Re: Bash crashes on tab completion after unset COMP_WORDBREAKS

[Roman Rakus]

D.J. Capelis wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: x86_64
> OS: linux-gnu
> Compiler: x86_64-pc-linux-gnu-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/share/locale' -DPACKAGE='bash'
> -DSHELL -DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib   -O2
> -march=native -pipe -fstack-protector
> uname output: Linux aes 2.6.26-DJC-AES #1 SMP Thu Jul 17 22:09:37 PDT
> 2008 x86_64 Intel(R) Core(TM)2 CPU 6600 @ 2.40GHz GenuineIntel GNU/Linux
> Machine Type: x86_64-pc-linux-gnu
>
> Bash Version: 3.2
> Patch Level: 33
> Release Status: release
>
> Description:
> It seems like once COMP_WORDBREAKS is unset, the actually completion
> mechanism of bash gets very unhappy.  Presumably maybe it shouldn't work
> very well after this is unset, but it's probably best if it doesn't
> crash outright.
>
> Sorry, I'm not sure if this has been fixed in trunk, but given that it's
> existing across several patch levels, I figured it might still be live.
>
> Blogged with an image on:
> http://djcapelis.livejournal.com/111233.html
>
> Reproduced by a friend using 3.2.17(1)-release  (The regular bash build
> on OS X.)
> Reproduced again using 3.2.39(1)-release (i686-pc-linux-gnu)
>
> Reproduced again using 3.1.17(1)-release (i686-redhat-linux-gnu) BUT GOT
> DIFFERENT OUTCOME: bash spins instead of crashing
>
> CANNOT REPRODUCE on 3.00.15(1)-release (i686-redhat-linux-gnu)
> CANNOT REPRODUCE on 3.00.16(1)-release (sparc-sun-solaris2.10)
>
> Reproduce by:
> 1) unset COMP_WORDBREAKS
> 2) type ba, press tab
> 3) Bash should crash
>
> Repeat-By:
> 1) unset COMP_WORDBREAKS
> 2) type ba, press tab
> 3) Bash should crash
>
>
>
>   
Program received signal SIGSEGV, Segmentation fault.
0x0000003d30278eb0 in strchr () from /lib64/libc.so.6


I don't take a deeper look, but it can be touching NULL pointer?
RR