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Re: [Qemu-devel] [PATCH 2/6] crypto: clear out buffer after timing pbkdf
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH 2/6] crypto: clear out buffer after timing pbkdf algorithm |
Date: |
Thu, 8 Sep 2016 12:47:43 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 |
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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- [Qemu-devel] [PATCH 0/6] crypto: misc tweaks & improvements to pbkdf code, Daniel P. Berrange, 2016/09/08
- [Qemu-devel] [PATCH 2/6] crypto: clear out buffer after timing pbkdf algorithm, Daniel P. Berrange, 2016/09/08
- Re: [Qemu-devel] [PATCH 2/6] crypto: clear out buffer after timing pbkdf algorithm,
Eric Blake <=
- [Qemu-devel] [PATCH 1/6] crypto: make PBKDF iterations configurable for LUKS format, Daniel P. Berrange, 2016/09/08
- [Qemu-devel] [PATCH 3/6] crypto: use correct derived key size when timing pbkdf, Daniel P. Berrange, 2016/09/08
- [Qemu-devel] [PATCH 6/6] crypto: support more hash algorithms for pbkdf, Daniel P. Berrange, 2016/09/08
- [Qemu-devel] [PATCH 4/6] crypto: remove bogus /= 2 for pbkdf iterations, Daniel P. Berrange, 2016/09/08