1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * SPDX-License-Identifier:	MIT
5  */
6 
7 #include "avb_hashtree_descriptor.h"
8 #include "avb_util.h"
9 
10 bool avb_hashtree_descriptor_validate_and_byteswap(
11     const AvbHashtreeDescriptor* src, AvbHashtreeDescriptor* dest) {
12   uint64_t expected_size;
13 
14   avb_memcpy(dest, src, sizeof(AvbHashtreeDescriptor));
15 
16   if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
17                                             (AvbDescriptor*)dest))
18     return false;
19 
20   if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_HASHTREE) {
21     avb_error("Invalid tag for hashtree descriptor.\n");
22     return false;
23   }
24 
25   dest->dm_verity_version = avb_be32toh(dest->dm_verity_version);
26   dest->image_size = avb_be64toh(dest->image_size);
27   dest->tree_offset = avb_be64toh(dest->tree_offset);
28   dest->tree_size = avb_be64toh(dest->tree_size);
29   dest->data_block_size = avb_be32toh(dest->data_block_size);
30   dest->hash_block_size = avb_be32toh(dest->hash_block_size);
31   dest->fec_num_roots = avb_be32toh(dest->fec_num_roots);
32   dest->fec_offset = avb_be64toh(dest->fec_offset);
33   dest->fec_size = avb_be64toh(dest->fec_size);
34   dest->partition_name_len = avb_be32toh(dest->partition_name_len);
35   dest->salt_len = avb_be32toh(dest->salt_len);
36   dest->root_digest_len = avb_be32toh(dest->root_digest_len);
37   dest->flags = avb_be32toh(dest->flags);
38 
39   /* Check that partition_name, salt, and root_digest are fully contained. */
40   expected_size = sizeof(AvbHashtreeDescriptor) - sizeof(AvbDescriptor);
41   if (!avb_safe_add_to(&expected_size, dest->partition_name_len) ||
42       !avb_safe_add_to(&expected_size, dest->salt_len) ||
43       !avb_safe_add_to(&expected_size, dest->root_digest_len)) {
44     avb_error("Overflow while adding up sizes.\n");
45     return false;
46   }
47   if (expected_size > dest->parent_descriptor.num_bytes_following) {
48     avb_error("Descriptor payload size overflow.\n");
49     return false;
50   }
51   return true;
52 }
53