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@@ -1,95 +0,0 @@
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-program grab_vcsa;
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-
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-{
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- This file is part of the Free Pascal run time library.
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- Copyright (c) 2005 by Daniël Mantione
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- member of the Free Pascal development team.
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-
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- VCSA grabber program for Linux.
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-
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- See the file COPYING.FPC, included in this distribution,
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- for details about the copyright.
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-
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- This program is distributed in the hope that it will be useful,
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- but WITHOUT ANY WARRANTY; without even the implied warranty of
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- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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-}
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-
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-uses baseunix,termio;
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-
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-{This program helps the video unit to use /dev/vcsa* to provide high
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- quality output.
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-
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- Normally, when you login, the owner of the tty you are running on,
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- /dev/tty0-31 is set to your username. Weird enough, this is not done
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- with the video buffer devices belonging to that tty, /dev/vcs0-31
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- and /dev/vcsa0-31. This makes it impossible to do high quality text
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- mode video output.
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-
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- This program, designed to be run suid root, reads the owner and mode
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- of the tty, and assigns them to the corresponding vcs and vcsa device.}
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-
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-{Security design:
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-
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- - It has been checked if the user can provide any input to the program.
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- The only input in the program is stdinputhandle, which cannot be
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- controlled by the user. The user has therefore no control in any way
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- about the code flow in the program; the code that is going to be
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- executed is fixed no matter what a user does.
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-
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- - Outputs are the file permissions of /dev/vcs* and /dev/vcsa*. It has
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- been considered if users could use the program this way to gain rights
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- they should not have. By having access to /dev/vcs* and /dev/vcsa*
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- the user can garble his own screen. This should not be a problem.
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-
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- After the user has logged out /dev/vcs* and /dev/vcsa* are automatically
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- changed back to root. This removes the need for us to change permissions
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- back again. If we would change permissions back, it would be useless, the
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- user can kill the process before it changes back permissions.
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-
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- - Normal users cannot write to /dev/ and can therefore not use the program
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- do change the permissions of other files than the actual devices.
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-}
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-
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-const result_success=0;
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- result_not_on_console=1;
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- result_stat_error=2;
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- result_chown_error=3;
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- result_chmod_error=4;
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-
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-var thistty:string;
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- vcs,vcsa:string;
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- ttystat:stat;
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-
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-begin
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- exitcode:=result_not_on_console;
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- thistty:=ttyname(stdinputhandle);
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- if isatty(stdinputhandle)=1 then
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- begin
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- { running on a tty, find out whether locally or remotely }
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- if (length(thistty)>=9) and
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- (copy(thistty,1,8)='/dev/tty') and
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- (thistty[9] in ['0'..'9']) then
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- begin
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- {We are running on the Linux console}
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- if fpstat(thistty,ttystat)<>0 then
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- halt(result_stat_error);
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- vcs:='/dev/vcs'+copy(thistty,9,255);
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- vcsa:='/dev/vcsa'+copy(thistty,9,255);
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-
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- {Change owner and group to that of /dev/tty??.}
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- if fpchown(vcs,ttystat.uid,ttystat.gid)<>0 then
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- halt(result_chown_error);
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- if fpchown(vcsa,ttystat.uid,ttystat.gid)<>0 then
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- halt(result_chown_error);
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-
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- {Change permissions to that of /dev/tty??.}
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- if fpchmod(vcs,ttystat.mode)<>0 then
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- halt(result_chmod_error);
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- if fpchmod(vcsa,ttystat.mode)<>0 then
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- halt(result_chmod_error);
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- writeln(vcsa);
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- exitcode:=result_success;
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- end;
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- end;
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-end.
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daniel