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SubjectRe: FWD: Re: Linux pipe question
Pipe buffers are not pagable at present (and probably never will be);
obviously for the below to be 'reasonable' immune from paging
sensitive data out then the _application_ buffers in question should
be mlocked. GPG already does this (if suid or run as root) so the
other application would need to do that same.


--cw

On Wed, Sep 20, 2000 at 12:31:25PM -0400, Mike Panetta wrote:
Can anyone answer this?
I am not sure if unnamed pipes in linux
are pageable or not. If an unnamed pipe
could be paged out what could be done
to prevent that from happening?

TIA,
Mike


----- Forwarded message from AW <aw@cavu.com> -----

Date: Wed, 20 Sep 2000 12:27:05 -0400
From: AW <aw@cavu.com>
To: mpanetta@applianceware.com
Subject: Re: Linux pipe question

> I am not sure... But would this be a named pipe or
> not?

This would be a UNnamed pipe, i.e.,

gen_confidential_data | gpg -e -r backup@pentacorp.com ...

The question is: is any of the clear text confidential data handled by the
unnamed pipe at risk for being written to disk? Comments in the kernel
code suggest that it's buffered in a single physical page but I suspect
that it's actually a virtual page that could be paged out.

Does the answer depend on if gen_confidential_data limits its write to
not exceed PIPE_BUF (4096)?

Clearly, gen_confidential_data is subject to being paged out unless it
locks itself into memory.

THANKS!

Bob

----- End forwarded message -----

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