Make firmware reading a bit more failsafe #30

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/devices/miband/MiBandFWHelper.java

@@ -8,9 +8,12 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.BufferedInputStream;
+import java.io.IOException;
 import java.io.InputStream;
 import java.util.Locale;
 
+import nodomain.freeyourgadget.gadgetbridge.util.FileUtils;
+
 public class MiBandFWHelper {
     private static final Logger LOG = LoggerFactory.getLogger(MiBandFWHelper.class);
 
@@ -29,41 +32,25 @@ public class MiBandFWHelper {
             16779568 //1.0.9.48 tested by developer
     };
 
-    public MiBandFWHelper(Uri uri, Context context) {
+    public MiBandFWHelper(Uri uri, Context context) throws IOException {
         this.uri = uri;
         cr = context.getContentResolver();
 
-        InputStream fin;
-
-        try {
-            fin = new BufferedInputStream(cr.openInputStream(uri));
-            this.fw = new byte[fin.available()];
-            fin.read(fw);
-            fin.close();
-
+        try (InputStream in = new BufferedInputStream(cr.openInputStream(uri))){
+            this.fw = FileUtils.readAll(in, 1024 * 1024); // 1 MB
+            if (fw.length > firmwareVersionMajor && fw[firmwareVersionMajor] != 1) {
+                throw new IOException("Firmware major version should be 1, probably this isn't a MiBand firmware.");
+            }
         } catch (Exception e) {
-            e.printStackTrace();
-            this.fw = null;
+            throw new IOException("Error reading firmware file: " + uri.toString(), e);
         }
-
-        if (fw[firmwareVersionMajor] != 1) {
-            LOG.error("Firmware major version should be 1, probably this isn't a MiBand firmware.");
-            this.fw = null;
-        }
-
     }
 
     public int getFirmwareVersion() {
-        if (fw == null) {
-            return -1;
-        }
         return (fw[firmwareVersionMajor] << 24) | (fw[firmwareVersionMinor] << 16) | (fw[firmwareVersionRevision] << 8) | fw[firmwareVersionBuild];
     }
 
     public String getHumanFirmwareVersion() {
-        if (fw == null) {
-            return "UNK";
-        }
         return String.format(Locale.US, "%d.%d.%d.%d", fw[firmwareVersionMajor], fw[firmwareVersionMinor], fw[firmwareVersionRevision], fw[firmwareVersionBuild]);
     }
 
@@ -94,5 +81,4 @@ public class MiBandFWHelper {
         crc &= 0xffff;
         return crc;
     }
-
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/miband/MiBandSupport.java

@@ -592,6 +592,7 @@ public class MiBandSupport extends AbstractBTLEDeviceSupport {
 
     @Override
     public void onInstallApp(Uri uri) {
+        try {
             MiBandFWHelper mFwHelper = new MiBandFWHelper(uri, getContext());
             String mMac = getDevice().getAddress();
             String[] mMacOctets = mMac.split(":");
@@ -605,8 +606,9 @@ public class MiBandSupport extends AbstractBTLEDeviceSupport {
                 newFirmware = mFwHelper.getFw();
                 //the firmware will be sent by the notification listener if the band confirms that the metadata are ok.
             }
-
-        return;
+        } catch (IOException ex) {
+            GB.toast(getContext(), "Firmware cannot be installed: " + ex.getMessage(), Toast.LENGTH_LONG, GB.ERROR);
+        }
     }
 
     @Override

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/FileUtils.java

@@ -1,9 +1,11 @@
 package nodomain.freeyourgadget.gadgetbridge.util;
 
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.nio.channels.FileChannel;
 
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
@@ -44,4 +46,27 @@ public class FileUtils {
         }
         return dir;
     }
+
+    /**
+     * Reads the contents of the given InputStream into a byte array, but does not
+     * read more than maxLen bytes.
+     * @param in the stream to read from
+     * @param maxLen the maximum number of bytes to read/return
+     * @return the bytes read from the InputStream
+     * @throws IOException when reading failed or when maxLen was exceeded
+     */
+    public static byte[] readAll(InputStream in, long maxLen) throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream(Math.max(8192, in.available()));
+        byte[] buf = new byte[8192];
+        int read = 0;
+        long totalRead = 0;
+        while ((read = in.read(buf)) > 0) {
+            out.write(buf, 0, read);
+            totalRead += read;
+            if (totalRead > maxLen) {
+                throw new IOException("Too much data to read into memory. Got already " + totalRead + buf);
+            }
+        }
+        return out.toByteArray();
+    }
 }