Implement Diffie-Hellman key exchange using FFDHE groups for NVMe In-Band Authentication. Signed-off-by: Hannes Reinecke <hare@xxxxxxx> --- drivers/nvme/host/Kconfig | 1 + drivers/nvme/host/auth.c | 412 +++++++++++++++++++++++++++++++++++++- drivers/nvme/host/auth.h | 8 + 3 files changed, 415 insertions(+), 6 deletions(-) diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig index 49269c581ec4..0fab5684feca 100644 --- a/drivers/nvme/host/Kconfig +++ b/drivers/nvme/host/Kconfig @@ -90,6 +90,7 @@ config NVME_AUTH select CRYPTO_HMAC select CRYPTO_SHA256 select CRYPTO_SHA512 + select CRYPTO_FFDHE help This provides support for NVMe over Fabrics In-Band Authentication. diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c index 6ab95a178213..f0b5f3044647 100644 --- a/drivers/nvme/host/auth.c +++ b/drivers/nvme/host/auth.c @@ -20,6 +20,7 @@ struct nvme_dhchap_queue_context { struct work_struct auth_work; struct nvme_ctrl *ctrl; struct crypto_shash *shash_tfm; + struct crypto_kpp *dh_tfm; void *buf; size_t buf_size; int qid; @@ -35,6 +36,12 @@ struct nvme_dhchap_queue_context { u8 c2[64]; u8 response[64]; u8 *host_response; + u8 *ctrl_key; + int ctrl_key_len; + u8 *host_key; + int host_key_len; + u8 *sess_key; + int sess_key_len; }; static struct nvme_auth_dhgroup_map { @@ -310,6 +317,218 @@ u8 *nvme_auth_transform_key(u8 *key, size_t key_len, u8 key_hash, char *nqn) } EXPORT_SYMBOL_GPL(nvme_auth_transform_key); +static int nvme_auth_hash_skey(int hmac_id, u8 *skey, size_t skey_len, u8 *hkey) +{ + const char *digest_name; + struct crypto_shash *tfm; + int ret; + + digest_name = nvme_auth_digest_name(hmac_id); + if (!digest_name) { + pr_debug("%s: failed to get digest for %d\n", __func__, + hmac_id); + return -EINVAL; + } + tfm = crypto_alloc_shash(digest_name, 0, 0); + if (IS_ERR(tfm)) + return -ENOMEM; + + ret = crypto_shash_tfm_digest(tfm, skey, skey_len, hkey); + if (ret < 0) + pr_debug("%s: Failed to hash digest len %zu\n", __func__, + skey_len); + + crypto_free_shash(tfm); + return ret; +} + +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; + + hashed_key = kmalloc(hlen, GFP_KERNEL); + if (!hashed_key) + return -ENOMEM; + + ret = nvme_auth_hash_skey(hmac_id, skey, + skey_len, hashed_key); + if (ret < 0) + goto out_free_key; + + hmac_name = nvme_auth_hmac_name(hmac_id); + if (!hmac_name) { + pr_warn("%s: invalid hash algoritm %d\n", + __func__, hmac_id); + ret = -EINVAL; + goto out_free_key; + } + + tfm = crypto_alloc_shash(hmac_name, 0, 0); + if (IS_ERR(tfm)) { + ret = PTR_ERR(tfm); + 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; + + ret = crypto_shash_final(desc, aug); +out_free_desc: + kfree_sensitive(desc); +out_free_hash: + crypto_free_shash(tfm); +out_free_key: + kfree_sensitive(hashed_key); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_augmented_challenge); + +int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, int dh_gid) +{ + char *pkey; + int ret, pkey_len; + + if (dh_gid == NVME_AUTH_DHCHAP_DHGROUP_2048 || + dh_gid == NVME_AUTH_DHCHAP_DHGROUP_3072 || + dh_gid == NVME_AUTH_DHCHAP_DHGROUP_4096 || + dh_gid == NVME_AUTH_DHCHAP_DHGROUP_6144 || + dh_gid == NVME_AUTH_DHCHAP_DHGROUP_8192) { + struct dh p = {0}; + int bits = nvme_auth_dhgroup_pubkey_size(dh_gid) << 3; + int dh_secret_len = 64; + u8 *dh_secret = kzalloc(dh_secret_len, GFP_KERNEL); + + if (!dh_secret) + return -ENOMEM; + + /* + * NVMe base spec v2.0: The DH value shall be set to the value + * of g^x mod p, where 'x' is a random number selected by the + * host that shall be at least 256 bits long. + * + * We will be using a 512 bit random number as private key. + * This is large enough to provide adequate security, but + * small enough such that we can trivially conform to + * NIST SB800-56A section 5.6.1.1.4 if + * we guarantee that the random number is not either + * all 0xff or all 0x00. But that should be guaranteed + * by the in-kernel RNG anyway. + */ + get_random_bytes(dh_secret, dh_secret_len); + + ret = crypto_ffdhe_params(&p, bits); + if (ret) { + kfree_sensitive(dh_secret); + return ret; + } + + p.key = dh_secret; + p.key_size = dh_secret_len; + + pkey_len = crypto_dh_key_len(&p); + pkey = kmalloc(pkey_len, GFP_KERNEL); + if (!pkey) { + kfree_sensitive(dh_secret); + return -ENOMEM; + } + + get_random_bytes(pkey, pkey_len); + ret = crypto_dh_encode_key(pkey, pkey_len, &p); + if (ret) { + pr_debug("failed to encode private key, error %d\n", + ret); + kfree_sensitive(dh_secret); + goto out; + } + } else { + pr_warn("invalid dh group %d\n", dh_gid); + return -EINVAL; + } + ret = crypto_kpp_set_secret(dh_tfm, pkey, pkey_len); + if (ret) + pr_debug("failed to set private key, error %d\n", ret); +out: + kfree_sensitive(pkey); + pkey = NULL; + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_privkey); + +int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, + u8 *host_key, size_t host_key_len) +{ + struct kpp_request *req; + struct crypto_wait wait; + struct scatterlist dst; + int ret; + + req = kpp_request_alloc(dh_tfm, GFP_KERNEL); + if (!req) + return -ENOMEM; + + crypto_init_wait(&wait); + kpp_request_set_input(req, NULL, 0); + sg_init_one(&dst, host_key, host_key_len); + kpp_request_set_output(req, &dst, host_key_len); + kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_req_done, &wait); + + ret = crypto_wait_req(crypto_kpp_generate_public_key(req), &wait); + kpp_request_free(req); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_pubkey); + +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) +{ + struct kpp_request *req; + struct crypto_wait wait; + struct scatterlist src, dst; + int ret; + + req = kpp_request_alloc(dh_tfm, GFP_KERNEL); + if (!req) + return -ENOMEM; + + crypto_init_wait(&wait); + sg_init_one(&src, ctrl_key, ctrl_key_len); + kpp_request_set_input(req, &src, ctrl_key_len); + sg_init_one(&dst, sess_key, sess_key_len); + kpp_request_set_output(req, &dst, sess_key_len); + kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_req_done, &wait); + + ret = crypto_wait_req(crypto_kpp_compute_shared_secret(req), &wait); + + kpp_request_free(req); + return ret; +} +EXPORT_SYMBOL_GPL(nvme_auth_gen_shared_secret); + static int nvme_auth_send(struct nvme_ctrl *ctrl, int qid, void *data, size_t tl) { @@ -436,6 +655,7 @@ static int nvme_auth_process_dhchap_challenge(struct nvme_ctrl *ctrl, struct nvmf_auth_dhchap_challenge_data *data = chap->buf; u16 dhvlen = le16_to_cpu(data->dhvlen); size_t size = sizeof(*data) + data->hl + dhvlen; + const char *gid_name = nvme_auth_dhgroup_name(data->dhgid); const char *hmac_name, *kpp_name; if (chap->buf_size < size) { @@ -506,15 +726,54 @@ static int nvme_auth_process_dhchap_challenge(struct nvme_ctrl *ctrl, "qid %d: invalid DH group id %d\n", chap->qid, data->dhgid); chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; + /* Leave previous dh_tfm intact */ return NVME_SC_AUTH_REQUIRED; } + /* Clear host and controller key to avoid accidental reuse */ + kfree_sensitive(chap->host_key); + chap->host_key = NULL; + chap->host_key_len = 0; + kfree_sensitive(chap->ctrl_key); + chap->ctrl_key = NULL; + chap->ctrl_key_len = 0; + + if (chap->dhgroup_id == data->dhgid && + (data->dhgid == NVME_AUTH_DHCHAP_DHGROUP_NULL || chap->dh_tfm)) { + dev_dbg(ctrl->device, + "qid %d: reuse existing DH group %s\n", + chap->qid, gid_name); + goto skip_kpp; + } + + /* Reset dh_tfm if it can't be reused */ + if (chap->dh_tfm) { + crypto_free_kpp(chap->dh_tfm); + chap->dh_tfm = NULL; + } + if (data->dhgid != NVME_AUTH_DHCHAP_DHGROUP_NULL) { - dev_warn(ctrl->device, - "qid %d: unsupported DH group %s\n", - chap->qid, kpp_name); - chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; - return NVME_SC_AUTH_REQUIRED; + if (dhvlen == 0) { + dev_warn(ctrl->device, + "qid %d: empty DH value\n", + chap->qid); + chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; + return NVME_SC_INVALID_FIELD; + } + + chap->dh_tfm = crypto_alloc_kpp(kpp_name, 0, 0); + if (IS_ERR(chap->dh_tfm)) { + int ret = PTR_ERR(chap->dh_tfm); + + dev_warn(ctrl->device, + "qid %d: error %d initializing DH group %s\n", + chap->qid, ret, gid_name); + chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; + chap->dh_tfm = NULL; + return NVME_SC_AUTH_REQUIRED; + } + dev_dbg(ctrl->device, "qid %d: selected DH group %s\n", + chap->qid, gid_name); } else if (dhvlen != 0) { dev_warn(ctrl->device, "qid %d: invalid DH value for NULL DH\n", @@ -524,8 +783,21 @@ static int nvme_auth_process_dhchap_challenge(struct nvme_ctrl *ctrl, } chap->dhgroup_id = data->dhgid; +skip_kpp: chap->s1 = le32_to_cpu(data->seqnum); memcpy(chap->c1, data->cval, chap->hash_len); + if (dhvlen) { + chap->ctrl_key = kmalloc(dhvlen, GFP_KERNEL); + if (!chap->ctrl_key) { + chap->status = NVME_AUTH_DHCHAP_FAILURE_FAILED; + return NVME_SC_AUTH_REQUIRED; + } + chap->ctrl_key_len = dhvlen; + memcpy(chap->ctrl_key, data->cval + chap->hash_len, + dhvlen); + dev_dbg(ctrl->device, "ctrl public key %*ph\n", + (int)chap->ctrl_key_len, chap->ctrl_key); + } return 0; } @@ -538,6 +810,9 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl, size += 2 * chap->hash_len; + if (chap->host_key_len) + size += chap->host_key_len; + if (chap->buf_size < size) { chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; return -EINVAL; @@ -548,7 +823,7 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl, data->auth_id = NVME_AUTH_DHCHAP_MESSAGE_REPLY; data->t_id = cpu_to_le16(chap->transaction); data->hl = chap->hash_len; - data->dhvlen = 0; + data->dhvlen = cpu_to_le16(chap->host_key_len); memcpy(data->rval, chap->response, chap->hash_len); if (ctrl->opts->dhchap_ctrl_secret) { get_random_bytes(chap->c2, chap->hash_len); @@ -564,6 +839,14 @@ static int nvme_auth_set_dhchap_reply_data(struct nvme_ctrl *ctrl, chap->s2 = 0; } data->seqnum = cpu_to_le32(chap->s2); + if (chap->host_key_len) { + dev_dbg(ctrl->device, "%s: qid %d host public key %*ph\n", + __func__, chap->qid, + chap->host_key_len, chap->host_key); + memcpy(data->rval + 2 * chap->hash_len, chap->host_key, + chap->host_key_len); + } + return size; } @@ -682,6 +965,21 @@ static int nvme_auth_dhchap_host_response(struct nvme_ctrl *ctrl, goto out; } + if (chap->dh_tfm) { + challenge = kmalloc(chap->hash_len, GFP_KERNEL); + if (!challenge) { + ret = -ENOMEM; + goto out; + } + ret = nvme_auth_augmented_challenge(chap->hash_id, + chap->sess_key, + chap->sess_key_len, + chap->c1, challenge, + chap->hash_len); + if (ret) + goto out; + } + shash->tfm = chap->shash_tfm; ret = crypto_shash_init(shash); if (ret) @@ -746,6 +1044,20 @@ static int nvme_auth_dhchap_ctrl_response(struct nvme_ctrl *ctrl, goto out; } + if (chap->dh_tfm) { + challenge = kmalloc(chap->hash_len, GFP_KERNEL); + if (!challenge) { + ret = -ENOMEM; + goto out; + } + ret = nvme_auth_augmented_challenge(chap->hash_id, + chap->sess_key, + chap->sess_key_len, + chap->c2, challenge, + chap->hash_len); + if (ret) + goto out; + } dev_dbg(ctrl->device, "%s: qid %d host response seq %d transaction %d\n", __func__, chap->qid, chap->s2, chap->transaction); dev_dbg(ctrl->device, "%s: qid %d challenge %*ph\n", @@ -852,8 +1164,82 @@ int nvme_auth_generate_ctrl_key(struct nvme_ctrl *ctrl) } EXPORT_SYMBOL_GPL(nvme_auth_generate_ctrl_key); +static int nvme_auth_dhchap_exponential(struct nvme_ctrl *ctrl, + struct nvme_dhchap_queue_context *chap) +{ + int ret; + + if (chap->host_key && chap->host_key_len) { + dev_dbg(ctrl->device, + "qid %d: reusing host key\n", chap->qid); + goto gen_sesskey; + } + ret = nvme_auth_gen_privkey(chap->dh_tfm, chap->dhgroup_id); + if (ret < 0) { + chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; + return ret; + } + + chap->host_key_len = + nvme_auth_dhgroup_pubkey_size(chap->dhgroup_id); + + chap->host_key = kzalloc(chap->host_key_len, GFP_KERNEL); + if (!chap->host_key) { + chap->host_key_len = 0; + chap->status = NVME_AUTH_DHCHAP_FAILURE_FAILED; + return -ENOMEM; + } + ret = nvme_auth_gen_pubkey(chap->dh_tfm, + chap->host_key, chap->host_key_len); + if (ret) { + dev_dbg(ctrl->device, + "failed to generate public key, error %d\n", ret); + kfree(chap->host_key); + chap->host_key = NULL; + chap->host_key_len = 0; + chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; + return ret; + } + +gen_sesskey: + chap->sess_key_len = chap->host_key_len; + chap->sess_key = kmalloc(chap->sess_key_len, GFP_KERNEL); + if (!chap->sess_key) { + chap->sess_key_len = 0; + chap->status = NVME_AUTH_DHCHAP_FAILURE_FAILED; + return -ENOMEM; + } + + ret = nvme_auth_gen_shared_secret(chap->dh_tfm, + chap->ctrl_key, chap->ctrl_key_len, + chap->sess_key, chap->sess_key_len); + if (ret) { + dev_dbg(ctrl->device, + "failed to generate shared secret, error %d\n", ret); + kfree_sensitive(chap->sess_key); + chap->sess_key = NULL; + chap->sess_key_len = 0; + chap->status = NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; + return ret; + } + dev_dbg(ctrl->device, "shared secret %*ph\n", + (int)chap->sess_key_len, chap->sess_key); + return 0; +} + static void __nvme_auth_reset(struct nvme_dhchap_queue_context *chap) { + kfree_sensitive(chap->host_response); + chap->host_response = NULL; + kfree_sensitive(chap->host_key); + chap->host_key = NULL; + chap->host_key_len = 0; + kfree_sensitive(chap->ctrl_key); + chap->ctrl_key = NULL; + chap->ctrl_key_len = 0; + kfree_sensitive(chap->sess_key); + chap->sess_key = NULL; + chap->sess_key_len = 0; chap->status = 0; chap->error = 0; chap->s1 = 0; @@ -867,6 +1253,11 @@ static void __nvme_auth_free(struct nvme_dhchap_queue_context *chap) { if (chap->shash_tfm) crypto_free_shash(chap->shash_tfm); + if (chap->dh_tfm) + crypto_free_kpp(chap->dh_tfm); + kfree_sensitive(chap->ctrl_key); + kfree_sensitive(chap->host_key); + kfree_sensitive(chap->sess_key); kfree_sensitive(chap->host_response); kfree(chap->buf); kfree(chap); @@ -924,6 +1315,15 @@ static void __nvme_auth_work(struct work_struct *work) goto fail2; } + if (chap->ctrl_key_len) { + dev_dbg(ctrl->device, + "%s: qid %d DH exponential\n", + __func__, chap->qid); + ret = nvme_auth_dhchap_exponential(ctrl, chap); + if (ret) + goto fail2; + } + dev_dbg(ctrl->device, "%s: qid %d host response\n", __func__, chap->qid); ret = nvme_auth_dhchap_host_response(ctrl, chap); diff --git a/drivers/nvme/host/auth.h b/drivers/nvme/host/auth.h index 216957848398..b45bf565720a 100644 --- a/drivers/nvme/host/auth.h +++ b/drivers/nvme/host/auth.h @@ -21,5 +21,13 @@ int nvme_auth_hmac_id(const char *hmac_name); unsigned char *nvme_auth_extract_secret(unsigned char *secret, u8 key_hash, size_t *key_len); u8 *nvme_auth_transform_key(u8 *key, size_t key_len, u8 key_hash, char *nqn); +int nvme_auth_augmented_challenge(u8 hmac_id, u8 *skey, size_t skey_len, + u8 *challenge, u8 *aug, size_t hlen); +int nvme_auth_gen_privkey(struct crypto_kpp *dh_tfm, int dh_gid); +int nvme_auth_gen_pubkey(struct crypto_kpp *dh_tfm, + u8 *host_key, size_t host_key_len); +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); #endif /* _NVME_AUTH_H */ -- 2.29.2