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