crypto: dh - remove struct dh's ->q member

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@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 0 insertions, 4 deletions

diff --git a/include/crypto/dh.h b/include/crypto/dh.h
index d71e9858ab86..2585f0e6bb69 100644
--- a/include/crypto/dh.h
+++ b/include/crypto/dh.h
@@ -24,21 +24,17 @@
  *
  * @key:	Private DH key
  * @p:		Diffie-Hellman parameter P
- * @q:		Diffie-Hellman parameter Q
  * @g:		Diffie-Hellman generator G
  * @key_size:	Size of the private DH key
  * @p_size:	Size of DH parameter P
- * @q_size:	Size of DH parameter Q
  * @g_size:	Size of DH generator G
  */
 struct dh {
 	void *key;
 	void *p;
-	void *q;
 	void *g;
 	unsigned int key_size;
 	unsigned int p_size;
-	unsigned int q_size;
 	unsigned int g_size;
 };