mcp: fix nil params crash vulnerability (#186) #214
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jba
requested changes
Jul 31, 2025
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@jba Thanks for the review! I've actually updated this PR based on the discussion in #186 - it now only contains test improvements and no longer includes the fix logic (since #210 already resolved the core issue). The code you're commenting on has been removed. The PR now just adds complementary unit test coverage for the methodFlags system. |
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It looks like this PR does not format cleanly. Could you please run |
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ok~ let me fix it |
Complements the methodFlags system from modelcontextprotocol#210 with additional unit tests: - Tests nil RawMessage and explicit JSON null handling in unmarshalParams - Tests edge cases with different JSON types (empty string, array, number, boolean) - Validates proper error handling for required vs optional params with methodFlags - Provides focused unit test coverage alongside existing conformance tests The tests verify that the panic vulnerability from modelcontextprotocol#186 is properly handled by the upstream methodFlags implementation.
findleyr
approved these changes
Aug 5, 2025
jba
approved these changes
Aug 5, 2025
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Handle nil RawMessage and explicit JSON "null" in unmarshalParams to prevent server crashes. When JSON-RPC requests are sent without parameters or with null parameters, ensure orZero receives a valid struct instead of nil.
Fixes #186 - DoS vulnerability where missing params caused server panic
Changes:
Behavior:
missingParamsOKflag: gracefully handle nil/null paramsSecurity Impact: