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linux/net/bluetooth/ecdh_helper.c

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/*
* 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/ecdh.h>
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]);
}
/* compute_ecdh_secret() - function assumes that the private key was
* already set.
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp().
* @public_key: pair's ecc public key.
* secret: memory where the ecdh computed shared secret will be saved.
*
* Return: zero on success; error code in case of error.
*/
int compute_ecdh_secret(struct crypto_kpp *tfm, const u8 public_key[64],
u8 secret[32])
{
DECLARE_CRYPTO_WAIT(result);
struct kpp_request *req;
u8 *tmp;
struct scatterlist src, dst;
int err;
tmp = kmalloc(64, GFP_KERNEL);
if (!tmp)
return -ENOMEM;
req = kpp_request_alloc(tfm, GFP_KERNEL);
if (!req) {
err = -ENOMEM;
goto free_tmp;
}
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,
crypto_req_done, &result);
err = crypto_kpp_compute_shared_secret(req);
err = crypto_wait_req(err, &result);
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:
kpp_request_free(req);
free_tmp:
mm, treewide: rename kzfree() to kfree_sensitive() As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-06 23:18:13 -07:00
kfree_sensitive(tmp);
return err;
}
/* set_ecdh_privkey() - set or generate ecc private key.
*
* Function generates an ecc private key in the crypto subsystem when receiving
* a NULL private key or sets the received key when not NULL.
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp().
* @private_key: user's ecc private key. When not NULL, the key is expected
* in little endian format.
*
* Return: zero on success; error code in case of error.
*/
int set_ecdh_privkey(struct crypto_kpp *tfm, const u8 private_key[32])
{
u8 *buf, *tmp = NULL;
unsigned int buf_len;
int err;
struct ecdh p = {0};
if (private_key) {
tmp = kmalloc(32, GFP_KERNEL);
if (!tmp)
return -ENOMEM;
swap_digits((u64 *)private_key, (u64 *)tmp, 4);
p.key = tmp;
p.key_size = 32;
}
buf_len = crypto_ecdh_key_len(&p);
buf = kmalloc(buf_len, GFP_KERNEL);
if (!buf) {
err = -ENOMEM;
goto free_tmp;
}
err = crypto_ecdh_encode_key(buf, buf_len, &p);
if (err)
goto free_all;
err = crypto_kpp_set_secret(tfm, buf, buf_len);
/* fall through */
free_all:
mm, treewide: rename kzfree() to kfree_sensitive() As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-06 23:18:13 -07:00
kfree_sensitive(buf);
free_tmp:
mm, treewide: rename kzfree() to kfree_sensitive() As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-06 23:18:13 -07:00
kfree_sensitive(tmp);
return err;
}
/* generate_ecdh_public_key() - function assumes that the private key was
* already set.
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp().
* @public_key: memory where the computed ecc public key will be saved.
*
* Return: zero on success; error code in case of error.
*/
int generate_ecdh_public_key(struct crypto_kpp *tfm, u8 public_key[64])
{
DECLARE_CRYPTO_WAIT(result);
struct kpp_request *req;
u8 *tmp;
struct scatterlist dst;
int err;
tmp = kmalloc(64, GFP_KERNEL);
if (!tmp)
return -ENOMEM;
req = kpp_request_alloc(tfm, GFP_KERNEL);
if (!req) {
err = -ENOMEM;
goto free_tmp;
}
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,
crypto_req_done, &result);
err = crypto_kpp_generate_public_key(req);
err = crypto_wait_req(err, &result);
if (err < 0)
goto free_all;
/* The public key is handed back in little endian as expected by
* the Security Manager Protocol.
*/
swap_digits((u64 *)tmp, (u64 *)public_key, 4); /* x */
swap_digits((u64 *)&tmp[32], (u64 *)&public_key[32], 4); /* y */
free_all:
kpp_request_free(req);
free_tmp:
kfree(tmp);
return err;
}
/* generate_ecdh_keys() - generate ecc key pair.
*
* @tfm: KPP tfm handle allocated with crypto_alloc_kpp().
* @public_key: memory where the computed ecc public key will be saved.
*
* Return: zero on success; error code in case of error.
*/
int generate_ecdh_keys(struct crypto_kpp *tfm, u8 public_key[64])
{
int err;
err = set_ecdh_privkey(tfm, NULL);
if (err)
return err;
return generate_ecdh_public_key(tfm, public_key);
}