1 // SPDX-License-Identifier: MIT
3 * Copyright (C) 2016 The Android Open Source Project
6 #include "avb_descriptor.h"
8 #include "avb_vbmeta_image.h"
12 bool avb_descriptor_validate_and_byteswap(const AvbDescriptor* src,
13 AvbDescriptor* dest) {
14 dest->tag = avb_be64toh(src->tag);
15 dest->num_bytes_following = avb_be64toh(src->num_bytes_following);
17 if ((dest->num_bytes_following & 0x07) != 0) {
18 avb_error("Descriptor size is not divisible by 8.\n");
24 bool avb_descriptor_foreach(const uint8_t* image_data,
26 AvbDescriptorForeachFunc foreach_func,
28 const AvbVBMetaImageHeader* header = NULL;
30 const uint8_t* image_end;
31 const uint8_t* desc_start;
32 const uint8_t* desc_end;
35 if (image_data == NULL) {
36 avb_error("image_data is NULL\n.");
40 if (foreach_func == NULL) {
41 avb_error("foreach_func is NULL\n.");
45 if (image_size < sizeof(AvbVBMetaImageHeader)) {
46 avb_error("Length is smaller than header.\n");
50 /* Ensure magic is correct. */
51 if (avb_memcmp(image_data, AVB_MAGIC, AVB_MAGIC_LEN) != 0) {
52 avb_error("Magic is incorrect.\n");
56 /* Careful, not byteswapped - also ensure it's aligned properly. */
57 avb_assert_aligned(image_data);
58 header = (const AvbVBMetaImageHeader*)image_data;
59 image_end = image_data + image_size;
61 desc_start = image_data + sizeof(AvbVBMetaImageHeader) +
62 avb_be64toh(header->authentication_data_block_size) +
63 avb_be64toh(header->descriptors_offset);
65 desc_end = desc_start + avb_be64toh(header->descriptors_size);
67 if (desc_start < image_data || desc_start > image_end ||
68 desc_end < image_data || desc_end > image_end || desc_end < desc_start) {
69 avb_error("Descriptors not inside passed-in data.\n");
73 for (p = desc_start; p < desc_end;) {
74 const AvbDescriptor* dh = (const AvbDescriptor*)p;
75 avb_assert_aligned(dh);
76 uint64_t nb_following = avb_be64toh(dh->num_bytes_following);
77 uint64_t nb_total = 0;
78 if (!avb_safe_add(&nb_total, sizeof(AvbDescriptor), nb_following)) {
79 avb_error("Invalid descriptor length.\n");
83 if ((nb_total & 7) != 0) {
84 avb_error("Invalid descriptor length.\n");
88 if (nb_total + p < desc_start || nb_total + p > desc_end) {
89 avb_error("Invalid data in descriptors array.\n");
93 if (foreach_func(dh, user_data) == 0) {
97 if (!avb_safe_add_to((uint64_t*)(&p), nb_total)) {
98 avb_error("Invalid descriptor length.\n");
109 static bool count_descriptors(const AvbDescriptor* descriptor,
111 size_t* num_descriptors = user_data;
112 *num_descriptors += 1;
117 size_t descriptor_number;
118 const AvbDescriptor** descriptors;
121 static bool set_descriptors(const AvbDescriptor* descriptor, void* user_data) {
122 SetDescriptorData* data = user_data;
123 data->descriptors[data->descriptor_number++] = descriptor;
127 const AvbDescriptor** avb_descriptor_get_all(const uint8_t* image_data,
129 size_t* out_num_descriptors) {
130 size_t num_descriptors = 0;
131 SetDescriptorData data;
133 avb_descriptor_foreach(
134 image_data, image_size, count_descriptors, &num_descriptors);
136 data.descriptor_number = 0;
138 avb_calloc(sizeof(const AvbDescriptor*) * (num_descriptors + 1));
139 if (data.descriptors == NULL) {
142 avb_descriptor_foreach(image_data, image_size, set_descriptors, &data);
143 avb_assert(data.descriptor_number == num_descriptors);
145 if (out_num_descriptors != NULL) {
146 *out_num_descriptors = num_descriptors;
149 return data.descriptors;