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…rity model audit (#2417, #2426, #2427) Implements the confused-deputy privilege boundary between ACP server and MCP client roles, formal 4-property security model mapping, and attack/defense taxonomy audit. Key changes: - Add `mcp_to_acp_boundary` config field (default: true) to ContentIsolationConfig; when enabled, MCP tool results in ACP sessions are unconditionally quarantined regardless of quarantine source config, preventing privilege amplification - Add `is_acp_session` flag to SecurityState, set at ACP agent construction - Add `CrossBoundaryMcpToAcp` SecurityEventCategory and `cross_boundary_mcp_to_acp` AuditEntry field; cross-boundary events are emitted to the persistent JSONL audit log - Add startup warning when `mcp_to_acp_boundary = true` but quarantine is unconfigured - Fix ACP-requested MCP servers receiving `tool_allowlist: Vec::new()` (allow all) — changed to `Option<Vec<String>>` with fail-closed semantics: None = inherit server config, Some([]) = deny all (BREAKING: existing `tool_allowlist = []` configs now deny all tools instead of warning and allowing all) - Filter dangerous env vars (LD_PRELOAD, LD_LIBRARY_PATH, DYLD_INSERT_LIBRARIES, DYLD_LIBRARY_PATH, _RLD_LIST, SHLIB_PATH) before passing to MCP stdio child processes to prevent injection attacks - Write security audit spec to .local/specs/security-model-audit.md mapping all Zeph security components to Task/Action/Source/Data alignment properties Closes #2417, #2426, #2427
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…nt drop Closes #2437, closes #2438. - Extend `is_dangerous_env_var()` in `mcp_bridge.rs` to block PATH (path hijacking), HTTP_PROXY/HTTPS_PROXY/ALL_PROXY/NO_PROXY (proxy interception), BASH_ENV/ENV (shell startup injection), and PYTHONPATH/NODE_PATH/RUBYLIB (runtime module injection). These vars were not filtered by PR #2436. - Replace silent `return` in `AuditLogger::log()` with `tracing::error!("audit entry serialization failed: {err}")` so serialization failures are observable in logs instead of silently dropped. - Update and extend tests for both changes. Note: #2412 was already resolved in PR #2423 (ProtocolVersion::LATEST in discovery handler); CHANGELOG entry added only.
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…nt drop (#2446) Closes #2437, closes #2438. - Extend `is_dangerous_env_var()` in `mcp_bridge.rs` to block PATH (path hijacking), HTTP_PROXY/HTTPS_PROXY/ALL_PROXY/NO_PROXY (proxy interception), BASH_ENV/ENV (shell startup injection), and PYTHONPATH/NODE_PATH/RUBYLIB (runtime module injection). These vars were not filtered by PR #2436. - Replace silent `return` in `AuditLogger::log()` with `tracing::error!("audit entry serialization failed: {err}")` so serialization failures are observable in logs instead of silently dropped. - Update and extend tests for both changes. Note: #2412 was already resolved in PR #2423 (ProtocolVersion::LATEST in discovery handler); CHANGELOG entry added only.
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Summary
mcp_to_acp_boundaryconfig (default:true) — unconditionally quarantines MCP tool results in ACP sessions, preventing confused-deputy privilege amplificationtool_allowlist: Vec::new()for ACP-requested MCP servers (was allow-all, now fail-closed viaOption<Vec<String>>)LD_PRELOAD,DYLD_INSERT_LIBRARIES, etc.) before passing to MCP stdio child processesCrossBoundaryMcpToAcpsecurity event +cross_boundary_mcp_to_acpaudit field for forensic traceability.local/specs/security-model-audit.mdBreaking change
tool_allowlist = []for MCP servers previously warned and allowed all tools. It now denies all tools (fail-closed). Settool_allowlistto the explicit list of allowed tools, or remove the field to inherit server config.Test plan
cargo nextest run --workspace --features full --lib --bins— 7279 passed (+10 over baseline)cargo clippy --all-targets --features full --workspace -- -D warnings— cleancargo +nightly fmt --check— cleansanitize_tool_output_cross_boundary_acp_mcp_quarantines,sanitize_tool_output_cross_boundary_disabled_skips_quarantine,sanitize_tool_output_non_acp_session_normal_pathFollow-up issues
PATHand*_proxymissing from env var blocklist inmcp_bridge.rsAuditLogger::log()silently drops entries on serialization failure (no error logged)Closes #2417, #2426, #2427