Merge "Fix allowlist for unreliable pinning." (0198ce0c) · Commits · e / os / android_system_core

fs_mgr/libfiemap/image_manager.cpp

+7 −7

Original line number	Diff line number	Diff line
		@@ -136,13 +136,13 @@ bool ImageManager::BackingImageExists(const std::string& name) {
		return !!FindPartition(*metadata.get(), name);
		}

		static bool IsTestDir(const std::string& path) {
		return android::base::StartsWith(path, kTestImageMetadataDir) \|\|
		android::base::StartsWith(path, kOtaTestImageMetadataDir);
		bool ImageManager::MetadataDirIsTest() const {
		return IsSubdir(metadata_dir_, kTestImageMetadataDir) \|\|
		IsSubdir(metadata_dir_, kOtaTestImageMetadataDir);
		}

		static bool IsUnreliablePinningAllowed(const std::string& path) {
		return android::base::StartsWith(path, "/data/gsi/dsu/") \|\| IsTestDir(path);
		bool ImageManager::IsUnreliablePinningAllowed() const {
		return IsSubdir(data_dir_, "/data/gsi/dsu/") \|\| MetadataDirIsTest();
		}

		FiemapStatus ImageManager::CreateBackingImage(
		@@ -159,7 +159,7 @@ FiemapStatus ImageManager::CreateBackingImage(
		if (!FilesystemHasReliablePinning(data_path, &reliable_pinning)) {
		return FiemapStatus::Error();
		}
		if (!reliable_pinning && !IsUnreliablePinningAllowed(data_path)) {
		if (!reliable_pinning && !IsUnreliablePinningAllowed()) {
		// For historical reasons, we allow unreliable pinning for certain use
		// cases (DSUs, testing) because the ultimate use case is either
		// developer-oriented or ephemeral (the intent is to boot immediately
		@@ -178,7 +178,7 @@ FiemapStatus ImageManager::CreateBackingImage(
		// if device-mapper is stacked in some complex way not supported by
		// FiemapWriter.
		auto device_path = GetDevicePathForFile(fw.get());
		if (android::base::StartsWith(device_path, "/dev/block/dm-") && !IsTestDir(metadata_dir_)) {
		if (android::base::StartsWith(device_path, "/dev/block/dm-") && !MetadataDirIsTest()) {
		LOG(ERROR) << "Cannot persist images against device-mapper device: " << device_path;

		fw = {};

fs_mgr/libfiemap/image_test.cpp

+48 −0

Original line number	Diff line number	Diff line
		@@ -34,10 +34,13 @@
		#include <libdm/dm.h>
		#include <libfiemap/image_manager.h>

		#include "utility.h"

		using namespace android::dm;
		using namespace std::literals;
		using android::base::unique_fd;
		using android::fiemap::ImageManager;
		using android::fiemap::IsSubdir;
		using android::fs_mgr::BlockDeviceInfo;
		using android::fs_mgr::PartitionOpener;
		using android::fs_mgr::WaitForFile;
		@@ -131,6 +134,51 @@ TEST_F(NativeTest, GetMappedImageDevice) {
		ASSERT_TRUE(manager_->UnmapImageDevice(base_name_));
		}

		namespace {

		struct IsSubdirTestParam {
		std::string child;
		std::string parent;
		bool result;
		};

		class IsSubdirTest : public ::testing::TestWithParam<IsSubdirTestParam> {};

		TEST_P(IsSubdirTest, Test) {
		const auto& param = GetParam();
		EXPECT_EQ(param.result, IsSubdir(param.child, param.parent))
		<< "IsSubdir(child=\"" << param.child << "\", parent=\"" << param.parent
		<< "\") != " << (param.result ? "true" : "false");
		}

		std::vector<IsSubdirTestParam> IsSubdirTestValues() {
		// clang-format off
		std::vector<IsSubdirTestParam> base_cases{
		{"/foo/bar", "/foo", true},
		{"/foo/bar/baz", "/foo", true},
		{"/foo", "/foo", true},
		{"/foo", "/", true},
		{"/", "/", true},
		{"/foo", "/foo/bar", false},
		{"/foo", "/bar", false},
		{"/foo-bar", "/foo", false},
		{"/", "/foo", false},
		};
		// clang-format on
		std::vector<IsSubdirTestParam> ret;
		for (const auto& e : base_cases) {
		ret.push_back(e);
		ret.push_back({e.child + "/", e.parent, e.result});
		ret.push_back({e.child, e.parent + "/", e.result});
		ret.push_back({e.child + "/", e.parent + "/", e.result});
		}
		return ret;
		}

		INSTANTIATE_TEST_SUITE_P(IsSubdirTest, IsSubdirTest, ::testing::ValuesIn(IsSubdirTestValues()));

		} // namespace

		bool Mkdir(const std::string& path) {
		if (mkdir(path.c_str(), 0700) && errno != EEXIST) {
		std::cerr << "Could not mkdir " << path << ": " << strerror(errno) << std::endl;

fs_mgr/libfiemap/include/libfiemap/image_manager.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -176,6 +176,8 @@ class ImageManager final : public IImageManager {
		bool MapWithDmLinear(const IPartitionOpener& opener, const std::string& name,
		const std::chrono::milliseconds& timeout_ms, std::string* path);
		bool UnmapImageDevice(const std::string& name, bool force);
		bool IsUnreliablePinningAllowed() const;
		bool MetadataDirIsTest() const;

		ImageManager(const ImageManager&) = delete;
		ImageManager& operator=(const ImageManager&) = delete;

fs_mgr/libfiemap/utility.cpp

+25 −0

Original line number	Diff line number	Diff line
		@@ -167,5 +167,30 @@ bool FilesystemHasReliablePinning(const std::string& file, bool* supported) {
		return F2fsPinBeforeAllocate(fd, supported);
		}

		bool IsSubdir(const std::string& child, const std::string& parent) {
		// Precondition: both are absolute paths.
		CHECK(android::base::StartsWith(child, "/")) << "Not an absolute path: " << child;
		CHECK(android::base::StartsWith(parent, "/")) << "Not an absolute path: " << parent;

		// Remove extraneous "/" at the end.
		std::string_view child_sv = child;
		while (child_sv != "/" && android::base::ConsumeSuffix(&child_sv, "/"))
		;

		std::string_view parent_sv = parent;
		while (parent_sv != "/" && android::base::ConsumeSuffix(&parent_sv, "/"))
		;

		// IsSubdir(anything, "/") => true
		if (parent_sv == "/") return true;

		// IsSubdir("/foo", "/foo") => true
		if (parent_sv == child_sv) return true;

		// IsSubdir("/foo/bar", "/foo") => true
		// IsSubdir("/foo-bar", "/foo") => false
		return android::base::StartsWith(child_sv, std::string(parent_sv) + "/");
		}

		} // namespace fiemap
		} // namespace android

fs_mgr/libfiemap/utility.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -51,5 +51,9 @@ bool BlockDeviceToName(uint32_t major, uint32_t minor, std::string* bdev_name);
		// cases (such as snapshots or adb remount).
		bool FilesystemHasReliablePinning(const std::string& file, bool* supported);

		// Crude implementation to check if \|child\| is a subdir of \|parent\|.
		// Assume both are absolute paths.
		bool IsSubdir(const std::string& child, const std::string& parent);

		} // namespace fiemap
		} // namespace android