super , keep LD_LIBRARY_PATH

[Simon Raffeiner (SCC)]

Hi,

you can't. The variable is not removed by super or sudo, but by the
dynamic linker for security reasons.


>From the manpage of ld.so(8):

"LD_LIBRARY_PATH
 A colon-separated list of directories in which to search for ELF
libraries at execution-time.  Similar to the PATH environment variable.
 Ignored in set-user-ID and set-group-ID programs."


The corresponding source code line is
https://sourceware.org/git/?p=glibc.git;a=blob;f=elf/dl-load.c;h=41b91fcc86664b39ea8c0ce5ed35109ab494c925;hb=HEAD#l817
, the __libc_enable_secure flag gets set when a binary is executed
setuid root and prevents the use of untrusted paths LD_LIBRARY_PATH. The
list of trusted paths is generated at compile time, so you can't change
it later.


I have never used super and the only solution I know is the following:


$ export LD_LIBRARY_PATH=/whatever/
$ sudo LD_LIBRARY_PATH=${LD_LIBRARY_PATH} env



kind regards,

Simon




On 31.03.2015 10:13, sanyechong12 at live.com wrote:> Hi everybody!
>     How can I keep the enviromet variable LD_LIBRARY_PATH when I excute
> a super command?
>
>     I have modified /etc/super.tab:
>     :global env=PATH,LD_LIBRARY_PATH,PYTHONPATH
>     bzytest /root/test admin
>
>     /root/test:
>     #!/bin/bash
>     export
>
>     I can get PATH, PYTHONPATH kept. But LD_LIBRARY_PATH is not.
>
>     Forgive my bad english.
>
>     Best wishes
>

>
>     Shuai
>     sanyechong12 at live.com


-- 
Karlsruhe Institut of Technology (KIT)
Steinbuch Centre for Computing (SCC)

M. Sc. Simon Raffeiner
High Performance Computing Administrator