Here is a message that should clear this up for you.

Rich


-----Original Message-----
From: Cort Dougan [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, February 21, 2001 1:41 PM
To: Basham, Richard R
Cc: [EMAIL PROTECTED]
Subject: Re: [rtl] root id


} I think the bigger question here is:  Why did this happen in the first
place?
} 
} Cort,
} 
} Is there anyone at FSM Labs know why this occurred?

The problem was with the psc module.  Well, actually it wasn't the psc
module it was bad user-land programs.

The PSC module grabs a free syscall when it's loaded.  With older kernels
we were getting a free syscall that happens to correspond with a syscall
added to later kernels to set/check privilege levels.  Some user-programs
would make a direct call to syscall #201 (not through glibc) and assume it
was the correct one.  On kernels that didn't support this syscall the
user-program would get an error.  When psc grabbed that syscall the
user-program would end up calling a syscall it didn't intend rather than
the privilege syscall.

We've changed the syscall hook code in psc so that it searches top-down
rather than bottom up.  That fixes the problem.

In short, if you have doubts just don't load psc.  It's not needed unless
you're using the user-level realtime features of RTLinux.






-----Original Message-----
From: Antonio Milici [mailto:[EMAIL PROTECTED]]
Sent: Monday, January 07, 2002 6:21 AM
To: [EMAIL PROTECTED]
Subject: [rtl] euid problem


Hi All.

I'm running rtl3.0 (kernel 2.2.18 patched) on a Mandrake 8.0 distribution.
When I load rtl modules (with 'rtlinux start'), something strange (to me!)
seems to happen: the euid becomes -1 (or better 2^32 - 1), while before
loading rtl basic modules it was 0, like uid. If I remove the module psc.o
the euid becomes again 0.
If I use rtl3.1 (kernel 2.4.4 patched) on the same distribution, the euid
remains 0, before and after loading rtl basic modules.

Is there someone who could explain me if this behaviour is correct and, if
not, if it is avoidable on the version of rtl I'm using?

I am new to this mailing list, so sorry if this object was already discussed
before.
Thank you in advance.

Antonio.





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