Commit b61775d1 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Jens Axboe

nvme-auth: Diffie-Hellman key exchange support

Implement Diffie-Hellman key exchange using FFDHE groups
for NVMe In-Band Authentication.
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 f50fff73
......@@ -295,6 +295,159 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, 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, 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;
......
......@@ -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.
......
......@@ -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 @@ 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_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 @@ 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;
}
......@@ -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 @@ static int nvme_auth_dhchap_setup_ctrl_response(struct nvme_ctrl *ctrl,
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);
......
......@@ -29,5 +29,13 @@ struct nvme_dhchap_key *nvme_auth_extract_key(unsigned char *secret,
void nvme_auth_free_key(struct nvme_dhchap_key *key);
u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn);
int nvme_auth_generate_key(u8 *secret, struct nvme_dhchap_key **ret_key);
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, u8 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 */
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