Fides Webserver Vulnerable to SVG Bomb File Uploads

@@ -8,6 +8,7 @@ colorama>=0.4.3
 cryptography==38.0.3
 dask==2022.9.2
 deepdiff==6.3.0
+defusedxml==0.7.1
 expandvars==0.9.0
 fastapi[all]==0.89.1
 fastapi-caching[redis]==0.3.0

@@ -40,7 +40,7 @@
     replace_dataset_placeholders,
     replace_version,
 )
-from fides.api.util.unsafe_file_util import verify_zip
+from fides.api.util.unsafe_file_util import verify_svg, verify_zip
 from fides.config import CONFIG
 
 
@@ -214,6 +214,7 @@ def save_template(cls, db: Session, zip_file: ZipFile) -> None:
                     )
             elif info.filename.endswith(".svg"):
                 if not icon_contents:
+                    verify_svg(file_contents)
                     icon_contents = str_to_b64_str(file_contents)
                 else:
                     raise ValidationError(

@@ -1,10 +1,34 @@
 from typing import Optional
 from zipfile import ZipFile
 
+from defusedxml.ElementTree import fromstring
+
+from fides.api.common_exceptions import ValidationError
+
 MAX_FILE_SIZE = 16 * 1024 * 1024  # 16 MB
 CHUNK_SIZE = 1024
 
 
+def verify_svg(contents: str) -> None:
+    """
+    Verifies the provided SVG content.
+
+    This function checks the given SVG content string for potential issues and throws an exception if any are found.
+    It first attempts to parse the SVG content using 'defusedxml.fromstring'. If the parsing is unsuccessful, this
+    will raise an exception, indicating that the SVG content may contain unsafe XML.
+
+    :param contents: The SVG content as a string.
+    :raises ValidationError: If the SVG content contains unsafe XML or 'use xlink'
+    """
+    try:
+        fromstring(contents)
+    except Exception:
+        raise ValidationError("SVG file contains unsafe XML.")
+
+    if "use xlink" in contents:
+        raise ValidationError("SVG files with xlink references are not allowed.")
+
+
 def verify_zip(zip_file: ZipFile, max_file_size: Optional[int] = None) -> None:
     """
     Function to safely verify the contents of zipped files. It prevents potential

@@ -3,10 +3,57 @@
 
 import pytest
 
-from fides.api.util.unsafe_file_util import verify_zip
+from fides.api.common_exceptions import ValidationError
+from fides.api.util.unsafe_file_util import verify_svg, verify_zip
 from tests.ops.test_helpers.saas_test_utils import create_zip_file
 
 
+class TestVerifySvg:
+    def test_verify_svg(self):
+        verify_svg(
+            """<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
+                <circle cx="50" cy="50" r="40"/>
+            </svg>
+            """
+        )
+
+    def test_verify_svg_no_laughing_allowed(self):
+        """Test "billion laughs attack" is prevented"""
+        with pytest.raises(ValidationError) as exc:
+            verify_svg(
+                """<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+                <!DOCTYPE svg [
+                <!ENTITY lol "lol">
+                <!ELEMENT lolz (#PCDATA)>
+                <!ENTITY lol1 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
+                <!ENTITY lol2 "&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;&lol1;">
+                <!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
+                <!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
+                <!ENTITY lol5 "&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;&lol4;">
+                <!ENTITY lol6 "&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;&lol5;">
+                <!ENTITY lol7 "&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;&lol6;">
+                <!ENTITY lol8 "&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;&lol7;">
+                <!ENTITY lol9 "&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;&lol8;">
+                ]>
+                <svg>
+                    <lolz>&lol9;</lolz>
+                </svg>
+                """
+            )
+        assert "SVG file contains unsafe XML." in str(exc.value)
+
+    def test_verify_svg_with_xlink(self):
+        with pytest.raises(ValidationError) as exc:
+            verify_svg(
+                """<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 100 100">
+                    <circle id="circle" cx="50" cy="50" r="40"/>
+                    <use xlink:href="#circle"/>
+                </svg>
+                """
+            )
+        assert "SVG files with xlink references are not allowed." in str(exc.value)
+
+
 class TestVerifyZip:
     @pytest.fixture
     def zip_file(self) -> BytesIO: