4 files changed, 732 insertions, 68 deletions

diff --git a/drivers/nvme/common/Kconfig b/drivers/nvme/common/Kconfig
index 4514f44362dd..da963e4f3f1f 100644
--- a/drivers/nvme/common/Kconfig
+++ b/drivers/nvme/common/Kconfig
@@ -1,4 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-config NVME_COMMON
+config NVME_KEYRING
        tristate
+       select KEYS
+
+config NVME_AUTH
+	tristate
+	select CRYPTO
+	select CRYPTO_HMAC
+	select CRYPTO_SHA256
+	select CRYPTO_SHA512
+	select CRYPTO_DH
+	select CRYPTO_DH_RFC7919_GROUPS
+	select CRYPTO_HKDF
diff --git a/drivers/nvme/common/Makefile b/drivers/nvme/common/Makefile
index 720c625b8a52..681514cf2e2f 100644
--- a/drivers/nvme/common/Makefile
+++ b/drivers/nvme/common/Makefile
@@ -2,6 +2,8 @@
 
 ccflags-y			+= -I$(src)
 
-obj-$(CONFIG_NVME_COMMON)	+= nvme-common.o
+obj-$(CONFIG_NVME_AUTH)		+= nvme-auth.o
+obj-$(CONFIG_NVME_KEYRING)	+= nvme-keyring.o
 
-nvme-common-y			+= auth.o
+nvme-auth-y			+= auth.o
+nvme-keyring-y			+= keyring.o
diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
index d90e4f0c08b7..e07e7d4bf8b6 100644
--- a/drivers/nvme/common/auth.c
+++ b/drivers/nvme/common/auth.c
@@ -8,12 +8,15 @@
 #include <linux/base64.h>
 #include <linux/prandom.h>
 #include <linux/scatterlist.h>
-#include <asm/unaligned.h>
+#include <linux/unaligned.h>
 #include <crypto/hash.h>
 #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);
 
@@ -150,6 +153,14 @@ 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)
 {
@@ -163,16 +174,11 @@ 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);
+	key_len = base64_decode(secret, allocated_len, key->key, true, BASE64_STD);
 	if (key_len < 0) {
 		pr_debug("base64 key decoding error %d\n",
 			 key_len);
@@ -187,14 +193,6 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
 		goto out_free_secret;
 	}
 
-	if (key_hash > 0 &&
-	    (key_len - 4) != nvme_auth_hmac_hash_len(key_hash)) {
-		pr_err("Mismatched key len %d for %s\n", key_len,
-		       nvme_auth_hmac_name(key_hash));
-		ret = -EINVAL;
-		goto out_free_secret;
-	}
-
 	/* The last four bytes is the CRC in little-endian format */
 	key_len -= 4;
 	/*
@@ -213,37 +211,51 @@ 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);
 
-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;
+	SHASH_DESC_ON_STACK(shash, key_tfm);
+	struct nvme_dhchap_key *transformed_key;
+	int ret, key_len;
 
-	if (!key || !key->key) {
+	if (!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) {
@@ -253,20 +265,13 @@ 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;
-
-	shash = kmalloc(sizeof(struct shash_desc) +
-			crypto_shash_descsize(key_tfm),
-			GFP_KERNEL);
-	if (!shash) {
-		ret = -ENOMEM;
-		goto out_free_key;
-	}
+		return ERR_CAST(key_tfm);
 
-	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;
+		goto out_free_key;
 	}
 
 	shash->tfm = key_tfm;
@@ -282,19 +287,16 @@ 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;
 
-	kfree(shash);
 	crypto_free_shash(key_tfm);
 
 	return transformed_key;
 
 out_free_transformed_key:
-	kfree_sensitive(transformed_key);
-out_free_shash:
-	kfree(shash);
+	nvme_auth_free_key(transformed_key);
 out_free_key:
 	crypto_free_shash(key_tfm);
 
@@ -331,7 +333,6 @@ int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
 		u8 *challenge, u8 *aug, size_t hlen)
 {
 	struct crypto_shash *tfm;
-	struct shash_desc *desc;
 	u8 *hashed_key;
 	const char *hmac_name;
 	int ret;
@@ -359,29 +360,11 @@ int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len,
 		goto out_free_key;
 	}
 
-	desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
-		       GFP_KERNEL);
-	if (!desc) {
-		ret = -ENOMEM;
-		goto out_free_hash;
-	}
-	desc->tfm = tfm;
-
 	ret = crypto_shash_setkey(tfm, hashed_key, hlen);
 	if (ret)
-		goto out_free_desc;
-
-	ret = crypto_shash_init(desc);
-	if (ret)
-		goto out_free_desc;
-
-	ret = crypto_shash_update(desc, challenge, hlen);
-	if (ret)
-		goto out_free_desc;
+		goto out_free_hash;
 
-	ret = crypto_shash_final(desc, aug);
-out_free_desc:
-	kfree_sensitive(desc);
+	ret = crypto_shash_tfm_digest(tfm, challenge, hlen, aug);
 out_free_hash:
 	crypto_free_shash(tfm);
 out_free_key:
@@ -480,4 +463,385 @@ int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key)
 }
 EXPORT_SYMBOL_GPL(nvme_auth_generate_key);
 
+/**
+ * nvme_auth_generate_psk - Generate a PSK for TLS
+ * @hmac_id: Hash function identifier
+ * @skey: Session key
+ * @skey_len: Length of @skey
+ * @c1: Value of challenge C1
+ * @c2: Value of challenge C2
+ * @hash_len: Hash length of the hash algorithm
+ * @ret_psk: Pointer to the resulting generated PSK
+ * @ret_len: length of @ret_psk
+ *
+ * Generate a PSK for TLS as specified in NVMe base specification, section
+ * 8.13.5.9: Generated PSK for TLS
+ *
+ * The generated PSK for TLS shall be computed applying the HMAC function
+ * using the hash function H( ) selected by the HashID parameter in the
+ * DH-HMAC-CHAP_Challenge message with the session key KS as key to the
+ * concatenation of the two challenges C1 and C2 (i.e., generated
+ * PSK = HMAC(KS, C1 || C2)).
+ *
+ * Returns 0 on success with a valid generated PSK pointer in @ret_psk and
+ * the length of @ret_psk in @ret_len, or a negative error number otherwise.
+ */
+int nvme_auth_generate_psk(u8 hmac_id, u8 *skey, size_t skey_len,
+		u8 *c1, u8 *c2, size_t hash_len, u8 **ret_psk, size_t *ret_len)
+{
+	struct crypto_shash *tfm;
+	SHASH_DESC_ON_STACK(shash, tfm);
+	u8 *psk;
+	const char *hmac_name;
+	int ret, psk_len;
+
+	if (!c1 || !c2)
+		return -EINVAL;
+
+	hmac_name = nvme_auth_hmac_name(hmac_id);
+	if (!hmac_name) {
+		pr_warn("%s: invalid hash algorithm %d\n",
+			__func__, hmac_id);
+		return -EINVAL;
+	}
+
+	tfm = crypto_alloc_shash(hmac_name, 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	psk_len = crypto_shash_digestsize(tfm);
+	psk = kzalloc(psk_len, GFP_KERNEL);
+	if (!psk) {
+		ret = -ENOMEM;
+		goto out_free_tfm;
+	}
+
+	shash->tfm = tfm;
+	ret = crypto_shash_setkey(tfm, skey, skey_len);
+	if (ret)
+		goto out_free_psk;
+
+	ret = crypto_shash_init(shash);
+	if (ret)
+		goto out_free_psk;
+
+	ret = crypto_shash_update(shash, c1, hash_len);
+	if (ret)
+		goto out_free_psk;
+
+	ret = crypto_shash_update(shash, c2, hash_len);
+	if (ret)
+		goto out_free_psk;
+
+	ret = crypto_shash_final(shash, psk);
+	if (!ret) {
+		*ret_psk = psk;
+		*ret_len = psk_len;
+	}
+
+out_free_psk:
+	if (ret)
+		kfree_sensitive(psk);
+out_free_tfm:
+	crypto_free_shash(tfm);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_generate_psk);
+
+/**
+ * nvme_auth_generate_digest - Generate TLS PSK digest
+ * @hmac_id: Hash function identifier
+ * @psk: Generated input PSK
+ * @psk_len: Length of @psk
+ * @subsysnqn: NQN of the subsystem
+ * @hostnqn: NQN of the host
+ * @ret_digest: Pointer to the returned digest
+ *
+ * Generate a TLS PSK digest as specified in TP8018 Section 3.6.1.3:
+ *   TLS PSK and PSK identity Derivation
+ *
+ * The PSK digest shall be computed by encoding in Base64 (refer to RFC
+ * 4648) the result of the application of the HMAC function using the hash
+ * function specified in item 4 above (ie the hash function of the cipher
+ * suite associated with the PSK identity) with the PSK as HMAC key to the
+ * concatenation of:
+ * - the NQN of the host (i.e., NQNh) not including the null terminator;
+ * - a space character;
+ * - the NQN of the NVM subsystem (i.e., NQNc) not including the null
+ *   terminator;
+ * - a space character; and
+ * - the seventeen ASCII characters "NVMe-over-Fabrics"
+ * (i.e., <PSK digest> = Base64(HMAC(PSK, NQNh || " " || NQNc || " " ||
+ *  "NVMe-over-Fabrics"))).
+ * The length of the PSK digest depends on the hash function used to compute
+ * it as follows:
+ * - If the SHA-256 hash function is used, the resulting PSK digest is 44
+ *   characters long; or
+ * - If the SHA-384 hash function is used, the resulting PSK digest is 64
+ *   characters long.
+ *
+ * Returns 0 on success with a valid digest pointer in @ret_digest, or a
+ * negative error number on failure.
+ */
+int nvme_auth_generate_digest(u8 hmac_id, u8 *psk, size_t psk_len,
+		char *subsysnqn, char *hostnqn, u8 **ret_digest)
+{
+	struct crypto_shash *tfm;
+	SHASH_DESC_ON_STACK(shash, tfm);
+	u8 *digest, *enc;
+	const char *hmac_name;
+	size_t digest_len, hmac_len;
+	int ret;
+
+	if (WARN_ON(!subsysnqn || !hostnqn))
+		return -EINVAL;
+
+	hmac_name = nvme_auth_hmac_name(hmac_id);
+	if (!hmac_name) {
+		pr_warn("%s: invalid hash algorithm %d\n",
+			__func__, hmac_id);
+		return -EINVAL;
+	}
+
+	switch (nvme_auth_hmac_hash_len(hmac_id)) {
+	case 32:
+		hmac_len = 44;
+		break;
+	case 48:
+		hmac_len = 64;
+		break;
+	default:
+		pr_warn("%s: invalid hash algorithm '%s'\n",
+			__func__, hmac_name);
+		return -EINVAL;
+	}
+
+	enc = kzalloc(hmac_len + 1, GFP_KERNEL);
+	if (!enc)
+		return -ENOMEM;
+
+	tfm = crypto_alloc_shash(hmac_name, 0, 0);
+	if (IS_ERR(tfm)) {
+		ret = PTR_ERR(tfm);
+		goto out_free_enc;
+	}
+
+	digest_len = crypto_shash_digestsize(tfm);
+	digest = kzalloc(digest_len, GFP_KERNEL);
+	if (!digest) {
+		ret = -ENOMEM;
+		goto out_free_tfm;
+	}
+
+	shash->tfm = tfm;
+	ret = crypto_shash_setkey(tfm, psk, psk_len);
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_init(shash);
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_update(shash, hostnqn, strlen(hostnqn));
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_update(shash, " ", 1);
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_update(shash, subsysnqn, strlen(subsysnqn));
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_update(shash, " NVMe-over-Fabrics", 18);
+	if (ret)
+		goto out_free_digest;
+
+	ret = crypto_shash_final(shash, digest);
+	if (ret)
+		goto out_free_digest;
+
+	ret = base64_encode(digest, digest_len, enc, true, BASE64_STD);
+	if (ret < hmac_len) {
+		ret = -ENOKEY;
+		goto out_free_digest;
+	}
+	*ret_digest = enc;
+	ret = 0;
+
+out_free_digest:
+	kfree_sensitive(digest);
+out_free_tfm:
+	crypto_free_shash(tfm);
+out_free_enc:
+	if (ret)
+		kfree_sensitive(enc);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_generate_digest);
+
+/**
+ * hkdf_expand_label - HKDF-Expand-Label (RFC 8846 section 7.1)
+ * @hmac_tfm: hash context keyed with pseudorandom key
+ * @label: ASCII label without "tls13 " prefix
+ * @labellen: length of @label
+ * @context: context bytes
+ * @contextlen: length of @context
+ * @okm: output keying material
+ * @okmlen: length of @okm
+ *
+ * Build the TLS 1.3 HkdfLabel structure and invoke hkdf_expand().
+ *
+ * Returns 0 on success with output keying material stored in @okm,
+ * or a negative errno value otherwise.
+ */
+static int hkdf_expand_label(struct crypto_shash *hmac_tfm,
+		const u8 *label, unsigned int labellen,
+		const u8 *context, unsigned int contextlen,
+		u8 *okm, unsigned int okmlen)
+{
+	int err;
+	u8 *info;
+	unsigned int infolen;
+	const char *tls13_prefix = "tls13 ";
+	unsigned int prefixlen = strlen(tls13_prefix);
+
+	if (WARN_ON(labellen > (255 - prefixlen)))
+		return -EINVAL;
+	if (WARN_ON(contextlen > 255))
+		return -EINVAL;
+
+	infolen = 2 + (1 + prefixlen + labellen) + (1 + contextlen);
+	info = kzalloc(infolen, GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	/* HkdfLabel.Length */
+	put_unaligned_be16(okmlen, info);
+
+	/* HkdfLabel.Label */
+	info[2] = prefixlen + labellen;
+	memcpy(info + 3, tls13_prefix, prefixlen);
+	memcpy(info + 3 + prefixlen, label, labellen);
+
+	/* HkdfLabel.Context */
+	info[3 + prefixlen + labellen] = contextlen;
+	memcpy(info + 4 + prefixlen + labellen, context, contextlen);
+
+	err = hkdf_expand(hmac_tfm, info, infolen, okm, okmlen);
+	kfree_sensitive(info);
+	return err;
+}
+
+/**
+ * nvme_auth_derive_tls_psk - Derive TLS PSK
+ * @hmac_id: Hash function identifier
+ * @psk: generated input PSK
+ * @psk_len: size of @psk
+ * @psk_digest: TLS PSK digest
+ * @ret_psk: Pointer to the resulting TLS PSK
+ *
+ * Derive a TLS PSK as specified in TP8018 Section 3.6.1.3:
+ *   TLS PSK and PSK identity Derivation
+ *
+ * The TLS PSK shall be derived as follows from an input PSK
+ * (i.e., either a retained PSK or a generated PSK) and a PSK
+ * identity using the HKDF-Extract and HKDF-Expand-Label operations
+ * (refer to RFC 5869 and RFC 8446) where the hash function is the
+ * one specified by the hash specifier of the PSK identity:
+ * 1. PRK = HKDF-Extract(0, Input PSK); and
+ * 2. TLS PSK = HKDF-Expand-Label(PRK, "nvme-tls-psk", PskIdentityContext, L),
+ * where PskIdentityContext is the hash identifier indicated in
+ * the PSK identity concatenated to a space character and to the
+ * Base64 PSK digest (i.e., "<hash> <PSK digest>") and L is the
+ * output size in bytes of the hash function (i.e., 32 for SHA-256
+ * and 48 for SHA-384).
+ *
+ * Returns 0 on success with a valid psk pointer in @ret_psk or a negative
+ * error number otherwise.
+ */
+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];
+	size_t prk_len;
+	const char *ctx;
+	unsigned char *prk, *tls_key;
+	int ret;
+
+	hmac_name = nvme_auth_hmac_name(hmac_id);
+	if (!hmac_name) {
+		pr_warn("%s: invalid hash algorithm %d\n",
+			__func__, hmac_id);
+		return -EINVAL;
+	}
+	if (hmac_id == NVME_AUTH_HASH_SHA512) {
+		pr_warn("%s: unsupported hash algorithm %s\n",
+			__func__, hmac_name);
+		return -EINVAL;
+	}
+
+	hmac_tfm = crypto_alloc_shash(hmac_name, 0, 0);
+	if (IS_ERR(hmac_tfm))
+		return PTR_ERR(hmac_tfm);
+
+	prk_len = crypto_shash_digestsize(hmac_tfm);
+	prk = kzalloc(prk_len, GFP_KERNEL);
+	if (!prk) {
+		ret = -ENOMEM;
+		goto out_free_shash;
+	}
+
+	if (WARN_ON(prk_len > HKDF_MAX_HASHLEN)) {
+		ret = -EINVAL;
+		goto out_free_prk;
+	}
+	ret = hkdf_extract(hmac_tfm, psk, psk_len,
+			   default_salt, prk_len, prk);
+	if (ret)
+		goto out_free_prk;
+
+	ret = crypto_shash_setkey(hmac_tfm, prk, prk_len);
+	if (ret)
+		goto out_free_prk;
+
+	ctx = kasprintf(GFP_KERNEL, "%02d %s", hmac_id, psk_digest);
+	if (!ctx) {
+		ret = -ENOMEM;
+		goto out_free_prk;
+	}
+
+	tls_key = kzalloc(psk_len, GFP_KERNEL);
+	if (!tls_key) {
+		ret = -ENOMEM;
+		goto out_free_ctx;
+	}
+	ret = hkdf_expand_label(hmac_tfm,
+				label, strlen(label),
+				ctx, strlen(ctx),
+				tls_key, psk_len);
+	if (ret) {
+		kfree(tls_key);
+		goto out_free_ctx;
+	}
+	*ret_psk = tls_key;
+
+out_free_ctx:
+	kfree(ctx);
+out_free_prk:
+	kfree(prk);
+out_free_shash:
+	crypto_free_shash(hmac_tfm);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nvme_auth_derive_tls_psk);
+
+MODULE_DESCRIPTION("NVMe Authentication framework");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/nvme/common/keyring.c b/drivers/nvme/common/keyring.c
new file mode 100644
index 000000000000..32d16c53133b
--- /dev/null
+++ b/drivers/nvme/common/keyring.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Hannes Reinecke, SUSE Labs
+ */
+
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/key-type.h>
+#include <keys/user-type.h>
+#include <linux/nvme.h>
+#include <linux/nvme-tcp.h>
+#include <linux/nvme-keyring.h>
+
+static struct key *nvme_keyring;
+
+key_serial_t nvme_keyring_id(void)
+{
+	return nvme_keyring->serial;
+}
+EXPORT_SYMBOL_GPL(nvme_keyring_id);
+
+static bool nvme_tls_psk_revoked(struct key *psk)
+{
+	return test_bit(KEY_FLAG_REVOKED, &psk->flags) ||
+		test_bit(KEY_FLAG_INVALIDATED, &psk->flags);
+}
+
+struct key *nvme_tls_key_lookup(key_serial_t key_id)
+{
+	struct key *key = key_lookup(key_id);
+
+	if (IS_ERR(key)) {
+		pr_err("key id %08x not found\n", key_id);
+		return key;
+	}
+	if (nvme_tls_psk_revoked(key)) {
+		pr_err("key id %08x revoked\n", key_id);
+		return ERR_PTR(-EKEYREVOKED);
+	}
+	return key;
+}
+EXPORT_SYMBOL_GPL(nvme_tls_key_lookup);
+
+static void nvme_tls_psk_describe(const struct key *key, struct seq_file *m)
+{
+	seq_puts(m, key->description);
+	seq_printf(m, ": %u", key->datalen);
+}
+
+static bool nvme_tls_psk_match(const struct key *key,
+			       const struct key_match_data *match_data)
+{
+	const char *match_id;
+	size_t match_len;
+
+	if (!key->description) {
+		pr_debug("%s: no key description\n", __func__);
+		return false;
+	}
+	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);
+}
+
+static int nvme_tls_psk_match_preparse(struct key_match_data *match_data)
+{
+	match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
+	match_data->cmp = nvme_tls_psk_match;
+	return 0;
+}
+
+static struct key_type nvme_tls_psk_key_type = {
+	.name           = "psk",
+	.flags          = KEY_TYPE_NET_DOMAIN,
+	.preparse       = user_preparse,
+	.free_preparse  = user_free_preparse,
+	.match_preparse = nvme_tls_psk_match_preparse,
+	.instantiate    = generic_key_instantiate,
+	.revoke         = user_revoke,
+	.destroy        = user_destroy,
+	.describe       = nvme_tls_psk_describe,
+	.read           = user_read,
+};
+
+static struct key *nvme_tls_psk_lookup(struct key *keyring,
+		const char *hostnqn, const char *subnqn,
+		u8 hmac, u8 psk_ver, bool generated)
+{
+	char *identity;
+	size_t identity_len = (NVMF_NQN_SIZE) * 2 + 11;
+	key_ref_t keyref;
+	key_serial_t keyring_id;
+
+	identity = kzalloc(identity_len, GFP_KERNEL);
+	if (!identity)
+		return ERR_PTR(-ENOMEM);
+
+	snprintf(identity, identity_len, "NVMe%u%c%02u %s %s",
+		 psk_ver, generated ? 'G' : 'R', hmac, hostnqn, subnqn);
+
+	if (!keyring)
+		keyring = nvme_keyring;
+	keyring_id = key_serial(keyring);
+	pr_debug("keyring %x lookup tls psk '%s'\n",
+		 keyring_id, identity);
+	keyref = keyring_search(make_key_ref(keyring, true),
+				&nvme_tls_psk_key_type,
+				identity, false);
+	if (IS_ERR(keyref)) {
+		pr_debug("lookup tls psk '%s' failed, error %ld\n",
+			 identity, PTR_ERR(keyref));
+		kfree(identity);
+		return ERR_PTR(-ENOKEY);
+	}
+	kfree(identity);
+
+	return key_ref_to_ptr(keyref);
+}
+
+/**
+ * nvme_tls_psk_refresh - Refresh TLS PSK
+ * @keyring: Keyring holding the TLS PSK
+ * @hostnqn: Host NQN to use
+ * @subnqn: Subsystem NQN to use
+ * @hmac_id: Hash function identifier
+ * @data: TLS PSK key material
+ * @data_len: Length of @data
+ * @digest: TLS PSK digest
+ *
+ * Refresh a generated version 1 TLS PSK with the identity generated
+ * from @hmac_id, @hostnqn, @subnqn, and @digest in the keyring given
+ * by @keyring.
+ *
+ * Returns the updated key success or an error pointer otherwise.
+ */
+struct key *nvme_tls_psk_refresh(struct key *keyring,
+		const char *hostnqn, const char *subnqn, u8 hmac_id,
+		u8 *data, size_t data_len, const char *digest)
+{
+	key_perm_t keyperm =
+		KEY_POS_SEARCH | KEY_POS_VIEW | KEY_POS_READ |
+		KEY_POS_WRITE | KEY_POS_LINK | KEY_POS_SETATTR |
+		KEY_USR_SEARCH | KEY_USR_VIEW | KEY_USR_READ;
+	char *identity;
+	key_ref_t keyref;
+	key_serial_t keyring_id;
+	struct key *key;
+
+	if (!hostnqn || !subnqn || !data || !data_len)
+		return ERR_PTR(-EINVAL);
+
+	identity = kasprintf(GFP_KERNEL, "NVMe1G%02d %s %s %s",
+		 hmac_id, hostnqn, subnqn, digest);
+	if (!identity)
+		return ERR_PTR(-ENOMEM);
+
+	if (!keyring)
+		keyring = nvme_keyring;
+	keyring_id = key_serial(keyring);
+	pr_debug("keyring %x refresh tls psk '%s'\n",
+		 keyring_id, identity);
+	keyref = key_create_or_update(make_key_ref(keyring, true),
+				"psk", identity, data, data_len,
+				keyperm, KEY_ALLOC_NOT_IN_QUOTA |
+				      KEY_ALLOC_BUILT_IN |
+				      KEY_ALLOC_BYPASS_RESTRICTION);
+	if (IS_ERR(keyref)) {
+		pr_debug("refresh tls psk '%s' failed, error %ld\n",
+			 identity, PTR_ERR(keyref));
+		kfree(identity);
+		return ERR_PTR(-ENOKEY);
+	}
+	kfree(identity);
+	/*
+	 * Set the default timeout to 1 hour
+	 * as suggested in TP8018.
+	 */
+	key = key_ref_to_ptr(keyref);
+	key_set_timeout(key, 3600);
+	return key;
+}
+EXPORT_SYMBOL_GPL(nvme_tls_psk_refresh);
+
+/*
+ * NVMe PSK priority list
+ *
+ * '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, },
+};
+
+/*
+ * nvme_tls_psk_default - Return the preferred PSK to use for TLS ClientHello
+ */
+key_serial_t nvme_tls_psk_default(struct key *keyring,
+		      const char *hostnqn, const char *subnqn)
+{
+	struct key *tls_key;
+	key_serial_t tls_key_id;
+	int prio;
+
+	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, ver, generated);
+		if (!IS_ERR(tls_key)) {
+			tls_key_id = tls_key->serial;
+			key_put(tls_key);
+			return tls_key_id;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvme_tls_psk_default);
+
+static int __init nvme_keyring_init(void)
+{
+	int err;
+
+	nvme_keyring = keyring_alloc(".nvme",
+				     GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
+				     current_cred(),
+				     (KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				     (KEY_USR_ALL & ~KEY_USR_SETATTR),
+				     KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
+	if (IS_ERR(nvme_keyring))
+		return PTR_ERR(nvme_keyring);
+
+	err = register_key_type(&nvme_tls_psk_key_type);
+	if (err) {
+		key_put(nvme_keyring);
+		return err;
+	}
+	return 0;
+}
+
+static void __exit nvme_keyring_exit(void)
+{
+	unregister_key_type(&nvme_tls_psk_key_type);
+	key_revoke(nvme_keyring);
+	key_put(nvme_keyring);
+}
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
+MODULE_DESCRIPTION("NVMe Keyring implementation");
+module_init(nvme_keyring_init);
+module_exit(nvme_keyring_exit);