fix(hooks): eliminate TOCTOU race in stop-feedback.sh plugin root lookup#151
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xiaolai wants to merge 1 commit intotanweai:mainfrom
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fix(hooks): eliminate TOCTOU race in stop-feedback.sh plugin root lookup#151xiaolai wants to merge 1 commit intotanweai:mainfrom
xiaolai wants to merge 1 commit intotanweai:mainfrom
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The hook wrote the plugin root path to /tmp/pua-plugin-root, then the heredoc instructed Claude to execute: bash "$(cat /tmp/pua-plugin-root)/hooks/sanitize-session.sh" ... Between the write and Claude's bash execution, a local user controlling /tmp/ could replace the file to redirect execution to an arbitrary script. Fix: remove the temp-file indirection entirely. CLAUDE_PLUGIN_ROOT is already set in the hook environment (and in Claude's bash context) by Claude Code — use it directly. The _PLUGIN_ROOT computation block is also removed as it is now dead code. Co-Authored-By: Claude Code <noreply@anthropic.com>
This was referenced Apr 26, 2026
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What's broken
hooks/stop-feedback.shresolves the plugin root path and writes it to a temporary file:Then, inside a heredoc, it instructs Claude to execute:
bash "$(cat /tmp/pua-plugin-root)/hooks/sanitize-session.sh" ...There is a time window between when the hook writes
/tmp/pua-plugin-rootand when Claude's bash execution reads it back. On a system where/tmp/is world-writable, a local user can replace the file contents between those two moments, redirecting thebashcall to an arbitrary script. This is a classic TOCTOU (Time-of-Check-Time-of-Use) race.Fix
Remove the temp-file indirection entirely.
CLAUDE_PLUGIN_ROOTis set in the hook's execution environment by Claude Code and is also available in Claude's bash context. Use it directly:The
_PLUGIN_ROOTcomputation block (theif [[ -n "${CLAUDE_PLUGIN_ROOT:-}" ]]block) is removed as dead code since it was only used to produce the now-eliminated temp file.This is a 9-line removal and a 1-word change — fully mechanical with no behavioral change in the normal code path.