feat(mcp): MCP-SAN + MCP-COV hardening#76
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josealekhine merged 1 commit intoMay 10, 2026
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Implements sanitization layer (MCP-SAN ActiveMemory#49) and coverage expansion (MCP-COV ActiveMemory#50) for the MCP server. Sanitization: - Add internal/sanitize package: Content, Reflect, SessionID, StripControl, truncate helpers - Add internal/config/sanitize constants (NullByte, DotDot, etc.) - Add internal/config/regex/sanitize compiled regexes - Add MaxSourceLimit, MaxContentLen, MaxNameLen, MaxQueryLen, MaxCallerLen, MaxURILen constants to internal/config/mcp/cfg - Add InputTooLong error constructor in internal/err/mcp - Add mcp.err-input-too-long and mcp.err-unknown-entry-type YAML keys - Apply sanitize.Content in extract EntryArgs and prompt buildEntry - Apply sanitize.Reflect for query, caller, name, URI in all tool/prompt/resource dispatch paths - Cap source limit to MaxSourceLimit in tool handler Coverage: - internal/entity/mcp_session_test.go: 10 tests covering MCPSession lifecycle methods including PendingCount, RecordSessionStart, RecordContextLoaded, RecordDriftCheck, RecordContextWrite, IncrementCallsSinceWrite - internal/mcp/server/server_test.go: 15+ new tests covering notification handling, subscribe/unsubscribe error paths, ctx_remind with active and future-dated reminders, ctx_drift missing-file violations, ctx_complete empty and non-matching query - internal/mcp/proto/schema_test.go: JSON round-trip tests - internal/mcp/server/def/{tool,prompt}/*_test.go: def count tests - internal/mcp/server/{extract,io,out,parse,stat}/*_test.go: unit tests Signed-off-by: CoderMungan <codermungan@gmail.com>
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Minor fixes needed; but I'll take care of those.
Mostly around unicode parsing edge cases.
Thanks for the good work 🙏 .
This was referenced May 10, 2026
omergk28
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May 11, 2026
Follow-up to PR ActiveMemory#76 (MCP-SAN + MCP-COV hardening) addressing three issues surfaced during post-merge review: 1. truncate() now backs up to a UTF-8 rune boundary via utf8.RuneStart so byte-level cuts never produce invalid UTF-8. Reflect() and SessionID() delegate to the shared helper. 2. StripControl() now drops U+2028 (LINE SEPARATOR) and U+2029 (PARAGRAPH SEPARATOR) explicitly. unicode.IsControl does not match these (categories Zl/Zp), yet Markdown renderers may treat them as line breaks — leaving them in opens a newline injection path through reflected content. Constants live in internal/config/sanitize. 3. SanitizedOpts now enforces MaxOptsFieldLen (4 KB) on context, rationale, consequence, lesson, and application — secondary prose fields that previously had no length cap. Signature changes to (entity.EntryOpts, error); the two call sites in route/tool/tool.go propagate the error to the MCP client via InputTooLong, naming the offending field. Spec: specs/sanitize-hardening-followup.md
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It’s been great working with you and being part of this project, Jose. Looking forward to the new features... @josealekhine |
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Closes #49, closes #50
Summary
Re-implementation of PR #52 adapted to the current codebase. Addresses
MCP-SAN (#49) sanitization requirements and MCP-COV (#50) coverage
requirements in full.
MCP-SAN (#49) — Sanitization layer
New packages
internal/sanitize:Content,Reflect,SessionID,StripControl,truncateinternal/config/sanitize: string/length constants (NullByte,DotDot,ForwardSlash,Backslash,HyphenReplace,MaxSessionIDLen)internal/config/regex/sanitize: compiled regexes for Markdown structure chars and session ID unsafe charsConfig constants
Added to
internal/config/mcp/cfg:MaxSourceLimit,MaxContentLen,MaxNameLen,MaxQueryLen,MaxCallerLen,MaxURILenError + text
internal/err/mcp:InputTooLong(field, maxLen)constructormcp.err-input-too-longandmcp.err-unknown-entry-typekeys in embed/text and YAMLApplied sanitization
extract.EntryArgs: MaxContentLen guard →InputTooLongerrorextract.SanitizedOpts: sanitizes all option fieldsroute/prompt/entry.buildEntry:sanitize.Contenton every field valueroute/tool/tool.go:sanitize.Contenton content,sanitize.Reflecton query/caller, cap limit toMaxSourceLimitroute/tool/dispatch.go,route/prompt/dispatch.go,resource/dispatch.go:sanitize.Reflectfor name/URI in unknown-branch pathsMCP-COV (#50) — Coverage expansion
New test files (12)
internal/entity/mcp_session_test.gointernal/mcp/proto/schema_test.gointernal/mcp/server/def/tool/tool_test.gointernal/mcp/server/def/prompt/prompt_test.gointernal/mcp/server/extract/extract_test.gointernal/mcp/server/io/write_test.gointernal/mcp/server/out/out_test.gointernal/mcp/server/parse/parse_test.gointernal/mcp/server/stat/stat_test.gointernal/sanitize/sanitize_test.goExtended:
internal/mcp/server/server_test.goAdded 15 new tests covering all COV gaps:
TestServeNotificationIgnored— notification silently consumedTestServeEmptyLines,TestServeParseErrorWriteFailure,TestServeDispatchWriteFailureTestResourcesSubscribeInvalidJSON/EmptyURI,TestResourcesUnsubscribeInvalidJSON/EmptyURITestToolRemindWithActive,TestToolRemindFutureDatedTestToolDriftMissingFileTestToolCompleteEmptyQuery,TestToolCompleteNoMatchTestPromptAddLearningCI
go build ./...✅go test ./...✅ (133 packages, 0 failures)go vet ./...✅golangci-lint run✅ (0 issues)