[SECURITY] Fix four externally reachable security findings - #174
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Password reset, email confirmation and email change links were built from the incoming request, so a forged Host header produced a genuine email carrying a valid token that pointed at the attacker's origin. Adds AppOptions.PublicBaseUrl and an IPublicUrlProvider that all five emailed link sites now use. It takes precedence over the request-derived base the registration filter passes in. Unset, behaviour is unchanged, and production startup warns when neither PublicBaseUrl nor AllowedHosts is pinned.
AgentHub has no [Authorize], so a device whose stored PublicKey was empty could be claimed by any anonymous caller that knew its id: the deprecated unsigned UpdateDevice accepted it outright, and UpdateDeviceSigned verified the signature against the key the caller supplied in the same message. Either rewrote ConnectionId, which routes viewer commands, and adopted the caller's key permanently. Removes UpdateDevice from the hub and IAgentHub, and restricts a caller- supplied key to bootstrapping a device the server has never seen. Re-keying an existing device now goes through the installer-key registration API. Current agents only call UpdateDeviceSigned; agents predating it will need to re-register. Decommission tests move to the signed path.
The check only ran when the caller left TenantId empty, so naming an existing tenant explicitly skipped it and self-bootstrap accepted a chosen tenant on a multi-tenant server. It now runs whenever self-bootstrap is the authority for the write, and the tenant is taken from the server rather than the caller.
SessionSignaler used an ordinary string comparison, which short-circuits on the first differing byte. The responder half of a relay session is unauthenticated, so this token is the only check on that side. Does not address the other two gaps in the finding: the requester still has no authorization policy beyond being authenticated, and the session is still created by whichever peer connects first.
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Summary
Fixes the four highest-rated findings from an external-perimeter security review of the server: two rated High and two Medium. All four are reachable from the internet without a foothold or an insider.
Hostheader (CVSS 8.1). Submitting the forgot-password form with a victim's email and a forgedHostproduced a genuine email from the real server containing a valid reset token pointing at the attacker's origin.AllowedHostsships as*, so nothing rejected the forged value.AgentHubcarries no[Authorize]. The deprecated unsignedUpdateDeviceaccepted such a device outright, andUpdateDeviceSignedverified the signature against the key the caller supplied in the same message. Either path rewroteConnectionId— the field that routes viewer commands — and adopted the caller's key permanently.TenantIdempty, so naming an existing tenant explicitly skipped it.==(CVSS 6.8, partial fix). The responder half of a relay session is unauthenticated, so that token is the only check on that side.Behaviour changes worth a reviewer's attention
IAgentHub.UpdateDeviceis removed. Current agents only callUpdateDeviceSigned, so they are unaffected. Agents predating signed updates will fail to connect and must re-register.PublicKeyis empty can no longer update over the hub. It must be re-registered through the installer-key API to adopt a key. Worth counting before rollout:SELECT count(*) FROM "Devices" WHERE "PublicKey" IS NULL OR "PublicKey" = '';PublicBaseUrlunset, link generation behaves exactly as before.Change List
F-01 — emailed links no longer derive from the request (
c231966)AppOptions.PublicBaseUrl: the absolute base URL the server is reachable at.IPublicUrlProvider/PublicUrlProvider(ControlR.Web.Server/Services/), registered scoped. It returns the configured base URL when one is set and falls back to the request only when it is not.ForgotPassword.razor,ResendEmailConfirmation.razor, both sites inManage/Email.razor, and the fallback inUserCreator.UserCreator, the configured base URL now takes precedence over the caller-suppliedconfirmationBaseUrl, becauseIdentityApiRegisterFilterderives that one fromRequest.Scheme+Request.Host.PublicBaseUrlnorAllowedHostsis pinned, following the existing Data Protection warning pattern.ControlR_AppOptions__PublicBaseUrlandControlR_AllowedHostsin both compose files; addedPublicBaseUrltoappsettings.json.F-02 — device takeover on the agent hub (
4fed504)UpdateDevicefromAgentHuband from theIAgentHubcontract.UpdateDeviceSignednow trusts a caller-supplied public key only to bootstrap a device the server has never seen. An existing device with no stored key is rejected rather than re-keyed; adoption goes through the installer-key-authenticated registration API.DecommissionServerTestsmigrated to the signed path;CreateTestDevicegained an optionalpublicKeyBase64parameter.F-03 — self-bootstrap tenant restriction (
02ac81b)TenantIdwas left empty, and the tenant is read from the server rather than the request.F-04 — relay access token comparison (
4c86806)SessionSignaler.ValidateTokenusesCryptographicOperations.FixedTimeEquals.IsAuthenticated(a tenant- or device-scoped check is not expressible throughIAuthorizationService.AuthorizeAsync(user, policyName)without a resource), and the session is still created by whichever peer connects first. Both need a wider change acrossViewerHuband the clients, and are better done with a working test loop.Accept CLA
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