[mirror_ubuntu-artful-kernel.git] / security / keys / dh.c

/* Crypto operations using stored keys
 *
 * Copyright (c) 2016, Intel Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
#include <crypto/kpp.h>
#include <crypto/dh.h>
#include <keys/user-type.h>
#include "internal.h"

static ssize_t dh_data_from_key(key_serial_t keyid, void **data)
{
	struct key *key;
	key_ref_t key_ref;
	long status;
	ssize_t ret;

	key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);
	if (IS_ERR(key_ref)) {
		ret = -ENOKEY;
		goto error;
	}

	key = key_ref_to_ptr(key_ref);

	ret = -EOPNOTSUPP;
	if (key->type == &key_type_user) {
		down_read(&key->sem);
		status = key_validate(key);
		if (status == 0) {
			const struct user_key_payload *payload;
			uint8_t *duplicate;

			payload = user_key_payload_locked(key);

			duplicate = kmemdup(payload->data, payload->datalen,
					    GFP_KERNEL);
			if (duplicate) {
				*data = duplicate;
				ret = payload->datalen;
			} else {
				ret = -ENOMEM;
			}
		}
		up_read(&key->sem);
	}

	key_put(key);
error:
	return ret;
}

static void dh_free_data(struct dh *dh)
{
	kzfree(dh->key);
	kzfree(dh->p);
	kzfree(dh->g);
}

struct dh_completion {
	struct completion completion;
	int err;
};

static void dh_crypto_done(struct crypto_async_request *req, int err)
{
	struct dh_completion *compl = req->data;

	if (err == -EINPROGRESS)
		return;

	compl->err = err;
	complete(&compl->completion);
}

struct kdf_sdesc {
	struct shash_desc shash;
	char ctx[];
};

static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname)
{
	struct crypto_shash *tfm;
	struct kdf_sdesc *sdesc;
	int size;
	int err;

	/* allocate synchronous hash */
	tfm = crypto_alloc_shash(hashname, 0, 0);
	if (IS_ERR(tfm)) {
		pr_info("could not allocate digest TFM handle %s\n", hashname);
		return PTR_ERR(tfm);
	}

	err = -EINVAL;
	if (crypto_shash_digestsize(tfm) == 0)
		goto out_free_tfm;

	err = -ENOMEM;
	size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm);
	sdesc = kmalloc(size, GFP_KERNEL);
	if (!sdesc)
		goto out_free_tfm;
	sdesc->shash.tfm = tfm;
	sdesc->shash.flags = 0x0;

	*sdesc_ret = sdesc;

	return 0;

out_free_tfm:
	crypto_free_shash(tfm);
	return err;
}

static void kdf_dealloc(struct kdf_sdesc *sdesc)
{
	if (!sdesc)
		return;

	if (sdesc->shash.tfm)
		crypto_free_shash(sdesc->shash.tfm);

	kzfree(sdesc);
}

/*
 * Implementation of the KDF in counter mode according to SP800-108 section 5.1
 * as well as SP800-56A section 5.8.1 (Single-step KDF).
 *
 * SP800-56A:
 * The src pointer is defined as Z || other info where Z is the shared secret
 * from DH and other info is an arbitrary string (see SP800-56A section
 * 5.8.1.2).
 */
static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
		   u8 *dst, unsigned int dlen, unsigned int zlen)
{
	struct shash_desc *desc = &sdesc->shash;
	unsigned int h = crypto_shash_digestsize(desc->tfm);
	int err = 0;
	u8 *dst_orig = dst;
	__be32 counter = cpu_to_be32(1);

	while (dlen) {
		err = crypto_shash_init(desc);
		if (err)
			goto err;

		err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
		if (err)
			goto err;

		if (zlen && h) {
			u8 tmpbuffer[h];
			size_t chunk = min_t(size_t, zlen, h);
			memset(tmpbuffer, 0, chunk);

			do {
				err = crypto_shash_update(desc, tmpbuffer,
							  chunk);
				if (err)
					goto err;

				zlen -= chunk;
				chunk = min_t(size_t, zlen, h);
			} while (zlen);
		}

		if (src && slen) {
			err = crypto_shash_update(desc, src, slen);
			if (err)
				goto err;
		}

		if (dlen < h) {
			u8 tmpbuffer[h];

			err = crypto_shash_final(desc, tmpbuffer);
			if (err)
				goto err;
			memcpy(dst, tmpbuffer, dlen);
			memzero_explicit(tmpbuffer, h);
			return 0;
		} else {
			err = crypto_shash_final(desc, dst);
			if (err)
				goto err;

			dlen -= h;
			dst += h;
			counter = cpu_to_be32(be32_to_cpu(counter) + 1);
		}
	}

	return 0;

err:
	memzero_explicit(dst_orig, dlen);
	return err;
}

static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
				 char __user *buffer, size_t buflen,
				 uint8_t *kbuf, size_t kbuflen, size_t lzero)
{
	uint8_t *outbuf = NULL;
	int ret;

	outbuf = kmalloc(buflen, GFP_KERNEL);
	if (!outbuf) {
		ret = -ENOMEM;
		goto err;
	}

	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen, lzero);
	if (ret)
		goto err;

	ret = buflen;
	if (copy_to_user(buffer, outbuf, buflen) != 0)
		ret = -EFAULT;

err:
	kzfree(outbuf);
	return ret;
}

long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
			 char __user *buffer, size_t buflen,
			 struct keyctl_kdf_params *kdfcopy)
{
	long ret;
	ssize_t dlen;
	int secretlen;
	int outlen;
	struct keyctl_dh_params pcopy;
	struct dh dh_inputs;
	struct scatterlist outsg;
	struct dh_completion compl;
	struct crypto_kpp *tfm;
	struct kpp_request *req;
	uint8_t *secret;
	uint8_t *outbuf;
	struct kdf_sdesc *sdesc = NULL;

	if (!params || (!buffer && buflen)) {
		ret = -EINVAL;
		goto out1;
	}
	if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
		ret = -EFAULT;
		goto out1;
	}

	if (kdfcopy) {
		char *hashname;

		if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
		    kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
			ret = -EMSGSIZE;
			goto out1;
		}

		/* get KDF name string */
		hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
		if (IS_ERR(hashname)) {
			ret = PTR_ERR(hashname);
			goto out1;
		}

		/* allocate KDF from the kernel crypto API */
		ret = kdf_alloc(&sdesc, hashname);
		kfree(hashname);
		if (ret)
			goto out1;
	}

	memset(&dh_inputs, 0, sizeof(dh_inputs));

	dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
	if (dlen < 0) {
		ret = dlen;
		goto out1;
	}
	dh_inputs.p_size = dlen;

	dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
	if (dlen < 0) {
		ret = dlen;
		goto out2;
	}
	dh_inputs.g_size = dlen;

	dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);
	if (dlen < 0) {
		ret = dlen;
		goto out2;
	}
	dh_inputs.key_size = dlen;

	secretlen = crypto_dh_key_len(&dh_inputs);
	secret = kmalloc(secretlen, GFP_KERNEL);
	if (!secret) {
		ret = -ENOMEM;
		goto out2;
	}
	ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
	if (ret)
		goto out3;

	tfm = crypto_alloc_kpp("dh", CRYPTO_ALG_TYPE_KPP, 0);
	if (IS_ERR(tfm)) {
		ret = PTR_ERR(tfm);
		goto out3;
	}

	ret = crypto_kpp_set_secret(tfm, secret, secretlen);
	if (ret)
		goto out4;

	outlen = crypto_kpp_maxsize(tfm);

	if (!kdfcopy) {
		/*
		 * When not using a KDF, buflen 0 is used to read the
		 * required buffer length
		 */
		if (buflen == 0) {
			ret = outlen;
			goto out4;
		} else if (outlen > buflen) {
			ret = -EOVERFLOW;
			goto out4;
		}
	}

	outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
			 GFP_KERNEL);
	if (!outbuf) {
		ret = -ENOMEM;
		goto out4;
	}

	sg_init_one(&outsg, outbuf, outlen);

	req = kpp_request_alloc(tfm, GFP_KERNEL);
	if (!req) {
		ret = -ENOMEM;
		goto out5;
	}

	kpp_request_set_input(req, NULL, 0);
	kpp_request_set_output(req, &outsg, outlen);
	init_completion(&compl.completion);
	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
				 CRYPTO_TFM_REQ_MAY_SLEEP,
				 dh_crypto_done, &compl);

	/*
	 * For DH, generate_public_key and generate_shared_secret are
	 * the same calculation
	 */
	ret = crypto_kpp_generate_public_key(req);
	if (ret == -EINPROGRESS) {
		wait_for_completion(&compl.completion);
		ret = compl.err;
		if (ret)
			goto out6;
	}

	if (kdfcopy) {
		/*
		 * Concatenate SP800-56A otherinfo past DH shared secret -- the
		 * input to the KDF is (DH shared secret || otherinfo)
		 */
		if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
				   kdfcopy->otherinfolen) != 0) {
			ret = -EFAULT;
			goto out6;
		}

		ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf,
					    req->dst_len + kdfcopy->otherinfolen,
					    outlen - req->dst_len);
	} else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
		ret = req->dst_len;
	} else {
		ret = -EFAULT;
	}

out6:
	kpp_request_free(req);
out5:
	kzfree(outbuf);
out4:
	crypto_free_kpp(tfm);
out3:
	kzfree(secret);
out2:
	dh_free_data(&dh_inputs);
out1:
	kdf_dealloc(sdesc);
	return ret;
}

long keyctl_dh_compute(struct keyctl_dh_params __user *params,
		       char __user *buffer, size_t buflen,
		       struct keyctl_kdf_params __user *kdf)
{
	struct keyctl_kdf_params kdfcopy;

	if (!kdf)
		return __keyctl_dh_compute(params, buffer, buflen, NULL);

	if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
		return -EFAULT;

	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
}
Commit	Line	Data
ddbb4114 MM	1	/* Crypto operations using stored keys
	2	*
	3	* Copyright (c) 2016, Intel Corporation
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*/
	10
ddbb4114 MM	11	#include <linux/slab.h>
ddbb4114 MM	12	#include <linux/uaccess.h>
7cbe0932	13	#include <linux/scatterlist.h>
f1c316a3 SM	14	#include <linux/crypto.h>
f1c316a3 SM	15	#include <crypto/hash.h>
7cbe0932 MM	16	#include <crypto/kpp.h>
7cbe0932 MM	17	#include <crypto/dh.h>
ddbb4114 MM	18	#include <keys/user-type.h>
	19	#include "internal.h"
	20
7cbe0932	21	static ssize_t dh_data_from_key(key_serial_t keyid, void **data)
ddbb4114 MM	22	{
	23	struct key *key;
	24	key_ref_t key_ref;
	25	long status;
	26	ssize_t ret;
	27
	28	key_ref = lookup_user_key(keyid, 0, KEY_NEED_READ);
	29	if (IS_ERR(key_ref)) {
	30	ret = -ENOKEY;
	31	goto error;
	32	}
	33
	34	key = key_ref_to_ptr(key_ref);
	35
	36	ret = -EOPNOTSUPP;
	37	if (key->type == &key_type_user) {
	38	down_read(&key->sem);
	39	status = key_validate(key);
	40	if (status == 0) {
	41	const struct user_key_payload *payload;
7cbe0932	42	uint8_t *duplicate;
ddbb4114	43
0837e49a	44	payload = user_key_payload_locked(key);
ddbb4114	45
7cbe0932 MM	46	duplicate = kmemdup(payload->data, payload->datalen,
	47	GFP_KERNEL);
	48	if (duplicate) {
	49	*data = duplicate;
ddbb4114	50	ret = payload->datalen;
ddbb4114	51	} else {
7cbe0932	52	ret = -ENOMEM;
ddbb4114 MM	53	}
	54	}
	55	up_read(&key->sem);
	56	}
	57
	58	key_put(key);
	59	error:
	60	return ret;
	61	}
	62
7cbe0932 MM	63	static void dh_free_data(struct dh *dh)
	64	{
	65	kzfree(dh->key);
	66	kzfree(dh->p);
	67	kzfree(dh->g);
	68	}
	69
	70	struct dh_completion {
	71	struct completion completion;
	72	int err;
	73	};
	74
	75	static void dh_crypto_done(struct crypto_async_request *req, int err)
	76	{
	77	struct dh_completion *compl = req->data;
	78
	79	if (err == -EINPROGRESS)
	80	return;
	81
	82	compl->err = err;
	83	complete(&compl->completion);
	84	}
	85
f1c316a3 SM	86	struct kdf_sdesc {
	87	struct shash_desc shash;
	88	char ctx[];
	89	};
	90
	91	static int kdf_alloc(struct kdf_sdesc *sdesc_ret, char hashname)
	92	{
	93	struct crypto_shash *tfm;
	94	struct kdf_sdesc *sdesc;
	95	int size;
bbe24045	96	int err;
f1c316a3 SM	97
	98	/* allocate synchronous hash */
	99	tfm = crypto_alloc_shash(hashname, 0, 0);
	100	if (IS_ERR(tfm)) {
	101	pr_info("could not allocate digest TFM handle %s\n", hashname);
	102	return PTR_ERR(tfm);
	103	}
	104
bbe24045 EB	105	err = -EINVAL;
	106	if (crypto_shash_digestsize(tfm) == 0)
	107	goto out_free_tfm;
	108
	109	err = -ENOMEM;
f1c316a3 SM	110	size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm);
	111	sdesc = kmalloc(size, GFP_KERNEL);
	112	if (!sdesc)
bbe24045	113	goto out_free_tfm;
f1c316a3 SM	114	sdesc->shash.tfm = tfm;
	115	sdesc->shash.flags = 0x0;
	116
	117	*sdesc_ret = sdesc;
	118
	119	return 0;
bbe24045 EB	120
	121	out_free_tfm:
	122	crypto_free_shash(tfm);
	123	return err;
f1c316a3 SM	124	}
	125
	126	static void kdf_dealloc(struct kdf_sdesc *sdesc)
	127	{
	128	if (!sdesc)
	129	return;
	130
	131	if (sdesc->shash.tfm)
	132	crypto_free_shash(sdesc->shash.tfm);
	133
	134	kzfree(sdesc);
	135	}
	136
f1c316a3 SM	137	/*
	138	* Implementation of the KDF in counter mode according to SP800-108 section 5.1
	139	* as well as SP800-56A section 5.8.1 (Single-step KDF).
	140	*
	141	* SP800-56A:
	142	* The src pointer is defined as Z \|\| other info where Z is the shared secret
	143	* from DH and other info is an arbitrary string (see SP800-56A section
	144	* 5.8.1.2).
	145	*/
	146	static int kdf_ctr(struct kdf_sdesc sdesc, const u8 src, unsigned int slen,
7cbe0932	147	u8 *dst, unsigned int dlen, unsigned int zlen)
f1c316a3 SM	148	{
	149	struct shash_desc *desc = &sdesc->shash;
	150	unsigned int h = crypto_shash_digestsize(desc->tfm);
	151	int err = 0;
	152	u8 *dst_orig = dst;
0ddd9f1a	153	__be32 counter = cpu_to_be32(1);
f1c316a3 SM	154
	155	while (dlen) {
	156	err = crypto_shash_init(desc);
	157	if (err)
	158	goto err;
	159
0ddd9f1a	160	err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
f1c316a3 SM	161	if (err)
	162	goto err;
	163
7cbe0932 MM	164	if (zlen && h) {
	165	u8 tmpbuffer[h];
	166	size_t chunk = min_t(size_t, zlen, h);
	167	memset(tmpbuffer, 0, chunk);
	168
	169	do {
	170	err = crypto_shash_update(desc, tmpbuffer,
	171	chunk);
	172	if (err)
	173	goto err;
	174
	175	zlen -= chunk;
	176	chunk = min_t(size_t, zlen, h);
	177	} while (zlen);
	178	}
	179
f1c316a3 SM	180	if (src && slen) {
	181	err = crypto_shash_update(desc, src, slen);
	182	if (err)
	183	goto err;
	184	}
	185
	186	if (dlen < h) {
	187	u8 tmpbuffer[h];
	188
	189	err = crypto_shash_final(desc, tmpbuffer);
	190	if (err)
	191	goto err;
	192	memcpy(dst, tmpbuffer, dlen);
	193	memzero_explicit(tmpbuffer, h);
	194	return 0;
	195	} else {
	196	err = crypto_shash_final(desc, dst);
	197	if (err)
	198	goto err;
	199
	200	dlen -= h;
	201	dst += h;
0ddd9f1a	202	counter = cpu_to_be32(be32_to_cpu(counter) + 1);
f1c316a3 SM	203	}
	204	}
	205
	206	return 0;
	207
	208	err:
	209	memzero_explicit(dst_orig, dlen);
	210	return err;
	211	}
	212
	213	static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
	214	char __user *buffer, size_t buflen,
7cbe0932	215	uint8_t *kbuf, size_t kbuflen, size_t lzero)
f1c316a3 SM	216	{
	217	uint8_t *outbuf = NULL;
	218	int ret;
	219
	220	outbuf = kmalloc(buflen, GFP_KERNEL);
	221	if (!outbuf) {
	222	ret = -ENOMEM;
	223	goto err;
	224	}
	225
7cbe0932	226	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen, lzero);
f1c316a3 SM	227	if (ret)
	228	goto err;
	229
	230	ret = buflen;
	231	if (copy_to_user(buffer, outbuf, buflen) != 0)
	232	ret = -EFAULT;
	233
	234	err:
	235	kzfree(outbuf);
	236	return ret;
	237	}
	238
	239	long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
	240	char __user *buffer, size_t buflen,
	241	struct keyctl_kdf_params *kdfcopy)
ddbb4114 MM	242	{
ddbb4114 MM	243	long ret;
7cbe0932 MM	244	ssize_t dlen;
	245	int secretlen;
	246	int outlen;
ddbb4114	247	struct keyctl_dh_params pcopy;
7cbe0932 MM	248	struct dh dh_inputs;
	249	struct scatterlist outsg;
	250	struct dh_completion compl;
	251	struct crypto_kpp *tfm;
	252	struct kpp_request *req;
	253	uint8_t *secret;
	254	uint8_t *outbuf;
f1c316a3	255	struct kdf_sdesc *sdesc = NULL;
ddbb4114 MM	256
	257	if (!params \|\| (!buffer && buflen)) {
	258	ret = -EINVAL;
7cbe0932	259	goto out1;
ddbb4114 MM	260	}
	261	if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
	262	ret = -EFAULT;
7cbe0932	263	goto out1;
ddbb4114 MM	264	}
ddbb4114 MM	265
f1c316a3 SM	266	if (kdfcopy) {
	267	char *hashname;
	268
	269	if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN \|\|
	270	kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
	271	ret = -EMSGSIZE;
7cbe0932	272	goto out1;
f1c316a3 SM	273	}
	274
	275	/* get KDF name string */
	276	hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
	277	if (IS_ERR(hashname)) {
	278	ret = PTR_ERR(hashname);
7cbe0932	279	goto out1;
f1c316a3 SM	280	}
	281
	282	/* allocate KDF from the kernel crypto API */
	283	ret = kdf_alloc(&sdesc, hashname);
	284	kfree(hashname);
	285	if (ret)
7cbe0932	286	goto out1;
4693fc73 SM	287	}
4693fc73 SM	288
7cbe0932 MM	289	memset(&dh_inputs, 0, sizeof(dh_inputs));
	290
	291	dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
	292	if (dlen < 0) {
	293	ret = dlen;
	294	goto out1;
ddbb4114	295	}
7cbe0932	296	dh_inputs.p_size = dlen;
ddbb4114	297
7cbe0932 MM	298	dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
	299	if (dlen < 0) {
	300	ret = dlen;
	301	goto out2;
	302	}
	303	dh_inputs.g_size = dlen;
ddbb4114	304
7cbe0932 MM	305	dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);
	306	if (dlen < 0) {
	307	ret = dlen;
	308	goto out2;
ddbb4114	309	}
7cbe0932	310	dh_inputs.key_size = dlen;
ddbb4114	311
7cbe0932 MM	312	secretlen = crypto_dh_key_len(&dh_inputs);
	313	secret = kmalloc(secretlen, GFP_KERNEL);
	314	if (!secret) {
	315	ret = -ENOMEM;
	316	goto out2;
	317	}
	318	ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
	319	if (ret)
	320	goto out3;
	321
	322	tfm = crypto_alloc_kpp("dh", CRYPTO_ALG_TYPE_KPP, 0);
	323	if (IS_ERR(tfm)) {
	324	ret = PTR_ERR(tfm);
	325	goto out3;
	326	}
	327
	328	ret = crypto_kpp_set_secret(tfm, secret, secretlen);
	329	if (ret)
	330	goto out4;
	331
	332	outlen = crypto_kpp_maxsize(tfm);
	333
	334	if (!kdfcopy) {
	335	/*
	336	* When not using a KDF, buflen 0 is used to read the
	337	* required buffer length
	338	*/
	339	if (buflen == 0) {
	340	ret = outlen;
	341	goto out4;
	342	} else if (outlen > buflen) {
	343	ret = -EOVERFLOW;
	344	goto out4;
	345	}
ddbb4114 MM	346	}
ddbb4114 MM	347
7cbe0932 MM	348	outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
	349	GFP_KERNEL);
	350	if (!outbuf) {
ddbb4114	351	ret = -ENOMEM;
7cbe0932	352	goto out4;
ddbb4114 MM	353	}
ddbb4114 MM	354
7cbe0932 MM	355	sg_init_one(&outsg, outbuf, outlen);
	356
	357	req = kpp_request_alloc(tfm, GFP_KERNEL);
	358	if (!req) {
ddbb4114	359	ret = -ENOMEM;
7cbe0932	360	goto out5;
ddbb4114 MM	361	}
ddbb4114 MM	362
7cbe0932 MM	363	kpp_request_set_input(req, NULL, 0);
	364	kpp_request_set_output(req, &outsg, outlen);
	365	init_completion(&compl.completion);
	366	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG \|
	367	CRYPTO_TFM_REQ_MAY_SLEEP,
	368	dh_crypto_done, &compl);
	369
f1c316a3	370	/*
7cbe0932 MM	371	* For DH, generate_public_key and generate_shared_secret are
7cbe0932 MM	372	* the same calculation
f1c316a3	373	*/
7cbe0932 MM	374	ret = crypto_kpp_generate_public_key(req);
	375	if (ret == -EINPROGRESS) {
	376	wait_for_completion(&compl.completion);
	377	ret = compl.err;
	378	if (ret)
	379	goto out6;
f1c316a3 SM	380	}
f1c316a3 SM	381
f1c316a3	382	if (kdfcopy) {
7cbe0932 MM	383	/*
	384	* Concatenate SP800-56A otherinfo past DH shared secret -- the
	385	* input to the KDF is (DH shared secret \|\| otherinfo)
	386	*/
	387	if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
	388	kdfcopy->otherinfolen) != 0) {
f1c316a3	389	ret = -EFAULT;
7cbe0932 MM	390	goto out6;
	391	}
	392
	393	ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf,
	394	req->dst_len + kdfcopy->otherinfolen,
	395	outlen - req->dst_len);
	396	} else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
	397	ret = req->dst_len;
	398	} else {
	399	ret = -EFAULT;
f1c316a3	400	}
ddbb4114	401
7cbe0932 MM	402	out6:
	403	kpp_request_free(req);
	404	out5:
	405	kzfree(outbuf);
	406	out4:
	407	crypto_free_kpp(tfm);
	408	out3:
	409	kzfree(secret);
	410	out2:
	411	dh_free_data(&dh_inputs);
	412	out1:
f1c316a3	413	kdf_dealloc(sdesc);
ddbb4114 MM	414	return ret;
ddbb4114 MM	415	}
f1c316a3 SM	416
	417	long keyctl_dh_compute(struct keyctl_dh_params __user *params,
	418	char __user *buffer, size_t buflen,
	419	struct keyctl_kdf_params __user *kdf)
	420	{
	421	struct keyctl_kdf_params kdfcopy;
	422
	423	if (!kdf)
	424	return __keyctl_dh_compute(params, buffer, buflen, NULL);
	425
	426	if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
	427	return -EFAULT;
	428
	429	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
	430	}