- /* Prefer NtSetSecurityObject() to SetFileSecurity(). SetFileSecurity()
- * itself necessarily uses NtSetSecurityObject() as the latter is the
- * underlying system call for setting security information, but
- * SetFileSecurity() opens the handle with NtCreateFile() without
- * FILE_OPEN_FILE_BACKUP_INTENT. Hence, access checks are done and due
- * to the Windows security model, even a process running as the
- * Administrator can have access denied. (Of course, this not mentioned
- * in the MS "documentation".) */
+ /*
+ * More API insanity. We want to set the entire security descriptor
+ * as-is. But all available APIs require specifying the specific parts
+ * of the security descriptor being set. Especially annoying is that
+ * mandatory integrity labels are part of the SACL, but they aren't set
+ * with SACL_SECURITY_INFORMATION. Instead, applications must also
+ * specify LABEL_SECURITY_INFORMATION (Windows Vista, Windows 7) or
+ * BACKUP_SECURITY_INFORMATION (Windows 8). But at least older versions
+ * of Windows don't error out if you provide these newer flags...
+ *
+ * Also, if the process isn't running as Administrator, then it probably
+ * doesn't have SE_RESTORE_PRIVILEGE. In this case, it will always get
+ * the STATUS_PRIVILEGE_NOT_HELD error by trying to set the SACL, even
+ * if the security descriptor it provided did not have a SACL. By
+ * default, in this case we try to recover and set as much of the
+ * security descriptor as possible --- potentially excluding the DACL, and
+ * even the owner, as well as the SACL.
+ */
+
+ info = OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION |
+ DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION |
+ LABEL_SECURITY_INFORMATION | BACKUP_SECURITY_INFORMATION;
+
+
+ /*
+ * It's also worth noting that SetFileSecurity() is unusable because it
+ * doesn't request "backup semantics" when it opens the file internally.
+ * NtSetSecurityObject() seems to be the best function to use in backup
+ * applications. (SetSecurityInfo() should also work, but it's harder
+ * to use and must call NtSetSecurityObject() internally anyway.
+ * BackupWrite() is theoretically usable as well, but it's inflexible
+ * and poorly documented.)
+ */
+