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