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Diffstat (limited to 'cmds/idmap2/libidmap2/ResourceMapping.cpp')
| -rw-r--r-- | cmds/idmap2/libidmap2/ResourceMapping.cpp | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/cmds/idmap2/libidmap2/ResourceMapping.cpp b/cmds/idmap2/libidmap2/ResourceMapping.cpp new file mode 100644 index 000000000000..34589a1c39dc --- /dev/null +++ b/cmds/idmap2/libidmap2/ResourceMapping.cpp @@ -0,0 +1,438 @@ +/* + * 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 android::idmap2::utils::IsReference; +using android::idmap2::utils::ResToTypeEntryName; +using PolicyBitmask = android::ResTable_overlayable_policy_header::PolicyBitmask; +using PolicyFlags = android::ResTable_overlayable_policy_header::PolicyFlags; + +namespace android::idmap2 { + +namespace { + +#define REWRITE_PACKAGE(resid, package_id) \ + (((resid)&0x00ffffffU) | (((uint32_t)(package_id)) << 24U)) +#define EXTRACT_PACKAGE(resid) ((0xff000000 & (resid)) >> 24) + +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 LoadedPackage& target_package, + const OverlayManifestInfo& overlay_info, + const PolicyBitmask& fulfilled_policies, + const ResourceId& target_resource) { + static constexpr const PolicyBitmask sDefaultPolicies = + PolicyFlags::ODM_PARTITION | PolicyFlags::OEM_PARTITION | PolicyFlags::SYSTEM_PARTITION | + PolicyFlags::VENDOR_PARTITION | PolicyFlags::PRODUCT_PARTITION | PolicyFlags::SIGNATURE; + + // If the resource does not have an overlayable definition, allow the resource to be overlaid if + // the overlay is preinstalled or signed with the same signature as the target. + if (!target_package.DefinesOverlayable()) { + return (sDefaultPolicies & fulfilled_policies) != 0 + ? Result<Unit>({}) + : Error( + "overlay must be preinstalled or signed with the same signature as the " + "target"); + } + + const OverlayableInfo* overlayable_info = target_package.GetOverlayableInfo(target_resource); + 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>({}); +} + +// TODO(martenkongstad): scan for package name instead of assuming package at index 0 +// +// idmap version 0x01 naively assumes that the package to use is always the first ResTable_package +// in the resources.arsc blob. In most cases, there is only a single ResTable_package anyway, so +// this assumption tends to work out. That said, the correct thing to do is to scan +// resources.arsc for a package with a given name as read from the package manifest instead of +// relying on a hard-coded index. This however requires storing the package name in the idmap +// header, which in turn requires incrementing the idmap version. Because the initial version of +// idmap2 is compatible with idmap, this will have to wait for now. +const LoadedPackage* GetPackageAtIndex0(const LoadedArsc& loaded_arsc) { + const std::vector<std::unique_ptr<const LoadedPackage>>& packages = loaded_arsc.GetPackages(); + if (packages.empty()) { + return nullptr; + } + int id = packages[0]->GetPackageId(); + return loaded_arsc.GetPackageById(id); +} + +Result<std::unique_ptr<Asset>> OpenNonAssetFromResource(const ResourceId& resource_id, + const AssetManager2& asset_manager) { + Res_value value{}; + ResTable_config selected_config{}; + uint32_t flags; + auto cookie = + asset_manager.GetResource(resource_id, /* may_be_bag */ false, + /* density_override */ 0U, &value, &selected_config, &flags); + if (cookie == kInvalidCookie) { + return Error("failed to find resource for id 0x%08x", resource_id); + } + + if (value.dataType != Res_value::TYPE_STRING) { + return Error("resource for is 0x%08x is not a file", resource_id); + } + + auto string_pool = asset_manager.GetStringPoolForCookie(cookie); + size_t len; + auto file_path16 = string_pool->stringAt(value.data, &len); + if (file_path16 == nullptr) { + return Error("failed to find string for index %d", value.data); + } + + // Load the overlay resource mappings from the file specified using android:resourcesMap. + auto file_path = String8(String16(file_path16)); + auto asset = asset_manager.OpenNonAsset(file_path.c_str(), Asset::AccessMode::ACCESS_BUFFER); + if (asset == nullptr) { + return Error("file \"%s\" not found", file_path.c_str()); + } + + return asset; +} + +} // namespace + +Result<ResourceMapping> ResourceMapping::CreateResourceMapping(const AssetManager2* target_am, + const LoadedPackage* target_package, + const LoadedPackage* overlay_package, + size_t string_pool_offset, + const XmlParser& overlay_parser, + LogInfo& log_info) { + ResourceMapping resource_mapping; + auto root_it = overlay_parser.tree_iterator(); + if (root_it->event() != XmlParser::Event::START_TAG || root_it->name() != "overlay") { + return Error("root element is not <overlay> tag"); + } + + const uint8_t target_package_id = target_package->GetPackageId(); + const uint8_t overlay_package_id = overlay_package->GetPackageId(); + auto overlay_it_end = root_it.end(); + for (auto overlay_it = root_it.begin(); overlay_it != overlay_it_end; ++overlay_it) { + if (overlay_it->event() == XmlParser::Event::BAD_DOCUMENT) { + return Error("failed to parse overlay xml document"); + } + + if (overlay_it->event() != XmlParser::Event::START_TAG) { + continue; + } + + if (overlay_it->name() != "item") { + return Error("unexpected tag <%s> in <overlay>", overlay_it->name().c_str()); + } + + Result<std::string> target_resource = overlay_it->GetAttributeStringValue("target"); + if (!target_resource) { + return Error(R"(<item> tag missing expected attribute "target")"); + } + + Result<android::Res_value> overlay_resource = overlay_it->GetAttributeValue("value"); + if (!overlay_resource) { + return Error(R"(<item> tag missing expected attribute "value")"); + } + + ResourceId target_id = + target_am->GetResourceId(*target_resource, "", target_package->GetPackageName()); + if (target_id == 0U) { + log_info.Warning(LogMessage() << "failed to find resource \"" << *target_resource + << "\" in target resources"); + continue; + } + + // Retrieve the compile-time resource id of the target resource. + target_id = REWRITE_PACKAGE(target_id, target_package_id); + + if (overlay_resource->dataType == Res_value::TYPE_STRING) { + overlay_resource->data += string_pool_offset; + } + + // Only rewrite resources defined within the overlay package to their corresponding target + // resource ids at runtime. + bool rewrite_overlay_reference = + IsReference(overlay_resource->dataType) + ? overlay_package_id == EXTRACT_PACKAGE(overlay_resource->data) + : false; + + if (rewrite_overlay_reference) { + overlay_resource->dataType = Res_value::TYPE_DYNAMIC_REFERENCE; + } + + resource_mapping.AddMapping(target_id, overlay_resource->dataType, overlay_resource->data, + rewrite_overlay_reference); + } + + return resource_mapping; +} + +Result<ResourceMapping> ResourceMapping::CreateResourceMappingLegacy( + const AssetManager2* target_am, const AssetManager2* overlay_am, + const LoadedPackage* target_package, const LoadedPackage* overlay_package) { + ResourceMapping resource_mapping; + const uint8_t target_package_id = target_package->GetPackageId(); + const auto end = overlay_package->end(); + for (auto iter = overlay_package->begin(); iter != end; ++iter) { + const ResourceId overlay_resid = *iter; + Result<std::string> name = utils::ResToTypeEntryName(*overlay_am, overlay_resid); + if (!name) { + continue; + } + + // Find the resource with the same type and entry name within the target package. + const std::string full_name = + base::StringPrintf("%s:%s", target_package->GetPackageName().c_str(), name->c_str()); + ResourceId target_resource = target_am->GetResourceId(full_name); + if (target_resource == 0U) { + continue; + } + + // Retrieve the compile-time resource id of the target resource. + target_resource = REWRITE_PACKAGE(target_resource, target_package_id); + + resource_mapping.AddMapping(target_resource, Res_value::TYPE_REFERENCE, overlay_resid, + /* rewrite_overlay_reference */ false); + } + + return resource_mapping; +} + +void ResourceMapping::FilterOverlayableResources(const AssetManager2* target_am, + const LoadedPackage* target_package, + const LoadedPackage* overlay_package, + const OverlayManifestInfo& overlay_info, + const PolicyBitmask& fulfilled_policies, + LogInfo& log_info) { + std::set<ResourceId> remove_ids; + for (const auto& target_map : target_map_) { + const ResourceId target_resid = target_map.first; + Result<Unit> success = + CheckOverlayable(*target_package, overlay_info, fulfilled_policies, target_resid); + if (success) { + continue; + } + + // Attempting to overlay a resource that is not allowed to be overlaid is treated as a + // warning. + Result<std::string> name = utils::ResToTypeEntryName(*target_am, target_resid); + if (!name) { + name = StringPrintf("0x%08x", target_resid); + } + + log_info.Warning(LogMessage() << "overlay \"" << overlay_package->GetPackageName() + << "\" is not allowed to overlay resource \"" << *name + << "\" in target: " << success.GetErrorMessage()); + + remove_ids.insert(target_resid); + } + + for (const ResourceId target_resid : remove_ids) { + RemoveMapping(target_resid); + } +} + +Result<ResourceMapping> ResourceMapping::FromApkAssets(const ApkAssets& target_apk_assets, + const ApkAssets& overlay_apk_assets, + const OverlayManifestInfo& overlay_info, + const PolicyBitmask& fulfilled_policies, + bool enforce_overlayable, + LogInfo& log_info) { + AssetManager2 target_asset_manager; + if (!target_asset_manager.SetApkAssets({&target_apk_assets}, true /* invalidate_caches */, + false /* filter_incompatible_configs*/)) { + return Error("failed to create target asset manager"); + } + + AssetManager2 overlay_asset_manager; + if (!overlay_asset_manager.SetApkAssets({&overlay_apk_assets}, true /* invalidate_caches */, + false /* filter_incompatible_configs */)) { + return Error("failed to create overlay asset manager"); + } + + const LoadedArsc* target_arsc = target_apk_assets.GetLoadedArsc(); + if (target_arsc == nullptr) { + return Error("failed to load target resources.arsc"); + } + + const LoadedArsc* overlay_arsc = overlay_apk_assets.GetLoadedArsc(); + if (overlay_arsc == nullptr) { + return Error("failed to load overlay resources.arsc"); + } + + const LoadedPackage* target_pkg = GetPackageAtIndex0(*target_arsc); + if (target_pkg == nullptr) { + return Error("failed to load target package from resources.arsc"); + } + + const LoadedPackage* overlay_pkg = GetPackageAtIndex0(*overlay_arsc); + if (overlay_pkg == nullptr) { + return Error("failed to load overlay package from resources.arsc"); + } + + size_t string_pool_data_length = 0U; + size_t string_pool_offset = 0U; + std::unique_ptr<uint8_t[]> string_pool_data; + Result<ResourceMapping> resource_mapping = {{}}; + if (overlay_info.resource_mapping != 0U) { + // Use the dynamic reference table to find the assigned resource id of the map xml. + const auto& ref_table = overlay_asset_manager.GetDynamicRefTableForCookie(0); + uint32_t resource_mapping_id = overlay_info.resource_mapping; + ref_table->lookupResourceId(&resource_mapping_id); + + // Load the overlay resource mappings from the file specified using android:resourcesMap. + auto asset = OpenNonAssetFromResource(resource_mapping_id, overlay_asset_manager); + if (!asset) { + return Error("failed opening xml for android:resourcesMap: %s", + asset.GetErrorMessage().c_str()); + } + + auto parser = + XmlParser::Create((*asset)->getBuffer(true /* wordAligned*/), (*asset)->getLength()); + if (!parser) { + return Error("failed opening ResXMLTree"); + } + + // Copy the xml string pool data before the parse goes out of scope. + auto& string_pool = (*parser)->get_strings(); + string_pool_data_length = string_pool.bytes(); + string_pool_data.reset(new uint8_t[string_pool_data_length]); + memcpy(string_pool_data.get(), string_pool.data(), string_pool_data_length); + + // Offset string indices by the size of the overlay resource table string pool. + string_pool_offset = overlay_arsc->GetStringPool()->size(); + + resource_mapping = CreateResourceMapping(&target_asset_manager, target_pkg, overlay_pkg, + string_pool_offset, *(*parser), log_info); + } else { + // If no file is specified using android:resourcesMap, it is assumed that the overlay only + // defines resources intended to override target resources of the same type and name. + resource_mapping = CreateResourceMappingLegacy(&target_asset_manager, &overlay_asset_manager, + target_pkg, overlay_pkg); + } + + if (!resource_mapping) { + return resource_mapping.GetError(); + } + + if (enforce_overlayable) { + // Filter out resources the overlay is not allowed to override. + (*resource_mapping) + .FilterOverlayableResources(&target_asset_manager, target_pkg, overlay_pkg, overlay_info, + fulfilled_policies, log_info); + } + + resource_mapping->target_package_id_ = target_pkg->GetPackageId(); + resource_mapping->overlay_package_id_ = overlay_pkg->GetPackageId(); + resource_mapping->string_pool_offset_ = string_pool_offset; + resource_mapping->string_pool_data_ = std::move(string_pool_data); + resource_mapping->string_pool_data_length_ = string_pool_data_length; + return std::move(*resource_mapping); +} + +OverlayResourceMap ResourceMapping::GetOverlayToTargetMap() const { + // An overlay resource can override multiple target resources at once. Rewrite the overlay + // resource as the first target resource it overrides. + OverlayResourceMap map; + for (const auto& mappings : overlay_map_) { + map.insert(std::make_pair(mappings.first, mappings.second)); + } + return map; +} + +Result<Unit> ResourceMapping::AddMapping(ResourceId target_resource, + TargetValue::DataType data_type, + TargetValue::DataValue data_value, + bool rewrite_overlay_reference) { + 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. + + target_map_.insert(std::make_pair(target_resource, TargetValue{data_type, data_value})); + + if (rewrite_overlay_reference && IsReference(data_type)) { + overlay_map_.insert(std::make_pair(data_value, target_resource)); + } + + return Result<Unit>({}); +} + +void ResourceMapping::RemoveMapping(ResourceId target_resource) { + auto target_iter = target_map_.find(target_resource); + if (target_iter == target_map_.end()) { + return; + } + + const TargetValue value = target_iter->second; + target_map_.erase(target_iter); + + if (!IsReference(value.data_type)) { + return; + } + + auto overlay_iter = overlay_map_.equal_range(value.data_value); + for (auto i = overlay_iter.first; i != overlay_iter.second; ++i) { + if (i->second == target_resource) { + overlay_map_.erase(i); + return; + } + } +} + +} // namespace android::idmap2 |