[48933] in Cypherpunks
Re: Unix swapfile security issues...
daemon@ATHENA.MIT.EDU (Steven L Baur)
Thu Feb 1 16:02:13 1996
To: cypherpunks@toad.com
From: Steven L Baur <steve@miranova.com>
Date: 01 Feb 1996 13:00:26 -0800
In-Reply-To: Anonymous's message of 31 Jan 1996 23:30:25 -0800
>>>>> "Anonymous" == Anonymous <mixmaster@alpha.c2.org> writes:
Anonymous> I'm working on a unix application where I want to store a
Anonymous> key in memory and don't want it to get written out to a
Anonymous> swap file. If the key is in any of the application's
Anonymous> memory pages, it could be swapped out at any time, and
Anonymous> potentially left in the swap file when the computer is
Anonymous> turned off.
That's only a problem if physical security doesn't exist at the
console. No operating system (or monitor) can overcome the lack of
that.
Anonymous> But, what if the program creates a pipe() and writes the
Anonymous> key into it, then reads the key out when necessary? A pipe
^^^^^ ^^^ ^^^ ^^^
In which case it's in memory and can be paged or swapped.
Anonymous> has a 4K buffer, but that buffer is in the kernel's memory,
Anonymous> not in the application's pages. Could a kernel buffer get
Anonymous> written out to a swapfile?
Depending on how the kernel is written, bringing down the machine
could result in a dump of kernel memory being written to the swap
device anyway.
--
steve@miranova.com baur
Unsolicited commercial e-mail will be proofread for $250/hour.
