nvme-keyring: restrict match length for version '1' identifiers

TP8018 introduced a new TLS PSK identifier version (version 1), which appended
a PSK hash value to the existing identifier (cf NVMe TCP specification v1.1,
section 3.6.1.3 'TLS PSK and PSK Identity Derivation').
An original (version 0) identifier has the form:

NVMe0<type><hmac> <hostnqn> <subsysnqn>

and a version 1 identifier has the form:

NVMe1<type><hmac> <hostnqn> <subsysnqn> <hash>

This patch modifies the lookup algorthm to compare only the first part
of the identifier (excluding the hash value) to handle both version 0 and
version 1 identifiers.
And the spec declares 'version 0' identifiers obsolete, so the lookup
algorithm is modified to prever v1 identifiers.
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/common/keyring.c

@@ -36,14 +36,12 @@ static bool nvme_tls_psk_match(const struct key *key,
 		pr_debug("%s: no key description\n", __func__);
 		return false;
 	}
-	match_len = strlen(key->description);
-	pr_debug("%s: id %s len %zd\n", __func__, key->description, match_len);
-
 	if (!match_data->raw_data) {
 		pr_debug("%s: no match data\n", __func__);
 		return false;
 	}
 	match_id = match_data->raw_data;
+	match_len = strlen(match_id);
 	pr_debug("%s: match '%s' '%s' len %zd\n",
 		 __func__, match_id, key->description, match_len);
 	return !memcmp(key->description, match_id, match_len);
@@ -71,7 +69,7 @@ static struct key_type nvme_tls_psk_key_type = {
 
 static struct key *nvme_tls_psk_lookup(struct key *keyring,
 		const char *hostnqn, const char *subnqn,
-		int hmac, bool generated)
+		u8 hmac, u8 psk_ver, bool generated)
 {
 	char *identity;
 	size_t identity_len = (NVMF_NQN_SIZE) * 2 + 11;
@@ -82,8 +80,8 @@ static struct key *nvme_tls_psk_lookup(struct key *keyring,
 	if (!identity)
 		return ERR_PTR(-ENOMEM);
 
-	snprintf(identity, identity_len, "NVMe0%c%02d %s %s",
-		 generated ? 'G' : 'R', hmac, hostnqn, subnqn);
+	snprintf(identity, identity_len, "NVMe%u%c%02u %s %s",
+		 psk_ver, generated ? 'G' : 'R', hmac, hostnqn, subnqn);
 
 	if (!keyring)
 		keyring = nvme_keyring;
@@ -107,21 +105,38 @@ static struct key *nvme_tls_psk_lookup(struct key *keyring,
 /*
  * NVMe PSK priority list
  *
- * 'Retained' PSKs (ie 'generated == false')
- * should be preferred to 'generated' PSKs,
- * and SHA-384 should be preferred to SHA-256.
+ * 'Retained' PSKs (ie 'generated == false') should be preferred to 'generated'
+ * PSKs, PSKs with hash (psk_ver 1) should be preferred to PSKs without hash
+ * (psk_ver 0), and SHA-384 should be preferred to SHA-256.
  */
 static struct nvme_tls_psk_priority_list {
 	bool generated;
+	u8 psk_ver;
 	enum nvme_tcp_tls_cipher cipher;
 } nvme_tls_psk_prio[] = {
 	{ .generated = false,
+	  .psk_ver = 1,
+	  .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
+	{ .generated = false,
+	  .psk_ver = 1,
+	  .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
+	{ .generated = false,
+	  .psk_ver = 0,
 	  .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
 	{ .generated = false,
+	  .psk_ver = 0,
+	  .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
+	{ .generated = true,
+	  .psk_ver = 1,
+	  .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
+	{ .generated = true,
+	  .psk_ver = 1,
 	  .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
 	{ .generated = true,
+	  .psk_ver = 0,
 	  .cipher = NVME_TCP_TLS_CIPHER_SHA384, },
 	{ .generated = true,
+	  .psk_ver = 0,
 	  .cipher = NVME_TCP_TLS_CIPHER_SHA256, },
 };
 
@@ -137,10 +152,11 @@ key_serial_t nvme_tls_psk_default(struct key *keyring,
 
 	for (prio = 0; prio < ARRAY_SIZE(nvme_tls_psk_prio); prio++) {
 		bool generated = nvme_tls_psk_prio[prio].generated;
+		u8 ver = nvme_tls_psk_prio[prio].psk_ver;
 		enum nvme_tcp_tls_cipher cipher = nvme_tls_psk_prio[prio].cipher;
 
 		tls_key = nvme_tls_psk_lookup(keyring, hostnqn, subnqn,
-					      cipher, generated);
+					      cipher, ver, generated);
 		if (!IS_ERR(tls_key)) {
 			tls_key_id = tls_key->serial;
 			key_put(tls_key);