fix(agent): const-time bearer + scope gates#389
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Closes #301, #304, #305, #311. - server.rs:235 bearer compare now uses subtle::ConstantTimeEq with length pre-check (timing-side-channel safe). - server.rs:166 read_resource gates on scope.allows_resource before delegating, matching call_tool's rejection pattern. - main.rs adds --scope {messaging,read,full}, defaulting to Messaging (least privilege) instead of Full via Default. Verified: cargo check / fmt / clippy -D warnings (willow-agent).
This was referenced Apr 27, 2026
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Fixes
==#301 + [SEC-A-01] Bearer token compared with non-constant-time equality #304 —crates/agent/src/server.rs:235bearer compare now usessubtle::ConstantTimeEqwith length pre-check. No early-exit on length mismatch, no byte-by-byte timing leak.read_resourcedoes not enforceallows_resourcescope #305 —crates/agent/src/server.rs:166read_resourcegates onscope.allows_resource(&request.uri)before delegating, mirroringcall_tool's rejection (ErrorCode::INVALID_REQUEST).crates/agent/src/main.rs:156adds--scope {messaging,read,full}(clapValueEnum), defaulting toMessaging(least privilege) instead ofDefault::default()(which wasFull). Threaded intoserve_http.closes #301 #304 #305 #311
Test plan
cargo check -p willow-agent— passcargo fmt -p willow-agent— cleancargo clippy -p willow-agent -- -D warnings— passGenerated by Claude Code