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/*
* Copyright (C) 2019 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 "idmap2/ResourceMapping.h"
#include <map>
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "android-base/stringprintf.h"
#include "androidfw/ResourceTypes.h"
#include "idmap2/PolicyUtils.h"
#include "idmap2/ResourceUtils.h"
using android::base::StringPrintf;
using android::idmap2::utils::BitmaskToPolicies;
using PolicyBitmask = android::ResTable_overlayable_policy_header::PolicyBitmask;
using PolicyFlags = android::ResTable_overlayable_policy_header::PolicyFlags;
namespace android::idmap2 {
namespace {
std::string ConcatPolicies(const std::vector<std::string>& policies) {
std::string message;
for (const std::string& policy : policies) {
if (!message.empty()) {
message.append("|");
}
message.append(policy);
}
return message;
}
Result<Unit> CheckOverlayable(const TargetResourceContainer& target,
const OverlayManifestInfo& overlay_info,
const PolicyBitmask& fulfilled_policies,
const ResourceId& target_resource) {
constexpr const PolicyBitmask kDefaultPolicies =
PolicyFlags::ODM_PARTITION | PolicyFlags::OEM_PARTITION | PolicyFlags::SYSTEM_PARTITION |
PolicyFlags::VENDOR_PARTITION | PolicyFlags::PRODUCT_PARTITION | PolicyFlags::SIGNATURE |
PolicyFlags::CONFIG_SIGNATURE;
// If the resource does not have an overlayable definition, allow the resource to be overlaid if
// the overlay is preinstalled, signed with the same signature as the target or signed with the
// same signature as reference package defined in SystemConfig under 'overlay-config-signature'
// tag.
const Result<bool> defines_overlayable = target.DefinesOverlayable();
if (!defines_overlayable) {
return Error(defines_overlayable.GetError(), "unable to retrieve overlayable info");
}
if (!*defines_overlayable) {
return (kDefaultPolicies & fulfilled_policies) != 0
? Result<Unit>({})
: Error(
"overlay must be preinstalled, signed with the same signature as the target,"
" or signed with the same signature as the package referenced through"
" <overlay-config-signature>.");
}
const auto overlayable_info = target.GetOverlayableInfo(target_resource);
if (!overlayable_info) {
return overlayable_info.GetError();
}
if (*overlayable_info == nullptr) {
// Do not allow non-overlayable resources to be overlaid.
return Error("target resource has no overlayable declaration");
}
if (overlay_info.target_name != (*overlayable_info)->name) {
// If the overlay supplies a target overlayable name, the resource must belong to the
// overlayable defined with the specified name to be overlaid.
return Error(R"(<overlay> android:targetName "%s" does not match overlayable name "%s")",
overlay_info.target_name.c_str(), (*overlayable_info)->name.c_str());
}
// Enforce policy restrictions if the resource is declared as overlayable.
if (((*overlayable_info)->policy_flags & fulfilled_policies) == 0) {
return Error(R"(overlay with policies "%s" does not fulfill any overlayable policies "%s")",
ConcatPolicies(BitmaskToPolicies(fulfilled_policies)).c_str(),
ConcatPolicies(BitmaskToPolicies((*overlayable_info)->policy_flags)).c_str());
}
return Result<Unit>({});
}
std::string GetDebugResourceName(const ResourceContainer& container, ResourceId resid) {
auto name = container.GetResourceName(resid);
if (name) {
return *name;
}
return StringPrintf("0x%08x", resid);
}
} // namespace
Result<ResourceMapping> ResourceMapping::FromContainers(const TargetResourceContainer& target,
const OverlayResourceContainer& overlay,
const OverlayManifestInfo& overlay_info,
const PolicyBitmask& fulfilled_policies,
bool enforce_overlayable,
LogInfo& log_info) {
auto overlay_data = overlay.GetOverlayData(overlay_info);
if (!overlay_data) {
return overlay_data.GetError();
}
ResourceMapping mapping;
for (const auto& overlay_pair : overlay_data->pairs) {
const auto target_resid = target.GetResourceId(overlay_pair.resource_name);
if (!target_resid) {
log_info.Warning(LogMessage() << target_resid.GetErrorMessage());
continue;
}
if (enforce_overlayable) {
// Filter out resources the overlay is not allowed to override.
auto overlayable = CheckOverlayable(target, overlay_info, fulfilled_policies, *target_resid);
if (!overlayable) {
log_info.Warning(LogMessage() << "overlay '" << overlay.GetPath()
<< "' is not allowed to overlay resource '"
<< GetDebugResourceName(target, *target_resid)
<< "' in target: " << overlayable.GetErrorMessage());
continue;
}
}
if (auto result = mapping.AddMapping(*target_resid, overlay_pair.value); !result) {
return Error(result.GetError(), "failed to add mapping for '%s'",
GetDebugResourceName(target, *target_resid).c_str());
}
}
auto& string_pool_data = overlay_data->string_pool_data;
if (string_pool_data.has_value()) {
mapping.string_pool_offset_ = string_pool_data->string_pool_offset;
mapping.string_pool_data_ = std::move(string_pool_data->data);
mapping.string_pool_data_length_ = string_pool_data->data_length;
}
return std::move(mapping);
}
Result<Unit> ResourceMapping::AddMapping(
ResourceId target_resource,
const std::variant<OverlayData::ResourceIdValue, TargetValue>& value) {
if (target_map_.find(target_resource) != target_map_.end()) {
return Error(R"(target resource id "0x%08x" mapped to multiple values)", target_resource);
}
// TODO(141485591): Ensure that the overlay type is compatible with the target type. If the
// runtime types are not compatible, it could cause runtime crashes when the resource is resolved.
if (auto overlay_resource = std::get_if<OverlayData::ResourceIdValue>(&value)) {
target_map_.insert(std::make_pair(target_resource, overlay_resource->overlay_id));
if (overlay_resource->rewrite_id) {
// An overlay resource can override multiple target resources at once. Rewrite the overlay
// resource as the first target resource it overrides.
overlay_map_.insert(std::make_pair(overlay_resource->overlay_id, target_resource));
}
} else {
auto overlay_value = std::get<TargetValue>(value);
target_map_.insert(std::make_pair(target_resource, overlay_value));
}
return Unit{};
}
} // namespace android::idmap2