return_from_function

THE RISK

High Risk

This tool forcibly alters the execution flow of a debugged process by issuing a GDB MI command to return from the current function immediately. This is an active execution control action that changes program state and control flow, making it Execute category. Misuse could corrupt program state, bypass security checks, or cause undefined behavior in the target binary.

From the tool's definition Force the current function to return immediately (MI -exec-return)

Documented attack patterns abuse exactly the kind of access return_from_function gives an agent:

HOW TO CONTROL RETURN_FROM_FUNCTION

PolicyLayer is an MCP gateway — it sits between your AI agents and Pwno, and nothing reaches the server without passing your rules. This is the rule we recommend for return_from_function:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "return_from_function": {
      "limits": [
        {
          "counter": "return_from_function_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

return_from_function stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Pwno — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

High-risk tools in Pwno → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
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FAQ

What does the return_from_function tool do? +

Force the current function to return immediately (MI -exec-return). It is categorised as a Execute tool in the Pwno MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on return_from_function? +

Register the Pwno MCP server in PolicyLayer and add a rule for return_from_function: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Pwno. Nothing to install.

What risk level is return_from_function? +

return_from_function is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit return_from_function? +

Yes. Add a rate_limit block to the return_from_function rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block return_from_function completely? +

Set action: deny in the PolicyLayer policy for return_from_function. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides return_from_function? +

return_from_function is provided by the Pwno MCP server (pwno-io/pwno-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Pwno tool call.

Deterministic rules across all 36 Pwno tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

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36 Pwno tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

// WHAT RETURN_FROM_FUNCTION ON PWNO DOES

// THE RISK

// HOW TO CONTROL RETURN_FROM_FUNCTION

// EXPLORE