[PATCH v4 1/3] nvme-auth: alloc nvme_dhchap_key as single buffer

[Mark O'Donovan]

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>
---
V2 -> V3: initial version

V3 -> V4: added function to get size of key struct

 drivers/nvme/common/auth.c | 35 ++++++++++++++++++++++++-----------
 include/linux/nvme-auth.h  |  4 +++-
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index d90e4f0c08b7..984f4320aca3 100644
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -150,6 +150,14 @@ size_t nvme_auth_hmac_hash_len(u8 hmac_id)
 }
 EXPORT_SYMBOL_GPL(nvme_auth_hmac_hash_len);
 
+u32 nvme_auth_key_struct_size(u32 key_len)
+{
+	struct nvme_dhchap_key key;
+
+	return struct_size(&key, key, key_len);
+}
+EXPORT_SYMBOL_GPL(nvme_auth_key_struct_size);
+
 struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
 					      u8 key_hash)
 {
@@ -163,14 +171,9 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
 	p = strrchr(secret, ':');
 	if (p)
 		allocated_len = p - secret;
-	key = kzalloc(sizeof(*key), GFP_KERNEL);
+	key = nvme_auth_alloc_key(allocated_len, 0);
 	if (!key)
 		return ERR_PTR(-ENOMEM);
-	key->key = kzalloc(allocated_len, GFP_KERNEL);
-	if (!key->key) {
-		ret = -ENOMEM;
-		goto out_free_key;
-	}
 
 	key_len = base64_decode(secret, allocated_len, key->key);
 	if (key_len < 0) {
@@ -213,19 +216,29 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
 	key->hash = key_hash;
 	return key;
 out_free_secret:
-	kfree_sensitive(key->key);
-out_free_key:
-	kfree(key);
+	nvme_auth_free_key(key);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(nvme_auth_extract_key);
 
+struct nvme_dhchap_key *nvme_auth_alloc_key(u32 len, u8 hash)
+{
+	u32 num_bytes = nvme_auth_key_struct_size(len);
+	struct nvme_dhchap_key *key = kzalloc(num_bytes, GFP_KERNEL);
+
+	if (key) {
+		key->len = len;
+		key->hash = hash;
+	}
+	return key;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_alloc_key);
+
 void nvme_auth_free_key(struct nvme_dhchap_key *key)
 {
 	if (!key)
 		return;
-	kfree_sensitive(key->key);
-	kfree(key);
+	kfree_sensitive(key);
 }
 EXPORT_SYMBOL_GPL(nvme_auth_free_key);
 
diff --git a/include/linux/nvme-auth.h b/include/linux/nvme-auth.h
index dcb8030062dd..a5ae9abe1ef6 100644
--- a/include/linux/nvme-auth.h
+++ b/include/linux/nvme-auth.h
@@ -9,9 +9,9 @@
 #include <crypto/kpp.h>
 
 struct nvme_dhchap_key {
-	u8 *key;
 	size_t len;
 	u8 hash;
+	u8 key[];
 };
 
 u32 nvme_auth_get_seqnum(void);
@@ -24,9 +24,11 @@ const char *nvme_auth_digest_name(u8 hmac_id);
 size_t nvme_auth_hmac_hash_len(u8 hmac_id);
 u8 nvme_auth_hmac_id(const char *hmac_name);
 
+u32 nvme_auth_key_struct_size(u32 key_len);
 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);
 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,
-- 
2.39.2