installd: allow enabling fs-verity to a given file
The caller is allowed to request installd to enable fs-verity to a
given file. Normally this is initiated by the app through an API, via
system server.
We must not allow an app to enable fs-verity to a file they don't own.
In addition, the design also treat the less-privilged system server as
untrusted and limit what it can do through the API.
See code comments for more details.
Bug: 285185747
Test: Call the API from a local client
Test: atest installd_service_test
Change-Id: I0782a9b23f3817898df0703cfdd9d8670f8fcdfb
diff --git a/cmds/installd/InstalldNativeService.h b/cmds/installd/InstalldNativeService.h
index 521afc3..0f28234 100644
--- a/cmds/installd/InstalldNativeService.h
+++ b/cmds/installd/InstalldNativeService.h
@@ -19,6 +19,7 @@
#define COMMANDS_H_
#include <inttypes.h>
+#include <sys/stat.h>
#include <unistd.h>
#include <shared_mutex>
@@ -35,8 +36,26 @@
namespace android {
namespace installd {
+using IFsveritySetupAuthToken = android::os::IInstalld::IFsveritySetupAuthToken;
+
class InstalldNativeService : public BinderService<InstalldNativeService>, public os::BnInstalld {
public:
+ class FsveritySetupAuthToken : public os::IInstalld::BnFsveritySetupAuthToken {
+ public:
+ FsveritySetupAuthToken() : mStatFromAuthFd() {}
+
+ binder::Status authenticate(const android::os::ParcelFileDescriptor& authFd, int32_t appUid,
+ int32_t userId);
+ bool isSameStat(const struct stat& st) const;
+
+ private:
+ // Not copyable or movable
+ FsveritySetupAuthToken(const FsveritySetupAuthToken&) = delete;
+ FsveritySetupAuthToken& operator=(const FsveritySetupAuthToken&) = delete;
+
+ struct stat mStatFromAuthFd;
+ };
+
static status_t start();
static char const* getServiceName() { return "installd"; }
virtual status_t dump(int fd, const Vector<String16> &args) override;
@@ -192,6 +211,13 @@
const std::optional<std::string>& outputPath,
int32_t* _aidl_return);
+ binder::Status createFsveritySetupAuthToken(const android::os::ParcelFileDescriptor& authFd,
+ int32_t appUid, int32_t userId,
+ android::sp<IFsveritySetupAuthToken>* _aidl_return);
+ binder::Status enableFsverity(const android::sp<IFsveritySetupAuthToken>& authToken,
+ const std::string& filePath, const std::string& packageName,
+ int32_t* _aidl_return);
+
private:
std::recursive_mutex mLock;
std::unordered_map<userid_t, std::weak_ptr<std::shared_mutex>> mUserIdLock;