please specify a command.");
>      SET_GUID();
>      SendCmdMessage(sty, SockMatch, av, queryflag >= 0);
>      exit(0);
>    }
>    else if (rflag || xflag) {
>      debug("screen -r: - is there anybody out there?\n");

>
> This diff was generated at revision 30c9a2a6c190647e35d1ce7b4758de9081f06d10.
>
> Let me know if there's a more-preferred way to submit patches. :)
> - Taj

comment #5:

> And eventually I've found Taj Morton's patch (here: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=626526), but I decided to use sudo to circumvent it.

Hello Oskar,

sorry that this problem still there despite the existing solution.
Can you try to test this patch with git version (screen-v4 branch) please? If it solves the problem, I will apply it immediately.

wfm wheezy on mac-mini and Raspberry pi

$ ssh me@remote-ip -t "screen -x myscreen -X stuff 'flite -t \"connecting you\"'`echo -ne '\015'`"

requires libncurses-dev

Oops, formatting fail (no preview button!?). Let's try again:

--- screen.c-orig 2013-02-03 13:44:35.039601124 -0800
+++ screen.c 2013-02-03 13:44:13.463601460 -0800
@@ -1069,6 +1069,10 @@
     {
       char *sty = 0;

+#ifdef MULTIUSER
+      if (multi)
+ real_uid = multi_uid;
+#endif
       /* attach_tty is not mandatory */
       if ((attach_tty = ttyname(0)) == 0)
         attach_tty = "";

In a multiuser environment, it seems that the -X option simply ignores the specified user and looks for the session in the current user's environment. 

Steps:

As user1, start a session and turn on multiuser mode

 screen -S myscrn
 ^A:multiuser on
 ^A:acladd user2

As user2, test the session with ls, then try to use stuff.

 screen -S user1/myscrn -ls
 screen -S user1/myscrn -X stuff "shutdown"

stuff fails to send characters to the screen session specified by -S  What should happen is that user1's screen session receive input from 'stuff'