Re: [PATCH 07/11] nvme-auth: augmented challenge support

["Stephan Müller" <smueller@chronox.de>]

Am Sonntag, 18. Juli 2021, 14:27:48 CEST schrieb Hannes Reinecke:

Hi Hannes,

> On 7/17/21 6:49 PM, Stephan Müller wrote:
> > Am Freitag, 16. Juli 2021, 13:04:24 CEST schrieb Hannes Reinecke:
> > 
> > Hi Hannes,
> > 
> >> Implement support for augmented challenge using FFDHE groups.
> >> 
> >> Signed-off-by: Hannes Reinecke <hare@suse.de>
> >> ---
> >> 
> >>   drivers/nvme/host/auth.c | 403 +++++++++++++++++++++++++++++++++++----
> >>   1 file changed, 371 insertions(+), 32 deletions(-)
> >> 
> >> diff --git a/drivers/nvme/host/auth.c b/drivers/nvme/host/auth.c
> >> index 448a3adebea6..754343aced19 100644
> >> --- a/drivers/nvme/host/auth.c
> >> +++ b/drivers/nvme/host/auth.c
> >> @@ -8,6 +8,8 @@
> >> 
> >>   #include <asm/unaligned.h>
> >>   #include <crypto/hash.h>
> >>   #include <crypto/kpp.h>
> >> 
> >> +#include <crypto/dh.h>
> >> +#include <crypto/ffdhe.h>
> >> 
> >>   #include "nvme.h"
> >>   #include "fabrics.h"
> >>   #include "auth.h"
> >> 
> >> @@ -16,6 +18,8 @@ static u32 nvme_dhchap_seqnum;
> >> 
> >>   struct nvme_dhchap_context {
> >>   
> >>   	struct crypto_shash *shash_tfm;
> >> 
> >> +	struct crypto_shash *digest_tfm;
> >> +	struct crypto_kpp *dh_tfm;
> >> 
> >>   	unsigned char *key;
> >>   	size_t key_len;
> >>   	int qid;
> >> 
> >> @@ -25,6 +29,8 @@ struct nvme_dhchap_context {
> >> 
> >>   	u8 status;
> >>   	u8 hash_id;
> >>   	u8 hash_len;
> >> 
> >> +	u8 dhgroup_id;
> >> +	u16 dhgroup_size;
> >> 
> >>   	u8 c1[64];
> >>   	u8 c2[64];
> >>   	u8 response[64];
> >> 
> >> @@ -36,6 +42,94 @@ struct nvme_dhchap_context {
> >> 
> >>   	int sess_key_len;
> >>   
> >>   };
> >> 
> >> +struct nvme_auth_dhgroup_map {
> >> +	int id;
> >> +	const char name[16];
> >> +	const char kpp[16];
> >> +	int privkey_size;
> >> +	int pubkey_size;
> >> +} dhgroup_map[] = {
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_NULL,
> >> +	  .name = "NULL", .kpp = "NULL",
> >> +	  .privkey_size = 0, .pubkey_size = 0 },
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_2048,
> >> +	  .name = "ffdhe2048", .kpp = "dh",
> >> +	  .privkey_size = 256, .pubkey_size = 256 },
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_3072,
> >> +	  .name = "ffdhe3072", .kpp = "dh",
> >> +	  .privkey_size = 384, .pubkey_size = 384 },
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_4096,
> >> +	  .name = "ffdhe4096", .kpp = "dh",
> >> +	  .privkey_size = 512, .pubkey_size = 512 },
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_6144,
> >> +	  .name = "ffdhe6144", .kpp = "dh",
> >> +	  .privkey_size = 768, .pubkey_size = 768 },
> >> +	{ .id = NVME_AUTH_DHCHAP_DHGROUP_8192,
> >> +	  .name = "ffdhe8192", .kpp = "dh",
> >> +	  .privkey_size = 1024, .pubkey_size = 1024 },
> >> +};
> >> +
> >> +const char *nvme_auth_dhgroup_name(int dhgroup_id)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
> >> +		if (dhgroup_map[i].id == dhgroup_id)
> >> +			return dhgroup_map[i].name;
> >> +	}
> >> +	return NULL;
> >> +}
> >> +EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_name);
> >> +
> >> +int nvme_auth_dhgroup_pubkey_size(int dhgroup_id)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
> >> +		if (dhgroup_map[i].id == dhgroup_id)
> >> +			return dhgroup_map[i].pubkey_size;
> >> +	}
> >> +	return -1;
> >> +}
> >> +EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_pubkey_size);
> >> +
> >> +int nvme_auth_dhgroup_privkey_size(int dhgroup_id)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
> >> +		if (dhgroup_map[i].id == dhgroup_id)
> >> +			return dhgroup_map[i].privkey_size;
> >> +	}
> >> +	return -1;
> >> +}
> >> +EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_privkey_size);
> >> +
> >> +const char *nvme_auth_dhgroup_kpp(int dhgroup_id)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
> >> +		if (dhgroup_map[i].id == dhgroup_id)
> >> +			return dhgroup_map[i].kpp;
> >> +	}
> >> +	return NULL;
> >> +}
> >> +EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_kpp);
> >> +
> >> +int nvme_auth_dhgroup_id(const char *dhgroup_name)
> >> +{
> >> +	int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dhgroup_map); i++) {
> >> +		if (!strncmp(dhgroup_map[i].name, dhgroup_name,
> >> +			     strlen(dhgroup_map[i].name)))
> >> +			return dhgroup_map[i].id;
> >> +	}
> >> +	return -1;
> >> +}
> >> +EXPORT_SYMBOL_GPL(nvme_auth_dhgroup_id);
> >> +
> >> 
> >>   struct nvmet_dhchap_hash_map {
> >>   
> >>   	int id;
> >>   	int hash_len;
> >> 
> >> @@ -243,11 +337,16 @@ static int nvme_auth_dhchap_negotiate(struct
> >> nvme_ctrl *ctrl, data->napd = 1;
> >> 
> >>   	data->auth_protocol[0].dhchap.authid = NVME_AUTH_DHCHAP_AUTH_ID;
> >>   	data->auth_protocol[0].dhchap.halen = 3;
> >> 
> >> -	data->auth_protocol[0].dhchap.dhlen = 1;
> >> +	data->auth_protocol[0].dhchap.dhlen = 6;
> >> 
> >>   	data->auth_protocol[0].dhchap.idlist[0] =
> >>   	NVME_AUTH_DHCHAP_HASH_SHA256;
> >>   	data->auth_protocol[0].dhchap.idlist[1] =
> >>   	NVME_AUTH_DHCHAP_HASH_SHA384;
> >>   	data->auth_protocol[0].dhchap.idlist[2] =
> >>   	NVME_AUTH_DHCHAP_HASH_SHA512;
> >>   	data->auth_protocol[0].dhchap.idlist[3] =
> >>   	NVME_AUTH_DHCHAP_DHGROUP_NULL;
> >> 
> >> +	data->auth_protocol[0].dhchap.idlist[4] =
> >> NVME_AUTH_DHCHAP_DHGROUP_2048;
> >> +	data->auth_protocol[0].dhchap.idlist[5] =
> >> NVME_AUTH_DHCHAP_DHGROUP_3072;
> >> +	data->auth_protocol[0].dhchap.idlist[6] =
> >> NVME_AUTH_DHCHAP_DHGROUP_4096;
> >> +	data->auth_protocol[0].dhchap.idlist[7] =
> >> NVME_AUTH_DHCHAP_DHGROUP_6144;
> >> +	data->auth_protocol[0].dhchap.idlist[8] =
> >> NVME_AUTH_DHCHAP_DHGROUP_8192;
> >> 
> >>   	return size;
> >>   
> >>   }
> >> 
> >> @@ -274,14 +373,7 @@ static int nvme_auth_dhchap_challenge(struct
> >> nvme_ctrl
> >> *ctrl, chap->status = NVME_AUTH_DHCHAP_FAILURE_HASH_UNUSABLE;
> >> 
> >>   		return -EPROTO;
> >>   	
> >>   	}
> >> 
> >> -	switch (data->dhgid) {
> >> -	case NVME_AUTH_DHCHAP_DHGROUP_NULL:
> >> -		gid_name = "null";
> >> -		break;
> >> -	default:
> >> -		gid_name = NULL;
> >> -		break;
> >> -	}
> >> +	gid_name = nvme_auth_dhgroup_kpp(data->dhgid);
> >> 
> >>   	if (!gid_name) {
> >>   	
> >>   		dev_warn(ctrl->device,
> >>   		
> >>   			 "qid %d: DH-HMAC-CHAP: invalid DH group id %d\n",
> >> 
> >> @@ -290,10 +382,24 @@ static int nvme_auth_dhchap_challenge(struct
> >> nvme_ctrl *ctrl, return -EPROTO;
> >> 
> >>   	}
> >>   	if (data->dhgid != NVME_AUTH_DHCHAP_DHGROUP_NULL) {
> >> 
> >> -		chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
> >> -		return -EPROTO;
> >> -	}
> >> -	if (data->dhgid == NVME_AUTH_DHCHAP_DHGROUP_NULL && data->dhvlen != 0)
> >> {
> >> +		if (data->dhvlen == 0) {
> >> +			dev_warn(ctrl->device,
> >> +				 "qid %d: DH-HMAC-CHAP: empty DH value\n",
> >> +				 chap->qid);
> >> +			chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
> >> +			return -EPROTO;
> >> +		}
> >> +		chap->dh_tfm = crypto_alloc_kpp(gid_name, 0, 0);
> >> +		if (IS_ERR(chap->dh_tfm)) {
> >> +			dev_warn(ctrl->device,
> >> +				 "qid %d: DH-HMAC-CHAP: failed to initialize %s\n",
> >> +				 chap->qid, gid_name);
> >> +			chap->status = NVME_AUTH_DHCHAP_FAILURE_DHGROUP_UNUSABLE;
> >> +			chap->dh_tfm = NULL;
> >> +			return -EPROTO;
> >> +		}
> >> +		chap->dhgroup_id = data->dhgid;
> >> +	} else if (data->dhvlen != 0) {
> >> 
> >>   		dev_warn(ctrl->device,
> >>   		
> >>   			 "qid %d: DH-HMAC-CHAP: invalid DH value for NULL 
DH\n",
> >>   			
> >>   			chap->qid);
> >> 
> >> @@ -313,6 +419,16 @@ static int nvme_auth_dhchap_challenge(struct
> >> nvme_ctrl
> >> *ctrl, chap->hash_len = data->hl;
> >> 
> >>   	chap->s1 = le32_to_cpu(data->seqnum);
> >>   	memcpy(chap->c1, data->cval, chap->hash_len);
> >> 
> >> +	if (data->dhvlen) {
> >> +		chap->ctrl_key = kmalloc(data->dhvlen, GFP_KERNEL);
> >> +		if (!chap->ctrl_key)
> >> +			return -ENOMEM;
> >> +		chap->ctrl_key_len = data->dhvlen;
> >> +		memcpy(chap->ctrl_key, data->cval + chap->hash_len,
> >> +		       data->dhvlen);
> >> +		dev_dbg(ctrl->device, "ctrl public key %*ph\n",
> >> +			 (int)chap->ctrl_key_len, chap->ctrl_key);
> >> +	}
> >> 
> >>   	return 0;
> >>   
> >>   }
> >> 
> >> @@ -353,10 +469,13 @@ static int nvme_auth_dhchap_reply(struct nvme_ctrl
> >> *ctrl, memcpy(data->rval + chap->hash_len, chap->c2,
> >> 
> >>   		       chap->hash_len);
> >>   	
> >>   	}
> >> 
> >> -	if (chap->host_key_len)
> >> +	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;
> >>   
> >>   }
> >> 
> >> @@ -440,23 +559,10 @@ static int nvme_auth_dhchap_failure2(struct
> >> nvme_ctrl
> >> *ctrl, int nvme_auth_select_hash(struct nvme_ctrl *ctrl,
> >> 
> >>   			  struct nvme_dhchap_context *chap)
> >>   
> >>   {
> >> 
> >> -	char *hash_name;
> >> +	const char *hash_name, *digest_name;
> >> 
> >>   	int ret;
> >> 
> >> -	switch (chap->hash_id) {
> >> -	case NVME_AUTH_DHCHAP_HASH_SHA256:
> >> -		hash_name = "hmac(sha256)";
> >> -		break;
> >> -	case NVME_AUTH_DHCHAP_HASH_SHA384:
> >> -		hash_name = "hmac(sha384)";
> >> -		break;
> >> -	case NVME_AUTH_DHCHAP_HASH_SHA512:
> >> -		hash_name = "hmac(sha512)";
> >> -		break;
> >> -	default:
> >> -		hash_name = NULL;
> >> -		break;
> >> -	}
> >> +	hash_name = nvme_auth_hmac_name(chap->hash_id);
> >> 
> >>   	if (!hash_name) {
> >>   	
> >>   		chap->status = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
> >>   		return -EPROTO;
> >> 
> >> @@ -468,26 +574,100 @@ int nvme_auth_select_hash(struct nvme_ctrl *ctrl,
> >> 
> >>   		chap->shash_tfm = NULL;
> >>   		return -EPROTO;
> >>   	
> >>   	}
> >> 
> >> +	digest_name = nvme_auth_digest_name(chap->hash_id);
> >> +	if (!digest_name) {
> >> +		crypto_free_shash(chap->shash_tfm);
> >> +		chap->shash_tfm = NULL;
> >> +		return -EPROTO;
> >> +	}
> >> +	chap->digest_tfm = crypto_alloc_shash(digest_name, 0, 0);
> >> +	if (IS_ERR(chap->digest_tfm)) {
> >> +		chap->status = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
> >> +		crypto_free_shash(chap->shash_tfm);
> >> +		chap->shash_tfm = NULL;
> >> +		chap->digest_tfm = NULL;
> >> +		return -EPROTO;
> >> +	}
> >> 
> >>   	if (!chap->key) {
> >>   	
> >>   		dev_warn(ctrl->device, "qid %d: cannot select hash, no 
key\n",
> >>   		
> >>   			 chap->qid);
> >>   		
> >>   		chap->status = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
> >> 
> >> +		crypto_free_shash(chap->digest_tfm);
> >> 
> >>   		crypto_free_shash(chap->shash_tfm);
> >>   		chap->shash_tfm = NULL;
> >> 
> >> +		chap->digest_tfm = NULL;
> >> 
> >>   		return -EINVAL;
> >>   	
> >>   	}
> >>   	ret = crypto_shash_setkey(chap->shash_tfm, chap->key, chap-
>key_len);
> >>   	if (ret) {
> >>   	
> >>   		chap->status = NVME_AUTH_DHCHAP_FAILURE_NOT_USABLE;
> >> 
> >> +		crypto_free_shash(chap->digest_tfm);
> >> 
> >>   		crypto_free_shash(chap->shash_tfm);
> >>   		chap->shash_tfm = NULL;
> >> 
> >> +		chap->digest_tfm = NULL;
> >> 
> >>   		return ret;
> >>   	
> >>   	}
> >> 
> >> -	dev_info(ctrl->device, "qid %d: DH-HMAC_CHAP: selected hash %s\n",
> >> -		 chap->qid, hash_name);
> >> +	dev_dbg(ctrl->device, "qid %d: DH-HMAC_CHAP: selected hash %s\n",
> >> +		chap->qid, hash_name);
> >> 
> >>   	return 0;
> >>   
> >>   }
> >> 
> >> +static int nvme_auth_augmented_challenge(struct nvme_dhchap_context
> >> *chap,
> >> +					 u8 *challenge, u8 *aug)
> >> +{
> >> +	struct crypto_shash *tfm;
> >> +	struct shash_desc *desc;
> >> +	u8 *hashed_key;
> >> +	const char *hash_name;
> >> +	int ret;
> >> +
> >> +	hashed_key = kmalloc(chap->hash_len, GFP_KERNEL);
> >> +	if (!hashed_key)
> >> +		return -ENOMEM;
> >> +
> >> +	ret = crypto_shash_tfm_digest(chap->digest_tfm, chap->sess_key,
> >> +				      chap->sess_key_len, 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(chap->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, chap->hash_len);
> >> +	if (ret)
> >> +		goto out_free_desc;
> >> +	ret = crypto_shash_init(desc);
> >> +	if (ret)
> >> +		goto out_free_desc;
> >> +	crypto_shash_update(desc, challenge, chap->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;
> >> +}
> >> +
> >> 
> >>   static int nvme_auth_dhchap_host_response(struct nvme_ctrl *ctrl,
> >>   
> >>   					  struct nvme_dhchap_context *chap)
> >>   
> >>   {
> >> 
> >> @@ -497,6 +677,16 @@ static int nvme_auth_dhchap_host_response(struct
> >> nvme_ctrl *ctrl,
> >> 
> >>   	dev_dbg(ctrl->device, "%s: qid %d host response seq %d 
transaction
> > 
> > %d\n",
> > 
> >>   		__func__, chap->qid, chap->s1, chap->transaction);
> >> 
> >> +	if (chap->dh_tfm) {
> >> +		challenge = kmalloc(chap->hash_len, GFP_KERNEL);
> > 
> > Again, alignment?
> 
> Again, why?

This buffer is the digest buffer of a shash_final, no? check 
crypto_shash_final and see that you could spare yourself some extra work if 
aligned.


Ciao
Stephan