As the ->q in struct dh_ctx gets never set anywhere, the code
in dh_is_pubkey_valid() for doing the full public key validation in
accordance to SP800-56Arev3 is effectively dead.
However, for safe-prime groups, Q = (P - 1)/2 by definition and this
enables dh_is_pubkey_valid() to calculate Q on the fly for these groups.
Implement this.
With this change, the last code accessing struct dh_ctx's ->q is now gone.
Remove this member from struct dh_ctx.
Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
---
crypto/dh.c | 40 +++++++++++++++++++++++++++++-----------
1 file changed, 29 insertions(+), 11 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>