Re: SECURITY: psql allows symlink games in /tmp

Thanks for the pointer. Here is a diff to fix the problem. How does it
look to you?

> This code in psql/command.c allows *any* system user to place a
> predictably named symbolic link in /tmp and use it to alter/destroy
> files owned by the user running psql. (tested - postgresql 7.0.2).
>
> All the information a potential attacker would need are available via a
> simple 'ps'.
>
> It might (untested) also allow an another user to exploit the race
> between the closing of the file by the editor and the re-reading of its
> contents to execute arbitrary SQL commands.
>
> IMHO these files, if they must be created in /tmp should at least be
> created O_EXCL, but there are still editor vulnerabilities with opening
> any files in a world writeable directory (see recent joe Vulnerability:
> http://lwn.net/2000/1123/a/sec-joe.php3)
>
> My system is RedHat 6.2 on an i686, with Postgresql 7.0.2 but the same
> code currently exists in CVS (or at least CVS-web).
>
> I am not subscribed to this list, so please CC me for replies. (Also
> tell me if there is a more appropriate forum for this, but
> www.postgresql.org doesn't have a listed security issue address).
> --
> Andrew Bartlett
> abartlet(at)pcug(dot)org(dot)au
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026