diff options
Diffstat (limited to 'packages/meshbay-hub/src')
4 files changed, 105 insertions, 19 deletions
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/app.js b/packages/meshbay-hub/src/meshbay_hub/static/app.js index ddff928..dee47ec 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/app.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/app.js @@ -979,8 +979,10 @@ function GroupPage({ groupId, group, token, username, userId }) { const transport = transportRef.current; if (!transport || !transport.connected) return; try { + // Signs an explicit transcript built by transport.js, not opaque bytes from + // the node — see MeshBayCrypto.adminTranscript and finding H5. const signFn = (_sessionKeys && window.MeshBayKeys) - ? (challenge) => window.MeshBayKeys.signChallenge(_sessionKeys.skEdB64, challenge) + ? (transcript) => window.MeshBayKeys.signBytes(_sessionKeys.skEdB64, transcript) : null; await transport.deleteFile(entry.id, signFn); const indexMsg = await transport.fetchIndex(); @@ -1405,9 +1407,16 @@ function MembersPanel({ groupId, group, token, transportRef, gekRef }) { } const gekBytes = transport.gekRaw; - // Wrap GEK for invitee and store on node via P2P + // Wrap GEK for invitee and store on node via P2P. + // The node requires the operator's Ed25519 signature to accept the bundle + // (C5b), so inviting from a browser that is not the node operator's will be + // refused by the node — deliberately: only the operator decides what is + // stored on their machine. + const signFn = (_sessionKeys && window.MeshBayKeys) + ? (transcript) => window.MeshBayKeys.signBytes(_sessionKeys.skEdB64, transcript) + : null; const bundle = await window.MeshBayCrypto.wrapGEK(gekBytes, pkXBytes); - await transport.storeGekBundle(pubkeys.user_id, groupId, bundle); + await transport.storeGekBundle(pubkeys.user_id, groupId, bundle, signFn); // Add member on hub (membership management only) await hubFetch(`/v1/groups/${groupId}/members/${username}`, { diff --git a/packages/meshbay-hub/src/meshbay_hub/static/crypto.js b/packages/meshbay-hub/src/meshbay_hub/static/crypto.js index 5ebf624..2346fa2 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/crypto.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/crypto.js @@ -230,6 +230,42 @@ function b64encode(bytes) { return btoa(String.fromCharCode(...bytes)); } +// ── Admin operation transcript ─────────────────────────────────────────────── +// Mirrors meshbay_common/adminop.py::admin_transcript(). Both sides build these +// bytes independently; they are never taken off the wire. +// +// Finding H5: the client used to sign 32 raw random bytes chosen by the node — a +// blind signing oracle. It now reconstructs a domain-separated, length-prefixed +// transcript naming the operation, subject, node and group, so the UI can show the +// user what they are authorizing and a signature cannot be reused elsewhere. + +const ADMIN_TRANSCRIPT_PREFIX = new TextEncoder().encode('meshbay:admin:v1'); + +function adminTranscript(op, nodePkB64, groupId, subject, nonceB64, ts) { + const enc = new TextEncoder(); + const fields = [ + enc.encode(op), + enc.encode(nodePkB64), + enc.encode(groupId), + enc.encode(subject), + b64decode(nonceB64), + enc.encode(String(ts)), + ]; + let total = ADMIN_TRANSCRIPT_PREFIX.length; + for (const f of fields) total += 4 + f.length; + + const out = new Uint8Array(total); + out.set(ADMIN_TRANSCRIPT_PREFIX, 0); + let off = ADMIN_TRANSCRIPT_PREFIX.length; + for (const f of fields) { + new DataView(out.buffer).setUint32(off, f.length, false); + off += 4; + out.set(f, off); + off += f.length; + } + return out; +} + // ── GEK proof (HMAC-SHA256 for handshake challenge) ───────────────────────── async function hmacGEK(gekRaw, nonceB64, offerFp, answerFp) { @@ -249,5 +285,5 @@ async function hmacGEK(gekRaw, nonceB64, offerFp, answerFp) { window.MeshBayCrypto = { importGEK, deriveChunkKey, decryptChunk, decryptChunkBin, decryptFile, generateGEK, wrapGEK, unwrapGEK, encryptChunk, b64encode, b64decode, - hmacGEK, + hmacGEK, adminTranscript, }; diff --git a/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js b/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js index ff3da33..3d9c3c6 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/keyderive.js @@ -246,16 +246,22 @@ async function regenerateKeys(token, username, password) { }; } -async function signChallenge(skEdPkcs8B64, challengeB64) { +/** + * Sign an explicit byte string with the user's Ed25519 identity key. + * + * Takes bytes rather than a base64 blob from the wire: callers are expected to + * build the message themselves (see MeshBayCrypto.adminTranscript) so that the + * user's identity key is never applied to content the peer chose. Finding H5. + */ +async function signBytes(skEdPkcs8B64, message) { const skRaw = Uint8Array.from(atob(skEdPkcs8B64), c => c.charCodeAt(0)); const sk = await crypto.subtle.importKey( 'pkcs8', skRaw, { name: 'Ed25519' }, false, ['sign']); - const challenge = Uint8Array.from(atob(challengeB64), c => c.charCodeAt(0)); - const sig = await crypto.subtle.sign('Ed25519', sk, challenge); + const sig = await crypto.subtle.sign('Ed25519', sk, message); return btoa(String.fromCharCode(...new Uint8Array(sig))); } window.MeshBayKeys = { - registerUser, loginAndRecover, regenerateKeys, generateKeypairs, signChallenge, + registerUser, loginAndRecover, regenerateKeys, generateKeypairs, signBytes, deriveAuthKey, decryptBundleWithKey, }; diff --git a/packages/meshbay-hub/src/meshbay_hub/static/transport.js b/packages/meshbay-hub/src/meshbay_hub/static/transport.js index ca9c60e..d636085 100644 --- a/packages/meshbay-hub/src/meshbay_hub/static/transport.js +++ b/packages/meshbay-hub/src/meshbay_hub/static/transport.js @@ -266,6 +266,39 @@ class MeshBayTransport { return msg; } + /** + * Authorize a privileged node operation with the user's Ed25519 identity key. + * + * The client rebuilds the signed transcript from the challenge fields and refuses + * to sign unless the operation and subject match what the user actually asked for. + * Previously the node sent 32 opaque random bytes and the client signed them + * blind, which let any peer obtain a signature over content of its choosing + * (finding H5). + */ + async _authorizeAdminOp(challenge, expectedOp, expectedSubject, signFn) { + if (challenge.op !== expectedOp || challenge.subject !== expectedSubject) { + throw new Error( + `Refusing to sign: node asked to authorize "${challenge.op}" on ` + + `"${challenge.subject}", but the requested action was "${expectedOp}" ` + + `on "${expectedSubject}"`); + } + if (!signFn) throw new Error('Admin challenge received but no signing key available'); + + const transcript = window.MeshBayCrypto.adminTranscript( + challenge.op, challenge.node_pk, challenge.group_id, + challenge.subject, challenge.nonce, challenge.ts); + + const signature = await signFn(transcript); + const ack = await this._sendAndWait({ + type: 'admin_response', + v: '0.1', + op_id: challenge.op_id, + signature, + }); + if (ack.type === 'error') throw new Error(ack.detail); + return ack; + } + async deleteFile(fileId, signFn) { const msg = await this._sendAndWait({ type: 'file_delete', @@ -274,16 +307,7 @@ class MeshBayTransport { }); if (msg.type === 'error') throw new Error(msg.detail); if (msg.type === 'admin_challenge') { - if (!signFn) throw new Error('Admin challenge received but no signing key available'); - const signature = await signFn(msg.challenge); - const ack = await this._sendAndWait({ - type: 'admin_response', - v: '0.1', - file_id: fileId, - signature, - }); - if (ack.type === 'error') throw new Error(ack.detail); - return ack; + return this._authorizeAdminOp(msg, 'file_delete', fileId, signFn); } return msg; } @@ -304,7 +328,15 @@ class MeshBayTransport { return msg; } - async storeGekBundle(userId, groupId, bundle) { + /** + * Store a wrapped GEK bundle on the node for a member. + * + * Node-operator operation: the node answers with an admin challenge and only the + * pinned operator key is accepted. Any member used to be able to write bundles — + * including one addressed to the operator, which the node then auto-adopted as the + * live group key (finding C5b). + */ + async storeGekBundle(userId, groupId, bundle, signFn) { const msg = await this._sendAndWait({ type: 'gek_bundle_store', v: '0.1', @@ -315,6 +347,9 @@ class MeshBayTransport { wrapped_b64: bundle.wrapped_b64, }); if (msg.type === 'error') throw new Error(msg.detail); + if (msg.type === 'admin_challenge') { + return this._authorizeAdminOp(msg, 'gek_bundle_store', userId, signFn); + } return msg; } |