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require opt-in for PowerShell whole-drive read access - #1463
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Matt Van Horn (mvanhorn) wants to merge 1 commit into
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The drive root is added only when allowPowerShellDriveRootRead is true; the default is false. Finding pwsh.exe still adds the PSReadLine history directory to readwritePaths, and a drive root that is already a PATH entry is still returned as a tool directory. The README and the helper comments state that the opt-in permits recursive whole-drive reads on BaseContainer, and they point at wxc-host-prep prepare-system-drive or enumeratePaths for a root check that does not grant subtree reads. FilesystemPolicyResult still only carries readonlyPaths and readwritePaths. Fixes microsoft#1455
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🟡 Changes recommended
The Rust helper remains vulnerable by default, and public Node documentation is incomplete or misleading.
4 open findings
What changed in this PR
Makes PowerShell whole-drive read access opt-in for Node SDK filesystem discovery.
Changes:
- Adds
allowPowerShellDriveRootRead. - Preserves PowerShell history/tool discovery.
- Adds tests and security guidance.
| File | Description |
|---|---|
sdk/node/src/v1/policy/filesystem.ts |
Gates synthetic drive-root grants. |
sdk/node/tests/unit/policy.test.ts |
Tests opt-in and discovery behavior. |
sdk/node/README.md |
Documents security implications and alternatives. |
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| const pwshPolicy = getPowerShellPolicy( | ||
| pathDirs, | ||
| environment, | ||
| options?.allowPowerShellDriveRootRead === true, |
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| emit a diagnostic warning. When `pwsh.exe` is on `PATH`, discovery adds the | ||
| PSReadLine history directory to `readwritePaths` and leaves the system-drive | ||
| root out of `readonlyPaths`. Set `allowPowerShellDriveRootRead: true` to | ||
| restore that root for callers who accept the compatibility grant. On | ||
| BaseContainer, a drive-root `readonlyPaths` entry permits recursive reads of | ||
| the whole drive, including unrelated user files. `getUserProfilePolicy` uses |
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| * Defaults to `false`. Opting in permits recursive whole-drive reads on | ||
| * BaseContainer. PowerShell startup that only needs to stat the drive root | ||
| * should use host preparation or tier-supported configuration instead. | ||
| */ | ||
| allowPowerShellDriveRootRead?: boolean; |
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| * Additionally, if PowerShell (`pwsh.exe`) is found on PATH, the PSReadLine | ||
| * history directory is added to `readwritePaths`. The system-drive root is | ||
| * added to `readonlyPaths` only when `options.allowPowerShellDriveRootRead` | ||
| * is true (the default is `false`). That opt-in permits recursive whole-drive | ||
| * reads on BaseContainer. PowerShell startup that stats the drive root may | ||
| * need explicit host preparation or tier-supported configuration; the opt-in | ||
| * is the compatibility path for callers who accept the broad read. |
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📖 Description
The drive root is added only when allowPowerShellDriveRootRead is true; the default is false. Finding pwsh.exe still adds the PSReadLine history directory to readwritePaths, and a drive root that is already a PATH entry is still returned as a tool directory. The README and the helper comments state that the opt-in permits recursive whole-drive reads on BaseContainer, and they point at wxc-host-prep prepare-system-drive or enumeratePaths for a root check that does not grant subtree reads. FilesystemPolicyResult still only carries readonlyPaths and readwritePaths.
With PowerShell 7 on PATH, getAvailableToolsPolicy puts the system-drive root in readonlyPaths. On BaseContainer that entry covers the whole drive, so a sandbox built from the recommended discovery baseline can list and read every file the user can, including the profile and credential stores, and the policy result gives no sign that reads are no longer limited. getPowerShellPolicy appended SystemDrive (falling back to C:) plus a trailing slash to readonlyPaths whenever it found pwsh.exe. BaseContainer treats a drive-root readonly path as a recursive read of the subtree, so the grant meant to let PowerShell stat the root became a whole-drive content read.
Fixes #1455
🔗 References
Not applicable to this change.
🔍 Validation
Ran
cargo test --workspacelocally; it fails the same way on the base branch, so the failure predates this change (it fails the same way on main).Tests for this live in
sdk/node/tests/unit/policy.test.ts.✅ Checklist
Left unticked: nothing in this change to
sdk/node/src/v1/policy/filesystem.tsbacks it.Cargo.lock, thedependency-feed-checkcheck passes (see pull request builds)Not claimed: ran
cargo test --workspacelocally; it fails the same way on the base branch, so the failure predates this change (it fails the same way on main).📋 Issue Type
GitHub Actions runs the PR validation build automatically. The ADO pipeline
(
MXC-PR-Build) is the Azure version of the PR pipeline, kept in parity with the GitHubActions build; it runs on merge to
main, and Microsoft reviewers with write access can trigger iton a PR with
/azp run. See pull request builds.If the
dependency-feed-checkcheck fails on a new dependency, the crate must be added tothe feed before the PR can pass. See pull request builds
for the steps.
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Microsoft Reviewers: Open in CodeFlow