NoneUnix swapfile security issues...

I'm working on a unix application where I want to store a key in memory and
don't want it to get written out to a swap file.  If the key is in any of
the application's memory pages, it could be swapped out at any time, and
potentially left in the swap file when the computer is turned off.

But, what if the program creates a pipe() and writes the key into it, then
reads the key out when necessary?  A pipe has a 4K buffer, but that buffer
is in the kernel's memory, not in the application's pages.  Could a kernel
buffer get written out to a swapfile?

>>>>> "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.

-- 
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