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| -rw-r--r-- | regress/unittests/sshsig/webauthn.html | 692 |
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diff --git a/regress/unittests/sshsig/webauthn.html b/regress/unittests/sshsig/webauthn.html new file mode 100644 index 0000000..953041e --- /dev/null +++ b/regress/unittests/sshsig/webauthn.html @@ -0,0 +1,692 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> +<title>webauthn test</title> +</head> +<body onload="init()"> +<h1>webauthn test</h1> +<p> +This is a demo/test page for generating FIDO keys and signatures in SSH +formats. The page initially displays a form to generate a FIDO key and +convert it to a SSH public key. +</p> +<p> +Once a key has been generated, an additional form will be displayed to +allow signing of data using the just-generated key. The data may be signed +as either a raw SSH signature or wrapped in a sshsig message (the latter is +easier to test using command-line tools. +</p> +<p> +Lots of debugging is printed along the way. +</p> +<h2>Enroll</h2> +<span id="error" style="color: #800; font-weight: bold; font-size: 150%;"></span> +<form id="enrollform"> +<table> +<tr> +<td><b>Username:</b></td> +<td><input id="username" type="text" size="20" name="user" value="test" /></td> +</tr> +<tr><td></td><td><input id="assertsubmit" type="submit" value="submit" /></td></tr> +</table> +</form> +<span id="enrollresult" style="visibility: hidden;"> +<h2>clientData</h2> +<pre id="enrollresultjson" style="color: #008; font-family: monospace;"></pre> +<h2>attestationObject raw</h2> +<pre id="enrollresultraw" style="color: #008; font-family: monospace;"></pre> +<h2>attestationObject</h2> +<pre id="enrollresultattestobj" style="color: #008; font-family: monospace;"></pre> +<h2>authData raw</h2> +<pre id="enrollresultauthdataraw" style="color: #008; font-family: monospace;"></pre> +<h2>authData</h2> +<pre id="enrollresultauthdata" style="color: #008; font-family: monospace;"></pre> +<h2>SSH pubkey blob</h2> +<pre id="enrollresultpkblob" style="color: #008; font-family: monospace;"></pre> +<h2>SSH pubkey string</h2> +<pre id="enrollresultpk" style="color: #008; font-family: monospace;"></pre> +</span> +<span id="assertsection" style="visibility: hidden;"> +<h2>Assert</h2> +<form id="assertform"> +<span id="asserterror" style="color: #800; font-weight: bold;"></span> +<table> +<tr> +<td><b>Data to sign:</b></td> +<td><input id="message" type="text" size="20" name="message" value="test" /></td> +</tr> +<tr> +<td><input id="message_sshsig" type="checkbox" checked /> use sshsig format</td> +</tr> +<tr> +<td><b>Signature namespace:</b></td> +<td><input id="message_namespace" type="text" size="20" name="namespace" value="test" /></td> +</tr> +<tr><td></td><td><input type="submit" value="submit" /></td></tr> +</table> +</form> +</span> +<span id="assertresult" style="visibility: hidden;"> +<h2>clientData</h2> +<pre id="assertresultjson" style="color: #008; font-family: monospace;"></pre> +<h2>signature raw</h2> +<pre id="assertresultsigraw" style="color: #008; font-family: monospace;"></pre> +<h2>authenticatorData raw</h2> +<pre id="assertresultauthdataraw" style="color: #008; font-family: monospace;"></pre> +<h2>authenticatorData</h2> +<pre id="assertresultauthdata" style="color: #008; font-family: monospace;"></pre> +<h2>signature in SSH format</h2> +<pre id="assertresultsshsigraw" style="color: #008; font-family: monospace;"></pre> +<h2>signature in SSH format (base64 encoded)</h2> +<pre id="assertresultsshsigb64" style="color: #008; font-family: monospace;"></pre> +</span> +</body> +<script> +// ------------------------------------------------------------------ +// a crappy CBOR decoder - 20200401 djm@openbsd.org + +var CBORDecode = function(buffer) { + this.buf = buffer + this.v = new DataView(buffer) + this.offset = 0 +} + +CBORDecode.prototype.empty = function() { + return this.offset >= this.buf.byteLength +} + +CBORDecode.prototype.getU8 = function() { + let r = this.v.getUint8(this.offset) + this.offset += 1 + return r +} + +CBORDecode.prototype.getU16 = function() { + let r = this.v.getUint16(this.offset) + this.offset += 2 + return r +} + +CBORDecode.prototype.getU32 = function() { + let r = this.v.getUint32(this.offset) + this.offset += 4 + return r +} + +CBORDecode.prototype.getU64 = function() { + let r = this.v.getUint64(this.offset) + this.offset += 8 + return r +} + +CBORDecode.prototype.getCBORTypeLen = function() { + let tl, t, l + tl = this.getU8() + t = (tl & 0xe0) >> 5 + l = tl & 0x1f + return [t, this.decodeInteger(l)] +} + +CBORDecode.prototype.decodeInteger = function(len) { + switch (len) { + case 0x18: return this.getU8() + case 0x19: return this.getU16() + case 0x20: return this.getU32() + case 0x21: return this.getU64() + default: + if (len <= 23) { + return len + } + throw new Error("Unsupported int type 0x" + len.toString(16)) + } +} + +CBORDecode.prototype.decodeNegint = function(len) { + let r = -(this.decodeInteger(len) + 1) + return r +} + +CBORDecode.prototype.decodeByteString = function(len) { + let r = this.buf.slice(this.offset, this.offset + len) + this.offset += len + return r +} + +CBORDecode.prototype.decodeTextString = function(len) { + let u8dec = new TextDecoder('utf-8') + r = u8dec.decode(this.decodeByteString(len)) + return r +} + +CBORDecode.prototype.decodeArray = function(len, level) { + let r = [] + for (let i = 0; i < len; i++) { + let v = this.decodeInternal(level) + r.push(v) + // console.log("decodeArray level " + level.toString() + " index " + i.toString() + " value " + JSON.stringify(v)) + } + return r +} + +CBORDecode.prototype.decodeMap = function(len, level) { + let r = {} + for (let i = 0; i < len; i++) { + let k = this.decodeInternal(level) + let v = this.decodeInternal(level) + r[k] = v + // console.log("decodeMap level " + level.toString() + " key " + k.toString() + " value " + JSON.stringify(v)) + // XXX check string keys, duplicates + } + return r +} + +CBORDecode.prototype.decodePrimitive = function(t) { + switch (t) { + case 20: return false + case 21: return true + case 22: return null + case 23: return undefined + default: + throw new Error("Unsupported primitive 0x" + t.toString(2)) + } +} + +CBORDecode.prototype.decodeInternal = function(level) { + if (level > 256) { + throw new Error("CBOR nesting too deep") + } + let t, l, r + [t, l] = this.getCBORTypeLen() + // console.log("decode level " + level.toString() + " type " + t.toString() + " len " + l.toString()) + switch (t) { + case 0: + r = this.decodeInteger(l) + break + case 1: + r = this.decodeNegint(l) + break + case 2: + r = this.decodeByteString(l) + break + case 3: + r = this.decodeTextString(l) + break + case 4: + r = this.decodeArray(l, level + 1) + break + case 5: + r = this.decodeMap(l, level + 1) + break + case 6: + console.log("XXX ignored semantic tag " + this.decodeInteger(l).toString()) + break; + case 7: + r = this.decodePrimitive(l) + break + default: + throw new Error("Unsupported type 0x" + t.toString(2) + " len " + l.toString()) + } + // console.log("decode level " + level.toString() + " value " + JSON.stringify(r)) + return r +} + +CBORDecode.prototype.decode = function() { + return this.decodeInternal(0) +} + +// ------------------------------------------------------------------ +// a crappy SSH message packer - 20200401 djm@openbsd.org + +var SSHMSG = function() { + this.r = [] +} + +SSHMSG.prototype.serialise = function() { + let len = 0 + for (buf of this.r) { + len += buf.length + } + let r = new ArrayBuffer(len) + let v = new Uint8Array(r) + let offset = 0 + for (buf of this.r) { + v.set(buf, offset) + offset += buf.length + } + if (offset != r.byteLength) { + throw new Error("djm can't count") + } + return r +} + +SSHMSG.prototype.serialiseBase64 = function(v) { + let b = this.serialise() + return btoa(String.fromCharCode(...new Uint8Array(b))); +} + +SSHMSG.prototype.putU8 = function(v) { + this.r.push(new Uint8Array([v])) +} + +SSHMSG.prototype.putU32 = function(v) { + this.r.push(new Uint8Array([ + (v >> 24) & 0xff, + (v >> 16) & 0xff, + (v >> 8) & 0xff, + (v & 0xff) + ])) +} + +SSHMSG.prototype.put = function(v) { + this.r.push(new Uint8Array(v)) +} + +SSHMSG.prototype.putString = function(v) { + let enc = new TextEncoder(); + let venc = enc.encode(v) + this.putU32(venc.length) + this.put(venc) +} + +SSHMSG.prototype.putSSHMSG = function(v) { + let msg = v.serialise() + this.putU32(msg.byteLength) + this.put(msg) +} + +SSHMSG.prototype.putBytes = function(v) { + this.putU32(v.byteLength) + this.put(v) +} + +SSHMSG.prototype.putECPoint = function(x, y) { + let x8 = new Uint8Array(x) + let y8 = new Uint8Array(y) + this.putU32(1 + x8.length + y8.length) + this.putU8(0x04) // Uncompressed point format. + this.put(x8) + this.put(y8) +} + +// ------------------------------------------------------------------ +// webauthn to SSH glue - djm@openbsd.org 20200408 + +function error(msg, ...args) { + document.getElementById("error").innerText = msg + console.log(msg) + for (const arg of args) { + console.dir(arg) + } +} +function hexdump(buf) { + const hex = Array.from(new Uint8Array(buf)).map( + b => b.toString(16).padStart(2, "0")) + const fmt = new Array() + for (let i = 0; i < hex.length; i++) { + if ((i % 16) == 0) { + // Prepend length every 16 bytes. + fmt.push(i.toString(16).padStart(4, "0")) + fmt.push(" ") + } + fmt.push(hex[i]) + fmt.push(" ") + if ((i % 16) == 15) { + fmt.push("\n") + } + } + return fmt.join("") +} +function enrollform_submit(event) { + event.preventDefault(); + console.log("submitted") + username = event.target.elements.username.value + if (username === "") { + error("no username specified") + return false + } + enrollStart(username) +} +function enrollStart(username) { + let challenge = new Uint8Array(32) + window.crypto.getRandomValues(challenge) + let userid = new Uint8Array(8) + window.crypto.getRandomValues(userid) + + console.log("challenge:" + btoa(challenge)) + console.log("userid:" + btoa(userid)) + + let pkopts = { + challenge: challenge, + rp: { + name: "mindrot.org", + id: "mindrot.org", + }, + user: { + id: userid, + name: username, + displayName: username, + }, + authenticatorSelection: { + authenticatorAttachment: "cross-platform", + userVerification: "discouraged", + }, + pubKeyCredParams: [{alg: -7, type: "public-key"}], // ES256 + timeout: 30 * 1000, + }; + console.dir(pkopts) + window.enrollOpts = pkopts + let credpromise = navigator.credentials.create({ publicKey: pkopts }); + credpromise.then(enrollSuccess, enrollFailure) +} +function enrollFailure(result) { + error("Enroll failed", result) +} +function enrollSuccess(result) { + console.log("Enroll succeeded") + console.dir(result) + window.enrollResult = result + document.getElementById("enrollresult").style.visibility = "visible" + + // Show the clientData + let u8dec = new TextDecoder('utf-8') + clientData = u8dec.decode(result.response.clientDataJSON) + document.getElementById("enrollresultjson").innerText = clientData + + // Decode and show the attestationObject + document.getElementById("enrollresultraw").innerText = hexdump(result.response.attestationObject) + let aod = new CBORDecode(result.response.attestationObject) + let attestationObject = aod.decode() + console.log("attestationObject") + console.dir(attestationObject) + document.getElementById("enrollresultattestobj").innerText = JSON.stringify(attestationObject) + + // Decode and show the authData + document.getElementById("enrollresultauthdataraw").innerText = hexdump(attestationObject.authData) + let authData = decodeAuthenticatorData(attestationObject.authData, true) + console.log("authData") + console.dir(authData) + window.enrollAuthData = authData + document.getElementById("enrollresultauthdata").innerText = JSON.stringify(authData) + + // Reformat the pubkey as a SSH key for easy verification + window.rawKey = reformatPubkey(authData.attestedCredentialData.credentialPublicKey, window.enrollOpts.rp.id) + console.log("SSH pubkey blob") + console.dir(window.rawKey) + document.getElementById("enrollresultpkblob").innerText = hexdump(window.rawKey) + let pk64 = btoa(String.fromCharCode(...new Uint8Array(window.rawKey))); + let pk = "sk-ecdsa-sha2-nistp256@openssh.com " + pk64 + document.getElementById("enrollresultpk").innerText = pk + + // Success: show the assertion form. + document.getElementById("assertsection").style.visibility = "visible" +} + +function decodeAuthenticatorData(authData, expectCred) { + let r = new Object() + let v = new DataView(authData) + + r.rpIdHash = authData.slice(0, 32) + r.flags = v.getUint8(32) + r.signCount = v.getUint32(33) + + // Decode attestedCredentialData if present. + let offset = 37 + let acd = new Object() + if (expectCred) { + acd.aaguid = authData.slice(offset, offset+16) + offset += 16 + let credentialIdLength = v.getUint16(offset) + offset += 2 + acd.credentialIdLength = credentialIdLength + acd.credentialId = authData.slice(offset, offset+credentialIdLength) + offset += credentialIdLength + r.attestedCredentialData = acd + } + console.log("XXXXX " + offset.toString()) + let pubkeyrest = authData.slice(offset, authData.byteLength) + let pkdecode = new CBORDecode(pubkeyrest) + if (expectCred) { + // XXX unsafe: doesn't mandate COSE canonical format. + acd.credentialPublicKey = pkdecode.decode() + } + if (!pkdecode.empty()) { + // Decode extensions if present. + r.extensions = pkdecode.decode() + } + return r +} + +function reformatPubkey(pk, rpid) { + // pk is in COSE format. We only care about a tiny subset. + if (pk[1] != 2) { + console.dir(pk) + throw new Error("pubkey is not EC") + } + if (pk[-1] != 1) { + throw new Error("pubkey is not in P256") + } + if (pk[3] != -7) { + throw new Error("pubkey is not ES256") + } + if (pk[-2].byteLength != 32 || pk[-3].byteLength != 32) { + throw new Error("pubkey EC coords have bad length") + } + let msg = new SSHMSG() + msg.putString("sk-ecdsa-sha2-nistp256@openssh.com") // Key type + msg.putString("nistp256") // Key curve + msg.putECPoint(pk[-2], pk[-3]) // EC key + msg.putString(rpid) // RP ID + return msg.serialise() +} + +async function assertform_submit(event) { + event.preventDefault(); + console.log("submitted") + message = event.target.elements.message.value + if (message === "") { + error("no message specified") + return false + } + let enc = new TextEncoder() + let encmsg = enc.encode(message) + window.assertSignRaw = !event.target.elements.message_sshsig.checked + console.log("using sshsig ", !window.assertSignRaw) + if (window.assertSignRaw) { + assertStart(encmsg) + return + } + // Format a sshsig-style message. + window.sigHashAlg = "sha512" + let msghash = await crypto.subtle.digest("SHA-512", encmsg); + console.log("raw message hash") + console.dir(msghash) + window.sigNamespace = event.target.elements.message_namespace.value + let sigbuf = new SSHMSG() + sigbuf.put(enc.encode("SSHSIG")) + sigbuf.putString(window.sigNamespace) + sigbuf.putU32(0) // Reserved string + sigbuf.putString(window.sigHashAlg) + sigbuf.putBytes(msghash) + let msg = sigbuf.serialise() + console.log("sigbuf") + console.dir(msg) + assertStart(msg) +} + +function assertStart(message) { + let assertReqOpts = { + challenge: message, + rpId: "mindrot.org", + allowCredentials: [{ + type: 'public-key', + id: window.enrollResult.rawId, + }], + userVerification: "discouraged", + timeout: (30 * 1000), + } + console.log("assertReqOpts") + console.dir(assertReqOpts) + window.assertReqOpts = assertReqOpts + let assertpromise = navigator.credentials.get({ + publicKey: assertReqOpts + }); + assertpromise.then(assertSuccess, assertFailure) +} +function assertFailure(result) { + error("Assertion failed", result) +} +function linewrap(s) { + const linelen = 70 + let ret = "" + for (let i = 0; i < s.length; i += linelen) { + end = i + linelen + if (end > s.length) { + end = s.length + } + if (i > 0) { + ret += "\n" + } + ret += s.slice(i, end) + } + return ret + "\n" +} +function assertSuccess(result) { + console.log("Assertion succeeded") + console.dir(result) + window.assertResult = result + document.getElementById("assertresult").style.visibility = "visible" + + // show the clientData. + let u8dec = new TextDecoder('utf-8') + clientData = u8dec.decode(result.response.clientDataJSON) + document.getElementById("assertresultjson").innerText = clientData + + // show the signature. + document.getElementById("assertresultsigraw").innerText = hexdump(result.response.signature) + + // decode and show the authData. + document.getElementById("assertresultauthdataraw").innerText = hexdump(result.response.authenticatorData) + authData = decodeAuthenticatorData(result.response.authenticatorData, false) + document.getElementById("assertresultauthdata").innerText = JSON.stringify(authData) + + // Parse and reformat the signature to an SSH style signature. + let sshsig = reformatSignature(result.response.signature, clientData, authData) + document.getElementById("assertresultsshsigraw").innerText = hexdump(sshsig) + let sig64 = btoa(String.fromCharCode(...new Uint8Array(sshsig))); + if (window.assertSignRaw) { + document.getElementById("assertresultsshsigb64").innerText = sig64 + } else { + document.getElementById("assertresultsshsigb64").innerText = + "-----BEGIN SSH SIGNATURE-----\n" + linewrap(sig64) + + "-----END SSH SIGNATURE-----\n"; + } +} + +function reformatSignature(sig, clientData, authData) { + if (sig.byteLength < 2) { + throw new Error("signature is too short") + } + let offset = 0 + let v = new DataView(sig) + // Expect an ASN.1 SEQUENCE that exactly spans the signature. + if (v.getUint8(offset) != 0x30) { + throw new Error("signature not an ASN.1 sequence") + } + offset++ + let seqlen = v.getUint8(offset) + offset++ + if ((seqlen & 0x80) != 0 || seqlen != sig.byteLength - offset) { + throw new Error("signature has unexpected length " + seqlen.toString() + " vs expected " + (sig.byteLength - offset).toString()) + } + + // Parse 'r' INTEGER value. + if (v.getUint8(offset) != 0x02) { + throw new Error("signature r not an ASN.1 integer") + } + offset++ + let rlen = v.getUint8(offset) + offset++ + if ((rlen & 0x80) != 0 || rlen > sig.byteLength - offset) { + throw new Error("signature r has unexpected length " + rlen.toString() + " vs buffer " + (sig.byteLength - offset).toString()) + } + let r = sig.slice(offset, offset + rlen) + offset += rlen + console.log("sig_r") + console.dir(r) + + // Parse 's' INTEGER value. + if (v.getUint8(offset) != 0x02) { + throw new Error("signature r not an ASN.1 integer") + } + offset++ + let slen = v.getUint8(offset) + offset++ + if ((slen & 0x80) != 0 || slen > sig.byteLength - offset) { + throw new Error("signature s has unexpected length " + slen.toString() + " vs buffer " + (sig.byteLength - offset).toString()) + } + let s = sig.slice(offset, offset + slen) + console.log("sig_s") + console.dir(s) + offset += slen + + if (offset != sig.byteLength) { + throw new Error("unexpected final offset during signature parsing " + offset.toString() + " expected " + sig.byteLength.toString()) + } + + // Reformat as an SSH signature. + let clientDataParsed = JSON.parse(clientData) + let innersig = new SSHMSG() + innersig.putBytes(r) + innersig.putBytes(s) + + let rawsshsig = new SSHMSG() + rawsshsig.putString("webauthn-sk-ecdsa-sha2-nistp256@openssh.com") + rawsshsig.putSSHMSG(innersig) + rawsshsig.putU8(authData.flags) + rawsshsig.putU32(authData.signCount) + rawsshsig.putString(clientDataParsed.origin) + rawsshsig.putString(clientData) + if (authData.extensions == undefined) { + rawsshsig.putU32(0) + } else { + rawsshsig.putBytes(authData.extensions) + } + + if (window.assertSignRaw) { + return rawsshsig.serialise() + } + // Format as SSHSIG. + let enc = new TextEncoder() + let sshsig = new SSHMSG() + sshsig.put(enc.encode("SSHSIG")) + sshsig.putU32(0x01) // Signature version. + sshsig.putBytes(window.rawKey) + sshsig.putString(window.sigNamespace) + sshsig.putU32(0) // Reserved string + sshsig.putString(window.sigHashAlg) + sshsig.putBytes(rawsshsig.serialise()) + return sshsig.serialise() +} + +function toggleNamespaceVisibility() { + const assertsigtype = document.getElementById('message_sshsig'); + const assertsignamespace = document.getElementById('message_namespace'); + assertsignamespace.disabled = !assertsigtype.checked; +} + +function init() { + if (document.location.protocol != "https:") { + error("This page must be loaded via https") + const assertsubmit = document.getElementById('assertsubmit') + assertsubmit.disabled = true + } + const enrollform = document.getElementById('enrollform'); + enrollform.addEventListener('submit', enrollform_submit); + const assertform = document.getElementById('assertform'); + assertform.addEventListener('submit', assertform_submit); + const assertsigtype = document.getElementById('message_sshsig'); + assertsigtype.onclick = toggleNamespaceVisibility; +} +</script> + +</html> |