104 lines
3.8 KiB
Go
104 lines
3.8 KiB
Go
// Copyright (c) 2020 Nikos Filippakis
|
|
// Copyright (c) 2022 Tulir Asokan
|
|
//
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
|
|
package crypto
|
|
|
|
import (
|
|
"maunium.net/go/mautrix/id"
|
|
)
|
|
|
|
// ResolveTrust resolves the trust state of the device from cross-signing.
|
|
func (mach *OlmMachine) ResolveTrust(device *id.Device) id.TrustState {
|
|
if device.Trust == id.TrustStateVerified || device.Trust == id.TrustStateBlacklisted {
|
|
return device.Trust
|
|
}
|
|
theirKeys, err := mach.CryptoStore.GetCrossSigningKeys(device.UserID)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving cross-singing key of user %v from database: %v", device.UserID, err)
|
|
return id.TrustStateUnset
|
|
}
|
|
theirMSK, ok := theirKeys[id.XSUsageMaster]
|
|
if !ok {
|
|
mach.Log.Error("Master key of user %v not found", device.UserID)
|
|
return id.TrustStateUnset
|
|
}
|
|
theirSSK, ok := theirKeys[id.XSUsageSelfSigning]
|
|
if !ok {
|
|
mach.Log.Error("Self-signing key of user %v not found", device.UserID)
|
|
return id.TrustStateUnset
|
|
}
|
|
sskSigExists, err := mach.CryptoStore.IsKeySignedBy(device.UserID, theirSSK.Key, device.UserID, theirMSK.Key)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving cross-singing signatures for master key of user %v from database: %v", device.UserID, err)
|
|
return id.TrustStateUnset
|
|
}
|
|
if !sskSigExists {
|
|
mach.Log.Warn("Self-signing key of user %v is not signed by their master key", device.UserID)
|
|
return id.TrustStateUnset
|
|
}
|
|
deviceSigExists, err := mach.CryptoStore.IsKeySignedBy(device.UserID, device.SigningKey, device.UserID, theirSSK.Key)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving cross-singing signatures for master key of user %v from database: %v", device.UserID, err)
|
|
return id.TrustStateUnset
|
|
}
|
|
if deviceSigExists {
|
|
if mach.IsUserTrusted(device.UserID) {
|
|
return id.TrustStateCrossSignedVerified
|
|
} else if theirMSK.Key == theirMSK.First {
|
|
return id.TrustStateCrossSignedTOFU
|
|
}
|
|
return id.TrustStateCrossSignedUntrusted
|
|
}
|
|
return id.TrustStateUnset
|
|
}
|
|
|
|
// IsDeviceTrusted returns whether a device has been determined to be trusted either through verification or cross-signing.
|
|
func (mach *OlmMachine) IsDeviceTrusted(device *id.Device) bool {
|
|
switch mach.ResolveTrust(device) {
|
|
case id.TrustStateVerified, id.TrustStateCrossSignedTOFU, id.TrustStateCrossSignedVerified:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// IsUserTrusted returns whether a user has been determined to be trusted by our user-signing key having signed their master key.
|
|
// In the case the user ID is our own and we have successfully retrieved our cross-signing keys, we trust our own user.
|
|
func (mach *OlmMachine) IsUserTrusted(userID id.UserID) bool {
|
|
csPubkeys := mach.GetOwnCrossSigningPublicKeys()
|
|
if csPubkeys == nil {
|
|
return false
|
|
}
|
|
if userID == mach.Client.UserID {
|
|
return true
|
|
}
|
|
// first we verify our user-signing key
|
|
ourUserSigningKeyTrusted, err := mach.CryptoStore.IsKeySignedBy(mach.Client.UserID, csPubkeys.UserSigningKey, mach.Client.UserID, csPubkeys.MasterKey)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving our self-singing key signatures: %v", err)
|
|
return false
|
|
} else if !ourUserSigningKeyTrusted {
|
|
return false
|
|
}
|
|
theirKeys, err := mach.CryptoStore.GetCrossSigningKeys(userID)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving cross-singing key of user %v from database: %v", userID, err)
|
|
return false
|
|
}
|
|
theirMskKey, ok := theirKeys[id.XSUsageMaster]
|
|
if !ok {
|
|
mach.Log.Error("Master key of user %v not found", userID)
|
|
return false
|
|
}
|
|
sigExists, err := mach.CryptoStore.IsKeySignedBy(userID, theirMskKey.Key, mach.Client.UserID, csPubkeys.UserSigningKey)
|
|
if err != nil {
|
|
mach.Log.Error("Error retrieving cross-singing signatures for master key of user %v from database: %v", userID, err)
|
|
return false
|
|
}
|
|
return sigExists
|
|
}
|