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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 "2sysincludes.h"
#include "2rsa.h"
#include "vb2_common.h"
const uint8_t *vb2_packed_key_data(const struct vb2_packed_key *key)
{
return (const uint8_t *)key + key->key_offset;
}
int vb2_verify_packed_key_inside(const void *parent,
uint32_t parent_size,
const struct vb2_packed_key *key)
{
return vb2_verify_member_inside(parent, parent_size,
key, sizeof(*key),
key->key_offset, key->key_size);
}
int vb2_unpack_key(struct vb2_public_key *key,
const uint8_t *buf,
uint32_t size)
{
const struct vb2_packed_key *packed_key =
(const struct vb2_packed_key *)buf;
const uint32_t *buf32;
uint32_t expected_key_size;
int rv;
/* Make sure passed buffer is big enough for the packed key */
rv = vb2_verify_packed_key_inside(buf, size, packed_key);
if (rv)
return rv;
/* Unpack key algorithm */
key->sig_alg = vb2_crypto_to_signature(packed_key->algorithm);
if (key->sig_alg == VB2_SIG_INVALID) {
VB2_DEBUG("Unsupported signature algorithm.\n");
return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM;
}
key->hash_alg = vb2_crypto_to_hash(packed_key->algorithm);
if (key->hash_alg == VB2_HASH_INVALID) {
VB2_DEBUG("Unsupported hash algorithm.\n");
return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM;
}
expected_key_size = vb2_packed_key_size(key->sig_alg);
if (!expected_key_size || expected_key_size != packed_key->key_size) {
VB2_DEBUG("Wrong key size for algorithm\n");
return VB2_ERROR_UNPACK_KEY_SIZE;
}
/* Make sure source buffer is 32-bit aligned */
buf32 = (const uint32_t *)vb2_packed_key_data(packed_key);
if (!vb2_aligned(buf32, sizeof(uint32_t)))
return VB2_ERROR_UNPACK_KEY_ALIGN;
/* Sanity check key array size */
key->arrsize = buf32[0];
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;
}