fix: harden allow-always shell multiplexer wrapper handling

CHANGELOG.md

@@ -23,6 +23,7 @@ Docs: https://docs.openclaw.ai
 - Security/Exec: harden `safeBins` long-option validation by rejecting unknown/ambiguous GNU long-option abbreviations and denying sort filesystem-dependent flags (`--random-source`, `--temporary-directory`, `-T`), closing safe-bin denylist bypasses. This ships in the next npm release. Thanks @tdjackey and @jiseoung for reporting.
 - Security/Channels: unify dangerous name-matching policy checks (`dangerouslyAllowNameMatching`) across core and extension channels, share mutable-allowlist detectors between `openclaw doctor` and `openclaw security audit`, and scan all configured accounts (not only the default account) in channel security audit findings.
 - Security/Exec approvals: enforce canonical wrapper execution plans across allowlist analysis and runtime execution (node host + gateway host), fail closed on semantic `env` wrapper usage, and reject unknown short safe-bin flags to prevent `env -S/--split-string` interpretation-mismatch bypasses. This ships in the next npm release. Thanks @tdjackey for reporting.
+- Security/Exec approvals: recognize `busybox`/`toybox` shell applets in wrapper analysis and allow-always persistence, persist inner executables instead of multiplexer wrapper binaries, and fail closed when multiplexer unwrapping is unsafe to prevent allow-always bypasses. This ships in the next npm release. Thanks @jiseoung for reporting.
 - Security/Image tool: enforce `tools.fs.workspaceOnly` for sandboxed `image` path resolution so mounted out-of-workspace paths are blocked before media bytes are loaded/sent to vision providers. This ships in the next npm release. Thanks @tdjackey for reporting.
 - Security/Session export: harden exported HTML image rendering against data-URL attribute injection by validating image MIME/base64 fields, rejecting malformed base64 input in media ingestion paths, and dropping invalid tool-image payloads.
 

docs/tools/exec-approvals.md

@@ -178,7 +178,9 @@ For shell wrappers (`bash|sh|zsh ... -c/-lc`), request-scoped env overrides are
 small explicit allowlist (`TERM`, `LANG`, `LC_*`, `COLORTERM`, `NO_COLOR`, `FORCE_COLOR`).
 For allow-always decisions in allowlist mode, known dispatch wrappers
 (`env`, `nice`, `nohup`, `stdbuf`, `timeout`) persist inner executable paths instead of wrapper
-paths. If a wrapper cannot be safely unwrapped, no allowlist entry is persisted automatically.
+paths. Shell multiplexers (`busybox`, `toybox`) are also unwrapped for shell applets (`sh`, `ash`,
+etc.) so inner executables are persisted instead of multiplexer binaries. If a wrapper or
+multiplexer cannot be safely unwrapped, no allowlist entry is persisted automatically.
 
 Default safe bins: `jq`, `cut`, `uniq`, `head`, `tail`, `tr`, `wc`.
 

src/infra/exec-approvals-allow-always.test.ts

@@ -153,6 +153,60 @@ describe("resolveAllowAlwaysPatterns", () => {
     expect(patterns).not.toContain("/usr/bin/nice");
   });
 
+  it("unwraps busybox/toybox shell applets and persists inner executables", () => {
+    if (process.platform === "win32") {
+      return;
+    }
+    const dir = makeTempDir();
+    const busybox = makeExecutable(dir, "busybox");
+    makeExecutable(dir, "toybox");
+    const whoami = makeExecutable(dir, "whoami");
+    const env = { PATH: `${dir}${path.delimiter}${process.env.PATH ?? ""}` };
+    const patterns = resolveAllowAlwaysPatterns({
+      segments: [
+        {
+          raw: `${busybox} sh -lc whoami`,
+          argv: [busybox, "sh", "-lc", "whoami"],
+          resolution: {
+            rawExecutable: busybox,
+            resolvedPath: busybox,
+            executableName: "busybox",
+          },
+        },
+      ],
+      cwd: dir,
+      env,
+      platform: process.platform,
+    });
+    expect(patterns).toEqual([whoami]);
+    expect(patterns).not.toContain(busybox);
+  });
+
+  it("fails closed for unsupported busybox/toybox applets", () => {
+    if (process.platform === "win32") {
+      return;
+    }
+    const dir = makeTempDir();
+    const busybox = makeExecutable(dir, "busybox");
+    const patterns = resolveAllowAlwaysPatterns({
+      segments: [
+        {
+          raw: `${busybox} sed -n 1p`,
+          argv: [busybox, "sed", "-n", "1p"],
+          resolution: {
+            rawExecutable: busybox,
+            resolvedPath: busybox,
+            executableName: "busybox",
+          },
+        },
+      ],
+      cwd: dir,
+      env: makePathEnv(dir),
+      platform: process.platform,
+    });
+    expect(patterns).toEqual([]);
+  });
+
   it("fails closed for unresolved dispatch wrappers", () => {
     const patterns = resolveAllowAlwaysPatterns({
       segments: [
@@ -171,6 +225,52 @@ describe("resolveAllowAlwaysPatterns", () => {
     expect(patterns).toEqual([]);
   });
 
+  it("prevents allow-always bypass for busybox shell applets", () => {
+    if (process.platform === "win32") {
+      return;
+    }
+    const dir = makeTempDir();
+    const busybox = makeExecutable(dir, "busybox");
+    const echo = makeExecutable(dir, "echo");
+    makeExecutable(dir, "id");
+    const safeBins = resolveSafeBins(undefined);
+    const env = { PATH: `${dir}${path.delimiter}${process.env.PATH ?? ""}` };
+
+    const first = evaluateShellAllowlist({
+      command: `${busybox} sh -c 'echo warmup-ok'`,
+      allowlist: [],
+      safeBins,
+      cwd: dir,
+      env,
+      platform: process.platform,
+    });
+    const persisted = resolveAllowAlwaysPatterns({
+      segments: first.segments,
+      cwd: dir,
+      env,
+      platform: process.platform,
+    });
+    expect(persisted).toEqual([echo]);
+
+    const second = evaluateShellAllowlist({
+      command: `${busybox} sh -c 'id > marker'`,
+      allowlist: [{ pattern: echo }],
+      safeBins,
+      cwd: dir,
+      env,
+      platform: process.platform,
+    });
+    expect(second.allowlistSatisfied).toBe(false);
+    expect(
+      requiresExecApproval({
+        ask: "on-miss",
+        security: "allowlist",
+        analysisOk: second.analysisOk,
+        allowlistSatisfied: second.allowlistSatisfied,
+      }),
+    ).toBe(true);
+  });
+
   it("prevents allow-always bypass for dispatch-wrapper + shell-wrapper chains", () => {
     if (process.platform === "win32") {
       return;

src/infra/exec-approvals-allowlist.ts

@@ -21,6 +21,7 @@ import {
   extractShellWrapperInlineCommand,
   isDispatchWrapperExecutable,
   isShellWrapperExecutable,
+  unwrapKnownShellMultiplexerInvocation,
   unwrapKnownDispatchWrapperInvocation,
 } from "./exec-wrapper-resolution.js";
 
@@ -299,6 +300,30 @@ function collectAllowAlwaysPatterns(params: {
     return;
   }
 
+  const shellMultiplexerUnwrap = unwrapKnownShellMultiplexerInvocation(params.segment.argv);
+  if (shellMultiplexerUnwrap.kind === "blocked") {
+    return;
+  }
+  if (shellMultiplexerUnwrap.kind === "unwrapped") {
+    collectAllowAlwaysPatterns({
+      segment: {
+        raw: shellMultiplexerUnwrap.argv.join(" "),
+        argv: shellMultiplexerUnwrap.argv,
+        resolution: resolveCommandResolutionFromArgv(
+          shellMultiplexerUnwrap.argv,
+          params.cwd,
+          params.env,
+        ),
+      },
+      cwd: params.cwd,
+      env: params.env,
+      platform: params.platform,
+      depth: params.depth + 1,
+      out: params.out,
+    });
+    return;
+  }
+
   const candidatePath = resolveAllowlistCandidatePath(params.segment.resolution, params.cwd);
   if (!candidatePath) {
     return;

src/infra/exec-safe-bin-runtime-policy.test.ts

@@ -15,6 +15,8 @@ describe("exec safe-bin runtime policy", () => {
     { bin: "node20", expected: true },
     { bin: "ruby3.2", expected: true },
     { bin: "bash", expected: true },
+    { bin: "busybox", expected: true },
+    { bin: "toybox", expected: true },
     { bin: "myfilter", expected: false },
     { bin: "jq", expected: false },
   ];

src/infra/exec-safe-bin-runtime-policy.ts

@@ -17,6 +17,7 @@ export type ExecSafeBinConfigScope = {
 const INTERPRETER_LIKE_SAFE_BINS = new Set([
   "ash",
   "bash",
+  "busybox",
   "bun",
   "cmd",
   "cmd.exe",
@@ -40,6 +41,7 @@ const INTERPRETER_LIKE_SAFE_BINS = new Set([
   "python3",
   "ruby",
   "sh",
+  "toybox",
   "wscript",
   "zsh",
 ]);

src/infra/exec-wrapper-resolution.ts

@@ -7,6 +7,7 @@ const WINDOWS_EXE_SUFFIX = ".exe";
 const POSIX_SHELL_WRAPPER_NAMES = ["ash", "bash", "dash", "fish", "ksh", "sh", "zsh"] as const;
 const WINDOWS_CMD_WRAPPER_NAMES = ["cmd"] as const;
 const POWERSHELL_WRAPPER_NAMES = ["powershell", "pwsh"] as const;
+const SHELL_MULTIPLEXER_WRAPPER_NAMES = ["busybox", "toybox"] as const;
 const DISPATCH_WRAPPER_NAMES = [
   "chrt",
   "doas",
@@ -42,6 +43,7 @@ export const DISPATCH_WRAPPER_EXECUTABLES = new Set(withWindowsExeAliases(DISPAT
 const POSIX_SHELL_WRAPPER_CANONICAL = new Set<string>(POSIX_SHELL_WRAPPER_NAMES);
 const WINDOWS_CMD_WRAPPER_CANONICAL = new Set<string>(WINDOWS_CMD_WRAPPER_NAMES);
 const POWERSHELL_WRAPPER_CANONICAL = new Set<string>(POWERSHELL_WRAPPER_NAMES);
+const SHELL_MULTIPLEXER_WRAPPER_CANONICAL = new Set<string>(SHELL_MULTIPLEXER_WRAPPER_NAMES);
 const DISPATCH_WRAPPER_CANONICAL = new Set<string>(DISPATCH_WRAPPER_NAMES);
 const SHELL_WRAPPER_CANONICAL = new Set<string>([
   ...POSIX_SHELL_WRAPPER_NAMES,
@@ -133,6 +135,39 @@ function findShellWrapperSpec(baseExecutable: string): ShellWrapperSpec | null {
   return null;
 }
 
+export type ShellMultiplexerUnwrapResult =
+  | { kind: "not-wrapper" }
+  | { kind: "blocked"; wrapper: string }
+  | { kind: "unwrapped"; wrapper: string; argv: string[] };
+
+export function unwrapKnownShellMultiplexerInvocation(
+  argv: string[],
+): ShellMultiplexerUnwrapResult {
+  const token0 = argv[0]?.trim();
+  if (!token0) {
+    return { kind: "not-wrapper" };
+  }
+  const wrapper = normalizeExecutableToken(token0);
+  if (!SHELL_MULTIPLEXER_WRAPPER_CANONICAL.has(wrapper)) {
+    return { kind: "not-wrapper" };
+  }
+
+  let appletIndex = 1;
+  if (argv[appletIndex]?.trim() === "--") {
+    appletIndex += 1;
+  }
+  const applet = argv[appletIndex]?.trim();
+  if (!applet || !isShellWrapperExecutable(applet)) {
+    return { kind: "blocked", wrapper };
+  }
+
+  const unwrapped = argv.slice(appletIndex);
+  if (unwrapped.length === 0) {
+    return { kind: "blocked", wrapper };
+  }
+  return { kind: "unwrapped", wrapper, argv: unwrapped };
+}
+
 export function isEnvAssignment(token: string): boolean {
   return /^[A-Za-z_][A-Za-z0-9_]*=.*/.test(token);
 }
@@ -474,6 +509,18 @@ function hasEnvManipulationBeforeShellWrapperInternal(
     );
   }
 
+  const shellMultiplexerUnwrap = unwrapKnownShellMultiplexerInvocation(argv);
+  if (shellMultiplexerUnwrap.kind === "blocked") {
+    return false;
+  }
+  if (shellMultiplexerUnwrap.kind === "unwrapped") {
+    return hasEnvManipulationBeforeShellWrapperInternal(
+      shellMultiplexerUnwrap.argv,
+      depth + 1,
+      envManipulationSeen,
+    );
+  }
+
   const wrapper = findShellWrapperSpec(normalizeExecutableToken(token0));
   if (!wrapper) {
     return false;
@@ -577,6 +624,14 @@ function extractShellWrapperCommandInternal(
     return extractShellWrapperCommandInternal(dispatchUnwrap.argv, rawCommand, depth + 1);
   }
 
+  const shellMultiplexerUnwrap = unwrapKnownShellMultiplexerInvocation(argv);
+  if (shellMultiplexerUnwrap.kind === "blocked") {
+    return { isWrapper: false, command: null };
+  }
+  if (shellMultiplexerUnwrap.kind === "unwrapped") {
+    return extractShellWrapperCommandInternal(shellMultiplexerUnwrap.argv, rawCommand, depth + 1);
+  }
+
   const base0 = normalizeExecutableToken(token0);
   const wrapper = findShellWrapperSpec(base0);
   if (!wrapper) {

src/infra/system-run-command.test.ts

@@ -57,6 +57,11 @@ describe("system run command helpers", () => {
     expect(extractShellCommandFromArgv(["pwsh", "-Command", "Get-Date"])).toBe("Get-Date");
   });
 
+  test("extractShellCommandFromArgv unwraps busybox/toybox shell applets", () => {
+    expect(extractShellCommandFromArgv(["busybox", "sh", "-c", "echo hi"])).toBe("echo hi");
+    expect(extractShellCommandFromArgv(["toybox", "ash", "-lc", "echo hi"])).toBe("echo hi");
+  });
+
   test("extractShellCommandFromArgv ignores env wrappers when no shell wrapper follows", () => {
     expect(extractShellCommandFromArgv(["/usr/bin/env", "FOO=bar", "/usr/bin/printf", "ok"])).toBe(
       null,