fix(gateway): generate device user_code with a CSPRNG#159
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The device-authorization user_code was built from Math.random(), a non-cryptographic PRNG, over an 8-char / 30-symbol alphabet. The user_code is the only secret an approver checks at /activate/approve, so a predictable generator lets an attacker who observes prior outputs predict in-flight codes and approve a victim's pending device — binding the attacker's org and a freshly minted session/ingest key onto the victim's device. Switch to crypto.randomInt over the same alphabet (unbiased, CSPRNG).
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Problem
The device-authorization
user_code(humanCode()) was generated withMath.random()— a non-cryptographic PRNG — over an 8-character / 30-symbol alphabet. Theuser_codeis the sole secret an approver verifies at/activate/approve.Impact
Math.random()'s internal state is recoverable from observed outputs, so an attacker can predict in-flightuser_codes within the code's TTL and call/activate/approvefor a victim's pending device. Approval binds the attacker's org plus a freshly minted CLI session token and ingest key onto the victim's device session — silently redirecting the victim's CLI/telemetry into the attacker's project. (Thedevice_codetoken pickup already usednanoid, so only the human-visible code was affected.)Fix
Generate
user_codewithcrypto.randomIntover the same alphabet (CSPRNG, unbiased).Follow-up worth considering separately: rate-limit
/activate/approveby IP/code. With a CSPRNG over ~30^8 the code space is now infeasible to brute-force, so this is defense-in-depth.Summary by cubic
Generate the device-authorization user_code with a CSPRNG using
crypto.randomIntto remove predictability. This prevents attackers from guessing in-flight codes and approving a victim’s device.Written for commit aba7ab8. Summary will update on new commits.