From 6b9b5394c5ec01c5de01b7bf23bc161792f38278 Mon Sep 17 00:00:00 2001 From: Christophe Besson Date: Fri, 25 Sep 2026 14:28:03 +0200 Subject: fix(hub): require the passphrase to change the e-mail on file MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A member hands its hub access token to every node it connects to (the MNP handshake), so a node operator holds a live bearer token for that member. PATCH /v1/users/me {email} needed only that token, and the confirmation code goes to the new address — so an operator could point the account's e-mail at their own inbox, confirm it, and then use the passphrase-reset path to take the account over. This is the immediate mitigation of that chain; the full fix (a node-audience token distinct from the API session token) follows. Changing the address now requires the passphrase-derived auth_key, verified through the same throttle as a passphrase change or an account deletion — the hub still never sees the passphrase. A PATCH that does not change the address is unaffected. The profile page prompts for the passphrase and derives auth_key with the existing MeshBayKeys.deriveAuthKey, as the delete and change-password flows already do. test_email_change_requires_passphrase.py: refused without / with a wrong passphrase, proceeds with the right one, and a no-email PATCH still works; red before, green after. test_mail_is_not_a_relay.py updated to pass the auth_key. Co-Authored-By: Claude Opus 4.8 --- packages/meshbay-hub/src/meshbay_hub/api/users.py | 24 +++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'packages/meshbay-hub/src/meshbay_hub/api') diff --git a/packages/meshbay-hub/src/meshbay_hub/api/users.py b/packages/meshbay-hub/src/meshbay_hub/api/users.py index a994acb..7046c2f 100644 --- a/packages/meshbay-hub/src/meshbay_hub/api/users.py +++ b/packages/meshbay-hub/src/meshbay_hub/api/users.py @@ -728,6 +728,14 @@ async def get_current_user_info( class UpdateProfileRequest(BaseModel): email: str | None = None + # Required to change the address on file. Changing it is the first step of + # an account takeover from a bare access token: the confirmation code goes + # to the new (attacker) address, and a verified address then unlocks the + # passphrase-reset path. A live access token is not enough for that — the + # passphrase is, exactly as for `change_password` and `delete_own_account`. + # This matters because a member hands its access token to every node it + # connects to (the MNP handshake), so a node operator holds one. + auth_key: str | None = None @field_validator("email") @classmethod @@ -768,6 +776,22 @@ async def update_profile( new_email = body.email.strip() eh = hash_email_blind(new_email) + # Changing the address on file requires the passphrase, not merely a + # live token. Same second factor, and the same throttle, as a passphrase + # change or an account deletion — the hub still never sees the + # passphrase, only the derived auth_key. + if not body.auth_key: + raise HTTPException( + status_code=403, + detail="Changing your e-mail requires your passphrase.") + await _take_login_attempt(db, current_user.username) + if not await verify_password_off_loop( + body.auth_key, current_user.pw_hash, current_user.pw_salt, + current_user.pw_version): + raise HTTPException(status_code=403, + detail="Passphrase does not match") + await login_throttle.clear(db, current_user.username) + # How often one account may point the hub at a *different* address. # Long, because this is the only path where a signed-in account chooses # who receives a message, and a short delay alone still allows one -- cgit v1.2.3