[PATCH v2 0/3] crypto: fixes for Marvell hash

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

Version 2, same as version 1 but with a different patch 1, thanks to
Herbert for an alternative approach on that one.

 crypto/ahash.c                | 3 ++-
 crypto/shash.c                | 3 ++-
 drivers/crypto/marvell/hash.c | 9 +++++++++
 3 files changed, 13 insertions(+), 2 deletions(-)

On Fri, Oct 09, 2015 at 11:29:04AM +0100, Russell King - ARM Linux wrote:
> This small series of patches addresses oopses seen when trying to use
> the AF_ALG interface via openssl with openssh.  This series does not
> address all problems, but merely stops the kernel from smashing its
> kernel stack and oopsing.
> 
> With these fixes in place, the kernel no longer oopses.  However, with
> the digests enabled in openssl, openssh refuses to work, producing the
> following when attempting to connect to the target system:
> 
> Corrupted MAC on input.
> Disconnecting: Packet corrupt
> 
> It's been hard enough to get this far; the crypto code is not the easiest
> code to debug for a new-comer due to the amount of state needed to be
> retained to understand the code (all the inline functions masking
> multiple levels of containerisation and pointer dereference does not
> make it easy to track what is stored where, and once I've been through
> one bit of code, I find I'm having to revisit the same piece of code a
> bit later to re-understand what it's doing.)
> 
> It's been difficult enough to find the engine plugin for openssl - the
> original git repo which hosted it is now dead
> (http://src.carnivore.it/users/common/af_alg/).  All that seems to be
> left is someone's modified version on github, which seems to get some
> maintanence.  Debian doesn't seem to carry AF_ALG openssl support, and
> seems to only carry one package (strongswan) which supports this
> interface.
> 
> Hence, I'm leaving further debugging to other parties, especially as
> the userspace tooling for the AF_ALG seems rather lacking.  (Are there
> any test programs, if so, can their location be documented and placed
> in Documentation/crypto please?)
> 
> I'm not sure who the maintainer for drivers/crypto/marvell is, so I've
> picked Thomas.  It would be nice if there was an entry in MAINTAINERS
> for this driver.
> 
> The first patch in this series avoids kernel stack smashing if a crypto
> driver forgets to set the 'statesize' member, but writes to what seems
> to be a valid pointer passed to its export function.  Of course, this
> won't completely stop stack smashing if the statesize member is
> smaller than the data which the export function writes.  This patch is
> optional.
> 
> The second patch adds the necessary statesize members to the Marvell
> code which were previously missing.  Fixing this uncovered a further
> problem, which the third patch addresses.

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