Added detection of invalid device Ids

Duplicati/Library/Utility/DeviceIDHelper.cs

@@ -18,30 +18,95 @@
 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 // DEALINGS IN THE SOFTWARE.
+#nullable enable
 
 using Duplicati.Library.Utility;
 using DeviceId;
+using System.Collections.Generic;
+using System.Linq;
 
 /// <summary>
 /// Helper class to get the device ID string and computed hash
 /// </summary>
 public static class DeviceIDHelper
 {
+    /// <summary>
+    /// Generates an empty ID
+    /// </summary>
+    /// <returns>An empty ID</returns>
+    private static string? GenerateEmptyId()
+    {
+        var builder = new DeviceIdBuilder();
+        builder.Components.Clear();
+        return builder.ToString();
+    }
+
+    /// <summary>
+    /// The empty ID produced by DeviceIdBuilder if no information is available
+    /// </summary>
+    private static readonly HashSet<string> EMPTY_DEVICE_IDS = new[] {
+        // Known empty Id
+        "WERC8GMRZGE196QVYK49JVXS4GKTWGF4CJDS6K54JPCHPY2JQ1AG",
+        // In case the library changes
+        GenerateEmptyId()
+    }
+    .Where(x => !string.IsNullOrWhiteSpace(x))
+    .Select(x => x!)
+    // Don't allow empty strings either
+    .Append(string.Empty)
+    .ToHashSet();
+
+    /// <summary>
+    /// Hashes a set of device IDs
+    /// </summary>
+    /// <param name="deviceIds">The deviceIds to hash</param>
+    /// <returns>The list of hashed ids</returns>
+    private static HashSet<string> HashDeviceIds(IEnumerable<string> deviceIds)
+    {
+        var hasher = HashFactory.CreateHasher("SHA256");
+        return deviceIds.Select(x => x.ComputeHashToHex(hasher)).ToHashSet();
+    }
+
+    /// <summary>
+    /// The empty deviceId hashes
+    /// </summary>
+    public static readonly HashSet<string> EMPTY_DEVICE_ID_HASHES = HashDeviceIds(EMPTY_DEVICE_IDS);
+
+    /// <summary>
+    /// Returns a configured builder
+    /// </summary>
+    /// <returns>The builder</returns>
+    private static DeviceIdBuilder GetBuilder()
+        => new DeviceIdBuilder()
+            .OnWindows(deviceid => deviceid
+                .AddMotherboardSerialNumber())
+            .OnLinux(deviceid => deviceid
+                .AddMotherboardSerialNumber())
+            .OnMac(deviceid => deviceid
+                .AddPlatformSerialNumber());
 
     /// <summary>
     /// Get the device ID string (motherboard serial number on Windows and Linux, platform serial number on Mac)
     /// </summary>
-    /// <returns>String</returns>
-    public static string GetDeviceID()
+    /// <returns>The device Id</returns>
+    public static string? GetDeviceID()
     {
-        return new DeviceIdBuilder()
-        .OnWindows(deviceid => deviceid
-            .AddMotherboardSerialNumber())
-        .OnLinux(deviceid => deviceid
-            .AddMotherboardSerialNumber())
-        .OnMac(deviceid => deviceid
-            .AddPlatformSerialNumber())
-        .ToString();
+        var id = GetBuilder().ToString();
+        if (string.IsNullOrWhiteSpace(id))
+            return EMPTY_DEVICE_IDS.First();
+
+        return id;
+    }
+
+    /// <summary>
+    /// Checks if the deviceId is a meaningful value
+    /// </summary>
+    /// <returns><c>true</c> if a deviceId can be obtained, <c>false</c> otherwise</returns>
+    public static bool CanGetDeviceId()
+    {
+        var builder = GetBuilder();
+        builder.UseFormatter(new DeviceId.Formatters.StringDeviceIdFormatter(new DeviceId.Encoders.PlainTextDeviceIdComponentEncoder()));
+        return !string.IsNullOrWhiteSpace(builder.ToString());
     }
 
     /// <summary>
@@ -50,6 +115,7 @@ public static class DeviceIDHelper
     /// <returns></returns>
     public static string GetDeviceIDHash()
     {
-        return GetDeviceID().ComputeHashToHex(HashFactory.CreateHasher("SHA256"));
+        using var hasher = HashFactory.CreateHasher("SHA256");
+        return (GetDeviceID() ?? "").ComputeHashToHex(hasher);
     }
 }