Schedule user settings cleanup next time user logs on

We are using Active Setup because eduVPN client is installed per-machine
and eduVPN client settings are stored per-user. Active Setup allows us
to cleanup the settings for all users, not just the one that performed
the uninstall.

On an eduVPN client uninstall, Active Setup is instructed to cleanup
user's client settings on next user logon. It does not cleanup the
settings immediately on uninstall for the user performing the uninstall,
as it would require a reliable detection to distinguish the ultimate
uninstall from an uninstall-before-next-version-install.

This means, if user wants to start the eduVPN experience anew, one needs
to uninstall the client, sign out&in or reboot, and reinstall the
client.

Fixes: #187
Fixes: #192
Signed-off-by: Simon Rozman <[email protected]>

doc/FAQ.md

@@ -4,10 +4,16 @@
 Right click on the server name. A menu should popup. Select _Forget_.
 
 ## How to reset all my client settings?
-Close the eduVPN Client first. Open a command prompt and paste this:
+
+### Resetting manually
+Close the eduVPN and Let's Encrypt! clients first. Open a command prompt and paste one or both lines:
 
 ```cmd
-rd /s "%LOCALAPPDATA%\SURF"
+for /d %i in ("%LOCALAPPDATA%\SURF\eduVPN.Client.exe_Url_*") do rd /s /q "%i"
+for /d %i in ("%LOCALAPPDATA%\SURF\LetsConnect.Client.exe_Url_*") do rd /s /q "%i"
 ```
 
-Hit _Enter_ and confirm the deletition. This will reset eduVPN Client to factory defaults.
+Don't forget to press _Enter_ key after the line is pasted. This will reset eduVPN and Let's Encrypt! clients to factory defaults.
+
+### Resetting after uninstall
+Uninstall the client. On next sign-in, the client settings of the user signing-in will be cleaned.

eduMSICA/exports.def

@@ -10,3 +10,5 @@ EXPORTS
 	EvaluateComponents
 	RemoveWintunDriver
 	KillExecutableProcesses
+	UnpublishActiveSetup
+	PublishActiveSetup

eduMSICA/main.cpp

@@ -18,6 +18,7 @@
 #include <WinStd/Win.h>
 #include <wintun.h>
 
+#include <memory>
 #include <vector>
 
 using namespace std;
@@ -170,7 +171,7 @@ EvaluateComponents(_In_ MSIHANDLE hInstall)
 	else
 		LOG_ERROR_NUM(uiResult, TEXT("MsiGetComponentState(\"%s\") failed"), WINTUN_COMPONENT);
 
-	static LPCTSTR szClientFilenames[] = {
+	static const LPCTSTR szClientFilenames[] = {
 		TEXT("eduVPN.Client.exe"),
 		TEXT("LetsConnect.Client.exe"),
 	};
@@ -188,6 +189,47 @@ EvaluateComponents(_In_ MSIHANDLE hInstall)
 			LOG_ERROR_NUM(uiResult, TEXT("MsiGetComponentState(\"%s\") failed"), szClientFilenames[i]);
 	}
 
+	static const LPCTSTR szActiveSetupActionCodes[] = {
+		TEXT("{B26CF707-1200-4760-A900-C4621CEEADC0}"),
+		TEXT("{B26CF707-1200-4760-A901-C4621CEEADC0}"),
+	};
+	for (size_t i = 0; i < _countof(szActiveSetupActionCodes) && i < _countof(szClientFilenames); ++i) {
+		// Get the client component state.
+		uiResult = MsiGetComponentState(hInstall, szClientFilenames[i], &iInstalled, &iAction);
+		if (uiResult == ERROR_SUCCESS) {
+			tstring sRegPath;
+			sprintf(sRegPath, TEXT("Software\\Microsoft\\Active Setup\\Installed Components\\%s"), szActiveSetupActionCodes[i]);
+			unsigned int uiVersion = 0;
+			reg_key key;
+			uiResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, sRegPath.c_str(), 0, KEY_QUERY_VALUE, key);
+			if (uiResult == ERROR_SUCCESS) {
+				DWORD dwType;
+				vector<TCHAR> aData;
+				if (RegQueryValueEx(key, TEXT("Version"), 0, &dwType, aData) == ERROR_SUCCESS && dwType == REG_SZ) {
+					aData.push_back(TEXT('\0'));
+					uiVersion = _tcstoul(aData.data(), NULL, 10);
+				}
+			}
+
+			if (iInstalled >= INSTALLSTATE_LOCAL && iAction >= INSTALLSTATE_REMOVED) {
+				// Client component is installed and shall be removed/upgraded/reinstalled.
+				// Schedule user configuration cleanup.
+				SetFormattedProperty(hInstall, TEXT("PublishActiveSetup"), tstring_printf(
+					TEXT("\"%s\" \"[ProductName]\" %u \"cmd.exe /c \\\"for /d %%i in (\\\"\\\"%%LOCALAPPDATA%%\\SURF\\%s_Url_*\\\"\\\") do rd /s /q \\\"\\\"%%i\\\"\\\"\\\"\""),
+					sRegPath.c_str(),
+					uiVersion + 1,
+					szClientFilenames[i]).c_str());
+			}
+			if (iAction >= INSTALLSTATE_LOCAL) {
+				// Client component shall be installed.
+				// Cancel user configuration cleanup.
+				MsiSetProperty(hInstall, TEXT("UnpublishActiveSetup"), tstring_printf(TEXT("\"%s\""), sRegPath.c_str()).c_str());
+			}
+		}
+		else if (uiResult != ERROR_UNKNOWN_COMPONENT)
+			LOG_ERROR_NUM(uiResult, TEXT("MsiGetComponentState(\"%s\") failed"), szClientFilenames[i]);
+	}
+
 	return ERROR_SUCCESS;
 }
 
@@ -297,3 +339,89 @@ KillExecutableProcesses(_In_ MSIHANDLE hInstall)
 	}
 	return ERROR_SUCCESS;
 }
+
+static LSTATUS
+RegSetValueEx(_In_ HKEY hKey, _In_opt_ LPCTSTR lpValueName, _Reserved_ DWORD Reserved, _In_ DWORD dwData)
+{
+	return RegSetValueEx(hKey, lpValueName, Reserved, REG_DWORD, reinterpret_cast<const BYTE*>(&dwData), sizeof(dwData));
+}
+
+static LSTATUS
+RegSetValueExW(_In_ HKEY hKey, _In_opt_ LPCWSTR lpValueName, _Reserved_ DWORD Reserved, _In_z_ LPCWSTR szData)
+{
+	size_t nSize = (wcslen(szData) + 1) * sizeof(WCHAR);
+	if (nSize > MAXDWORD)
+		return ERROR_INVALID_PARAMETER;
+	return RegSetValueExW(hKey, lpValueName, Reserved, REG_SZ, reinterpret_cast<const BYTE*>(szData), (DWORD)nSize);
+}
+
+_Return_type_success_(return == ERROR_SUCCESS) UINT __stdcall
+UnpublishActiveSetup(_In_ MSIHANDLE hInstall)
+{
+	com_initializer com_init(NULL);
+	s_hInstall = hInstall;
+
+	wstring sData;
+	UINT uiResult = MsiGetPropertyW(hInstall, L"CustomActionData", sData);
+	if (uiResult != ERROR_SUCCESS) {
+		LOG_ERROR_NUM(uiResult, TEXT("MsiGetProperty(\"CustomActionData\") failed"));
+		return ERROR_SUCCESS;
+	}
+	if (sData.empty())
+		return ERROR_SUCCESS;
+	int wargc;
+	unique_ptr<LPWSTR[], LocalFree_delete<LPWSTR[]>> wargv(CommandLineToArgvW(sData.c_str(), &wargc));
+	if (wargv == NULL) {
+		LOG_ERROR_NUM(GetLastError(), TEXT("CommandLineToArgvW failed"));
+		return ERROR_SUCCESS;
+	}
+	if (wargc < 1)
+		return ERROR_SUCCESS;
+
+	reg_key key;
+	if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, wargv[0], 0, KEY_SET_VALUE, key) != ERROR_SUCCESS)
+		return ERROR_SUCCESS;
+	RegSetValueEx(key, TEXT("IsInstalled"), 0, 0ul);
+	if (wargc > 1)
+		RegSetValueExW(key, L"StubPath", 0, wargv[1]);
+	else
+		RegDeleteValue(key, TEXT("StubPath"));
+	return ERROR_SUCCESS;
+}
+
+_Return_type_success_(return == ERROR_SUCCESS) UINT __stdcall
+PublishActiveSetup(_In_ MSIHANDLE hInstall)
+{
+	com_initializer com_init(NULL);
+	s_hInstall = hInstall;
+
+	wstring sData;
+	UINT uiResult = MsiGetPropertyW(hInstall, L"CustomActionData", sData);
+	if (uiResult != ERROR_SUCCESS) {
+		LOG_ERROR_NUM(uiResult, TEXT("MsiGetProperty(\"CustomActionData\") failed"));
+		return ERROR_SUCCESS;
+	}
+	if (sData.empty())
+		return ERROR_SUCCESS;
+	int wargc;
+	unique_ptr<LPWSTR[], LocalFree_delete<LPWSTR[]>> wargv(CommandLineToArgvW(sData.c_str(), &wargc));
+	if (wargv == NULL) {
+		LOG_ERROR_NUM(GetLastError(), TEXT("CommandLineToArgvW failed"));
+		return ERROR_SUCCESS;
+	}
+	if (wargc < 3)
+		return ERROR_SUCCESS;
+
+	reg_key key;
+	if (RegCreateKeyExW(HKEY_LOCAL_MACHINE, wargv[0], 0, NULL, REG_OPTION_NON_VOLATILE, KEY_SET_VALUE, NULL, key, NULL) != ERROR_SUCCESS)
+		return ERROR_SUCCESS;
+	RegSetValueExW(key, NULL, 0, wargv[1]);
+	RegSetValueExW(key, L"Version", 0, wargv[2]);
+	RegSetValueEx(key, TEXT("IsInstalled"), 0, 1ul);
+	RegSetValueEx(key, TEXT("DontAsk"), 0, 2ul);
+	if (wargc > 3)
+		RegSetValueExW(key, L"StubPath", 0, wargv[3]);
+	else
+		RegDeleteValue(key, TEXT("StubPath"));
+	return ERROR_SUCCESS;
+}

eduVPNClient.wxs

@@ -553,7 +553,21 @@
             BinaryKey="eduMSICA.dll"
             DllEntry="KillExecutableProcesses"
             Execute="deferred"
-            Impersonate="no" />
+            Impersonate="no"/>
+
+        <CustomAction
+            Id="UnpublishActiveSetup"
+            BinaryKey="eduMSICA.dll"
+            DllEntry="UnpublishActiveSetup"
+            Execute="deferred"
+            Impersonate="no"/>
+
+        <CustomAction
+            Id="PublishActiveSetup"
+            BinaryKey="eduMSICA.dll"
+            DllEntry="PublishActiveSetup"
+            Execute="deferred"
+            Impersonate="no"/>
 
         <InstallExecuteSequence>
             <Custom
@@ -566,7 +580,15 @@
 
             <Custom
                 Action="KillExecutableProcesses"
-                Before="StopServices" />
+                Before="StopServices"/>
+
+            <Custom
+                Action="UnpublishActiveSetup"
+                Before="UnpublishFeatures"/>
+
+            <Custom
+                Action="PublishActiveSetup"
+                After="PublishFeatures"/>
         </InstallExecuteSequence>
 
         <UI>