Implement support for augmented challenge with FFDHE groups.
This patch adds a new configfs attribute 'dhchap_dhgroup' to
select the DH group to use.
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/nvme/target/auth.c | 241 ++++++++++++++++++++++++-
drivers/nvme/target/configfs.c | 31 ++++
drivers/nvme/target/fabrics-cmd-auth.c | 14 +-
3 files changed, 281 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/target/auth.c b/drivers/nvme/target/auth.c
index 00c7d051dfb1..cc7f12a7c8bf 100644
--- a/drivers/nvme/target/auth.c
+++ b/drivers/nvme/target/auth.c
@@ -58,11 +58,56 @@ int nvmet_auth_set_host_key(struct nvmet_host *host, const char *secret)
int nvmet_setup_dhgroup(struct nvmet_ctrl *ctrl, int dhgroup_id)
{
+ struct nvmet_host_link *p;
+ struct nvmet_host *host = NULL;
+ const char *dhgroup_kpp;
int ret = -ENOTSUPP;
if (dhgroup_id == NVME_AUTH_DHCHAP_DHGROUP_NULL)
return 0;
+ down_read(&nvmet_config_sem);
+ if (ctrl->subsys->type == NVME_NQN_DISC)
+ goto out_unlock;
+
+ list_for_each_entry(p, &ctrl->subsys->hosts, entry) {
+ if (strcmp(nvmet_host_name(p->host), ctrl->hostnqn))
+ continue;
+ host = p->host;
+ break;
+ }
+ if (!host) {
+ pr_debug("host %s not found\n", ctrl->hostnqn);
+ ret = -ENXIO;
+ goto out_unlock;
+ }
+
+ if (host->dhchap_dhgroup_id != dhgroup_id) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ dhgroup_kpp = nvme_auth_dhgroup_kpp(dhgroup_id);
+ if (!dhgroup_kpp) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+ ctrl->dh_tfm = crypto_alloc_kpp(dhgroup_kpp, 0, 0);
+ if (IS_ERR(ctrl->dh_tfm)) {
+ pr_debug("failed to setup DH group %d, err %ld\n",
+ dhgroup_id, PTR_ERR(ctrl->dh_tfm));
+ ret = PTR_ERR(ctrl->dh_tfm);
+ ctrl->dh_tfm = NULL;
+ } else {
+ ctrl->dh_gid = dhgroup_id;
+ ctrl->dh_keysize = nvme_auth_dhgroup_pubkey_size(dhgroup_id);
+ pr_debug("select DH group %d keysize %d\n",
+ ctrl->dh_gid, ctrl->dh_keysize);
+ ret = 0;
+ }
+
+out_unlock:
+ up_read(&nvmet_config_sem);
+
return ret;
}
@@ -192,6 +237,101 @@ bool nvmet_check_auth_status(struct nvmet_req *req)
return true;
}
+static int nvmet_auth_hash_sesskey(struct nvmet_req *req, u8 *hashed_key)
+{
+ struct nvmet_ctrl *ctrl = req->sq->ctrl;
+ const char *hmac_name, *digest_name;
+ struct crypto_shash *tfm;
+ int hmac_id, ret;
+
+ if (!ctrl->shash_tfm) {
+ pr_debug("%s: hash alg not set\n", __func__);
+ return -EINVAL;
+ }
+ hmac_name = crypto_shash_alg_name(ctrl->shash_tfm);
+ hmac_id = nvme_auth_hmac_id(hmac_name);
+ if (hmac_id < 0) {
+ pr_debug("%s: unsupported hmac %s\n", __func__,
+ hmac_name);
+ return -EINVAL;
+ }
+ digest_name = nvme_auth_digest_name(hmac_id);
+ if (!digest_name) {
+ pr_debug("%s: failed to get digest for %s\n", __func__,
+ hmac_name);
+ return -EINVAL;
+ }
+ tfm = crypto_alloc_shash(digest_name, 0, 0);
+ if (IS_ERR(tfm))
+ return -ENOMEM;
+
+ ret = crypto_shash_tfm_digest(tfm, req->sq->dhchap_skey,
+ req->sq->dhchap_skey_len, hashed_key);
+ if (ret < 0)
+ pr_debug("%s: Failed to hash digest len %d\n", __func__,
+ req->sq->dhchap_skey_len);
+
+ crypto_free_shash(tfm);
+ return ret;
+}
+
+static int nvmet_auth_augmented_challenge(struct nvmet_req *req,
+ u8 *challenge, u8 *aug)
+{
+ struct nvmet_ctrl *ctrl = req->sq->ctrl;
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ u8 *hashed_key;
+ const char *hash_name;
+ int hash_len = req->sq->dhchap_hash_len;
+ int ret;
+
+ hashed_key = kmalloc(hash_len, GFP_KERNEL);
+ if (!hashed_key)
+ return -ENOMEM;
+
+ ret = nvmet_auth_hash_sesskey(req, hashed_key);
+ if (ret < 0) {
+ pr_debug("failed to hash session key, err %d\n", ret);
+ kfree(hashed_key);
+ return ret;
+ }
+ hash_name = crypto_shash_alg_name(ctrl->shash_tfm);
+ if (!hash_name) {
+ pr_debug("Invalid hash algoritm\n");
+ return -EINVAL;
+ }
+ tfm = crypto_alloc_shash(hash_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, hash_len);
+ if (ret)
+ goto out_free_desc;
+ ret = crypto_shash_init(desc);
+ if (ret)
+ goto out_free_desc;
+ crypto_shash_update(desc, challenge, hash_len);
+ crypto_shash_final(desc, aug);
+
+out_free_desc:
+ kfree_sensitive(desc);
+out_free_hash:
+ crypto_free_shash(tfm);
+out_free_key:
+ kfree(hashed_key);
+ return ret;
+}
+
int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
unsigned int shash_len)
{
@@ -202,8 +342,15 @@ int nvmet_auth_host_hash(struct nvmet_req *req, u8 *response,
int ret;
if (ctrl->dh_gid != NVME_AUTH_DHCHAP_DHGROUP_NULL) {
- ret = -ENOTSUPP;
- goto out;
+ challenge = kmalloc(shash_len, GFP_KERNEL);
+ if (!challenge) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = nvmet_auth_augmented_challenge(req, req->sq->dhchap_c1,
+ challenge);
+ if (ret)
+ goto out;
}
shash->tfm = ctrl->shash_tfm;
@@ -264,8 +411,15 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
ctrl->cntlid, ctrl->hostnqn);
if (ctrl->dh_gid != NVME_AUTH_DHCHAP_DHGROUP_NULL) {
- ret = -ENOTSUPP;
- goto out;
+ challenge = kmalloc(shash_len, GFP_KERNEL);
+ if (!challenge) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = nvmet_auth_augmented_challenge(req, req->sq->dhchap_c2,
+ challenge);
+ if (ret)
+ goto out;
}
shash->tfm = ctrl->shash_tfm;
@@ -307,6 +461,85 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
return 0;
}
+int nvmet_auth_ctrl_exponential(struct nvmet_req *req,
+ u8 *buf, int buf_size)
+{
+ struct nvmet_ctrl *ctrl = req->sq->ctrl;
+ struct kpp_request *kpp_req;
+ struct crypto_wait wait;
+ char *pkey;
+ struct scatterlist dst;
+ int ret, pkey_len;
+
+ if (ctrl->dh_gid == NVME_AUTH_DHCHAP_DHGROUP_2048 ||
+ ctrl->dh_gid == NVME_AUTH_DHCHAP_DHGROUP_3072 ||
+ ctrl->dh_gid == NVME_AUTH_DHCHAP_DHGROUP_4096 ||
+ ctrl->dh_gid == NVME_AUTH_DHCHAP_DHGROUP_6144 ||
+ ctrl->dh_gid == NVME_AUTH_DHCHAP_DHGROUP_8192) {
+ struct dh p = {0};
+ int bits = nvme_auth_dhgroup_pubkey_size(ctrl->dh_gid) << 3;
+
+ ret = crypto_ffdhe_params(&p, bits);
+ if (ret)
+ return ret;
+
+ p.key = ctrl->dhchap_key;
+ p.key_size = ctrl->dhchap_key_len;
+
+ pkey_len = crypto_dh_key_len(&p);
+ pkey = kmalloc(pkey_len, GFP_KERNEL);
+ if (!pkey)
+ 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);
+ goto out;
+ }
+ } else {
+ pr_warn("invalid dh group %d\n", ctrl->dh_gid);
+ return -EINVAL;
+ }
+ ret = crypto_kpp_set_secret(ctrl->dh_tfm, pkey, pkey_len);
+ if (ret) {
+ pr_debug("failed to set private key, error %d\n", ret);
+ goto out;
+ }
+
+ kpp_req = kpp_request_alloc(ctrl->dh_tfm, GFP_KERNEL);
+ if (!kpp_req) {
+ pr_debug("cannot allocate kpp request\n");
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ crypto_init_wait(&wait);
+ kpp_request_set_input(kpp_req, NULL, 0);
+ sg_init_one(&dst, buf, buf_size);
+ kpp_request_set_output(kpp_req, &dst, buf_size);
+ kpp_request_set_callback(kpp_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &wait);
+
+ ret = crypto_wait_req(crypto_kpp_generate_public_key(kpp_req), &wait);
+ kpp_request_free(kpp_req);
+ if (ret == -EOVERFLOW) {
+ pr_debug("public key buffer too small, need %d is %d\n",
+ crypto_kpp_maxsize(ctrl->dh_tfm), buf_size);
+ ret = -ENOKEY;
+ } else if (ret) {
+ pr_debug("failed to generate public key, err %d\n", ret);
+ ret = -ENOKEY;
+ } else
+ pr_debug("%s: ctrl public key %*ph\n", __func__,
+ (int)buf_size, buf);
+
+out:
+ kfree_sensitive(pkey);
+ return ret;
+}
+
int nvmet_auth_ctrl_sesskey(struct nvmet_req *req,
u8 *pkey, int pkey_size)
{
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index e0760911a761..e9b8884a83b0 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -1712,9 +1712,40 @@ 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 < 0)
+ return -EINVAL;
+ if (dhgroup_id != NVME_AUTH_DHCHAP_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_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 962f9f5e9d89..478ac351c645 100644
--- a/drivers/nvme/target/fabrics-cmd-auth.c
+++ b/drivers/nvme/target/fabrics-cmd-auth.c
@@ -98,7 +98,11 @@ static u16 nvmet_auth_reply(struct nvmet_req *req, void *d)
return NVME_AUTH_DHCHAP_FAILURE_INVALID_PAYLOAD;
if (data->dhvlen) {
- return NVME_AUTH_DHCHAP_FAILURE_INVALID_PAYLOAD;
+ if (!ctrl->dh_tfm)
+ return NVME_AUTH_DHCHAP_FAILURE_INVALID_PAYLOAD;
+ if (nvmet_auth_ctrl_sesskey(req, data->rval + 2 * data->hl,
+ data->dhvlen) < 0)
+ return NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
}
response = kmalloc(data->hl, GFP_KERNEL);
@@ -299,6 +303,8 @@ static int nvmet_auth_challenge(struct nvmet_req *req, void *d, int al)
int ret = 0;
int data_size = sizeof(*d) + req->sq->dhchap_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);
@@ -317,6 +323,12 @@ 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);
+ if (ctrl->dh_tfm) {
+ data->dhgid = ctrl->dh_gid;
+ data->dhvlen = ctrl->dh_keysize;
+ ret = nvmet_auth_ctrl_exponential(req, data->cval + data->hl,
+ data->dhvlen);
+ }
pr_debug("%s: ctrl %d qid %d seq %d transaction %d hl %d dhvlen %d\n",
__func__, ctrl->cntlid, req->sq->qid, req->sq->dhchap_s1,
req->sq->dhchap_tid, data->hl, data->dhvlen);
--
2.29.2
