/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "avb_property_descriptor.h"
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#include "avb_util.h"
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bool avb_property_descriptor_validate_and_byteswap(
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const AvbPropertyDescriptor* src, AvbPropertyDescriptor* dest) {
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uint64_t expected_size;
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avb_memcpy(dest, src, sizeof(AvbPropertyDescriptor));
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if (!avb_descriptor_validate_and_byteswap((const AvbDescriptor*)src,
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(AvbDescriptor*)dest))
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return false;
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if (dest->parent_descriptor.tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
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avb_error("Invalid tag for property descriptor.\n");
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return false;
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}
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dest->key_num_bytes = avb_be64toh(dest->key_num_bytes);
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dest->value_num_bytes = avb_be64toh(dest->value_num_bytes);
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/* Check that key and value are fully contained. */
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expected_size = sizeof(AvbPropertyDescriptor) - sizeof(AvbDescriptor) + 2;
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if (!avb_safe_add_to(&expected_size, dest->key_num_bytes) ||
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!avb_safe_add_to(&expected_size, dest->value_num_bytes)) {
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avb_error("Overflow while adding up sizes.\n");
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return false;
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}
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if (expected_size > dest->parent_descriptor.num_bytes_following) {
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avb_error("Descriptor payload size overflow.\n");
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return false;
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}
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return true;
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}
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typedef struct {
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const char* key;
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size_t key_size;
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const char* ret_value;
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size_t ret_value_size;
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} PropertyIteratorData;
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static bool property_lookup_desc_foreach(const AvbDescriptor* header,
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void* user_data) {
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PropertyIteratorData* data = (PropertyIteratorData*)user_data;
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AvbPropertyDescriptor prop_desc;
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const uint8_t* p;
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bool ret = true;
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if (header->tag != AVB_DESCRIPTOR_TAG_PROPERTY) {
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goto out;
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}
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if (!avb_property_descriptor_validate_and_byteswap(
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(const AvbPropertyDescriptor*)header, &prop_desc)) {
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goto out;
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}
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p = (const uint8_t*)header;
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if (p[sizeof(AvbPropertyDescriptor) + prop_desc.key_num_bytes] != 0) {
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avb_error("No terminating NUL byte in key.\n");
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goto out;
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}
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if (data->key_size == prop_desc.key_num_bytes) {
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if (avb_memcmp(p + sizeof(AvbPropertyDescriptor),
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data->key,
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data->key_size) == 0) {
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data->ret_value = (const char*)(p + sizeof(AvbPropertyDescriptor) +
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prop_desc.key_num_bytes + 1);
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data->ret_value_size = prop_desc.value_num_bytes;
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/* Stop iterating. */
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ret = false;
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goto out;
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}
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}
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out:
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return ret;
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}
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const char* avb_property_lookup(const uint8_t* image_data,
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size_t image_size,
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const char* key,
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size_t key_size,
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size_t* out_value_size) {
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PropertyIteratorData data;
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if (key_size == 0) {
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key_size = avb_strlen(key);
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}
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data.key = key;
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data.key_size = key_size;
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if (avb_descriptor_foreach(
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image_data, image_size, property_lookup_desc_foreach, &data) == 0) {
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if (out_value_size != NULL) {
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*out_value_size = data.ret_value_size;
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}
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return data.ret_value;
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}
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if (out_value_size != NULL) {
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*out_value_size = 0;
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}
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return NULL;
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}
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bool avb_property_lookup_uint64(const uint8_t* image_data,
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size_t image_size,
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const char* key,
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size_t key_size,
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uint64_t* out_value) {
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const char* value;
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bool ret = false;
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uint64_t parsed_val;
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int base;
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int n;
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value = avb_property_lookup(image_data, image_size, key, key_size, NULL);
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if (value == NULL) {
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goto out;
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}
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base = 10;
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if (avb_memcmp(value, "0x", 2) == 0) {
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base = 16;
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value += 2;
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}
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parsed_val = 0;
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for (n = 0; value[n] != '\0'; n++) {
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int c = value[n];
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int digit;
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parsed_val *= base;
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if (c >= '0' && c <= '9') {
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digit = c - '0';
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} else if (base == 16 && c >= 'a' && c <= 'f') {
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digit = c - 'a' + 10;
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} else if (base == 16 && c >= 'A' && c <= 'F') {
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digit = c - 'A' + 10;
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} else {
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avb_error("Invalid digit.\n");
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goto out;
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}
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parsed_val += digit;
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}
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ret = true;
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if (out_value != NULL) {
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*out_value = parsed_val;
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}
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out:
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return ret;
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}
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