Perform additional URI validation in ShareRepository.

app/src/test/java/org/thoughtcrime/securesms/util/UriUtilTest_isValidExternalUri.java

@@ -0,0 +1,55 @@
+package org.thoughtcrime.securesms.util;
+
+import android.app.Application;
+import android.content.Context;
+import android.net.Uri;
+
+import androidx.test.core.app.ApplicationProvider;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.ParameterizedRobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(ParameterizedRobolectricTestRunner.class)
+@Config(manifest = Config.NONE, application = Application.class)
+public class UriUtilTest_isValidExternalUri {
+
+  private final String  input;
+  private final boolean output;
+
+  @ParameterizedRobolectricTestRunner.Parameters
+  public static Collection<Object[]> data() {
+    return Arrays.asList(new Object[][]{
+        { "content://other.app.package.name.org/path/public.txt",             true  },
+        { "file:///sdcard/public.txt",                                        true  },
+        { "file:///data/data/org.thoughtcrime.securesms/private.txt",         false },
+        { "file:///any/path/with/package/name/org.thoughtcrime.securesms",    false },
+        { "file:///org.thoughtcrime.securesms/any/path/with/package/name",    false },
+        { "file:///any/path/../with/back/references/private.txt",             false },
+        { "file:///any/path/with/back/references/../private.txt",             false },
+        { "file:///../any/path/with/back/references/private.txt",             false },
+        { "file:///encoded/back/reference/%2F..%2F..path%2Fto%2Fprivate.txt", false },
+        { "file:///public/%2E%2E%2Fprivate%2Fprivate.txt",                    false },
+        { "file:///data/no/paths/in/data",                                    false },
+    });
+  }
+
+  public UriUtilTest_isValidExternalUri(String input, boolean output) {
+    this.input  = input;
+    this.output = output;
+  }
+
+  @Test
+  public void parse() {
+    Context context = ApplicationProvider.getApplicationContext();
+    Uri     uri     = Uri.parse(input);
+
+    assertEquals(output, UriUtil.isValidExternalUri(context, uri));
+  }
+}