From b61775d185a395f26fecdc7898e39de677a6c3dd Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 27 Jun 2022 11:52:03 +0200 Subject: nvme-auth: Diffie-Hellman key exchange support Implement Diffie-Hellman key exchange using FFDHE groups for NVMe In-Band Authentication. Signed-off-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/common/auth.c | 153 ++++++++++++++++++++++++++++++++++ drivers/nvme/host/Kconfig | 2 + drivers/nvme/host/auth.c | 201 +++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 350 insertions(+), 6 deletions(-) (limited to 'drivers/nvme') diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c index adb43d341ffb..94cc7cafbb9d 100644 --- a/drivers/nvme/common/auth.c +++ b/drivers/nvme/common/auth.c @@ -295,6 +295,159 @@ out_free_key: } 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, u8 dh_gid) +{ + int ret; + + ret = crypto_kpp_set_secret(dh_tfm, NULL, 0); + if (ret) + pr_debug("failed to set private key, error %d\n", ret); + + 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); + int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key) { struct nvme_dhchap_key *key; diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig index 6c503f42f3c6..2f6a7f8c94e8 100644 --- a/drivers/nvme/host/Kconfig +++ b/drivers/nvme/host/Kconfig @@ -100,6 +100,8 @@ config NVME_AUTH select CRYPTO_HMAC select CRYPTO_SHA256 select CRYPTO_SHA512 + select CRYPTO_DH + select CRYPTO_DH_RFC7919_GROUPS 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 9766bfffecac..c8a6db7c4498 100644 --- a/drivers/nvme/host/auth.c +++ b/drivers/nvme/host/auth.c @@ -18,6 +18,7 @@ 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; @@ -33,6 +34,12 @@ 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; }; #define nvme_auth_flags_from_qid(qid) \ @@ -137,6 +144,7 @@ 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) { @@ -207,15 +215,54 @@ select_kpp: "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_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_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", @@ -225,8 +272,21 @@ select_kpp: } 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; } @@ -239,6 +299,9 @@ 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; @@ -249,7 +312,7 @@ 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->ctrl_key) { get_random_bytes(chap->c2, chap->hash_len); @@ -264,6 +327,14 @@ 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; } @@ -381,6 +452,21 @@ static int nvme_auth_dhchap_setup_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) @@ -443,6 +529,20 @@ static int nvme_auth_dhchap_setup_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 ctrl response seq %u transaction %d\n", __func__, chap->qid, chap->s2, chap->transaction); dev_dbg(ctrl->device, "%s: qid %d challenge %*ph\n", @@ -492,8 +592,81 @@ out: return ret; } +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 = crypto_kpp_maxsize(chap->dh_tfm); + + 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; @@ -508,6 +681,11 @@ static void __nvme_auth_free(struct nvme_dhchap_queue_context *chap) __nvme_auth_reset(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); @@ -566,6 +744,17 @@ 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) { + chap->error = ret; + goto fail2; + } + } + dev_dbg(ctrl->device, "%s: qid %d host response\n", __func__, chap->qid); ret = nvme_auth_dhchap_setup_host_response(ctrl, chap); -- cgit v1.2.3