fix(approval): pair config.yaml write protection across file tools + terminal (#14639) - #36732
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…nt silent approval bypass
Subway2023's #14639 blocks write_file/patch to ~/.hermes/config.yaml, but the terminal side was only partially paired: echo>/tee/cp/mv to config.yaml already tripped the project-config pattern, while `sed -i` and direct edits slipped through with auto-approve. An unpaired write_file deny is theater per SECURITY.md — the agent could flip approvals.mode=off via `sed -i` and the mtime-keyed config cache reloads it mid-session. config.yaml IS the security policy (approvals.mode/yolo/permanent allowlist live there), so it warrants real pairing, not a half-door. Add a _HERMES_CONFIG_PATH fragment mirroring _HERMES_ENV_PATH, fold it into _SENSITIVE_WRITE_TARGET (covers tee/>/>>/cp/mv), and add sed -i coverage for both config.yaml and .env. Pins 9 regression tests including no-regression guards (reads pass, /tmp writes pass). Co-authored-by: sbw2025 <subw3@mail2.sysu.edu.cn>
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The bug (verified live on main)
~/.hermes/config.yamlholds the security policy itself —approvals.mode, yolo state, the permanent-approval allowlist. The config cache is mtime+size keyed (hermes_cli/config.py:_load_config_impl), so a write invalidates it and the next_get_approval_mode()call re-reads from disk mid-session. A prompt-injected or misguided agent can therefore setapprovals.mode: offand immediately bypass the dangerous-command gate on all subsequent calls.Why the original PR (#14639) was necessary but not sufficient
@Subway2023's #14639 correctly adds a
write_file/patchdeny for~/.hermes/config.yaml. But a tool-level write deny is only a real boundary when paired with equivalent terminal-side coverage (SECURITY.md §2.4 / paired-restriction rule) — otherwise the agent just uses the terminal tool.I verified the terminal side on main:
echo >,>>,tee,cp,mvto config.yaml already tripped the project-config pattern, butsed -iandsed --in-placeslipped through with auto-approve. So #14639 alone would have left an open door.What this PR does (salvage + pairing)
tools/file_tools.py::_check_sensitive_path) — authorship preserved, conflict with current main resolved.tools/approval.py): a_HERMES_CONFIG_PATHfragment mirroring the existing_HERMES_ENV_PATH, folded into_SENSITIVE_WRITE_TARGET(covers tee/>/>>/cp/mv) plus a dedicatedsed -i/sed --in-placepattern for bothconfig.yamland.env.This treats config.yaml as the security policy file (same category as auth.json / pairing/), warranting real two-surface pairing rather than a half-door.
No regression
Verified — only writes to the Hermes config/env files are newly gated:
~/.hermes/config.yamlpass (not a write)echo > /tmp/x.txt), normalsed -ion project files passTests
tests/tools/test_file_tools.py::TestSensitivePathCheck(5, @Subway2023's) — write_file/patch denytests/tools/test_approval.py::TestHermesConfigWriteProtection(9, new) — terminal-side pairing incl. thesed -igap and no-regression guardsCloses #14639.
Co-authored-by: sbw2025 subw3@mail2.sysu.edu.cn
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