[PATCH v4 2/3] nvme-auth: use transformed key size to create resp

[Mark O'Donovan]

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 <Akash.Appaiah@xxxxxxxx>
Signed-off-by: Akash Appaiah <Akash.Appaiah@xxxxxxxx>
Signed-off-by: Mark O'Donovan <shiftee@xxxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
---
V1 -> V2: support target implementation and controller secrets also
V2 -> V3: return key from nvme_auth_transform_key
V3 -> V4: use helper to get key struct len, added ERR_CAST

 drivers/nvme/common/auth.c | 23 ++++++++++++++---------
 drivers/nvme/host/auth.c   | 30 +++++++++++++++---------------
 drivers/nvme/target/auth.c | 31 +++++++++++++++++--------------
 include/linux/nvme-auth.h  |  3 ++-
 4 files changed, 48 insertions(+), 39 deletions(-)

diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index 984f4320aca3..f9e7ed8e729d 100644
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -242,21 +242,25 @@ void nvme_auth_free_key(struct nvme_dhchap_key *key)
 }
 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 || !key->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) {
@@ -266,7 +270,7 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
 
 	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),
@@ -276,7 +280,8 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
 		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;
@@ -295,7 +300,7 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
 	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;
 
@@ -305,7 +310,7 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
 	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:
diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index daf5d144a8ea..de1390d705dc 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -23,6 +23,7 @@ struct nvme_dhchap_queue_context {
 	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;
@@ -36,7 +37,6 @@ struct nvme_dhchap_queue_context {
 	u8 c1[64];
 	u8 c2[64];
 	u8 response[64];
-	u8 *host_response;
 	u8 *ctrl_key;
 	u8 *host_key;
 	u8 *sess_key;
@@ -428,12 +428,12 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 	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 {
@@ -442,7 +442,7 @@ static int nvme_auth_dhchap_setup_host_response(struct nvme_ctrl *ctrl,
 	}
 
 	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);
@@ -508,19 +508,19 @@ static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 		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);
@@ -586,7 +586,7 @@ static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
 out:
 	if (challenge != chap->c2)
 		kfree(challenge);
-	kfree(ctrl_response);
+	nvme_auth_free_key(transformed_key);
 	return ret;
 }
 
@@ -648,8 +648,8 @@ static int nvme_auth_dhchap_exponential(struct nvme_ctrl *ctrl,
 
 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;
diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c
index 4dcddcf95279..3ddbc3880cac 100644
--- a/drivers/nvme/target/auth.c
+++ b/drivers/nvme/target/auth.c
@@ -267,7 +267,8 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
 	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;
 
@@ -291,14 +292,15 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
 		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;
 
@@ -365,7 +367,7 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *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;
@@ -378,7 +380,8 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
 	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;
 
@@ -402,15 +405,15 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
 		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;
 
@@ -474,7 +477,7 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *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;
diff --git a/include/linux/nvme-auth.h b/include/linux/nvme-auth.h
index a5ae9abe1ef6..c1d0bc5d9624 100644
--- a/include/linux/nvme-auth.h
+++ b/include/linux/nvme-auth.h
@@ -29,7 +29,8 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
 					      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);
-- 
2.39.2