[PATCH v2 11/18] crypto: dh - introduce support for ephemeral key generation to hpre driver

[Nicolai Stange <nstange@xxxxxxx>]

A previous patch made the dh-generic implementation's ->set_secret() to
generate an ephemeral key in case the input ->key_size is zero, just in
analogy with ecdh. Make the hpre crypto driver's DH implementation to
behave consistently by doing the same.

Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
---
 drivers/crypto/hisilicon/hpre/hpre_crypto.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/crypto/hisilicon/hpre/hpre_crypto.c b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
index a032c192ef1d..02ca79e263f1 100644
--- a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
+++ b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
@@ -701,11 +701,20 @@ static int hpre_dh_set_secret(struct crypto_kpp *tfm, const void *buf,
 {
 	struct hpre_ctx *ctx = kpp_tfm_ctx(tfm);
 	struct dh params;
+	char key[CRYPTO_DH_MAX_PRIVKEY_SIZE];
 	int ret;
 
 	if (crypto_dh_decode_key(buf, len, &params) < 0)
 		return -EINVAL;
 
+	if (!params.key_size) {
+		ret = crypto_dh_gen_privkey(params.group_id, key,
+					    &params.key_size);
+		if (ret)
+			return ret;
+		params.key = key;
+	}
+
 	/* Free old secret if any */
 	hpre_dh_clear_ctx(ctx, false);
 
@@ -716,6 +725,8 @@ static int hpre_dh_set_secret(struct crypto_kpp *tfm, const void *buf,
 	memcpy(ctx->dh.xa_p + (ctx->key_sz - params.key_size), params.key,
 	       params.key_size);
 
+	memzero_explicit(key, sizeof(key));
+
 	return 0;
 
 err_clear_ctx:
-- 
2.26.2