bash decode prompt string broken for 'W'

[Marty Pauley]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-pc-linux-gnu'
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/shar
uname output: Linux gohan 2.6.37-2-amd64 #1 SMP Sun Feb 27 10:12:22
UTC 2011 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 4.1
Patch Level: 5
Release Status: release

Description:
The "\W" escape in the prompt is expanded incorrectly for some
directories. The problem is caused by the use of strcpy with
overlapping strings; but strcpy has undefined behaviour when the
strings overlap.

Repeat-By:
Set PS1 to include the "\W" escape, then cd to /home or /media to see
the problem: "home" is displayed as "hmee" and "media" is displayed as
"meiia". A transcript from my bash session is below:

bash-4.1$ PS1='\W$ '
~$ cd /home
hmee$ cd /media
meiia$ cd /etc
etc$ cd
~$ exit

Fix:
The patch below fixes the problem.

--- y.tab.c.orig 2011-04-04 01:12:23.000000000 +0900
+++ y.tab.c 2011-04-04 01:19:48.000000000 +0900
@@ -7481,7 +7481,8 @@
{
t = strrchr (t_string, '/');
if (t)
- strcpy (t_string, t + 1);
+ for ( temp = t_string; *t; temp++ )
+ *temp = *++t;
}
}
#undef ROOT_PATH

[Chet Ramey]

> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-pc-linux-gnu'
> -DCONF_VENDOR='pc' -DLOCALEDIR='/usr/shar
> uname output: Linux gohan 2.6.37-2-amd64 #1 SMP Sun Feb 27 10:12:22
> UTC 2011 x86_64 GNU/Linux
> Machine Type: x86_64-pc-linux-gnu
>
> Bash Version: 4.1
> Patch Level: 5
> Release Status: release
>
> Description:
> The "\W" escape in the prompt is expanded incorrectly for some
> directories. The problem is caused by the use of strcpy with
> overlapping strings; but strcpy has undefined behaviour when the
> strings overlap.

Upgrade. This is fixed by bash-4.1 patch 10.

Chet

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU ch...@case.edu http://cnswww.cns.cwru.edu/~chet/