Re: Syslets, signals, and security
From: Andi Kleen
Date: Mon Jun 04 2007 - 16:01:18 EST
Jeff Dike <jdike@xxxxxxxxxxx> writes:
> How about splitting the credentials out of the task_struct and making
> them sharable ala ->mm et al? You change uid there and it changes for
> everyone. It will make fork slightly more expensive though.
Strictly that's required by POSIX anyways. But it's a real mess.
The problem is that you would need to reference count/lock them in every
syscall or ioctl or similar. Otherwise another thread
could change them in the middle of a syscall which wouldn't be
good. Doing this full reference counting would be probably somewhat
expensive with more locked cycles and also a lot of work to implement.
You would need to audit large parts of the source tree.
I don't think it's a good idea.
-Andi
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