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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Key unpacking functions
*/
#include "2common.h"
#include "2rsa.h"
#include "2sysincludes.h"
#include "vb21_common.h"
vb2_error_t vb2_unpack_key_data(struct vb2_public_key *key,
const uint8_t *key_data, uint32_t key_size)
{
const uint32_t *buf32 = (const uint32_t *)key_data;
uint32_t expected_key_size = vb2_packed_key_size(key->sig_alg);
/* Make sure buffer is the correct length */
if (!expected_key_size || expected_key_size != key_size) {
VB2_DEBUG("Wrong key size for algorithm\n");
return VB2_ERROR_UNPACK_KEY_SIZE;
}
/* Check for alignment */
if (!vb2_aligned(buf32, sizeof(uint32_t)))
return VB2_ERROR_UNPACK_KEY_ALIGN;
key->arrsize = buf32[0];
/* Sanity check key array size */
if (key->arrsize * sizeof(uint32_t) != vb2_rsa_sig_size(key->sig_alg))
return VB2_ERROR_UNPACK_KEY_ARRAY_SIZE;
key->n0inv = buf32[1];
/* Arrays point inside the key data */
key->n = buf32 + 2;
key->rr = buf32 + 2 + key->arrsize;
return VB2_SUCCESS;
}
vb2_error_t vb21_unpack_key(struct vb2_public_key *key, const uint8_t *buf,
uint32_t size)
{
const struct vb21_packed_key *pkey =
(const struct vb21_packed_key *)buf;
uint32_t sig_size;
uint32_t min_offset = 0;
vb2_error_t rv;
/* Check magic number */
if (pkey->c.magic != VB21_MAGIC_PACKED_KEY)
return VB2_ERROR_UNPACK_KEY_MAGIC;
rv = vb21_verify_common_header(buf, size);
if (rv)
return rv;
/* Make sure key data is inside */
rv = vb21_verify_common_member(pkey, &min_offset,
pkey->key_offset, pkey->key_size);
if (rv)
return rv;
/*
* Check for compatible version. No need to check minor version, since
* that's compatible across readers matching the major version, and we
* haven't added any new fields.
*/
if (pkey->c.struct_version_major != VB21_PACKED_KEY_VERSION_MAJOR)
return VB2_ERROR_UNPACK_KEY_STRUCT_VERSION;
/* Copy key algorithms */
key->hash_alg = pkey->hash_alg;
if (!vb2_digest_size(key->hash_alg))
return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM;
key->sig_alg = pkey->sig_alg;
if (key->sig_alg != VB2_SIG_NONE) {
sig_size = vb2_rsa_sig_size(key->sig_alg);
if (!sig_size)
return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM;
rv = vb2_unpack_key_data(
key,
(const uint8_t *)pkey + pkey->key_offset,
pkey->key_size);
if (rv)
return rv;
}
/* Key description */
key->desc = vb21_common_desc(pkey);
key->version = pkey->key_version;
key->id = &pkey->id;
return VB2_SUCCESS;
}
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