| dp-arm | b3e8580 | 2016-12-12 14:48:13 +0000 | [diff] [blame] | 1 | /* |
| 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 | */ |
| 48 | int 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 | */ |
| 63 | if (!trusted_nv_ctr || (trusted_nv_ctr && img_desc->parent == NULL)) |
| 64 | 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 | } |