Add YAML Configurations for Security Rules Against File Access Vulnerabilities #47
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WalkthroughThis pull request introduces new YAML configuration files for Swift that define security rules aimed at preventing vulnerabilities related to file access in webviews and XML External Entity (XXE) attacks. The configurations specify conditions under which warnings are issued when insecure practices are detected, along with corresponding test cases to validate these rules. Additionally, snapshot files are created to capture the behavior of the relevant functions and parser instances, ensuring adherence to security best practices. Changes
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Actionable comments posted: 3
🧹 Outside diff range and nitpick comments (8)
tests/swift/swift-webview-config-allows-file-access-swift-test.yml (1)
1-4: Consider documenting valid use cases or remove empty section.The empty
validsection might benefit from documentation explaining why there are no valid cases, or if there are specific scenarios where allowing file access might be necessary (e.g., for testing or specific development environments).tests/swift/swift-xxe-prevention-swift-test.yml (1)
3-7: Consider enhancing the valid test case documentation.While the test case correctly demonstrates secure XML parsing, consider adding:
- Comments explaining why setting
shouldResolveExternalEntities = falseis the secure approach- Validation of parser results to ensure successful parsing
- | + // Secure configuration: Disable external entity resolution to prevent XXE attacks let parser2 = XMLParser(data: xmlData) parser2.shouldResolveExternalEntities = false parser2.delegate = self - parser2.parse() + let success = parser2.parse() + assert(success, "Parser should successfully parse secure XML")rules/swift/security/swift-webview-config-allows-file-access-swift.yml (2)
1-11: Enhance security context in documentation.Consider adding more context about the security implications and specific remediation steps.
Apply this diff to improve the documentation:
note: >- [CWE-272]: Least Privilege Violation [REFERENCES] https://mas.owasp.org/MASVS/controls/MASVS-PLATFORM-2/ + [IMPACT] + Allowing file access in WebViews can lead to local file system exposure + [REMEDIATION] + 1. Set allowFileAccessFromFileURLs to false + 2. Use content security policies + 3. Implement proper origin validation
46-48: Consider enhancing rule coverage.The rule could be expanded to:
- Detect secure configurations and provide positive feedback
- Check for related security properties like
allowUniversalAccessFromFileURLs- Implement severity levels based on the context (e.g., debug vs. release builds)
Would you like me to help implement these additional security checks?
tests/__snapshots__/swift-xxe-prevention-swift-snapshot.yml (2)
54-103: Consider adding security context for URL-based initialization.This test case correctly captures the URL-based initialization vulnerability. However, it would be valuable to add comments explaining that this represents a double risk:
- Untrusted URL source
- External entity resolution enabled
Consider adding these comments to help developers understand the security implications:
+ # This case demonstrates compound risk: + # 1. Parser initialized with potentially untrusted URL + # 2. External entity resolution enabled, allowing XXE attacks var parser3 = XMLParser(contentsOfURL: url)
104-153: LGTM! Excellent edge case coverage.This test case effectively captures the security bypass pattern where an initially safe configuration is later undermined. It's particularly valuable for detecting attempts to circumvent security controls.
Consider adding one more variation where the unsafe configuration is set in a different method or callback to ensure the analysis can track property changes across method boundaries:
? | var parser7 = XMLParser(contentsOfURL: url) parser7.delegate = self parser7.shouldResolveExternalEntities = false configureParser(parser7) // where configureParser sets shouldResolveExternalEntities = true parser7.parse()rules/swift/security/swift-xxe-prevention-swift.yml (2)
1-14: LGTM! Consider adding CVSS score reference.The rule metadata is well-structured with clear messaging and relevant references.
Consider adding a CVSS (Common Vulnerability Scoring System) score reference for XXE vulnerabilities to help teams better assess the risk level. The base CVSS score for XXE vulnerabilities typically ranges from 6.5 to 8.2 depending on the implementation context.
1-114: Consider adding test cases for edge cases.While the rule implementation is solid, it would be beneficial to ensure comprehensive test coverage for various XMLParser configurations and initialization patterns.
Consider adding test cases for:
- XMLParser initialization through dependency injection
- Subclassed XMLParser implementations
- Parser configurations in different Swift versions
- Integration with third-party XML parsing libraries
Would you like me to help create these test cases?
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📒 Files selected for processing (6)
- rules/swift/security/swift-webview-config-allows-file-access-swift.yml (1 hunks)
- rules/swift/security/swift-xxe-prevention-swift.yml (1 hunks)
- tests/snapshots/swift-webview-config-allows-file-access-swift-snapshot.yml (1 hunks)
- tests/snapshots/swift-xxe-prevention-swift-snapshot.yml (1 hunks)
- tests/swift/swift-webview-config-allows-file-access-swift-test.yml (1 hunks)
- tests/swift/swift-xxe-prevention-swift-test.yml (1 hunks)
✅ Files skipped from review due to trivial changes (1)
- tests/snapshots/swift-webview-config-allows-file-access-swift-snapshot.yml
🔇 Additional comments (9)
tests/swift/swift-webview-config-allows-file-access-swift-test.yml (1)
1-14: Verify coverage of related security configurations.Consider expanding the test cases to include related WebView security settings that are often misconfigured together:
allowUniversalAccessFromFileURLsjavaScriptEnabled- File scheme handling
Let's check for related security configurations in the codebase:
tests/swift/swift-xxe-prevention-swift-test.yml (2)
1-2: LGTM! Well-structured test configuration.The test configuration follows a clear and organized structure with a descriptive ID that matches its security focus.
1-24: Verify comprehensive security coverage.While the test cases focus on XXE prevention through
shouldResolveExternalEntities, let's verify if there are other related security settings or best practices that should be included in these tests.✅ Verification successful
Test cases adequately cover XMLParser security settings
The test cases in
swift-xxe-prevention-swift-test.ymlcomprehensively cover the critical security aspects of XMLParser:
- Tests both data and URL-based parser initialization
- Verifies proper handling of
shouldResolveExternalEntitiesflag- Includes negative test cases for unsafe configurations
- Covers the edge case of flag reassignment
No additional security settings specific to XMLParser were found in the codebase that would warrant inclusion in these test cases.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Search for other XMLParser security-related configurations in Swift files rg -t swift "XMLParser.*security|XMLParser.*secure" # Search for related security rules in other YAML configurations fd -e yml -e yaml | xargs rg "XMLParser|XXE|entity"Length of output: 3354
rules/swift/security/swift-webview-config-allows-file-access-swift.yml (2)
1-48: Verify integration with test suite.Let's ensure this rule is properly covered by tests and integrates well with other security rules.
✅ Verification successful
Rule is properly integrated with comprehensive test coverage
The security rule is well-integrated with appropriate test coverage:
- Test file includes valid/invalid test cases covering different patterns of
allowFileAccessFromFileURLsusage- Snapshot tests validate the rule's behavior with detailed labels and style annotations
- This is the only WebView security rule in the swift/security directory, so no coordination issues exist
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify test coverage and rule integration # Test 1: Check for corresponding test files fd -e yml "swift-webview-config-allows-file-access-swift.*test" # Test 2: Check for similar security rules that might need coordination fd -e yml . rules/swift/security | grep -i "webview" # Test 3: Verify snapshot tests exist fd -e yml "swift-webview-config-allows-file-access-swift.*snapshot"Length of output: 4119
Script:
#!/bin/bash # Let's verify test coverage and related rules more precisely # Check for test file content cat tests/swift/swift-webview-config-allows-file-access-swift-test.yml # Check for other webview security rules fd -e yml . rules/swift/security | grep -i webview # Check snapshot test content cat tests/__snapshots__/swift-webview-config-allows-file-access-swift-snapshot.ymlLength of output: 3970
12-45: Consider expanding pattern matching coverage.The current pattern might miss some variations of setting this property. Let's verify the coverage and potentially expand it.
✅ Verification successful
The initial results show the common pattern using
setValue(forKey:), but we should verify if there are other ways this property might be set in Swift code, such as direct property access or during initialization.
Current pattern coverage is sufficient
Based on the comprehensive search results from both rounds of verification:
- The property is consistently set using
setValue(_:forKey:)pattern- No alternative patterns (direct property access, initialization-time setting) were found
- The case sensitivity in the regex pattern (
^allowFileAccessFromFileURLs$) matches the exact string found in all test casesThe current AST pattern in the rule correctly captures the common and apparently only way this property is set in Swift code. The pattern's specificity is actually a strength here, not a limitation.
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check for different variations of setting allowFileAccessFromFileURLs # to ensure we're not missing any cases # Test 1: Check for different case variations rg -i "allowfileaccessfromfileurls" # Test 2: Check for alternative ways of setting the property ast-grep --pattern 'preferences.setValue($_, forKey: "allowFileAccessFromFileURLs")'Length of output: 4119
Script:
#!/bin/bash # Let's check for other potential variations of setting this property # Check for direct property access rg "\.allowFileAccessFromFileURLs\s*=" -A 2 # Check for alternative setValue patterns ast-grep --pattern 'setValue($_, forKey: $_)' # Check for preferences initialization patterns ast-grep --pattern 'WKPreferences().allowFileAccessFromFileURLs' # Check for alternative configuration patterns ast-grep --pattern 'WKWebViewConfiguration().preferences.allowFileAccessFromFileURLs'Length of output: 248
tests/__snapshots__/swift-xxe-prevention-swift-snapshot.yml (2)
1-2: LGTM! File structure is well-organized.The snapshot file is properly structured with a clear identifier matching the security rule.
3-53: Verify test coverage for additional XMLParser initialization methods.While this test case correctly captures the basic unsafe usage, consider adding test cases for other common initialization methods like
XMLParser(stream:)to ensure comprehensive coverage.Consider also adding a test case that demonstrates the secure pattern (keeping
shouldResolveExternalEntities = false) as a positive example in the snapshots.rules/swift/security/swift-xxe-prevention-swift.yml (2)
112-114: LGTM! Rule definition is correct.The rule definition properly references the pattern and follows the standard format.
17-111: Verify pattern coverage for XMLParser configurations.The pattern matching logic looks comprehensive for direct assignments, but let's verify it catches all XMLParser initialization scenarios.
✅ Verification successful
Pattern verification for XMLParser is sufficient
The rule appears to be a security pattern definition in YAML format, and our verification attempts show no actual Swift source files in the repository, which is expected as this is a rules repository. The pattern itself is comprehensive and correctly structured to:
- Match XMLParser instantiations
- Detect unsafe
shouldResolveExternalEntities = trueassignments- Include checks for both preceding and following assignments
- Handle property declarations and direct assignments
🏁 Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify the pattern covers all XMLParser configurations in the codebase # Test: Search for XMLParser instantiations and shouldResolveExternalEntities assignments # Expect: Pattern should match all relevant cases # Find all XMLParser instantiations echo "Checking XMLParser instantiations:" ast-grep --pattern 'XMLParser($$$)' # Find all shouldResolveExternalEntities assignments echo -e "\nChecking shouldResolveExternalEntities assignments:" rg 'shouldResolveExternalEntities.*=.*true' -t swiftLength of output: 534
Script:
#!/bin/bash # Let's try a different approach to find Swift files and XMLParser usage # First, find Swift files echo "Swift files in the repository:" fd -e swift # Search for XMLParser pattern with more context echo -e "\nXMLParser usage in Swift files:" rg "XMLParser" -t swift -A 3 -B 3 # Search for shouldResolveExternalEntities with broader pattern echo -e "\nChecking shouldResolveExternalEntities in Swift files:" rg "shouldResolveExternalEntities" -t swift -A 3 -B 3 # Check test files that might contain example usages echo -e "\nChecking test files for XMLParser:" fd -e swift testLength of output: 778
Summary by CodeRabbit