[mirror_ubuntu-hirsute-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).
 *
 * 'dlen' must be a multiple of the digest size.
 */
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[32];
			size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
			memset(tmpbuffer, 0, chunk);

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

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

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

		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;
	size_t outbuf_len = roundup(buflen,
				    crypto_shash_digestsize(sdesc->shash.tfm));

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

	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len, 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 (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {
			ret = -EINVAL;
			goto out1;
		}

		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.dh_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", 0, 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).
3619dec5 EB	145	*
3619dec5 EB	146	* 'dlen' must be a multiple of the digest size.
f1c316a3 SM	147	*/
f1c316a3 SM	148	static int kdf_ctr(struct kdf_sdesc sdesc, const u8 src, unsigned int slen,
7cbe0932	149	u8 *dst, unsigned int dlen, unsigned int zlen)
f1c316a3 SM	150	{
	151	struct shash_desc *desc = &sdesc->shash;
	152	unsigned int h = crypto_shash_digestsize(desc->tfm);
	153	int err = 0;
	154	u8 *dst_orig = dst;
0ddd9f1a	155	__be32 counter = cpu_to_be32(1);
f1c316a3 SM	156
	157	while (dlen) {
	158	err = crypto_shash_init(desc);
	159	if (err)
	160	goto err;
	161
0ddd9f1a	162	err = crypto_shash_update(desc, (u8 *)&counter, sizeof(__be32));
f1c316a3 SM	163	if (err)
	164	goto err;
	165
7cbe0932	166	if (zlen && h) {
890e2abe TA	167	u8 tmpbuffer[32];
890e2abe TA	168	size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
7cbe0932 MM	169	memset(tmpbuffer, 0, chunk);
	170
	171	do {
	172	err = crypto_shash_update(desc, tmpbuffer,
	173	chunk);
	174	if (err)
	175	goto err;
	176
	177	zlen -= chunk;
890e2abe	178	chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
7cbe0932 MM	179	} while (zlen);
	180	}
	181
f1c316a3 SM	182	if (src && slen) {
	183	err = crypto_shash_update(desc, src, slen);
	184	if (err)
	185	goto err;
	186	}
	187
383203ef TA	188	err = crypto_shash_final(desc, dst);
	189	if (err)
	190	goto err;
f1c316a3	191
383203ef TA	192	dlen -= h;
	193	dst += h;
	194	counter = cpu_to_be32(be32_to_cpu(counter) + 1);
f1c316a3 SM	195	}
	196
	197	return 0;
	198
	199	err:
	200	memzero_explicit(dst_orig, dlen);
	201	return err;
	202	}
	203
	204	static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
	205	char __user *buffer, size_t buflen,
7cbe0932	206	uint8_t *kbuf, size_t kbuflen, size_t lzero)
f1c316a3 SM	207	{
	208	uint8_t *outbuf = NULL;
	209	int ret;
3619dec5 EB	210	size_t outbuf_len = roundup(buflen,
3619dec5 EB	211	crypto_shash_digestsize(sdesc->shash.tfm));
f1c316a3	212
383203ef	213	outbuf = kmalloc(outbuf_len, GFP_KERNEL);
f1c316a3 SM	214	if (!outbuf) {
	215	ret = -ENOMEM;
	216	goto err;
	217	}
	218
383203ef	219	ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, outbuf_len, lzero);
f1c316a3 SM	220	if (ret)
	221	goto err;
	222
	223	ret = buflen;
	224	if (copy_to_user(buffer, outbuf, buflen) != 0)
	225	ret = -EFAULT;
	226
	227	err:
	228	kzfree(outbuf);
	229	return ret;
	230	}
	231
	232	long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
	233	char __user *buffer, size_t buflen,
	234	struct keyctl_kdf_params *kdfcopy)
ddbb4114 MM	235	{
ddbb4114 MM	236	long ret;
7cbe0932 MM	237	ssize_t dlen;
	238	int secretlen;
	239	int outlen;
ddbb4114	240	struct keyctl_dh_params pcopy;
7cbe0932 MM	241	struct dh dh_inputs;
	242	struct scatterlist outsg;
	243	struct dh_completion compl;
	244	struct crypto_kpp *tfm;
	245	struct kpp_request *req;
	246	uint8_t *secret;
	247	uint8_t *outbuf;
f1c316a3	248	struct kdf_sdesc *sdesc = NULL;
ddbb4114 MM	249
	250	if (!params \|\| (!buffer && buflen)) {
	251	ret = -EINVAL;
7cbe0932	252	goto out1;
ddbb4114 MM	253	}
	254	if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
	255	ret = -EFAULT;
7cbe0932	256	goto out1;
ddbb4114 MM	257	}
ddbb4114 MM	258
f1c316a3 SM	259	if (kdfcopy) {
	260	char *hashname;
	261
4f9dabfa EB	262	if (memchr_inv(kdfcopy->__spare, 0, sizeof(kdfcopy->__spare))) {
	263	ret = -EINVAL;
	264	goto out1;
	265	}
	266
f1c316a3 SM	267	if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN \|\|
	268	kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
	269	ret = -EMSGSIZE;
7cbe0932	270	goto out1;
f1c316a3 SM	271	}
	272
	273	/* get KDF name string */
	274	hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
	275	if (IS_ERR(hashname)) {
	276	ret = PTR_ERR(hashname);
7cbe0932	277	goto out1;
f1c316a3 SM	278	}
	279
	280	/* allocate KDF from the kernel crypto API */
	281	ret = kdf_alloc(&sdesc, hashname);
	282	kfree(hashname);
	283	if (ret)
7cbe0932	284	goto out1;
4693fc73 SM	285	}
4693fc73 SM	286
7cbe0932 MM	287	memset(&dh_inputs, 0, sizeof(dh_inputs));
	288
	289	dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
	290	if (dlen < 0) {
	291	ret = dlen;
	292	goto out1;
ddbb4114	293	}
7cbe0932	294	dh_inputs.p_size = dlen;
ddbb4114	295
7cbe0932 MM	296	dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
	297	if (dlen < 0) {
	298	ret = dlen;
	299	goto out2;
	300	}
	301	dh_inputs.g_size = dlen;
ddbb4114	302
8a2336e5	303	dlen = dh_data_from_key(pcopy.dh_private, &dh_inputs.key);
7cbe0932 MM	304	if (dlen < 0) {
	305	ret = dlen;
	306	goto out2;
ddbb4114	307	}
7cbe0932	308	dh_inputs.key_size = dlen;
ddbb4114	309
7cbe0932 MM	310	secretlen = crypto_dh_key_len(&dh_inputs);
	311	secret = kmalloc(secretlen, GFP_KERNEL);
	312	if (!secret) {
	313	ret = -ENOMEM;
	314	goto out2;
	315	}
	316	ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
	317	if (ret)
	318	goto out3;
	319
85d7311f	320	tfm = crypto_alloc_kpp("dh", 0, 0);
7cbe0932 MM	321	if (IS_ERR(tfm)) {
	322	ret = PTR_ERR(tfm);
	323	goto out3;
	324	}
	325
	326	ret = crypto_kpp_set_secret(tfm, secret, secretlen);
	327	if (ret)
	328	goto out4;
	329
	330	outlen = crypto_kpp_maxsize(tfm);
	331
	332	if (!kdfcopy) {
	333	/*
	334	* When not using a KDF, buflen 0 is used to read the
	335	* required buffer length
	336	*/
	337	if (buflen == 0) {
	338	ret = outlen;
	339	goto out4;
	340	} else if (outlen > buflen) {
	341	ret = -EOVERFLOW;
	342	goto out4;
	343	}
ddbb4114 MM	344	}
ddbb4114 MM	345
7cbe0932 MM	346	outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
	347	GFP_KERNEL);
	348	if (!outbuf) {
ddbb4114	349	ret = -ENOMEM;
7cbe0932	350	goto out4;
ddbb4114 MM	351	}
ddbb4114 MM	352
7cbe0932 MM	353	sg_init_one(&outsg, outbuf, outlen);
	354
	355	req = kpp_request_alloc(tfm, GFP_KERNEL);
	356	if (!req) {
ddbb4114	357	ret = -ENOMEM;
7cbe0932	358	goto out5;
ddbb4114 MM	359	}
ddbb4114 MM	360
7cbe0932 MM	361	kpp_request_set_input(req, NULL, 0);
	362	kpp_request_set_output(req, &outsg, outlen);
	363	init_completion(&compl.completion);
	364	kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG \|
	365	CRYPTO_TFM_REQ_MAY_SLEEP,
	366	dh_crypto_done, &compl);
	367
f1c316a3	368	/*
7cbe0932 MM	369	* For DH, generate_public_key and generate_shared_secret are
7cbe0932 MM	370	* the same calculation
f1c316a3	371	*/
7cbe0932 MM	372	ret = crypto_kpp_generate_public_key(req);
	373	if (ret == -EINPROGRESS) {
	374	wait_for_completion(&compl.completion);
	375	ret = compl.err;
	376	if (ret)
	377	goto out6;
f1c316a3 SM	378	}
f1c316a3 SM	379
f1c316a3	380	if (kdfcopy) {
7cbe0932 MM	381	/*
	382	* Concatenate SP800-56A otherinfo past DH shared secret -- the
	383	* input to the KDF is (DH shared secret \|\| otherinfo)
	384	*/
	385	if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
	386	kdfcopy->otherinfolen) != 0) {
f1c316a3	387	ret = -EFAULT;
7cbe0932 MM	388	goto out6;
	389	}
	390
	391	ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf,
	392	req->dst_len + kdfcopy->otherinfolen,
	393	outlen - req->dst_len);
	394	} else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
	395	ret = req->dst_len;
	396	} else {
	397	ret = -EFAULT;
f1c316a3	398	}
ddbb4114	399
7cbe0932 MM	400	out6:
	401	kpp_request_free(req);
	402	out5:
	403	kzfree(outbuf);
	404	out4:
	405	crypto_free_kpp(tfm);
	406	out3:
	407	kzfree(secret);
	408	out2:
	409	dh_free_data(&dh_inputs);
	410	out1:
f1c316a3	411	kdf_dealloc(sdesc);
ddbb4114 MM	412	return ret;
ddbb4114 MM	413	}
f1c316a3 SM	414
	415	long keyctl_dh_compute(struct keyctl_dh_params __user *params,
	416	char __user *buffer, size_t buflen,
	417	struct keyctl_kdf_params __user *kdf)
	418	{
	419	struct keyctl_kdf_params kdfcopy;
	420
	421	if (!kdf)
	422	return __keyctl_dh_compute(params, buffer, buflen, NULL);
	423
	424	if (copy_from_user(&kdfcopy, kdf, sizeof(kdfcopy)) != 0)
	425	return -EFAULT;
	426
	427	return __keyctl_dh_compute(params, buffer, buflen, &kdfcopy);
	428	}