wimlib: Automatically try to acquire needed privileges on Windows

[wimlib] / src / win32_common.c

diff --git a/src/win32_common.c b/src/win32_common.c
index fc55709a7a7ce42090cc219aac5302772f999323..a996378a82e4826a9eeab6a4e69d7d40d1594844 100644 (file)
--- a/src/win32_common.c
+++ b/src/win32_common.c
@@ -450,6 +450,69 @@ out:
        return 0;
 }
 
+static bool
+win32_modify_privilege(const wchar_t *privilege, bool enable)
+{
+       HANDLE hToken;
+       LUID luid;
+       TOKEN_PRIVILEGES newState;
+       bool ret = FALSE;
+
+       if (!OpenProcessToken(GetCurrentProcess(),
+                             TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY,
+                             &hToken))
+               goto out;
+
+       if (!LookupPrivilegeValue(NULL, privilege, &luid))
+               goto out_close_handle;
+
+       newState.PrivilegeCount = 1;
+       newState.Privileges[0].Luid = luid;
+       newState.Privileges[0].Attributes = (enable ? SE_PRIVILEGE_ENABLED : 0);
+       SetLastError(ERROR_SUCCESS);
+       ret = AdjustTokenPrivileges(hToken, FALSE, &newState, 0, NULL, NULL);
+       if (ret && GetLastError() == ERROR_NOT_ALL_ASSIGNED)
+               ret = FALSE;
+out_close_handle:
+       CloseHandle(hToken);
+out:
+       return ret;
+}
+
+static void
+win32_modify_capture_privileges(bool enable)
+{
+       win32_modify_privilege(SE_BACKUP_NAME, enable);
+       win32_modify_privilege(SE_SECURITY_NAME, enable);
+}
+
+static void
+win32_modify_apply_privileges(bool enable)
+{
+       win32_modify_privilege(SE_RESTORE_NAME, enable);
+       win32_modify_privilege(SE_SECURITY_NAME, enable);
+       win32_modify_privilege(SE_TAKE_OWNERSHIP_NAME, enable);
+}
+
+static void
+win32_modify_capture_and_apply_privileges(bool enable)
+{
+       win32_modify_capture_privileges(enable);
+       win32_modify_apply_privileges(enable);
+}
+
+static void
+win32_acquire_capture_and_apply_privileges(void)
+{
+       win32_modify_capture_privileges(true);
+}
+
+static void
+win32_release_capture_and_apply_privileges(void)
+{
+       win32_modify_capture_privileges(false);
+}
+
 HANDLE
 win32_open_existing_file(const wchar_t *path, DWORD dwDesiredAccess)
 {
@@ -489,6 +552,8 @@ static OSVERSIONINFO windows_version_info = {
 
 static HMODULE hKernel32 = NULL;
 
+static bool acquired_privileges = false;
+
 bool
 windows_version_is_at_least(unsigned major, unsigned minor)
 {
@@ -497,22 +562,25 @@ windows_version_is_at_least(unsigned major, unsigned minor)
                 windows_version_info.dwMinorVersion >= minor);
 }
 
-/* Try to dynamically load some functions */
+/* One-time initialization for Windows capture/apply code.  */
 void
-win32_global_init(void)
+win32_global_init(int init_flags)
 {
        DWORD err;
 
-       if (hKernel32 == NULL) {
-               DEBUG("Loading Kernel32.dll");
-               hKernel32 = LoadLibraryW(L"Kernel32.dll");
-               if (hKernel32 == NULL) {
-                       err = GetLastError();
-                       WARNING("Can't load Kernel32.dll");
-                       win32_error(err);
-               }
+       /* Try to acquire useful privileges.  */
+       if (!(init_flags & WIMLIB_INIT_FLAG_DONT_ACQUIRE_PRIVILEGES)) {
+               win32_acquire_capture_and_apply_privileges();
+               acquired_privileges = true;
        }
 
+       /* Get Windows version information.  */
+       GetVersionEx(&windows_version_info);
+
+       /* Try to dynamically load some functions.  */
+       if (hKernel32 == NULL)
+               hKernel32 = LoadLibrary(L"Kernel32.dll");
+
        if (hKernel32) {
                win32func_FindFirstStreamW = (void*)GetProcAddress(hKernel32,
                                                                   "FindFirstStreamW");
@@ -524,14 +592,14 @@ win32_global_init(void)
                }
        }
 
-       GetVersionEx(&windows_version_info);
 }
 
 void
 win32_global_cleanup(void)
 {
+       if (acquired_privileges)
+               win32_release_capture_and_apply_privileges();
        if (hKernel32 != NULL) {
-               DEBUG("Closing Kernel32.dll");
                FreeLibrary(hKernel32);
                hKernel32 = NULL;
        }