Files
shockbot/agents/claude.ts
T
Colin McDonnell 8cd36d221a sandbox native filesystem tools to prevent /proc/self/environ exfiltration (#509)
* sandbox native filesystem tools to prevent /proc/self/environ exfiltration

the agent's native Read/Grep/Edit tools can bypass the shell sandbox by
reading /proc/self/environ directly. this adds agent-native filesystem
restrictions using the highest-precedence, non-overridable config for each CLI:

OpenCode: OPENCODE_PERMISSION env var with external_directory deny-all + /tmp allow,
plus deletion of untrusted .opencode/plugins/ and .opencode/tools/ before launch.

Claude Code: managed-settings.json at /etc/claude-code/ with denyRead, permissions.deny,
allowManagedPermissionRulesOnly, allowManagedHooksOnly. also --setting-sources user and
--disallowedTools path patterns as belt-and-suspenders.

Made-with: Cursor

* add Glob to Claude Code /proc and /sys deny lists

closes gap identified in review — Glob can enumerate /proc entries.
added to both managed-settings.json permissions.deny and --disallowedTools.

Made-with: Cursor

* run token-exfil test with both agents, hint at native /proc reads

changed tag from "agnostic" (opentoad-only) to "security" so the test
runs with both opentoad and claude. updated prompt to explicitly instruct
the agent to try reading /proc/self/environ via native Read tool.
added API keys to action-agnostic CI job for claude support.

Made-with: Cursor

* move token-exfil to crossagent matrix, remove redundant permissions.deny

- moved token-exfil from agnostic/ to crossagent/ so it runs via the
  agent matrix (claude + opentoad in parallel) instead of sequentially
- removed permissions.deny per-tool rules from managed-settings.json;
  sandbox.filesystem.denyRead is the single enforcement mechanism
- reverted action-agnostic env vars to minimal set
- updated wiki to match

Made-with: Cursor

* document post-spawn API key deletion analysis in security wiki

evaluated whether API key env vars can be deleted from agent processes
after spawn. OpenCode snapshots env at startup (safe to delete), but
Claude Code re-reads process.env per request (not viable). documented
as further exploration item with per-agent breakdown and caveats.

Made-with: Cursor

* fix stale tokenExfil path references in wiki docs

moved from test/agnostic/ to test/crossagent/ in directory tree
and adversarial test example.

Made-with: Cursor

* revert accidental prisma.config.ts changes

Made-with: Cursor

* hardcode PULLFROG_MODEL per agent in test runner to avoid DB model mismatch

when PULLFROG_AGENT forces a specific agent, the DB-configured model may
belong to a different provider (e.g. openai model with claude agent).
PULLFROG_MODEL short-circuits the DB slug resolution entirely.

Made-with: Cursor
2026-04-02 22:31:41 +00:00

604 lines
20 KiB
TypeScript

/**
* Claude Code agent — secure harness around the `claude` CLI.
*
* mirrors the opentoad harness's security model:
* - native Bash blocked via --disallowedTools (agent cannot shell out)
* - managed-settings.json: filesystem sandbox — deny /proc, /sys reads
* - MCP ShellTool provides restricted shell (filtered env, no secrets)
* - MCP server injected via --mcp-config (not replacing project config)
* - ASKPASS handles git auth separately (token never in subprocess env)
*
* the agent process itself gets full env (needs LLM API keys, PATH, etc.).
* security is enforced at the tool layer, not the process layer.
*/
import { execFileSync } from "node:child_process";
import { mkdirSync, writeFileSync } from "node:fs";
import { join } from "node:path";
import { performance } from "node:perf_hooks";
import { ghPullfrogMcpName } from "../external.ts";
import { getIdleMs, markActivity } from "../utils/activity.ts";
import { log } from "../utils/cli.ts";
import { installFromNpmTarball } from "../utils/install.ts";
import { detectProviderError } from "../utils/providerErrors.ts";
import { addSkill } from "../utils/skills.ts";
import { spawn } from "../utils/subprocess.ts";
import { ThinkingTimer } from "../utils/timer.ts";
import type { TodoTracker } from "../utils/todoTracking.ts";
import { getDevDependencyVersion } from "../utils/version.ts";
import {
type AgentResult,
type AgentRunContext,
type AgentUsage,
agent,
MAX_STDERR_LINES,
} from "./shared.ts";
async function installClaudeCli(): Promise<string> {
return await installFromNpmTarball({
packageName: "@anthropic-ai/claude-code",
version: getDevDependencyVersion("@anthropic-ai/claude-code"),
executablePath: "cli.js",
installDependencies: false,
});
}
// ── config ─────────────────────────────────────────────────────────────────────
function writeMcpConfig(ctx: AgentRunContext): string {
const configDir = join(ctx.tmpdir, ".claude");
mkdirSync(configDir, { recursive: true });
const configPath = join(configDir, "mcp.json");
writeFileSync(
configPath,
JSON.stringify({
mcpServers: {
[ghPullfrogMcpName]: { type: "http", url: ctx.mcpServerUrl },
},
})
);
return configPath;
}
// ── model helpers ─────────────────────────────────────────────────────────────
// claude CLI expects bare model names (e.g. "claude-sonnet-4-6"), not provider-prefixed specifiers
function stripProviderPrefix(specifier: string): string {
const slashIndex = specifier.indexOf("/");
return slashIndex > 0 ? specifier.slice(slashIndex + 1) : specifier;
}
// `max` effort is Opus 4.6 only — errors on other models.
// use `max` when the resolved model is Opus, `high` otherwise.
function resolveEffort(model: string | undefined): "max" | "high" {
if (model?.includes("opus")) return "max";
return "high";
}
// ── NDJSON event types ─────────────────────────────────────────────────────────
interface ContentBlock {
type: string;
text?: string;
id?: string;
name?: string;
input?: unknown;
tool_use_id?: string;
content?: string | unknown;
is_error?: boolean;
[key: string]: unknown;
}
interface ClaudeSystemEvent {
type: "system";
[key: string]: unknown;
}
interface ClaudeAssistantEvent {
type: "assistant";
message?: {
role?: string;
content?: ContentBlock[];
model?: string;
usage?: {
input_tokens?: number;
output_tokens?: number;
cache_creation_input_tokens?: number;
cache_read_input_tokens?: number;
};
[key: string]: unknown;
};
[key: string]: unknown;
}
interface ClaudeUserEvent {
type: "user";
message?: {
role?: string;
content?: ContentBlock[];
[key: string]: unknown;
};
[key: string]: unknown;
}
interface ClaudeResultEvent {
type: "result";
subtype?: string;
result?: string;
session_id?: string;
num_turns?: number;
total_cost_usd?: number;
total_input_tokens?: number;
total_output_tokens?: number;
usage?: {
input_tokens?: number;
output_tokens?: number;
cache_read_input_tokens?: number;
cache_creation_input_tokens?: number;
};
[key: string]: unknown;
}
// additional event types emitted by Claude CLI (handled as no-ops / debug)
interface ClaudeStreamEvent {
type: "stream_event";
[key: string]: unknown;
}
interface ClaudeToolProgressEvent {
type: "tool_progress";
[key: string]: unknown;
}
interface ClaudeToolUseSummaryEvent {
type: "tool_use_summary";
[key: string]: unknown;
}
interface ClaudeAuthStatusEvent {
type: "auth_status";
[key: string]: unknown;
}
type ClaudeEvent =
| ClaudeSystemEvent
| ClaudeAssistantEvent
| ClaudeUserEvent
| ClaudeResultEvent
| ClaudeStreamEvent
| ClaudeToolProgressEvent
| ClaudeToolUseSummaryEvent
| ClaudeAuthStatusEvent;
// ── runner ──────────────────────────────────────────────────────────────────────
type RunParams = {
label: string;
args: string[];
cwd: string;
env: Record<string, string | undefined>;
todoTracker?: TodoTracker | undefined;
};
async function runClaude(params: RunParams): Promise<AgentResult> {
const startTime = performance.now();
let eventCount = 0;
const thinkingTimer = new ThinkingTimer();
let finalOutput = "";
let accumulatedTokens = { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 };
let tokensLogged = false;
function buildUsage(): AgentUsage | undefined {
const totalInput =
accumulatedTokens.input + accumulatedTokens.cacheRead + accumulatedTokens.cacheWrite;
return totalInput > 0 || accumulatedTokens.output > 0
? {
agent: "claude",
inputTokens: totalInput,
outputTokens: accumulatedTokens.output,
cacheReadTokens: accumulatedTokens.cacheRead || undefined,
cacheWriteTokens: accumulatedTokens.cacheWrite || undefined,
}
: undefined;
}
const handlers = {
system: (_event: ClaudeSystemEvent) => {
log.debug(`» ${params.label} system event`);
},
assistant: (event: ClaudeAssistantEvent) => {
const content = event.message?.content;
if (!content) return;
for (const block of content) {
if (block.type === "text" && block.text?.trim()) {
const message = block.text.trim();
log.box(message, { title: params.label });
finalOutput = message;
} else if (block.type === "tool_use") {
const toolName = block.name || "unknown";
thinkingTimer.markToolCall();
log.toolCall({ toolName, input: block.input || {} });
// agent's explicit MCP report_progress takes priority over todo tracking
if (toolName.includes("report_progress") && params.todoTracker) {
log.debug("» report_progress detected, disabling todo tracking");
params.todoTracker.cancel();
}
// parse TodoWrite events for live progress tracking
if (toolName === "TodoWrite" && params.todoTracker?.enabled) {
params.todoTracker.update(block.input);
}
}
}
// accumulate per-message usage if available
const msgUsage = event.message?.usage;
if (msgUsage) {
accumulatedTokens.input += msgUsage.input_tokens || 0;
accumulatedTokens.output += msgUsage.output_tokens || 0;
}
},
user: (event: ClaudeUserEvent) => {
const content = event.message?.content;
if (!content) return;
for (const block of content) {
if (typeof block === "string") continue;
if (block.type === "tool_result") {
thinkingTimer.markToolResult();
const outputContent =
typeof block.content === "string"
? block.content
: Array.isArray(block.content)
? (block.content as unknown[])
.map((entry: unknown) =>
typeof entry === "string"
? entry
: typeof entry === "object" && entry !== null && "text" in entry
? String((entry as { text: unknown }).text)
: JSON.stringify(entry)
)
.join("\n")
: String(block.content);
if (block.is_error) {
log.info(`» tool error: ${outputContent}`);
} else {
log.debug(`» tool output: ${outputContent}`);
}
}
}
},
result: (event: ClaudeResultEvent) => {
const subtype = event.subtype || "unknown";
const numTurns = event.num_turns || 0;
if (subtype === "success") {
// extract detailed usage from result event (most accurate source)
const usage = event.usage;
const inputTokens = usage?.input_tokens || 0;
const cacheRead = usage?.cache_read_input_tokens || 0;
const cacheWrite = usage?.cache_creation_input_tokens || 0;
const outputTokens = usage?.output_tokens || 0;
const totalInput = inputTokens + cacheRead + cacheWrite;
accumulatedTokens = { input: inputTokens, output: outputTokens, cacheRead, cacheWrite };
log.info(`» ${params.label} result: subtype=${subtype}, turns=${numTurns}`);
if (!tokensLogged) {
log.table([
[
{ data: "Input", header: true },
{ data: "Cache Read", header: true },
{ data: "Cache Write", header: true },
{ data: "Output", header: true },
],
[String(totalInput), String(cacheRead), String(cacheWrite), String(outputTokens)],
]);
tokensLogged = true;
}
} else if (subtype === "error_max_turns") {
log.info(`» ${params.label} max turns reached: ${JSON.stringify(event)}`);
} else if (subtype === "error_during_execution") {
log.info(`» ${params.label} execution error: ${JSON.stringify(event)}`);
} else {
log.info(`» ${params.label} result: subtype=${subtype}, data=${JSON.stringify(event)}`);
}
if (event.result?.trim()) {
finalOutput = event.result.trim();
}
},
// additional Claude CLI event types — debug-logged only
stream_event: () => {},
tool_progress: () => {},
tool_use_summary: () => {},
auth_status: () => {},
};
const recentStderr: string[] = [];
let lastProviderError: string | null = null;
let output = "";
let stdoutBuffer = "";
try {
const result = await spawn({
cmd: "node",
args: params.args,
cwd: params.cwd,
env: params.env,
activityTimeout: 300_000,
stdio: ["ignore", "pipe", "pipe"],
onStdout: async (chunk) => {
const text = chunk.toString();
output += text;
markActivity();
stdoutBuffer += text;
const lines = stdoutBuffer.split("\n");
stdoutBuffer = lines.pop() || "";
for (const line of lines) {
const trimmed = line.trim();
if (!trimmed) continue;
try {
const event = JSON.parse(trimmed) as ClaudeEvent;
eventCount++;
log.debug(JSON.stringify(event, null, 2));
const timeSinceLastActivity = getIdleMs();
if (timeSinceLastActivity > 10000) {
log.info(
`» no activity for ${(timeSinceLastActivity / 1000).toFixed(1)}s (${params.label} may be processing internally) (${eventCount} events processed so far)`
);
}
markActivity();
const handler = handlers[event.type as keyof typeof handlers];
if (handler) {
(handler as (e: ClaudeEvent) => void)(event);
} else {
log.debug(`» ${params.label} event (unhandled): type=${event.type}`);
}
} catch {
log.debug(`» non-JSON stdout line: ${trimmed.substring(0, 200)}`);
}
}
},
onStderr: (chunk) => {
const trimmed = chunk.trim();
if (!trimmed) return;
recentStderr.push(trimmed);
if (recentStderr.length > MAX_STDERR_LINES) recentStderr.shift();
const providerError = detectProviderError(trimmed);
if (providerError) {
lastProviderError = providerError;
log.info(`» provider error detected (${providerError}): ${trimmed.substring(0, 500)}`);
} else {
log.debug(trimmed);
}
},
});
if (result.exitCode === 0) {
await params.todoTracker?.flush();
} else {
params.todoTracker?.cancel();
}
const duration = performance.now() - startTime;
log.info(
`» ${params.label} completed in ${Math.round(duration)}ms with exit code ${result.exitCode}`
);
if (eventCount === 0) {
const stderrContext = recentStderr.join("\n");
const diagnosis = lastProviderError
? `provider error: ${lastProviderError}`
: "unknown cause (no stdout events received)";
log.info(`» ${params.label} produced 0 events (${diagnosis})`);
if (stderrContext) log.info(`» last stderr output:\n${stderrContext}`);
}
if (!tokensLogged && (accumulatedTokens.input > 0 || accumulatedTokens.output > 0)) {
const totalTokens = accumulatedTokens.input + accumulatedTokens.output;
log.table([
[
{ data: "Input Tokens", header: true },
{ data: "Output Tokens", header: true },
{ data: "Total Tokens", header: true },
],
[String(accumulatedTokens.input), String(accumulatedTokens.output), String(totalTokens)],
]);
}
const usage = buildUsage();
if (result.exitCode !== 0) {
const errorContext = lastProviderError ? ` (${lastProviderError})` : "";
const errorMessage =
result.stderr ||
result.stdout ||
`unknown error - no output from Claude CLI${errorContext}`;
log.error(
`${params.label} exited with code ${result.exitCode}${errorContext}: ${errorMessage}`
);
log.debug(`stdout: ${result.stdout?.substring(0, 500)}`);
log.debug(`stderr: ${result.stderr?.substring(0, 500)}`);
return { success: false, output: finalOutput || output, error: errorMessage, usage };
}
if (eventCount === 0 && lastProviderError) {
return {
success: false,
output: finalOutput || output,
error: `provider error: ${lastProviderError}`,
usage,
};
}
return { success: true, output: finalOutput || output, usage };
} catch (error) {
params.todoTracker?.cancel();
const duration = performance.now() - startTime;
const errorMessage = error instanceof Error ? error.message : String(error);
const isActivityTimeout = errorMessage.includes("activity timeout");
const stderrContext = recentStderr.slice(-10).join("\n");
const diagnosis = lastProviderError
? `likely cause: ${lastProviderError}`
: eventCount === 0
? "Claude produced 0 stdout events - check if the API is reachable"
: `${eventCount} events were processed before the hang`;
log.info(
`» ${params.label} ${isActivityTimeout ? "hung" : "failed"} after ${(duration / 1000).toFixed(1)}s: ${errorMessage}`
);
log.info(`» diagnosis: ${diagnosis}`);
if (stderrContext)
log.info(
`» recent stderr (last ${Math.min(recentStderr.length, 10)} lines):\n${stderrContext}`
);
return {
success: false,
output: finalOutput || output,
error: `${errorMessage} [${diagnosis}]`,
usage: buildUsage(),
};
}
}
// ── managed settings ────────────────────────────────────────────────────────────
const MANAGED_SETTINGS_DIR = "/etc/claude-code";
const MANAGED_SETTINGS_PATH = `${MANAGED_SETTINGS_DIR}/managed-settings.json`;
// managed-settings.json has absolute highest precedence in Claude Code's config hierarchy.
// it cannot be overridden by user, project, or local settings — safe against malicious PRs.
//
// permissions.deny blocks native tools (Read, Grep, Edit, Glob) from accessing /proc and /sys.
// sandbox.filesystem.denyRead blocks the Bash tool sandbox from reading those paths.
// allowManagedPermissionRulesOnly prevents malicious PRs from adding allow rules that override
// our deny rules — safe in CI because --dangerously-skip-permissions makes allow/ask irrelevant.
// allowManagedHooksOnly prevents malicious project hooks from bypassing deny rules.
const managedSettings = {
allowManagedPermissionRulesOnly: true,
allowManagedHooksOnly: true,
permissions: {
deny: [
"Read(//proc/**)",
"Read(//sys/**)",
"Grep(//proc/**)",
"Grep(//sys/**)",
"Edit(//proc/**)",
"Edit(//sys/**)",
"Glob(//proc/**)",
"Glob(//sys/**)",
],
},
sandbox: {
filesystem: {
denyRead: ["/proc", "/sys"],
},
},
};
function installManagedSettings(): void {
if (process.env.CI !== "true") return;
const content = JSON.stringify(managedSettings, null, 2);
try {
execFileSync("sudo", ["mkdir", "-p", MANAGED_SETTINGS_DIR]);
execFileSync("sudo", ["tee", MANAGED_SETTINGS_PATH], {
input: content,
stdio: ["pipe", "ignore", "pipe"],
});
log.debug(`» wrote managed settings to ${MANAGED_SETTINGS_PATH}`);
} catch (err) {
log.warning(`» failed to install managed settings: ${err}`);
}
}
// ── agent ───────────────────────────────────────────────────────────────────────
export const claude = agent({
name: "claude",
install: installClaudeCli,
run: async (ctx) => {
const cliPath = await installClaudeCli();
const specifier = ctx.payload.proxyModel ?? ctx.resolvedModel;
const model = specifier ? stripProviderPrefix(specifier) : undefined;
const homeEnv = {
HOME: ctx.tmpdir,
XDG_CONFIG_HOME: join(ctx.tmpdir, ".config"),
};
mkdirSync(join(homeEnv.XDG_CONFIG_HOME, "claude"), { recursive: true });
const agentBrowserVersion = getDevDependencyVersion("agent-browser");
addSkill({
ref: `vercel-labs/agent-browser@v${agentBrowserVersion}`,
skill: "agent-browser",
env: homeEnv,
agent: "claude",
});
const mcpConfigPath = writeMcpConfig(ctx);
const effort = resolveEffort(model);
installManagedSettings();
const args = [
cliPath,
"-p",
ctx.instructions.full,
"--output-format",
"stream-json",
"--dangerously-skip-permissions",
"--mcp-config",
mcpConfigPath,
"--verbose",
"--no-session-persistence",
"--effort",
effort,
"--disallowedTools",
"Bash",
"Agent(Bash)",
];
if (model) {
args.push("--model", model);
}
// agent process gets full env — needs LLM API keys, PATH, locale, etc.
// security is enforced via managed-settings.json, --disallowedTools (Bash), and MCP tool filtering.
const env: Record<string, string | undefined> = {
...process.env,
...homeEnv,
};
const repoDir = process.cwd();
log.info(`» effort: ${effort}`);
log.debug(`» starting Pullfrog (Claude Code): node ${args.join(" ")}`);
log.debug(`» working directory: ${repoDir}`);
return runClaude({
label: "Pullfrog",
args,
cwd: repoDir,
env,
todoTracker: ctx.todoTracker,
});
},
});