nvme-auth: use transformed key size to create resp

This does not change current behaviour as the driver currently
verifies that the secret size is the same size as the length of
the transformation hash.

Co-developed-by: Akash Appaiah <[e-mail]>
Signed-off-by: Akash Appaiah <[e-mail]>
Signed-off-by: Mark O'Donovan <[e-mail]>
Reviewed-by: Hannes Reinecke <[e-mail]>
Signed-off-by: Keith Busch <[e-mail]>

drivers/nvme/common/auth.c

···
 }
 EXPORT_SYMBOL_GPL(nvme_auth_free_key);
 
-u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
+struct nvme_dhchap_key *nvme_auth_transform_key(
+		struct nvme_dhchap_key *key, char *nqn)
 {
 	const char *hmac_name;
 	struct crypto_shash *key_tfm;
 	struct shash_desc *shash;
-	u8 *transformed_key;
-	int ret;
+	struct nvme_dhchap_key *transformed_key;
+	int ret, key_len;
 
 	if (!key) {
 		pr_warn("No key specified\n");
 		return ERR_PTR(-ENOKEY);
 	}
 	if (key->hash == 0) {
-		transformed_key = kmemdup(key->key, key->len, GFP_KERNEL);
-		return transformed_key ? transformed_key : ERR_PTR(-ENOMEM);
+		key_len = nvme_auth_key_struct_size(key->len);
+		transformed_key = kmemdup(key, key_len, GFP_KERNEL);
+		if (!transformed_key)
+			return ERR_PTR(-ENOMEM);
+		return transformed_key;
 	}
 	hmac_name = nvme_auth_hmac_name(key->hash);
 	if (!hmac_name) {
···
 
 	key_tfm = crypto_alloc_shash(hmac_name, 0, 0);
 	if (IS_ERR(key_tfm))
-		return (u8 *)key_tfm;
+		return ERR_CAST(key_tfm);
 
 	shash = kmalloc(sizeof(struct shash_desc) +
 			crypto_shash_descsize(key_tfm),
···
 		goto out_free_key;
 	}
 
-	transformed_key = kzalloc(crypto_shash_digestsize(key_tfm), GFP_KERNEL);
+	key_len = crypto_shash_digestsize(key_tfm);
+	transformed_key = nvme_auth_alloc_key(key_len, key->hash);
 	if (!transformed_key) {
 		ret = -ENOMEM;
 		goto out_free_shash;
···
 	ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
 	if (ret < 0)
 		goto out_free_transformed_key;
-	ret = crypto_shash_final(shash, transformed_key);
+	ret = crypto_shash_final(shash, transformed_key->key);
 	if (ret < 0)
 		goto out_free_transformed_key;
 
···
 	return transformed_key;
 
 out_free_transformed_key:
-	kfree_sensitive(transformed_key);
+	nvme_auth_free_key(transformed_key);
 out_free_shash:
 	kfree(shash);
 out_free_key:

drivers/nvme/host/auth.c

···
 	struct nvme_ctrl *ctrl;
 	struct crypto_shash *shash_tfm;
 	struct crypto_kpp *dh_tfm;
+	struct nvme_dhchap_key *transformed_key;
 	void *buf;
 	int qid;
 	int error;
···
 	u8 c1[64];
 	u8 c2[64];
 	u8 response[64];
-	u8 *host_response;
 	u8 *ctrl_key;
 	u8 *host_key;
 	u8 *sess_key;
···
 	dev_dbg(ctrl->device, "%s: qid %d host response seq %u transaction %d\n",
 		__func__, chap->qid, chap->s1, chap->transaction);
 
-	if (!chap->host_response) {
-		chap->host_response = nvme_auth_transform_key(ctrl->host_key,
+	if (!chap->transformed_key) {
+		chap->transformed_key = nvme_auth_transform_key(ctrl->host_key,
 						ctrl->opts->host->nqn);
-		if (IS_ERR(chap->host_response)) {
-			ret = PTR_ERR(chap->host_response);
-			chap->host_response = NULL;
+		if (IS_ERR(chap->transformed_key)) {
+			ret = PTR_ERR(chap->transformed_key);
+			chap->transformed_key = NULL;
 			return ret;
 		}
 	} else {
···
 	}
 
 	ret = crypto_shash_setkey(chap->shash_tfm,
-			chap->host_response, ctrl->host_key->len);
+			chap->transformed_key->key, chap->transformed_key->len);
 	if (ret) {
 		dev_warn(ctrl->device, "qid %d: failed to set key, error %d\n",
 			 chap->qid, ret);
···
 		struct nvme_dhchap_queue_context *chap)
 {
 	SHASH_DESC_ON_STACK(shash, chap->shash_tfm);
-	u8 *ctrl_response;
+	struct nvme_dhchap_key *transformed_key;
 	u8 buf[4], *challenge = chap->c2;
 	int ret;
 
-	ctrl_response = nvme_auth_transform_key(ctrl->ctrl_key,
+	transformed_key = nvme_auth_transform_key(ctrl->ctrl_key,
 				ctrl->opts->subsysnqn);
-	if (IS_ERR(ctrl_response)) {
-		ret = PTR_ERR(ctrl_response);
+	if (IS_ERR(transformed_key)) {
+		ret = PTR_ERR(transformed_key);
 		return ret;
 	}
 
 	ret = crypto_shash_setkey(chap->shash_tfm,
-			ctrl_response, ctrl->ctrl_key->len);
+			transformed_key->key, transformed_key->len);
 	if (ret) {
 		dev_warn(ctrl->device, "qid %d: failed to set key, error %d\n",
 			 chap->qid, ret);
···
 out:
 	if (challenge != chap->c2)
 		kfree(challenge);
-	kfree(ctrl_response);
+	nvme_auth_free_key(transformed_key);
 	return ret;
 }
 
···
 
 static void nvme_auth_reset_dhchap(struct nvme_dhchap_queue_context *chap)
 {
-	kfree_sensitive(chap->host_response);
-	chap->host_response = NULL;
+	nvme_auth_free_key(chap->transformed_key);
+	chap->transformed_key = NULL;
 	kfree_sensitive(chap->host_key);
 	chap->host_key = NULL;
 	chap->host_key_len = 0;

drivers/nvme/target/auth.c

···
 	struct shash_desc *shash;
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	const char *hash_name;
-	u8 *challenge = req->sq->dhchap_c1, *host_response;
+	u8 *challenge = req->sq->dhchap_c1;
+	struct nvme_dhchap_key *transformed_key;
 	u8 buf[4];
 	int ret;
 
···
 		goto out_free_tfm;
 	}
 
-	host_response = nvme_auth_transform_key(ctrl->host_key, ctrl->hostnqn);
-	if (IS_ERR(host_response)) {
-		ret = PTR_ERR(host_response);
+	transformed_key = nvme_auth_transform_key(ctrl->host_key,
+						  ctrl->hostnqn);
+	if (IS_ERR(transformed_key)) {
+		ret = PTR_ERR(transformed_key);
 		goto out_free_tfm;
 	}
 
-	ret = crypto_shash_setkey(shash_tfm, host_response,
-				  ctrl->host_key->len);
+	ret = crypto_shash_setkey(shash_tfm, transformed_key->key,
+				  transformed_key->len);
 	if (ret)
 		goto out_free_response;
 
···
 		kfree(challenge);
 	kfree(shash);
 out_free_response:
-	kfree_sensitive(host_response);
+	nvme_auth_free_key(transformed_key);
 out_free_tfm:
 	crypto_free_shash(shash_tfm);
 	return 0;
···
 	struct shash_desc *shash;
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	const char *hash_name;
-	u8 *challenge = req->sq->dhchap_c2, *ctrl_response;
+	u8 *challenge = req->sq->dhchap_c2;
+	struct nvme_dhchap_key *transformed_key;
 	u8 buf[4];
 	int ret;
 
···
 		goto out_free_tfm;
 	}
 
-	ctrl_response = nvme_auth_transform_key(ctrl->ctrl_key,
+	transformed_key = nvme_auth_transform_key(ctrl->ctrl_key,
 						ctrl->subsysnqn);
-	if (IS_ERR(ctrl_response)) {
-		ret = PTR_ERR(ctrl_response);
+	if (IS_ERR(transformed_key)) {
+		ret = PTR_ERR(transformed_key);
 		goto out_free_tfm;
 	}
 
-	ret = crypto_shash_setkey(shash_tfm, ctrl_response,
-				  ctrl->ctrl_key->len);
+	ret = crypto_shash_setkey(shash_tfm, transformed_key->key,
+				  transformed_key->len);
 	if (ret)
 		goto out_free_response;
 
···
 		kfree(challenge);
 	kfree(shash);
 out_free_response:
-	kfree_sensitive(ctrl_response);
+	nvme_auth_free_key(transformed_key);
 out_free_tfm:
 	crypto_free_shash(shash_tfm);
 	return 0;

include/linux/nvme-auth.h

···
 					      u8 key_hash);
 void nvme_auth_free_key(struct nvme_dhchap_key *key);
 struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash);
-u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn);
+struct nvme_dhchap_key *nvme_auth_transform_key(
+				struct nvme_dhchap_key *key, char *nqn);
 int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key);
 int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
 				  u8 *challenge, u8 *aug, size_t hlen);