blob: 9f03b9777ab96866124c1171f119dc5f17d0368d [file] [log] [blame]
Tom Rini421a5d02018-06-19 11:21:44 -04001// SPDX-License-Identifier: MIT
Igor Opaniuk8b23ae22018-06-03 21:56:36 +03002/*
3 * Copyright (C) 2016 The Android Open Source Project
Igor Opaniuk8b23ae22018-06-03 21:56:36 +03004 */
5
6#include "avb_descriptor.h"
7#include "avb_util.h"
8#include "avb_vbmeta_image.h"
9
10bool avb_descriptor_validate_and_byteswap(const AvbDescriptor* src,
11 AvbDescriptor* dest) {
12 dest->tag = avb_be64toh(src->tag);
13 dest->num_bytes_following = avb_be64toh(src->num_bytes_following);
14
15 if ((dest->num_bytes_following & 0x07) != 0) {
16 avb_error("Descriptor size is not divisible by 8.\n");
17 return false;
18 }
19 return true;
20}
21
22bool avb_descriptor_foreach(const uint8_t* image_data,
23 size_t image_size,
24 AvbDescriptorForeachFunc foreach_func,
25 void* user_data) {
26 const AvbVBMetaImageHeader* header = NULL;
27 bool ret = false;
28 const uint8_t* image_end;
29 const uint8_t* desc_start;
30 const uint8_t* desc_end;
31 const uint8_t* p;
32
33 if (image_data == NULL) {
34 avb_error("image_data is NULL\n.");
35 goto out;
36 }
37
38 if (foreach_func == NULL) {
39 avb_error("foreach_func is NULL\n.");
40 goto out;
41 }
42
43 if (image_size < sizeof(AvbVBMetaImageHeader)) {
44 avb_error("Length is smaller than header.\n");
45 goto out;
46 }
47
48 /* Ensure magic is correct. */
49 if (avb_memcmp(image_data, AVB_MAGIC, AVB_MAGIC_LEN) != 0) {
50 avb_error("Magic is incorrect.\n");
51 goto out;
52 }
53
54 /* Careful, not byteswapped - also ensure it's aligned properly. */
55 avb_assert_aligned(image_data);
56 header = (const AvbVBMetaImageHeader*)image_data;
57 image_end = image_data + image_size;
58
59 desc_start = image_data + sizeof(AvbVBMetaImageHeader) +
60 avb_be64toh(header->authentication_data_block_size) +
61 avb_be64toh(header->descriptors_offset);
62
63 desc_end = desc_start + avb_be64toh(header->descriptors_size);
64
65 if (desc_start < image_data || desc_start > image_end ||
66 desc_end < image_data || desc_end > image_end || desc_end < desc_start) {
67 avb_error("Descriptors not inside passed-in data.\n");
68 goto out;
69 }
70
71 for (p = desc_start; p < desc_end;) {
72 const AvbDescriptor* dh = (const AvbDescriptor*)p;
73 avb_assert_aligned(dh);
74 uint64_t nb_following = avb_be64toh(dh->num_bytes_following);
Sam Protsenko6a717022019-08-15 23:04:02 +030075 uint64_t nb_total = 0;
76 if (!avb_safe_add(&nb_total, sizeof(AvbDescriptor), nb_following)) {
77 avb_error("Invalid descriptor length.\n");
78 goto out;
79 }
Igor Opaniuk8b23ae22018-06-03 21:56:36 +030080
81 if ((nb_total & 7) != 0) {
82 avb_error("Invalid descriptor length.\n");
83 goto out;
84 }
85
86 if (nb_total + p < desc_start || nb_total + p > desc_end) {
87 avb_error("Invalid data in descriptors array.\n");
88 goto out;
89 }
90
91 if (foreach_func(dh, user_data) == 0) {
92 goto out;
93 }
94
Sam Protsenko6a717022019-08-15 23:04:02 +030095 if (!avb_safe_add_to((uint64_t*)(&p), nb_total)) {
96 avb_error("Invalid descriptor length.\n");
97 goto out;
98 }
Igor Opaniuk8b23ae22018-06-03 21:56:36 +030099 }
100
101 ret = true;
102
103out:
104 return ret;
105}
106
107static bool count_descriptors(const AvbDescriptor* descriptor,
108 void* user_data) {
109 size_t* num_descriptors = user_data;
110 *num_descriptors += 1;
111 return true;
112}
113
114typedef struct {
115 size_t descriptor_number;
116 const AvbDescriptor** descriptors;
117} SetDescriptorData;
118
119static bool set_descriptors(const AvbDescriptor* descriptor, void* user_data) {
120 SetDescriptorData* data = user_data;
121 data->descriptors[data->descriptor_number++] = descriptor;
122 return true;
123}
124
125const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
126 size_t image_size,
127 size_t* out_num_descriptors) {
128 size_t num_descriptors = 0;
129 SetDescriptorData data;
130
131 avb_descriptor_foreach(
132 image_data, image_size, count_descriptors, &num_descriptors);
133
134 data.descriptor_number = 0;
135 data.descriptors =
136 avb_calloc(sizeof(const AvbDescriptor*) * (num_descriptors + 1));
137 if (data.descriptors == NULL) {
138 return NULL;
139 }
140 avb_descriptor_foreach(image_data, image_size, set_descriptors, &data);
141 avb_assert(data.descriptor_number == num_descriptors);
142
143 if (out_num_descriptors != NULL) {
144 *out_num_descriptors = num_descriptors;
145 }
146
147 return data.descriptors;
148}