Messages in this thread | | | From | Peter Chubb <> | Date | Mon, 13 May 2002 08:04:16 +1000 | Subject | Re: [RFC] ext2 and ext3 block reservations can be bypassed |
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>>>>> "elladan" == elladan <elladan@eskimo.com> writes:
elladan> It's perfectly legal for the shell to sit around with a file elladan> open and pass it off to a child, even if the disk is full.
elladan> It's also perfectly legal for root to write to the fd, even elladan> if the disk is full (for normal users).
elladan> It just happens that the suid program wasn't the one who elladan> chose what file it was going to write stdout to - the shell elladan> did.
This is why in SVr4, struct cred is cloned at open time, and passed down to each VFS operation.
There's a choice of security modules here--- should the credentials of the opener or the credentials of the writer determine the use of the extra space? I think in this case it ought to be the credentials of the opener. Also, I'm not sure that mount(8) should be a setuid program. (I know it's convenient for floppy mounts, but I'd rather they were handled by autofs)
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