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- // SPDX-License-Identifier: MIT
- /*
- * Copyright (C) 2016 The Android Open Source Project
- */
- #include "avb_property_descriptor.h"
- #include "avb_util.h"
- bool avb_property_descriptor_validate_and_byteswap(
- const AvbPropertyDescriptor* src, AvbPropertyDescriptor* dest) {
- uint64_t expected_size;
- avb_memcpy(dest, src, sizeof(AvbPropertyDescriptor));
- if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
- (AvbDescriptor*)dest))
- return false;
- if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
- avb_error("Invalid tag for property descriptor.\n");
- return false;
- }
- dest->key_num_bytes = avb_be64toh(dest->key_num_bytes);
- dest->value_num_bytes = avb_be64toh(dest->value_num_bytes);
- /* Check that key and value are fully contained. */
- expected_size = sizeof(AvbPropertyDescriptor) - sizeof(AvbDescriptor) + 2;
- if (!avb_safe_add_to(&expected_size, dest->key_num_bytes) ||
- !avb_safe_add_to(&expected_size, dest->value_num_bytes)) {
- avb_error("Overflow while adding up sizes.\n");
- return false;
- }
- if (expected_size > dest->parent_descriptor.num_bytes_following) {
- avb_error("Descriptor payload size overflow.\n");
- return false;
- }
- return true;
- }
- typedef struct {
- const char* key;
- size_t key_size;
- const char* ret_value;
- size_t ret_value_size;
- } PropertyIteratorData;
- static bool property_lookup_desc_foreach(const AvbDescriptor* header,
- void* user_data) {
- PropertyIteratorData* data = (PropertyIteratorData*)user_data;
- AvbPropertyDescriptor prop_desc;
- const uint8_t* p;
- bool ret = true;
- if (header->tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
- goto out;
- }
- if (!avb_property_descriptor_validate_and_byteswap(
- (const AvbPropertyDescriptor*)header, &prop_desc)) {
- goto out;
- }
- p = (const uint8_t*)header;
- if (p[sizeof(AvbPropertyDescriptor) + prop_desc.key_num_bytes] != 0) {
- avb_error("No terminating NUL byte in key.\n");
- goto out;
- }
- if (data->key_size == prop_desc.key_num_bytes) {
- if (avb_memcmp(p + sizeof(AvbPropertyDescriptor),
- data->key,
- data->key_size) == 0) {
- data->ret_value = (const char*)(p + sizeof(AvbPropertyDescriptor) +
- prop_desc.key_num_bytes + 1);
- data->ret_value_size = prop_desc.value_num_bytes;
- /* Stop iterating. */
- ret = false;
- goto out;
- }
- }
- out:
- return ret;
- }
- const char* avb_property_lookup(const uint8_t* image_data,
- size_t image_size,
- const char* key,
- size_t key_size,
- size_t* out_value_size) {
- PropertyIteratorData data;
- if (key_size == 0) {
- key_size = avb_strlen(key);
- }
- data.key = key;
- data.key_size = key_size;
- if (avb_descriptor_foreach(
- image_data, image_size, property_lookup_desc_foreach, &data) == 0) {
- if (out_value_size != NULL) {
- *out_value_size = data.ret_value_size;
- }
- return data.ret_value;
- }
- if (out_value_size != NULL) {
- *out_value_size = 0;
- }
- return NULL;
- }
- bool avb_property_lookup_uint64(const uint8_t* image_data,
- size_t image_size,
- const char* key,
- size_t key_size,
- uint64_t* out_value) {
- const char* value;
- bool ret = false;
- uint64_t parsed_val;
- int base;
- int n;
- value = avb_property_lookup(image_data, image_size, key, key_size, NULL);
- if (value == NULL) {
- goto out;
- }
- base = 10;
- if (avb_memcmp(value, "0x", 2) == 0) {
- base = 16;
- value += 2;
- }
- parsed_val = 0;
- for (n = 0; value[n] != '\0'; n++) {
- int c = value[n];
- int digit;
- parsed_val *= base;
- if (c >= '0' && c <= '9') {
- digit = c - '0';
- } else if (base == 16 && c >= 'a' && c <= 'f') {
- digit = c - 'a' + 10;
- } else if (base == 16 && c >= 'A' && c <= 'F') {
- digit = c - 'A' + 10;
- } else {
- avb_error("Invalid digit.\n");
- goto out;
- }
- parsed_val += digit;
- }
- ret = true;
- if (out_value != NULL) {
- *out_value = parsed_val;
- }
- out:
- return ret;
- }
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