Commit 7a277c37 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Jens Axboe

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: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent db1312dd
......@@ -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
......
......@@ -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 @@ int nvmet_auth_ctrl_hash(struct nvmet_req *req, u8 *response,
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;
}
......@@ -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 */
......
......@@ -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;
}
......
......@@ -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)
{
......
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