fix(security): Predictable global cache directory in /tmp enables symlink/hijack risks#1314
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The cache directory is a fixed, shared path (`/tmp/ncc-cache`). On multi-user systems this can be pre-created or manipulated by another user (symlink/hardlink attacks), potentially causing cache poisoning, unintended file writes, or data leakage between builds/users depending on how cache files are later written. Affected files: ncc-cache-dir.js Signed-off-by: tuanaiseo <221258316+tuanaiseo@users.noreply.github.com>
styfle
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styfle
reviewed
Apr 3, 2026
| const path = require("path"); | ||
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| const cacheBase = process.env.XDG_CACHE_HOME || path.join(os.homedir(), ".cache"); | ||
| const projectKey = crypto.createHash("sha256").update(process.cwd()).digest("hex").slice(0, 12); |
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Suggested change
| const projectKey = crypto.createHash("sha256").update(process.cwd()).digest("hex").slice(0, 12); | |
| const projectKey = crypto.createHash("sha1").update(process.cwd()).digest("hex"); |
No reason to truncate. Just use a smaller hashing function if you don't need the entropy.
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Problem
The cache directory is a fixed, shared path (
/tmp/ncc-cache). On multi-user systems this can be pre-created or manipulated by another user (symlink/hardlink attacks), potentially causing cache poisoning, unintended file writes, or data leakage between builds/users depending on how cache files are later written.Severity:
mediumFile:
src/utils/ncc-cache-dir.jsSolution
Use a per-user/per-project cache directory with secure creation semantics (e.g.,
fs.mkdtempunder user-owned base dir), enforce permissions (0700), and verify path is not a symlink before writing.Changes
src/utils/ncc-cache-dir.js(modified)Testing