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
Test: recovery_component_test - all passing
Merged-In: Ibc9b095036a2fa624e8edf6c347ed4f12aef072f
Change-Id: Ibc9b095036a2fa624e8edf6c347ed4f12aef072f
diff --git a/tests/component/install_test.cpp b/tests/component/install_test.cpp
index 3851329..c1f0ca8 100644
--- a/tests/component/install_test.cpp
+++ b/tests/component/install_test.cpp
@@ -34,6 +34,7 @@
#include "install/install.h"
#include "otautil/paths.h"
+#include "otautil/roots.h"
#include "private/setup_commands.h"
static void BuildZipArchive(const std::map<std::string, std::string>& file_map, int fd,
@@ -595,3 +596,30 @@
"\n");
test_check_package_metadata(metadata, OtaType::AB, 0);
}
+
+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<std::string>{
+ 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));
+}