From cd18b086ddb1438cc47ef11410a0cddd7caa0938 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 27 Jun 2022 11:52:06 +0200 Subject: [PATCH] nvmet-auth: Diffie-Hellman key exchange support Implement Diffie-Hellman key exchange using FFDHE groups for NVMe In-Band Authentication. This patch adds a new host configfs attribute 'dhchap_dhgroup' to select the FFDHE group to use. Signed-off-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/nvme/target/Kconfig | 2 + drivers/nvme/target/auth.c | 157 +++++++++++++++++++++++++ drivers/nvme/target/configfs.c | 31 +++++ drivers/nvme/target/fabrics-cmd-auth.c | 41 +++++-- drivers/nvme/target/nvmet.h | 9 ++ 5 files changed, 232 insertions(+), 8 deletions(-) diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig index df526b59b509f..f0c91f7686a39 100644 --- a/drivers/nvme/target/Kconfig +++ b/drivers/nvme/target/Kconfig @@ -92,6 +92,8 @@ config NVME_TARGET_AUTH select CRYPTO_HMAC select CRYPTO_SHA256 select CRYPTO_SHA512 + select CRYPTO_DH + select CRYPTO_DH_GROUPS_RFC7919 help This enables support for NVMe over Fabrics In-band Authentication diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c index 5cdd23c341853..d5624bdf834b8 100644 --- a/drivers/nvme/target/auth.c +++ b/drivers/nvme/target/auth.c @@ -54,6 +54,74 @@ int nvmet_auth_set_key(struct nvmet_host *host, const char *secret, return 0; } +int nvmet_setup_dhgroup(struct nvmet_ctrl *ctrl, u8 dhgroup_id) +{ + const char *dhgroup_kpp; + int ret = 0; + + pr_debug("%s: ctrl %d selecting dhgroup %d\n", + __func__, ctrl->cntlid, dhgroup_id); + + if (ctrl->dh_tfm) { + if (ctrl->dh_gid == dhgroup_id) { + pr_debug("%s: ctrl %d reuse existing DH group %d\n", + __func__, ctrl->cntlid, dhgroup_id); + return 0; + } + crypto_free_kpp(ctrl->dh_tfm); + ctrl->dh_tfm = NULL; + ctrl->dh_gid = 0; + } + + if (dhgroup_id == NVME_AUTH_DHGROUP_NULL) + return 0; + + dhgroup_kpp = nvme_auth_dhgroup_kpp(dhgroup_id); + if (!dhgroup_kpp) { + pr_debug("%s: ctrl %d invalid DH group %d\n", + __func__, ctrl->cntlid, dhgroup_id); + return -EINVAL; + } + ctrl->dh_tfm = crypto_alloc_kpp(dhgroup_kpp, 0, 0); + if (IS_ERR(ctrl->dh_tfm)) { + pr_debug("%s: ctrl %d failed to setup DH group %d, err %ld\n", + __func__, ctrl->cntlid, dhgroup_id, + PTR_ERR(ctrl->dh_tfm)); + ret = PTR_ERR(ctrl->dh_tfm); + ctrl->dh_tfm = NULL; + ctrl->dh_gid = 0; + } else { + ctrl->dh_gid = dhgroup_id; + pr_debug("%s: ctrl %d setup DH group %d\n", + __func__, ctrl->cntlid, ctrl->dh_gid); + ret = nvme_auth_gen_privkey(ctrl->dh_tfm, ctrl->dh_gid); + if (ret < 0) { + pr_debug("%s: ctrl %d failed to generate private key, err %d\n", + __func__, ctrl->cntlid, ret); + kfree_sensitive(ctrl->dh_key); + return ret; + } + ctrl->dh_keysize = crypto_kpp_maxsize(ctrl->dh_tfm); + kfree_sensitive(ctrl->dh_key); + ctrl->dh_key = kzalloc(ctrl->dh_keysize, GFP_KERNEL); + if (!ctrl->dh_key) { + pr_warn("ctrl %d failed to allocate public key\n", + ctrl->cntlid); + return -ENOMEM; + } + ret = nvme_auth_gen_pubkey(ctrl->dh_tfm, ctrl->dh_key, + ctrl->dh_keysize); + if (ret < 0) { + pr_warn("ctrl %d failed to generate public key\n", + ctrl->cntlid); + kfree(ctrl->dh_key); + ctrl->dh_key = NULL; + } + } + + return ret; +} + int nvmet_setup_auth(struct nvmet_ctrl *ctrl) { int ret = 0; @@ -81,6 +149,10 @@ int nvmet_setup_auth(struct nvmet_ctrl *ctrl) goto out_unlock; } + ret = nvmet_setup_dhgroup(ctrl, host->dhchap_dhgroup_id); + if (ret < 0) + pr_warn("Failed to setup DH group"); + if (!host->dhchap_secret) { pr_debug("No authentication provided\n"); goto out_unlock; @@ -158,6 +230,14 @@ void nvmet_destroy_auth(struct nvmet_ctrl *ctrl) { ctrl->shash_id = 0; + if (ctrl->dh_tfm) { + crypto_free_kpp(ctrl->dh_tfm); + ctrl->dh_tfm = NULL; + ctrl->dh_gid = 0; + } + kfree_sensitive(ctrl->dh_key); + ctrl->dh_key = NULL; + if (ctrl->host_key) { nvme_auth_free_key(ctrl->host_key); ctrl->host_key = NULL; @@ -218,6 +298,21 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response, if (ret) goto out_free_response; + if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) { + challenge = kmalloc(shash_len, GFP_KERNEL); + if (!challenge) { + ret = -ENOMEM; + goto out_free_response; + } + ret = nvme_auth_augmented_challenge(ctrl->shash_id, + req->sq->dhchap_skey, + req->sq->dhchap_skey_len, + req->sq->dhchap_c1, + challenge, shash_len); + if (ret) + goto out_free_response; + } + pr_debug("ctrl %d qid %d host response seq %u transaction %d\n", ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1, req->sq->dhchap_tid); @@ -315,6 +410,21 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response, if (ret) goto out_free_response; + if (ctrl->dh_gid != NVME_AUTH_DHGROUP_NULL) { + challenge = kmalloc(shash_len, GFP_KERNEL); + if (!challenge) { + ret = -ENOMEM; + goto out_free_response; + } + ret = nvme_auth_augmented_challenge(ctrl->shash_id, + req->sq->dhchap_skey, + req->sq->dhchap_skey_len, + req->sq->dhchap_c2, + challenge, shash_len); + if (ret) + goto out_free_response; + } + shash = kzalloc(sizeof(*shash) + crypto_shash_descsize(shash_tfm), GFP_KERNEL); if (!shash) { @@ -365,3 +475,50 @@ out_free_tfm: crypto_free_shash(shash_tfm); return 0; } + +int nvmet_auth_ctrl_exponential(struct nvmet_req *req, + u8 *buf, int buf_size) +{ + struct nvmet_ctrl *ctrl = req->sq->ctrl; + int ret = 0; + + if (!ctrl->dh_key) { + pr_warn("ctrl %d no DH public key!\n", ctrl->cntlid); + return -ENOKEY; + } + if (buf_size != ctrl->dh_keysize) { + pr_warn("ctrl %d DH public key size mismatch, need %lu is %d\n", + ctrl->cntlid, ctrl->dh_keysize, buf_size); + ret = -EINVAL; + } else { + memcpy(buf, ctrl->dh_key, buf_size); + pr_debug("%s: ctrl %d public key %*ph\n", __func__, + ctrl->cntlid, (int)buf_size, buf); + } + + return ret; +} + +int nvmet_auth_ctrl_sesskey(struct nvmet_req *req, + u8 *pkey, int pkey_size) +{ + struct nvmet_ctrl *ctrl = req->sq->ctrl; + int ret; + + req->sq->dhchap_skey_len = ctrl->dh_keysize; + req->sq->dhchap_skey = kzalloc(req->sq->dhchap_skey_len, GFP_KERNEL); + if (!req->sq->dhchap_skey) + return -ENOMEM; + ret = nvme_auth_gen_shared_secret(ctrl->dh_tfm, + pkey, pkey_size, + req->sq->dhchap_skey, + req->sq->dhchap_skey_len); + if (ret) + pr_debug("failed to compute shared secred, err %d\n", ret); + else + pr_debug("%s: shared secret %*ph\n", __func__, + (int)req->sq->dhchap_skey_len, + req->sq->dhchap_skey); + + return ret; +} diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c index cf2f771e4314f..e826a22f5e07e 100644 --- a/drivers/nvme/target/configfs.c +++ b/drivers/nvme/target/configfs.c @@ -1766,10 +1766,41 @@ static ssize_t nvmet_host_dhchap_hash_store(struct config_item *item, CONFIGFS_ATTR(nvmet_host_, dhchap_hash); +static ssize_t nvmet_host_dhchap_dhgroup_show(struct config_item *item, + char *page) +{ + struct nvmet_host *host = to_host(item); + const char *dhgroup = nvme_auth_dhgroup_name(host->dhchap_dhgroup_id); + + return sprintf(page, "%s\n", dhgroup ? dhgroup : "none"); +} + +static ssize_t nvmet_host_dhchap_dhgroup_store(struct config_item *item, + const char *page, size_t count) +{ + struct nvmet_host *host = to_host(item); + int dhgroup_id; + + dhgroup_id = nvme_auth_dhgroup_id(page); + if (dhgroup_id == NVME_AUTH_DHGROUP_INVALID) + return -EINVAL; + if (dhgroup_id != NVME_AUTH_DHGROUP_NULL) { + const char *kpp = nvme_auth_dhgroup_kpp(dhgroup_id); + + if (!crypto_has_kpp(kpp, 0, 0)) + return -EINVAL; + } + host->dhchap_dhgroup_id = dhgroup_id; + return count; +} + +CONFIGFS_ATTR(nvmet_host_, dhchap_dhgroup); + static struct configfs_attribute *nvmet_host_attrs[] = { &nvmet_host_attr_dhchap_key, &nvmet_host_attr_dhchap_ctrl_key, &nvmet_host_attr_dhchap_hash, + &nvmet_host_attr_dhchap_dhgroup, NULL, }; #endif /* CONFIG_NVME_TARGET_AUTH */ diff --git a/drivers/nvme/target/fabrics-cmd-auth.c b/drivers/nvme/target/fabrics-cmd-auth.c index 776073a10e04e..5b1be7e607e2a 100644 --- a/drivers/nvme/target/fabrics-cmd-auth.c +++ b/drivers/nvme/target/fabrics-cmd-auth.c @@ -27,7 +27,7 @@ static u16 nvmet_auth_negotiate(struct nvmet_req *req, void *d) { struct nvmet_ctrl *ctrl = req->sq->ctrl; struct nvmf_auth_dhchap_negotiate_data *data = d; - int i, hash_id = 0, fallback_hash_id = 0, dhgid; + int i, hash_id = 0, fallback_hash_id = 0, dhgid, fallback_dhgid; pr_debug("%s: ctrl %d qid %d: data sc_d %d napd %d authid %d halen %d dhlen %d\n", __func__, ctrl->cntlid, req->sq->qid, @@ -69,22 +69,35 @@ static u16 nvmet_auth_negotiate(struct nvmet_req *req, void *d) } dhgid = -1; + fallback_dhgid = -1; for (i = 0; i < data->auth_protocol[0].dhchap.dhlen; i++) { int tmp_dhgid = data->auth_protocol[0].dhchap.idlist[i + 30]; - if (tmp_dhgid == NVME_AUTH_DHGROUP_NULL) { + if (tmp_dhgid != ctrl->dh_gid) { dhgid = tmp_dhgid; break; } + if (fallback_dhgid < 0) { + const char *kpp = nvme_auth_dhgroup_kpp(tmp_dhgid); + + if (crypto_has_kpp(kpp, 0, 0)) + fallback_dhgid = tmp_dhgid; + } } if (dhgid < 0) { - pr_debug("%s: ctrl %d qid %d: no usable DH group found\n", + if (fallback_dhgid < 0) { + pr_debug("%s: ctrl %d qid %d: no usable DH group found\n", __func__, ctrl->cntlid, req->sq->qid); - return NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; + return NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; + } + pr_debug("%s: ctrl %d qid %d: configured DH group %s not found\n", + __func__, ctrl->cntlid, req->sq->qid, + nvme_auth_dhgroup_name(fallback_dhgid)); + ctrl->dh_gid = fallback_dhgid; } pr_debug("%s: ctrl %d qid %d: selected DH group %s (%d)\n", __func__, ctrl->cntlid, req->sq->qid, - nvme_auth_dhgroup_name(dhgid), dhgid); + nvme_auth_dhgroup_name(ctrl->dh_gid), ctrl->dh_gid); return 0; } @@ -100,7 +113,11 @@ static u16 nvmet_auth_reply(struct nvmet_req *req, void *d) data->hl, data->cvalid, dhvlen); if (dhvlen) { - return NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; + if (!ctrl->dh_tfm) + return NVME_AUTH_DHCHAP_FAILURE_INCORRECT_PAYLOAD; + if (nvmet_auth_ctrl_sesskey(req, data->rval + 2 * data->hl, + dhvlen) < 0) + return NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE; } response = kmalloc(data->hl, GFP_KERNEL); @@ -332,6 +349,8 @@ static int nvmet_auth_challenge(struct nvmet_req *req, void *d, int al) int hash_len = nvme_auth_hmac_hash_len(ctrl->shash_id); int data_size = sizeof(*d) + hash_len; + if (ctrl->dh_tfm) + data_size += ctrl->dh_keysize; if (al < data_size) { pr_debug("%s: buffer too small (al %d need %d)\n", __func__, al, data_size); @@ -350,9 +369,15 @@ static int nvmet_auth_challenge(struct nvmet_req *req, void *d, int al) return -ENOMEM; get_random_bytes(req->sq->dhchap_c1, data->hl); memcpy(data->cval, req->sq->dhchap_c1, data->hl); - pr_debug("%s: ctrl %d qid %d seq %u transaction %d hl %d dhvlen %u\n", + if (ctrl->dh_tfm) { + data->dhgid = ctrl->dh_gid; + data->dhvlen = cpu_to_le16(ctrl->dh_keysize); + ret = nvmet_auth_ctrl_exponential(req, data->cval + data->hl, + ctrl->dh_keysize); + } + pr_debug("%s: ctrl %d qid %d seq %d transaction %d hl %d dhvlen %zu\n", __func__, ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1, - req->sq->dhchap_tid, data->hl, 0); + req->sq->dhchap_tid, data->hl, ctrl->dh_keysize); return ret; } diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h index 988551a3770f8..b76b2911234a8 100644 --- a/drivers/nvme/target/nvmet.h +++ b/drivers/nvme/target/nvmet.h @@ -225,6 +225,10 @@ struct nvmet_ctrl { struct nvme_dhchap_key *host_key; struct nvme_dhchap_key *ctrl_key; u8 shash_id; + struct crypto_kpp *dh_tfm; + u8 dh_gid; + u8 *dh_key; + size_t dh_keysize; #endif }; @@ -702,6 +706,7 @@ int nvmet_setup_auth(struct nvmet_ctrl *ctrl); void nvmet_init_auth(struct nvmet_ctrl *ctrl, struct nvmet_req *req); void nvmet_destroy_auth(struct nvmet_ctrl *ctrl); void nvmet_auth_sq_free(struct nvmet_sq *sq); +int nvmet_setup_dhgroup(struct nvmet_ctrl *ctrl, u8 dhgroup_id); bool nvmet_check_auth_status(struct nvmet_req *req); int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response, unsigned int hash_len); @@ -711,6 +716,10 @@ static inline bool nvmet_has_auth(struct nvmet_ctrl *ctrl) { return ctrl->host_key != NULL; } +int nvmet_auth_ctrl_exponential(struct nvmet_req *req, + u8 *buf, int buf_size); +int nvmet_auth_ctrl_sesskey(struct nvmet_req *req, + u8 *buf, int buf_size); #else static inline int nvmet_setup_auth(struct nvmet_ctrl *ctrl) { -- 2.39.5