/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* Key unpacking functions
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*/
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#include "2sysincludes.h"
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#include "2common.h"
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#include "2rsa.h"
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#include "vb2_common.h"
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int vb2_unpack_key_data(struct vb2_public_key *key,
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const uint8_t *key_data,
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uint32_t key_size)
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{
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const uint32_t *buf32 = (const uint32_t *)key_data;
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uint32_t expected_key_size = vb2_packed_key_size(key->sig_alg);
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/* Make sure buffer is the correct length */
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if (!expected_key_size || expected_key_size != key_size) {
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VB2_DEBUG("Wrong key size for algorithm\n");
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return VB2_ERROR_UNPACK_KEY_SIZE;
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}
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/* Check for alignment */
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if (!vb2_aligned(buf32, sizeof(uint32_t)))
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return VB2_ERROR_UNPACK_KEY_ALIGN;
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key->arrsize = buf32[0];
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/* Sanity check key array size */
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if (key->arrsize * sizeof(uint32_t) != vb2_rsa_sig_size(key->sig_alg))
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return VB2_ERROR_UNPACK_KEY_ARRAY_SIZE;
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key->n0inv = buf32[1];
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/* Arrays point inside the key data */
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key->n = buf32 + 2;
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key->rr = buf32 + 2 + key->arrsize;
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return VB2_SUCCESS;
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}
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int vb2_unpack_key(struct vb2_public_key *key,
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const uint8_t *buf,
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uint32_t size)
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{
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const struct vb2_packed_key *pkey =
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(const struct vb2_packed_key *)buf;
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uint32_t sig_size;
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uint32_t min_offset = 0;
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int rv;
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/* Check magic number */
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if (pkey->c.magic != VB2_MAGIC_PACKED_KEY)
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return VB2_ERROR_UNPACK_KEY_MAGIC;
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rv = vb2_verify_common_header(buf, size);
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if (rv)
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return rv;
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/* Make sure key data is inside */
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rv = vb2_verify_common_member(pkey, &min_offset,
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pkey->key_offset, pkey->key_size);
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if (rv)
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return rv;
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/*
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* Check for compatible version. No need to check minor version, since
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* that's compatible across readers matching the major version, and we
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* haven't added any new fields.
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*/
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if (pkey->c.struct_version_major != VB2_PACKED_KEY_VERSION_MAJOR)
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return VB2_ERROR_UNPACK_KEY_STRUCT_VERSION;
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/* Copy key algorithms */
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key->hash_alg = pkey->hash_alg;
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if (!vb2_digest_size(key->hash_alg))
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return VB2_ERROR_UNPACK_KEY_HASH_ALGORITHM;
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key->sig_alg = pkey->sig_alg;
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if (key->sig_alg != VB2_SIG_NONE) {
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sig_size = vb2_rsa_sig_size(key->sig_alg);
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if (!sig_size)
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return VB2_ERROR_UNPACK_KEY_SIG_ALGORITHM;
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rv = vb2_unpack_key_data(
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key,
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(const uint8_t *)pkey + pkey->key_offset,
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pkey->key_size);
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if (rv)
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return rv;
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}
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/* Key description */
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key->desc = vb2_common_desc(pkey);
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key->version = pkey->key_version;
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key->guid = &pkey->guid;
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return VB2_SUCCESS;
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}
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