Re: [PATCH 01/18] crypto: dh - remove struct dh's ->q member

[Hannes Reinecke]

On 12/1/21 1:48 AM, Nicolai Stange wrote:
> The only current user of the DH KPP algorithm, the
> keyctl(KEYCTL_DH_COMPUTE) syscall, doesn't set the domain parameter ->q
> in struct dh. Remove it and any associated (de)serialization code in
> crypto_dh_encode_key() and crypto_dh_decode_key. Adjust the encoded
> ->secret values in testmgr's DH test vectors accordingly.
>
> Note that the dh-generic implementation would have initialized its
> struct dh_ctx's ->q from the decoded struct dh's ->q, if present. If this
> struct dh_ctx's ->q would ever have been non-NULL, it would have enabled a
> full key validation as specified in NIST SP800-56A in dh_is_pubkey_valid().
> However, as outlined above, ->q is always NULL in practice and the full key
> validation code is effectively dead. A later patch will make
> dh_is_pubkey_valid() to calculate Q from P on the fly, if possible, so
> don't remove struct dh_ctx's ->q now, but leave it there until that has
> happened.
>
> Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
> ---
>   crypto/dh.c         |  6 ------
>   crypto/dh_helper.c  | 17 ++++-------------
>   crypto/testmgr.h    | 16 ++++++----------
>   include/crypto/dh.h |  4 ----
>   4 files changed, 10 insertions(+), 33 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
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Dr. Hannes Reinecke                Kernel Storage Architect
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