Re: [Qemu-devel] [PATCH 2/6] crypto: clear out buffer after timing pbkdf algorithm

[Eric Blake]

On 09/08/2016 11:27 AM, Daniel P. Berrange wrote:
> The 'out' buffer will hold a key derived from master
> password, so it is best practice to clear this buffer
> when no longer required.
> 
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
>  crypto/pbkdf.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

It still doesn't prevent the memory from being copied elsewhere (such as
the stack being paged out), unless we go to extraordinary lengths to
explicitly request volatile memory that can't be paged out.  I don't
know if we need to worry about that, though.  Do any of our crypto
libraries provide APIs for allocating local-use-only memory for
sensitive data?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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