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fix(sandbox): drop Authenticated Users from both restricting lists — close the C:\\-root escape, CIM unavailable in every confined mode

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workspace-write now runs [logon SID, Everyone, orphan]: the two lists differ only by the orphan, and the keep-alive group (logon SID + Everyone) is the single shared invariant. The WMI namespace security check fails in BOTH modes (0x80041003), so CIM/Get-ComputerInfo are unavailable everywhere — the price of closing the C:\\-root tree-creation escape (AU:(AD) + AU:(OI)(CI)(IO)(M)) in workspace-write too. The unused WinLocalSid/WinInteractiveSid/WinAuthenticatedUserSid constants and their ABI-probe prints are removed; the enforcement 'full' claim now stands on a closed NTFS surface. New regression: a C:\\Users\\Public subdirectory write is denied under BOTH modes (the ambient-writable blind spot the review flagged — INTERACTIVE is absent from both lists). FAT-class (non-ACL) targets outside the granted roots remain writable (no security descriptors to intersect) — documented as a legacy residue, warn-only, not engineered around. Docs/design note/PR body updated in both languages (list I/J terminology gone everywhere).
This commit is contained in:
Huanqi Cao
2026-08-08 21:55:02 +08:00
parent 9d10a1888b
commit 441927c526
14 changed files with 104 additions and 81 deletions
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55
packages/sandbox/sandbox-windows-acl/tests/runner.spec.ts
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@@ -38,6 +38,13 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
let isolatedTemp!: string
let secretFile!: string
let escapeFile!: string
// The ambient-writable probe target: a subdirectory of C:\Users\Public.
// INTERACTIVE/LOCAL are absent from BOTH restricting lists, so the Public
// tree's INTERACTIVE grant must NOT satisfy the write check — the ambient
// boundary the dual-list design closes (bot-reported blind spot). The
// Public tree may be unavailable or unwritable for the test user on some
// hosts; the probe test skips itself when the directory cannot be created.
let publicProbeDir: string | undefined
beforeAll(() => {
scratchRoot = mkdtempSync(join(tmpdir(), 'dsh-acl-runner-'))
@@ -47,11 +54,17 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
secretFile = join(scratchRoot, 'secret.txt')
writeFileSync(secretFile, 'top secret - must stay readable to prove the read boundary')
escapeFile = join(scratchRoot, 'escaped.txt')
try {
publicProbeDir = mkdtempSync(join(process.env.PUBLIC ?? 'C:\\Users\\Public', 'dsh-acl-public-'))
} catch {
publicProbeDir = undefined
}
})
afterAll(() => {
rmSync(scratchRoot, { recursive: true, force: true })
rmSync(isolatedTemp, { recursive: true, force: true })
if (publicProbeDir !== undefined) rmSync(publicProbeDir, { recursive: true, force: true })
})
it('workspace-write: the confined child writes granted directories only', () => {
@@ -65,8 +78,10 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
`try{Set-Content -Path '${isolatedTemp}\\child-wrote.txt' -Value ok -ErrorAction Stop;'TEMP-WRITE: OK'}catch{'TEMP-WRITE: DENIED'};`,
`try{Set-Content -Path '${escapeFile}' -Value ok -ErrorAction Stop;'ESCAPE-WRITE: OK (ESCAPE!)'}catch{'ESCAPE-WRITE: DENIED'};`,
`try{Get-Content '${secretFile}' -ErrorAction Stop | Out-Null;'SECRET-READ: OK'}catch{'SECRET-READ: DENIED'};`,
// List J carries Authenticated Users: the CIM path (WMI namespace
// security check) stays alive under workspace-write.
// Authenticated Users is absent from BOTH lists: the WMI namespace
// security check fails (0x80041003) — CIM is unavailable under every
// confined mode (the documented contract; the C:\-root tree-creation
// escape is closed in both as the other side of the trade).
"try{Get-CimInstance Win32_OperatingSystem -ErrorAction Stop | Out-Null;'CIM: OK'}catch{'CIM: DENIED'}",
].join('')
const result = runRunner([
@@ -79,12 +94,12 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
expect(result.stdout).toContain('TEMP-WRITE: OK')
expect(result.stdout).toContain('ESCAPE-WRITE: DENIED')
expect(result.stdout).toContain('SECRET-READ: OK')
expect(result.stdout).toContain('CIM: OK')
expect(result.stdout).toContain('CIM: DENIED')
expect(existsSync(escapeFile)).toBe(false)
expect(existsSync(join(writableDir, 'child-wrote.txt'))).toBe(true)
}, 30_000)
it('read-only: strict zero grants — no writes anywhere (not even NUL), reads and $null redirection fine, CIM unavailable (list I)', () => {
it('read-only: strict zero grants — no writes anywhere (not even NUL), reads and $null redirection fine, CIM unavailable', () => {
const probe = [
"$ErrorActionPreference='SilentlyContinue';",
'\'LANGMODE: \' + $ExecutionContext.SessionState.LanguageMode;',
@@ -95,9 +110,9 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
// PowerShell's $null redirection discards without opening NUL — must keep working.
'echo hi > $null;\'DOLLAR-NULL: OK\';',
`try{Get-Content '${secretFile}' -ErrorAction Stop | Out-Null;'SECRET-READ: OK'}catch{'SECRET-READ: DENIED'};`,
// List I drops Authenticated Users: the WMI namespace security check
// fails (0x80041003) — the documented read-only CIM boundary, the
// price of the zero ambient-write surface.
// BOTH lists drop Authenticated Users: the WMI namespace security
// check fails (0x80041003) — the documented CIM boundary of every
// confined mode, the price of the zero ambient-write surface.
"try{Get-CimInstance Win32_OperatingSystem -ErrorAction Stop | Out-Null;'CIM: OK'}catch{'CIM: DENIED'}",
].join('')
const result = runRunner([
@@ -177,7 +192,7 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
it('mode-downgrade leak regression: a STANDING workspace grant is inert under read-only and effective again on re-upgrade', () => {
// The reported defect: a session that materialized its grant in
// workspace-write keeps the ACE standing for the server lifetime. After
// switching to read-only, the restricted token's list I must carry NO
// switching to read-only, the restricted token's read-only list must carry NO
// orphan SID — the standing ACE stays but the pass-2 check cannot use
// it, so the workspace write is denied (previously it LEAKED). The
// switch back reuses the SAME standing ACE: the re-upgrade write lands
@@ -214,6 +229,30 @@ describe.skipIf(!isWin32 || !pwshAvailable())('windows-acl runner', () => {
}
}, 30_000)
it('ambient-writable escape regression: a C:\\Users\\Public subdirectory is denied under BOTH modes (INTERACTIVE absent from both lists)', (ctx) => {
// The Public tree grants write to INTERACTIVE; the D1-D6 matrix pinned
// that removing INTERACTIVE from the restricting lists closes the escape.
// The committed suites never probed it — this pins the ambient boundary
// end to end with the real restricted token.
if (publicProbeDir === undefined) {
ctx.skip() // Public unavailable/unwritable on this host
return
}
const probe = [
"$ErrorActionPreference='SilentlyContinue';",
`try{Set-Content -Path '${publicProbeDir}\\public-escaped.txt' -Value ok -ErrorAction Stop;'PUBLIC-WRITE: OK (ESCAPE!)'}catch{'PUBLIC-WRITE: DENIED'}`,
].join('')
for (const mode of ['read-only', 'workspace-write'] as const) {
const result = runRunner([
'--workspace', writableDir, '--temp', isolatedTemp, '--mode', mode,
'--', 'pwsh', '/NoLogo', '/NonInteractive', '/NoProfile', '/Command', probe,
])
expect(result.status, `stderr: ${result.stderr}`).toBe(0)
expect(result.stdout, `mode: ${mode}`).toContain('PUBLIC-WRITE: DENIED')
expect(existsSync(join(publicProbeDir, 'public-escaped.txt')), `mode: ${mode}`).toBe(false)
}
}, 30_000)
it('runner-side failure: signature on stderr and exit 127, the command never runs', () => {
const result = runRunner(['--workspace', writableDir, '--temp', isolatedTemp, '--mode', 'workspace-write'])
expect(result.status).toBe(127)