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fix: escape package names before shell interpolation in npm install (CWE-78) #341

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fix: escape package names before shell interpolation in npm install (CWE-78) #341

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2 changes: 1 addition & 1 deletion src/__tests__/tools-security.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -654,7 +654,7 @@ describe("package install inline validation", () => {
const tool = tools.find((t) => t.name === "install_npm_package")!;
await tool.execute({ package: "axios" }, ctx);
expect(conway.execCalls.length).toBe(1);
expect(conway.execCalls[0].command).toBe("npm install -g axios");
expect(conway.execCalls[0].command).toBe("npm install -g 'axios'");
});

it("install_npm_package allows scoped packages", async () => {
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10 changes: 8 additions & 2 deletions src/agent/tools.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -568,7 +568,10 @@ export function createBuiltinTools(sandboxId: string): AutomatonTool[] {
if (!/^[@a-zA-Z0-9._\/-]+$/.test(pkg)) {
return `Blocked: invalid package name "${pkg}"`;
}
const result = await ctx.conway.exec(`npm install -g ${pkg}`, 60000);
const result = await ctx.conway.exec(
`npm install -g ${escapeShellArg(pkg)}`,
60000,
);

const { ulid } = await import("ulid");
ctx.db.insertModification({
Expand Down Expand Up @@ -964,7 +967,10 @@ Model: ${ctx.inference.getDefaultModel()}
if (!/^[@a-zA-Z0-9._\/-]+$/.test(pkg)) {
return `Blocked: invalid package name "${pkg}"`;
}
const result = await ctx.conway.exec(`npm install -g ${pkg}`, 60000);
const result = await ctx.conway.exec(
`npm install -g ${escapeShellArg(pkg)}`,
60000,
);

if (result.exitCode !== 0) {
return `Failed to install MCP server: ${result.stderr}`;
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7 changes: 6 additions & 1 deletion src/self-mod/tools-manager.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,11 @@ import type {
import { logModification } from "./audit-log.js";
import { ulid } from "ulid";

/** Escape a string for safe shell interpolation. */
function escapeShellArg(arg: string): string {
return `'${arg.replace(/'/g, "'\\''")}'`;
}

/**
* Install an npm package globally in the sandbox.
*/
Expand All @@ -29,7 +34,7 @@ export async function installNpmPackage(
}

const result = await conway.exec(
`npm install -g ${packageName}`,
`npm install -g ${escapeShellArg(packageName)}`,
120000,
);

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