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dp-armb3e85802016-12-12 14:48:13 +00001/*
2 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * Redistributions of source code must retain the above copyright notice, this
8 * list of conditions and the following disclaimer.
9 *
10 * Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 *
14 * Neither the name of ARM nor the names of its contributors may be used
15 * to endorse or promote products derived from this software without specific
16 * prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <assert.h>
32#include <auth/auth_mod.h>
33#include <platform.h>
34#include <platform_oid.h>
35#include <string.h>
36
37/*
38 * Store a new non-volatile counter value. This implementation
39 * only allows updating of the platform's Trusted NV counter when a
40 * certificate protected by the Trusted NV counter is signed with
41 * the ROT key. This avoids a compromised secondary certificate from
42 * updating the platform's Trusted NV counter, which could lead to the
43 * platform becoming unusable. The function is suitable for all TBBR
44 * compliant platforms.
45 *
46 * Return: 0 = success, Otherwise = error
47 */
48int plat_set_nv_ctr2(void *cookie, const auth_img_desc_t *img_desc,
49 unsigned int nv_ctr)
50{
51 int trusted_nv_ctr;
52
53 assert(cookie != NULL);
54 assert(img_desc != NULL);
55
56 trusted_nv_ctr = strcmp(cookie, TRUSTED_FW_NVCOUNTER_OID) == 0;
57
58 /*
59 * Only update the Trusted NV Counter if the certificate
60 * has been signed with the ROT key. Non Trusted NV counter
61 * updates are unconditional.
62 */
dp-arm3d1b8a62017-01-31 10:54:39 +000063 if (!trusted_nv_ctr || img_desc->parent == NULL)
dp-armb3e85802016-12-12 14:48:13 +000064 return plat_set_nv_ctr(cookie, nv_ctr);
65
66 /*
67 * Trusted certificates not signed with the ROT key are not
68 * allowed to update the Trusted NV Counter.
69 */
70 return 1;
71}