Re: [Bug-ed] "red" doesn't restrict like "ed -r"

[Alexander Jones]

On Saturday, January 17, 2015 16:33:31 Tim Chase wrote:

> To reproduce:

>

> $ uname -a

> Linux laptop 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64

> GNU/Linux

> $ red --version | head -1

> GNU Ed 1.6

> $ file `which red`

> /usr/bin/red: symbolic link to `/bin/ed'

> $ pwd

> /home/tim

> $ echo hello > edit_this.txt

> $ red edit_this.txt

> 6

> e /etc/passwd

> 2120

> !pwd

> /home/tim

> !

> q

> $

>

> Based on the documentation[1], "A restricted version of ed, red, can

> only edit files in the current directory and cannot execute shell

> commands" which is the same as "ed -r". However, as best I can tell

> from looking at the source[2], neither 1.10 nor 1.11rc1 has anything

> in the source that looks for argv[0] being "red" rather than "ed" (and

> thus "restricted_" doesn't get set accordingly, meaning that invoking

> red(1) doesn't appear restrict file/shell access).

>

> Invoking as "ed -r" appears to work without issues.

>

> -tkc

>

 

I think the issue is in the Debian packaging. In the ed source distribution, red is built as a shell script executing "ed --restricted". The Debian package must be setting /usr/bin/red as a symlink to /bin/ed instead of installing the built shell script to that location.

 

Alexander