On 9/23/2013 9:51 PM, Kim Phillips wrote:
On Sat, 21 Sep 2013 14:26:35 +0530
Yashpal Dutta <yashpal.dutta@xxxxxxxxxxxxx> wrote:
KMap the buffers before copying trailing bytes during hmac into a session
temporary buffer. This is required if pinned buffer from user-space is send
during hmac and is safe even if hmac request is generated from within kernel.
it may be "safe" but it adversely affects performance for AF_ALG users,
no?
why does ocf-linux need this, and not AF_ALG? Is a patch to ocf-linux
more appropriate here?
SW hashing (crypto/ahash.c, crypto/shash.c) do the kmap/kunmap.
Crypto engine drivers should do this too. Either by themselves or
(probably better) try to use existing support in crypto/scatterwalk.c
At the interface level, AF_ALG issues get_user_pages via
af_alg_make_sg(), similar to what ocf-linux does.
Cc:stable@xxxxxxxxxxxxxxx
fyi, this violates the following rule in
Documentation/stable_kernel_rules.txt:
- It or an equivalent fix must already exist in Linus' tree (upstream).
AFAICT, rules are more flexible, at least that's my understanding.
Adding a Cc:stable in the signed-off area is more convenient, since it
provides for automatic inclusion in -stable tree (once patch reaches
Linus' tree):
- To have the patch automatically included in the stable tree, add the tag
Cc: stable@xxxxxxxxxxxxxxx
in the sign-off area. Once the patch is merged it will be applied to
the stable tree without anything else needing to be done by the author
or subsystem maintainer.
Horia
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