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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <string.h>
#include <stddef.h>
#include <assert.h>
#include "authorization_set.h"
namespace keymaster {
static inline bool is_blob_tag(keymaster_tag_t tag) {
return (keymaster_tag_get_type(tag) == KM_BYTES || keymaster_tag_get_type(tag) == KM_BIGNUM);
}
const size_t STARTING_ELEMS_CAPACITY = 8;
AuthorizationSet::~AuthorizationSet() {
FreeData();
}
bool AuthorizationSet::Reinitialize(const keymaster_key_param_t* elems, const size_t count) {
FreeData();
elems_size_ = count;
elems_capacity_ = count;
indirect_data_size_ = ComputeIndirectDataSize(elems, count);
indirect_data_capacity_ = indirect_data_size_;
error_ = OK_GROWABLE;
indirect_data_ = new uint8_t[indirect_data_size_];
elems_ = new keymaster_key_param_t[elems_size_];
if (indirect_data_ == NULL || elems_ == NULL) {
set_invalid(ALLOCATION_FAILURE);
return false;
}
owns_data_ = true;
memcpy(elems_, elems, sizeof(keymaster_key_param_t) * elems_size_);
CopyIndirectData();
ConvertPointersToOffsets(elems_, elems_size_, indirect_data_);
return true;
}
AuthorizationSet::AuthorizationSet(uint8_t* serialized_set, size_t length) : owns_data_(false) {
if (!DeserializeInPlace(&serialized_set, serialized_set + length))
set_invalid(MALFORMED_DATA);
}
void AuthorizationSet::Reinitialize(keymaster_key_param_t* elems_array, size_t elems_buf_count,
uint8_t* indirect_data_buf, size_t indirect_data_buf_size) {
FreeData();
elems_ = elems_array;
elems_size_ = 0;
elems_capacity_ = elems_buf_count;
indirect_data_ = indirect_data_buf;
indirect_data_size_ = 0;
indirect_data_capacity_ = indirect_data_buf_size;
owns_data_ = false;
if (CheckIndirectDataOffsets()) {
error_ = OK_GROWABLE;
}
}
void AuthorizationSet::set_invalid(Error error) {
error_ = error;
FreeData();
}
int AuthorizationSet::find(keymaster_tag_t tag, int begin) const {
int i = ++begin;
for (; i < (int)elems_size_ && elems_[i].tag != tag; ++i) {
}
if (i == (int)elems_size_)
return -1;
else
return i;
}
keymaster_key_param_t empty;
keymaster_key_param_t AuthorizationSet::operator[](int at) const {
if (at < (int)elems_size_) {
keymaster_key_param_t retval = elems_[at];
if (is_blob_tag(elems_[at].tag)) {
// Data "pointer" is actually an offset. Convert it to a pointer.
retval.blob.data = indirect_data_ + reinterpret_cast<ptrdiff_t>(retval.blob.data);
}
return retval;
}
memset(&empty, 0, sizeof(empty));
return empty;
}
bool AuthorizationSet::push_back(keymaster_key_param_t elem) {
if (elems_size_ >= elems_capacity_) {
if (owns_data_) {
size_t new_capacity = elems_capacity_ ? elems_capacity_ * 2 : STARTING_ELEMS_CAPACITY;
keymaster_key_param_t* new_elems = new keymaster_key_param_t[new_capacity];
if (new_elems == NULL) {
set_invalid(ALLOCATION_FAILURE);
return false;
}
memcpy(new_elems, elems_, sizeof(*elems_) * elems_size_);
delete[] elems_;
elems_ = new_elems;
elems_capacity_ = new_capacity;
} else {
return false;
}
}
if (is_blob_tag(elem.tag)) {
if (indirect_data_capacity_ - indirect_data_size_ < elem.blob.data_length) {
if (owns_data_) {
size_t new_capacity = 2 * (indirect_data_capacity_ + elem.blob.data_length);
uint8_t* new_data = new uint8_t[new_capacity];
if (new_data == false) {
set_invalid(ALLOCATION_FAILURE);
return false;
}
memcpy(new_data, indirect_data_, indirect_data_size_);
delete[] indirect_data_;
indirect_data_ = new_data;
indirect_data_capacity_ = new_capacity;
} else {
return false;
}
}
memcpy(indirect_data_ + indirect_data_size_, elem.blob.data, elem.blob.data_length);
elem.blob.data = reinterpret_cast<uint8_t*>(indirect_data_size_);
indirect_data_size_ += elem.blob.data_length;
}
elems_[elems_size_++] = elem;
if (elems_size_ == elems_capacity_ && !owns_data_) {
error_ = OK_FULL;
}
return true;
}
uint8_t* AuthorizationSet::Serialize(uint8_t* serialized_set) const {
serialized_set =
append_size_and_data_to_buf(serialized_set, elems_, elems_size_ * sizeof(*elems_));
return append_size_and_data_to_buf(serialized_set, indirect_data_, indirect_data_size_);
}
bool AuthorizationSet::DeserializeInPlace(uint8_t** buf, const uint8_t* end) {
uint32_t elems_buf_size;
if (!copy_from_buf(buf, end, &elems_buf_size) ||
(elems_buf_size % sizeof(keymaster_key_param_t)) != 0 || end < (*buf + elems_buf_size)) {
return false;
}
keymaster_key_param_t* elems = reinterpret_cast<keymaster_key_param_t*>(*buf);
*buf += elems_buf_size;
uint32_t indirect_size;
if (!copy_from_buf(buf, end, &indirect_size) ||
indirect_size !=
ComputeIndirectDataSize(elems, elems_buf_size / sizeof(keymaster_key_param_t)))
return false;
uint8_t* indirect_data = *buf;
*buf += indirect_size;
FreeData();
owns_data_ = false;
elems_ = elems;
elems_size_ = elems_buf_size / sizeof(keymaster_key_param_t);
elems_capacity_ = elems_size_;
indirect_data_ = indirect_data;
indirect_data_size_ = indirect_size;
indirect_data_capacity_ = indirect_size;
if (CheckIndirectDataOffsets()) {
error_ = OK_FULL;
return true;
}
return false;
}
bool AuthorizationSet::DeserializeToCopy(const uint8_t** buf, const uint8_t* end) {
FreeData();
owns_data_ = true;
uint32_t elems_buf_size;
if (!copy_from_buf(buf, end, &elems_buf_size) ||
(elems_buf_size % sizeof(keymaster_key_param_t)) != 0 || end < (*buf + elems_buf_size)) {
return false;
}
elems_ = new keymaster_key_param_t[elems_buf_size / sizeof(keymaster_key_param_t)];
if (elems_ == NULL) {
set_invalid(ALLOCATION_FAILURE);
return false;
}
memcpy(elems_, *buf, elems_buf_size);
*buf += elems_buf_size;
uint32_t indirect_size;
if (!copy_from_buf(buf, end, &indirect_size) ||
indirect_size !=
ComputeIndirectDataSize(elems_, elems_buf_size / sizeof(keymaster_key_param_t)))
return false;
indirect_data_ = new uint8_t[indirect_size];
if (indirect_data_ == NULL) {
set_invalid(ALLOCATION_FAILURE);
return false;
}
memcpy(indirect_data_, *buf, indirect_size);
*buf += indirect_size;
elems_size_ = elems_buf_size / sizeof(keymaster_key_param_t);
elems_capacity_ = elems_size_;
indirect_data_size_ = indirect_size;
indirect_data_capacity_ = indirect_size;
owns_data_ = true;
error_ = OK_GROWABLE;
return CheckIndirectDataOffsets();
}
void AuthorizationSet::FreeData() {
if (owns_data_) {
delete[] elems_;
delete[] indirect_data_;
}
elems_ = NULL;
indirect_data_ = NULL;
elems_size_ = 0;
elems_capacity_ = 0;
indirect_data_size_ = 0;
indirect_data_capacity_ = 0;
}
/* static */
size_t AuthorizationSet::ComputeIndirectDataSize(const keymaster_key_param_t* elems, size_t count) {
size_t size = 0;
for (size_t i = 0; i < count; ++i) {
if (is_blob_tag(elems[i].tag)) {
size += elems[i].blob.data_length;
}
}
return size;
}
void AuthorizationSet::CopyIndirectData() {
memset(indirect_data_, 0, indirect_data_size_);
uint8_t* indirect_data_pos = indirect_data_;
for (size_t i = 0; i < elems_size_; ++i) {
assert(indirect_data_pos <= indirect_data_ + indirect_data_size_);
if (is_blob_tag(elems_[i].tag)) {
memcpy(indirect_data_pos, elems_[i].blob.data, elems_[i].blob.data_length);
elems_[i].blob.data = indirect_data_pos;
indirect_data_pos += elems_[i].blob.data_length;
}
}
assert(indirect_data_pos == indirect_data_ + indirect_data_size_);
}
/* static */
void AuthorizationSet::ConvertPointersToOffsets(keymaster_key_param_t* elems, size_t count,
const uint8_t* indirect_base) {
for (size_t i = 0; i < count; ++i) {
if (is_blob_tag(elems[i].tag)) {
elems[i].blob.data = reinterpret_cast<uint8_t*>(elems[i].blob.data - indirect_base);
}
}
}
bool AuthorizationSet::CheckIndirectDataOffsets() {
// TODO(swillden): Find an efficient way to test for overlaps. Verifying that the total size of
// the indirect blobs found matches the size of the indirect data buffer and that all of the
// offsets fall into the correct region precludes most sorts of indirect data table
// malformation, but it doesn't prevent overlaps which are accompanied by unused regions whose
// total size exactly offsets the overlaps.
size_t computed_indirect_data_size = 0;
for (size_t i = 0; i < elems_size_; ++i) {
if (is_blob_tag(elems_[i].tag)) {
computed_indirect_data_size += elems_[i].blob.data_length;
ptrdiff_t offset = reinterpret_cast<ptrdiff_t>(elems_[i].blob.data);
if (offset < 0 || offset > (ptrdiff_t)indirect_data_size_ ||
offset + elems_[i].blob.data_length > indirect_data_size_) {
set_invalid(BOUNDS_CHECKING_FAILURE);
return false;
}
}
}
if (computed_indirect_data_size != indirect_data_size_) {
set_invalid(MALFORMED_DATA);
return false;
}
return true;
}
bool AuthorizationSet::GetTagValueEnum(keymaster_tag_t tag, uint32_t* val) const {
int pos = find(tag);
if (pos == -1) {
return false;
}
*val = (*this)[pos].enumerated;
return true;
}
bool AuthorizationSet::GetTagValueEnumRep(keymaster_tag_t tag, size_t instance,
uint32_t* val) const {
size_t count = 0;
int pos = -1;
while (count <= instance) {
pos = find(tag, pos);
if (pos == -1) {
return false;
}
++count;
}
*val = (*this)[pos].enumerated;
return true;
}
bool AuthorizationSet::GetTagValueInt(keymaster_tag_t tag, uint32_t* val) const {
int pos = find(tag);
if (pos == -1) {
return false;
}
*val = (*this)[pos].integer;
return true;
}
bool AuthorizationSet::GetTagValueIntRep(keymaster_tag_t tag, size_t instance,
uint32_t* val) const {
size_t count = 0;
int pos = -1;
while (count <= instance) {
pos = find(tag, pos);
if (pos == -1) {
return false;
}
++count;
}
*val = (*this)[pos].integer;
return true;
}
bool AuthorizationSet::GetTagValueLong(keymaster_tag_t tag, uint64_t* val) const {
int pos = find(tag);
if (pos == -1) {
return false;
}
*val = (*this)[pos].long_integer;
return true;
}
bool AuthorizationSet::GetTagValueDate(keymaster_tag_t tag, uint64_t* val) const {
int pos = find(tag);
if (pos == -1) {
return false;
}
*val = (*this)[pos].date_time;
return true;
}
bool AuthorizationSet::GetTagValueBlob(keymaster_tag_t tag, keymaster_blob_t* val) const {
int pos = find(tag);
if (pos == -1) {
return false;
}
*val = (*this)[pos].blob;
return true;
}
} // namespace keymaster