linux/net/bluetooth/ecdh_helper.c
Markus Elfring 5d4acfc141 Bluetooth: Delete error messages for failed memory allocations in two functions
Omit two extra messages for memory allocation failures in these functions.

This issue was detected by using the Coccinelle software.

Link: http://events.linuxfoundation.org/sites/events/files/slides/LCJ16-Refactor_Strings-WSang_0.pdf
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2017-05-22 10:23:41 +02:00

227 lines
5.4 KiB
C

/*
* ECDH helper functions - KPP wrappings
*
* Copyright (C) 2017 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
* CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS,
* COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS
* SOFTWARE IS DISCLAIMED.
*/
#include "ecdh_helper.h"
#include <linux/scatterlist.h>
#include <crypto/kpp.h>
#include <crypto/ecdh.h>
struct ecdh_completion {
struct completion completion;
int err;
};
static void ecdh_complete(struct crypto_async_request *req, int err)
{
struct ecdh_completion *res = req->data;
if (err == -EINPROGRESS)
return;
res->err = err;
complete(&res->completion);
}
static inline void swap_digits(u64 *in, u64 *out, unsigned int ndigits)
{
int i;
for (i = 0; i < ndigits; i++)
out[i] = __swab64(in[ndigits - 1 - i]);
}
bool compute_ecdh_secret(const u8 public_key[64], const u8 private_key[32],
u8 secret[32])
{
struct crypto_kpp *tfm;
struct kpp_request *req;
struct ecdh p;
struct ecdh_completion result;
struct scatterlist src, dst;
u8 *tmp, *buf;
unsigned int buf_len;
int err = -ENOMEM;
tmp = kmalloc(64, GFP_KERNEL);
if (!tmp)
return false;
tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
if (IS_ERR(tfm)) {
pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
PTR_ERR(tfm));
goto free_tmp;
}
req = kpp_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto free_kpp;
init_completion(&result.completion);
/* Security Manager Protocol holds digits in litte-endian order
* while ECC API expect big-endian data
*/
swap_digits((u64 *)private_key, (u64 *)tmp, 4);
p.key = (char *)tmp;
p.key_size = 32;
/* Set curve_id */
p.curve_id = ECC_CURVE_NIST_P256;
buf_len = crypto_ecdh_key_len(&p);
buf = kmalloc(buf_len, GFP_KERNEL);
if (!buf)
goto free_req;
crypto_ecdh_encode_key(buf, buf_len, &p);
/* Set A private Key */
err = crypto_kpp_set_secret(tfm, (void *)buf, buf_len);
if (err)
goto free_all;
swap_digits((u64 *)public_key, (u64 *)tmp, 4); /* x */
swap_digits((u64 *)&public_key[32], (u64 *)&tmp[32], 4); /* y */
sg_init_one(&src, tmp, 64);
sg_init_one(&dst, secret, 32);
kpp_request_set_input(req, &src, 64);
kpp_request_set_output(req, &dst, 32);
kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
ecdh_complete, &result);
err = crypto_kpp_compute_shared_secret(req);
if (err == -EINPROGRESS) {
wait_for_completion(&result.completion);
err = result.err;
}
if (err < 0) {
pr_err("alg: ecdh: compute shared secret failed. err %d\n",
err);
goto free_all;
}
swap_digits((u64 *)secret, (u64 *)tmp, 4);
memcpy(secret, tmp, 32);
free_all:
kzfree(buf);
free_req:
kpp_request_free(req);
free_kpp:
crypto_free_kpp(tfm);
free_tmp:
kfree(tmp);
return (err == 0);
}
bool generate_ecdh_keys(u8 public_key[64], u8 private_key[32])
{
struct crypto_kpp *tfm;
struct kpp_request *req;
struct ecdh p;
struct ecdh_completion result;
struct scatterlist dst;
u8 *tmp, *buf;
unsigned int buf_len;
int err = -ENOMEM;
const unsigned short max_tries = 16;
unsigned short tries = 0;
tmp = kmalloc(64, GFP_KERNEL);
if (!tmp)
return false;
tfm = crypto_alloc_kpp("ecdh", CRYPTO_ALG_INTERNAL, 0);
if (IS_ERR(tfm)) {
pr_err("alg: kpp: Failed to load tfm for kpp: %ld\n",
PTR_ERR(tfm));
goto free_tmp;
}
req = kpp_request_alloc(tfm, GFP_KERNEL);
if (!req)
goto free_kpp;
init_completion(&result.completion);
/* Set curve_id */
p.curve_id = ECC_CURVE_NIST_P256;
p.key_size = 32;
buf_len = crypto_ecdh_key_len(&p);
buf = kmalloc(buf_len, GFP_KERNEL);
if (!buf)
goto free_req;
do {
if (tries++ >= max_tries)
goto free_all;
/* Set private Key */
p.key = (char *)private_key;
crypto_ecdh_encode_key(buf, buf_len, &p);
err = crypto_kpp_set_secret(tfm, buf, buf_len);
if (err)
goto free_all;
sg_init_one(&dst, tmp, 64);
kpp_request_set_input(req, NULL, 0);
kpp_request_set_output(req, &dst, 64);
kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
ecdh_complete, &result);
err = crypto_kpp_generate_public_key(req);
if (err == -EINPROGRESS) {
wait_for_completion(&result.completion);
err = result.err;
}
/* Private key is not valid. Regenerate */
if (err == -EINVAL)
continue;
if (err < 0)
goto free_all;
else
break;
} while (true);
/* Keys are handed back in little endian as expected by Security
* Manager Protocol
*/
swap_digits((u64 *)tmp, (u64 *)public_key, 4); /* x */
swap_digits((u64 *)&tmp[32], (u64 *)&public_key[32], 4); /* y */
swap_digits((u64 *)private_key, (u64 *)tmp, 4);
memcpy(private_key, tmp, 32);
free_all:
kzfree(buf);
free_req:
kpp_request_free(req);
free_kpp:
crypto_free_kpp(tfm);
free_tmp:
kfree(tmp);
return (err == 0);
}