[PATCH 01/16] nvme-keyring: restrict match length for version '1' identifiers

[Hannes Reinecke]

TP8018 changed the TLS PSK identifiers to append a PSK hash value,
so to lookup identifiers we should just consider the length of
the match value, not the length of the identifiers to compare
against.
And we should modify the PSK lookup algorithm to prefer v1 identifiers
as they can be uniquely identified.

Signed-off-by: Hannes Reinecke <hare at kernel.org>
---
 drivers/nvme/common/keyring.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c
index 6f7e7a8fa5ae..c60ebbdc52b8 100644
--- a/drivers/nvme/common/keyring.c
+++ b/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;
@@ -109,19 +107,38 @@ static struct key *nvme_tls_psk_lookup(struct key *keyring,
  *
  * 'Retained' PSKs (ie 'generated == false')
  * should be preferred to 'generated' PSKs,
+ * PSKs with hash (psk_ver 1) should be
+ * preferred to PSKs without (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 +154,11 @@ 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);
-- 
2.35.3