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Re^2: securing a remailer

by geektron (Curate)
on Oct 12, 2005 at 03:54 UTC ( #499360=note: print w/replies, xml ) Need Help??


in reply to Re: securing a remailer
in thread securing a remailer

if user input isn't validated/untainted, newlines can be passed into the input, allowing someone to hijack the script and use it as a spam-remailer.

sure, if you're not accepting user input you could get away with it, but i don't recommend it.

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Re^3: securing a remailer
by sgifford (Prior) on Oct 12, 2005 at 15:41 UTC
    So the solution is to validate user input. No need to throw the baby out with the bathwater. You'd have similar problems with using unvalidated input with SMTP or any other mechanism for sending mail.

    Still, if the OP finds they can replace a significant chunk of their code with a well-maintained Perl module, that seems like a pretty clear good idea.

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[Corion]: But yes, "who started this process" is interesting information :)
[tye]: no, I really believe that "login user" was added as a fundamental bit of info about each process in order to enhance the usefulness of auditing
[Corion]: Ah - if that information is saved in a file, then you could theoretically spam that file and confuse getlogin(). So, don't use it for authentication :)
[tye]: that is what getlogin() certainly *used* to do. I don't believe that is what it certainly should do.
[davido]: /var/run/utmp is 664 i think.
[tye]: Note that my "man getlogin" says that it uses stdin when it should use /dev/tty (calling a glibc bug). But that does not appear to be the case when I test it. But maybe Perl's getlogin() is not using glibc's getlogin().
[oiskuu]: well, run a strace and see what the getlogin does for you.... As I said. SELinux probably has those security labels. But not regular linux.
[tye]: for example, read https://unix. stackexchange.com/ questions/146138/ loginuid-should-be -allowed-to-change -or-not-mutable-or -not
[tye]: I'm not using SELinux and it certainly appears to disagree with you. shrug
[tye]: Since you brought up /proc, oiskuu, I didn't see you respond to my suggestion of 'loginuid'. Does your /proc not have such?

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