blob: 098296e40362579ffcce1e34cb059b25da857ef2 [file] [log] [blame]
Randall Spanglerf18038b2014-10-23 15:55:21 -07001/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 *
5 * Key unpacking functions
6 */
7
8#include "2sysincludes.h"
9#include "2common.h"
10#include "2rsa.h"
11
12const uint8_t *vb2_packed_key_data(const struct vb2_packed_key *key)
13{
14 return (const uint8_t *)key + key->key_offset;
15}
16
17int vb2_verify_packed_key_inside(const void *parent,
18 uint32_t parent_size,
19 const struct vb2_packed_key *key)
20{
21 return vb2_verify_member_inside(parent, parent_size,
22 key, sizeof(*key),
23 key->key_offset, key->key_size);
24}
25
26int vb2_unpack_key(struct vb2_public_key *key,
27 const uint8_t *buf,
28 uint32_t size)
29{
30 const struct vb2_packed_key *packed_key =
31 (const struct vb2_packed_key *)buf;
32 const uint32_t *buf32;
33 uint32_t expected_key_size;
34 int rv;
35
36 /* Make sure passed buffer is big enough for the packed key */
37 rv = vb2_verify_packed_key_inside(buf, size, packed_key);
38 if (rv)
39 return rv;
40
41 /* Unpack key algorithm */
42 key->sig_alg = vb2_crypto_to_signature(packed_key->algorithm);
43 if (key->sig_alg == VB2_SIG_INVALID) {
44 VB2_DEBUG("Unsupported signature algorithm.\n");
45 return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM;
46 }
47
48 key->hash_alg = vb2_crypto_to_hash(packed_key->algorithm);
49 if (key->hash_alg == VB2_HASH_INVALID) {
50 VB2_DEBUG("Unsupported hash algorithm.\n");
51 return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM;
52 }
53
54 expected_key_size = vb2_packed_key_size(key->sig_alg);
55 if (!expected_key_size || expected_key_size != packed_key->key_size) {
56 VB2_DEBUG("Wrong key size for algorithm\n");
57 return VB2_ERROR_UNPACK_KEY_SIZE;
58 }
59
60 /* Make sure source buffer is 32-bit aligned */
61 buf32 = (const uint32_t *)vb2_packed_key_data(packed_key);
Randall Spanglerd274a2e2014-10-23 17:38:18 -070062 if (!vb2_aligned(buf32, sizeof(uint32_t)))
Randall Spanglerf18038b2014-10-23 15:55:21 -070063 return VB2_ERROR_UNPACK_KEY_ALIGN;
64
65 /* Sanity check key array size */
66 key->arrsize = buf32[0];
67 if (key->arrsize * sizeof(uint32_t) != vb2_rsa_sig_size(key->sig_alg))
68 return VB2_ERROR_UNPACK_KEY_ARRAY_SIZE;
69
70 key->n0inv = buf32[1];
71
72 /* Arrays point inside the key data */
73 key->n = buf32 + 2;
74 key->rr = buf32 + 2 + key->arrsize;
75
76 return VB2_SUCCESS;
77}