exec after seteuid

[Corinna Vinschen]

On Sat, Jun 07, 2003 at 03:34:56PM -0400, Pierre A. Humblet wrote:
> I was just thinking about the security implications. For example
> login uses seteuid. With the change, the shell would still start
> with ruid = 18, and a simple RevertToSelf would bring privileges 
> back. I think (all ?) shells setuid(geteuid()), but in Cygwin the 
> change wouldn't really be effective until the next exec.
> Perhaps it would be safer to have login and such use setuid.

I just had a look into the current login.c implementation on NetBSD.
It is using setuid/setgid.  Actually it's using setusercontext(3)
but with all options set which implies setuid/setgid.  Yes, using
only seteuid/setegid in login has to be considered an error which
just didn't matter so far.

Corinna

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Corinna Vinschen                  Please, send mails regarding Cygwin to
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