From 5c12a9cdb5ad54621f1b7c02df7993a4a1b86a46 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 24 Feb 2025 13:38:10 +0100 Subject: [PATCH] nvme: add nvme_auth_generate_psk() Add a function to generate a NVMe PSK from the shared credentials negotiated by DH-HMAC-CHAP. Signed-off-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Signed-off-by: Keith Busch --- drivers/nvme/common/auth.c | 87 ++++++++++++++++++++++++++++++++++++++ include/linux/nvme-auth.h | 3 ++ 2 files changed, 90 insertions(+) diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c index 9b7126e1a19d..76e4a12f005e 100644 --- a/drivers/nvme/common/auth.c +++ b/drivers/nvme/common/auth.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -471,5 +472,91 @@ 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 too 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); + MODULE_DESCRIPTION("NVMe Authentication framework"); MODULE_LICENSE("GPL v2"); diff --git a/include/linux/nvme-auth.h b/include/linux/nvme-auth.h index c1d0bc5d9624..b13884b04dfd 100644 --- a/include/linux/nvme-auth.h +++ b/include/linux/nvme-auth.h @@ -40,5 +40,8 @@ int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, int nvme_auth_gen_shared_secret(struct crypto_kpp *dh_tfm, u8 *ctrl_key, size_t ctrl_key_len, u8 *sess_key, size_t sess_key_len); +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); #endif /* _NVME_AUTH_H */ -- 2.50.1