Files
clinch/app/models/oidc_refresh_token.rb
T
Dan MilneandClaude Opus 4.8 71ee301dd2 Device flow: replay-revocation, user_code CSPRNG, /device rate limit
More device-flow security-review fixes.

Replay-revocation on device_code redemption (was: destroy on use):
- Redemption now marks the code redeemed_at and links the issued access/refresh
  tokens back to it (new oidc_device_code_id FKs, on_delete: :nullify) instead of
  destroying the row. A replayed redeemed code is detected as reuse — revoking
  every descended token and returning a distinguishable "already been used"
  invalid_grant rather than the generic "Invalid device_code" — mirroring the
  authorization-code reuse semantics (RFC 6749 §4.1.2). The device_code FK is
  carried forward across refresh rotation so revocation reaches the whole chain.
  Redeemed codes are reaped by the existing expiry cleanup sweep.

user_code CSPRNG (RFC 8628 §6.1):
- The 8-char user_code is a credential (type it + Approve mints tokens), so draw
  it from SecureRandom instead of Ruby's global Mersenne Twister (Array#sample).

Rate-limit the /device verification endpoint (RFC 8628 §5.1):
- Add the app's standard 10/min limit on show + verify so a signed-in user can't
  brute-force the short code space to deny or hijack a pending authorization.

Also carried in this commit (other agent's working-tree change):
- Give each OidcController rate_limit a distinct name: so frequent device polling
  on the token endpoint no longer shares one counter with (and 429s) unrelated
  token/refresh/revoke/introspect calls.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Q4ATZHoMCWqvSpE2yYoie
2026-07-19 13:38:40 +10:00

90 lines
2.7 KiB
Ruby

class OidcRefreshToken < ApplicationRecord
belongs_to :application
belongs_to :user
belongs_to :oidc_access_token
belongs_to :oidc_authorization_code, optional: true
belongs_to :oidc_device_code, optional: true
before_validation :generate_token, on: :create
before_validation :set_expiry, on: :create
before_validation :set_token_family_id, on: :create
validates :token_hmac, presence: true, uniqueness: true
scope :valid, -> { where("expires_at > ?", Time.current).where(revoked_at: nil) }
scope :expired, -> { where("expires_at <= ?", Time.current) }
scope :revoked, -> { where.not(revoked_at: nil) }
scope :active, -> { valid }
# For token rotation detection (prevents reuse attacks)
scope :in_family, ->(family_id) { where(token_family_id: family_id) }
attr_accessor :token # Store plaintext token temporarily for returning to client
# Find refresh token by plaintext token using HMAC verification
def self.find_by_token(plaintext_token)
return nil if plaintext_token.blank?
token_hmac = compute_token_hmac(plaintext_token)
find_by(token_hmac: token_hmac)
end
# Compute HMAC for token lookup
def self.compute_token_hmac(plaintext_token)
OpenSSL::HMAC.hexdigest("SHA256", TokenHmac::KEY, plaintext_token)
end
def expired?
expires_at <= Time.current
end
def revoked?
revoked_at.present?
end
def active?
!expired? && !revoked?
end
def revoke!
update!(revoked_at: Time.current)
end
# Revoke all refresh tokens in the same family (token rotation security).
# Also revoke every access token issued within the family: on a detected reuse
# attack the stolen chain's access tokens must not remain usable at /userinfo
# until they expire.
def revoke_family!
return unless token_family_id.present?
now = Time.current
family = OidcRefreshToken.in_family(token_family_id)
access_token_ids = family.pluck(:oidc_access_token_id).compact.uniq
family.update_all(revoked_at: now)
if access_token_ids.any?
OidcAccessToken.where(id: access_token_ids, revoked_at: nil).update_all(revoked_at: now)
end
end
private
def generate_token
# Generate random plaintext token
self.token ||= SecureRandom.urlsafe_base64(48)
# Store HMAC in database (not plaintext)
self.token_hmac ||= self.class.compute_token_hmac(token)
end
def set_expiry
# Use application's configured refresh token TTL
self.expires_at ||= application.refresh_token_expiry
end
def set_token_family_id
# Use a random ID to group tokens in the same rotation chain
# This helps detect token reuse attacks
self.token_family_id ||= SecureRandom.random_number(2**31)
end
end