From 58a27693b22da9b93c634d053a53deb4c4a71e4e Mon Sep 17 00:00:00 2001 From: Tianjie Xu Date: Tue, 6 Aug 2019 12:32:05 -0700 Subject: Force package installation with FUSE unless the package stores on device The non-A/B package installation is subject to TOC/TOU flaw if the attacker can switch the package in the middle of installation. And the most pratical case is to store the package on an external device, e.g. a sdcard, and swap the device in the middle. To prevent that, we can adopt the same protection as used in sideloading a package with FUSE. Specifically, when we install the package with FUSE, we read the entire package to cryptographically verify its signature. The hash for each transfer block is recorded in the memory (TOC), and the subsequent reads (TOU) will be rejected upon dectecting a mismatch. This CL forces the package installation with FUSE when the package stays on a removable media. Bug: 136498130 Test: Run bin/recovery --update_package with various paths; and packages are installed from FUSE as expected Change-Id: Ibc9b095036a2fa624e8edf6c347ed4f12aef072f --- tests/Android.bp | 1 + tests/unit/install_test.cpp | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) (limited to 'tests') diff --git a/tests/Android.bp b/tests/Android.bp index 5b881e367..ec49c07af 100644 --- a/tests/Android.bp +++ b/tests/Android.bp @@ -94,6 +94,7 @@ librecovery_static_libs = [ "liblp", "libvndksupport", "libtinyxml2", + "libc++fs", ] cc_test { diff --git a/tests/unit/install_test.cpp b/tests/unit/install_test.cpp index 4ec409908..60cdc1105 100644 --- a/tests/unit/install_test.cpp +++ b/tests/unit/install_test.cpp @@ -36,6 +36,7 @@ #include "install/wipe_device.h" #include "otautil/paths.h" #include "private/setup_commands.h" +#include "recovery_utils/roots.h" static void BuildZipArchive(const std::map& file_map, int fd, int compression_type) { @@ -595,3 +596,30 @@ TEST(InstallTest, CheckPackageMetadata_ab_post_timestamp) { "\n"); TestCheckPackageMetadata(metadata, OtaType::AB, true); } + +TEST(InstallTest, SetupPackageMount_package_path) { + load_volume_table(); + bool install_with_fuse; + + // Setup should fail if the input path doesn't exist. + ASSERT_FALSE(SetupPackageMount("/does_not_exist", &install_with_fuse)); + + // Package should be installed with fuse if it's not in /cache. + TemporaryDir temp_dir; + TemporaryFile update_package(temp_dir.path); + ASSERT_TRUE(SetupPackageMount(update_package.path, &install_with_fuse)); + ASSERT_TRUE(install_with_fuse); + + // Setup should fail if the input path isn't canonicalized. + std::string uncanonical_package_path = android::base::Join( + std::vector{ + temp_dir.path, + "..", + android::base::Basename(temp_dir.path), + android::base::Basename(update_package.path), + }, + '/'); + + ASSERT_EQ(0, access(uncanonical_package_path.c_str(), R_OK)); + ASSERT_FALSE(SetupPackageMount(uncanonical_package_path, &install_with_fuse)); +} -- cgit v1.2.3