topic Re: Frecovering suid programs in Operating System - HP-UX

Frecovering suid programs

Chris Evans_1 — Wed, 05 Sep 2001 15:19:02 GMT

Hi all,

I am suffering a little at the moment with a problem using frecover.

As root I can frecover any file with the suid bit set but as a non root user the file is recovered with just the execute bits set. Is this the standard behaviour? Am I doing something stupid?

I have tried this on 10.20 and on 11.00 so I don't think it is a patch level problem.

Re: Frecovering suid programs

Sridhar Bhaskarla — Wed, 05 Sep 2001 15:26:24 GMT

Chris,

It makes perfect sense to me frecover not recovering SUID programs for ordinary user. So the case, I can restore an SUID program from the back myself and become a super user.

I believe it's a feature of frecover though officially I am not sure :-)

-Sri

Re: Frecovering suid programs

A. Clay Stephenson — Wed, 05 Sep 2001 17:19:06 GMT

Hi Chris,

This is perfectly normal behavior otherwise there would be a huge security problem. In fact, try this: Create a file my.exe owned by root and make it 4755 \via chmod. Nexp cp -p my.exe my2.exe as an ordinary user. You will see that the setuid bit is cleared in the copy.
If it worked any other way, it would be trivially easy for any user to create a setuid program owned by root.

Re: Frecovering suid programs

Chris Evans_1 — Thu, 06 Sep 2001 07:51:50 GMT

Thanks Guys,

I am trying to recover files owned by the ingres user as the ingres user. I understand the security implecations of letting users recover other users suid programs but what is the problem with recovering your own?

Re: Frecovering suid programs

Klaus Crusius — Thu, 06 Sep 2001 08:29:20 GMT

fbackup / frecover seem not to support non-root users quite well. (I get a "fbackup(1010): semget failed for the semaphore" if I try fbackup).

You can use tar -px to recover the setuid bit of a file owned by yourself. I do not see a security hole there, because it is possible to set the bit to the original file as well. cp -p works this way, too.

Klaus