[PATCH 01/21] nvme-auth: add NVME_AUTH_MAX_DIGEST_SIZE constant

[Eric Biggers <ebiggers@kernel.org>]

Define a NVME_AUTH_MAX_DIGEST_SIZE constant and use it in the
appropriate places.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 drivers/nvme/common/auth.c | 6 ++----
 drivers/nvme/host/auth.c   | 6 +++---
 include/linux/nvme.h       | 5 +++++
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index e07e7d4bf8b68..78d751481fe31 100644
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -13,12 +13,10 @@
 #include <crypto/dh.h>
 #include <crypto/hkdf.h>
 #include <linux/nvme.h>
 #include <linux/nvme-auth.h>
 
-#define HKDF_MAX_HASHLEN 64
-
 static u32 nvme_dhchap_seqnum;
 static DEFINE_MUTEX(nvme_dhchap_mutex);
 
 u32 nvme_auth_get_seqnum(void)
 {
@@ -767,11 +765,11 @@ int nvme_auth_derive_tls_psk(int hmac_id, u8 *psk, size_t psk_len,
 		u8 *psk_digest, u8 **ret_psk)
 {
 	struct crypto_shash *hmac_tfm;
 	const char *hmac_name;
 	const char *label = "nvme-tls-psk";
-	static const char default_salt[HKDF_MAX_HASHLEN];
+	static const char default_salt[NVME_AUTH_MAX_DIGEST_SIZE];
 	size_t prk_len;
 	const char *ctx;
 	unsigned char *prk, *tls_key;
 	int ret;
 
@@ -796,11 +794,11 @@ int nvme_auth_derive_tls_psk(int hmac_id, u8 *psk, size_t psk_len,
 	if (!prk) {
 		ret = -ENOMEM;
 		goto out_free_shash;
 	}
 
-	if (WARN_ON(prk_len > HKDF_MAX_HASHLEN)) {
+	if (WARN_ON(prk_len > NVME_AUTH_MAX_DIGEST_SIZE)) {
 		ret = -EINVAL;
 		goto out_free_prk;
 	}
 	ret = hkdf_extract(hmac_tfm, psk, psk_len,
 			   default_salt, prk_len, prk);
diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
index 405e7c03b1cfe..301c858b7c577 100644
--- a/drivers/nvme/host/auth.c
+++ b/drivers/nvme/host/auth.c
@@ -36,13 +36,13 @@ struct nvme_dhchap_queue_context {
 	u8 status;
 	u8 dhgroup_id;
 	u8 hash_id;
 	u8 sc_c;
 	size_t hash_len;
-	u8 c1[64];
-	u8 c2[64];
-	u8 response[64];
+	u8 c1[NVME_AUTH_MAX_DIGEST_SIZE];
+	u8 c2[NVME_AUTH_MAX_DIGEST_SIZE];
+	u8 response[NVME_AUTH_MAX_DIGEST_SIZE];
 	u8 *ctrl_key;
 	u8 *host_key;
 	u8 *sess_key;
 	int ctrl_key_len;
 	int host_key_len;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 655d194f8e722..edfebbce67453 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -1835,10 +1835,15 @@ enum {
 	NVME_AUTH_HASH_SHA384	= 0x02,
 	NVME_AUTH_HASH_SHA512	= 0x03,
 	NVME_AUTH_HASH_INVALID	= 0xff,
 };
 
+/* Maximum digest size for any NVME_AUTH_HASH_* value */
+enum {
+	NVME_AUTH_MAX_DIGEST_SIZE = 64,
+};
+
 /* Defined Diffie-Hellman group identifiers for DH-HMAC-CHAP authentication */
 enum {
 	NVME_AUTH_DHGROUP_NULL		= 0x00,
 	NVME_AUTH_DHGROUP_2048		= 0x01,
 	NVME_AUTH_DHGROUP_3072		= 0x02,
-- 
2.53.0