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Add support for SSH certificates #137

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8cda5c6
SSH2Stream: authPK: Rename algoLen to pubKeyTypeLen
TimWolla Jul 19, 2019
88943e6
SSH2Stream: authPK: Add new signatureType variable
TimWolla Jul 19, 2019
a7abff5
SSH2Stream: convertSignature: Convert the key type as well
TimWolla Jul 19, 2019
447a0c6
keyParser: Properly parse ssh certificates
TimWolla Jul 21, 2019
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14 changes: 10 additions & 4 deletions lib/keyParser.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1223,7 +1223,7 @@ function parseDER(data, baseType, comment, fullType) {
if (n === false)
return new Error('Malformed OpenSSH public key');
pubPEM = genOpenSSLRSAPub(n, e);
pubSSH = genOpenSSHRSAPub(n, e);
pubSSH = data;
algo = 'sha1';
break;
case 'ssh-dss':
Expand All @@ -1240,15 +1240,15 @@ function parseDER(data, baseType, comment, fullType) {
if (y === false)
return new Error('Malformed OpenSSH public key');
pubPEM = genOpenSSLDSAPub(p, q, g, y);
pubSSH = genOpenSSHDSAPub(p, q, g, y);
pubSSH = data;
algo = 'sha1';
break;
case 'ssh-ed25519':
var edpub = utils.readString(data, data._pos);
if (edpub === false || edpub.length !== 32)
return new Error('Malformed OpenSSH public key');
pubPEM = genOpenSSLEdPub(edpub);
pubSSH = genOpenSSHEdPub(edpub);
pubSSH = data;
algo = null;
break;
case 'ecdsa-sha2-nistp256':
Expand All @@ -1271,7 +1271,7 @@ function parseDER(data, baseType, comment, fullType) {
if (ecpub === false)
return new Error('Malformed OpenSSH public key');
pubPEM = genOpenSSLECDSAPub(oid, ecpub);
pubSSH = genOpenSSHECDSAPub(oid, ecpub);
pubSSH = data;
break;
default:
return new Error('Unsupported OpenSSH public key type: ' + baseType);
Expand Down Expand Up @@ -1316,6 +1316,12 @@ OpenSSH_Public.prototype = BaseKey;
var type = utils.readString(data, data._pos, 'ascii');
if (type === false || type.indexOf(baseType) !== 0)
return new Error('Malformed OpenSSH public key');
if (/-cert-v0[01]@openssh.com/.test(type)) {
var nonce = utils.readString(data, data._pos);
if (nonce === false) {
return new Error('Malformed OpenSSH certificate');
}
}

return parseDER(data, baseType, comment, fullType);
};
Expand Down
76 changes: 51 additions & 25 deletions lib/ssh.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1580,19 +1580,19 @@ SSH2Stream.prototype.authPK = function(username, pubKey, cbSign) {

var self = this;
var outstate = this._state.outgoing;
var keyType;
var pubKeyType;

if (typeof pubKey.getPublicSSH === 'function') {
keyType = pubKey.type;
pubKeyType = pubKey.type;
pubKey = pubKey.getPublicSSH();
} else {
keyType = pubKey.toString('ascii',
pubKeyType = pubKey.toString('ascii',
4,
4 + readUInt32BE(pubKey, 0));
}

var userLen = Buffer.byteLength(username);
var algoLen = Buffer.byteLength(keyType);
var pubKeyTypeLen = Buffer.byteLength(pubKeyType);
var pubKeyLen = pubKey.length;
var sesLen = outstate.sessionId.length;
var p = 0;
Expand All @@ -1602,7 +1602,7 @@ SSH2Stream.prototype.authPK = function(username, pubKey, cbSign) {
+ 4 + 14 // "ssh-connection"
+ 4 + 9 // "publickey"
+ 1
+ 4 + algoLen
+ 4 + pubKeyTypeLen
+ 4 + pubKeyLen
);

Expand All @@ -1625,10 +1625,10 @@ SSH2Stream.prototype.authPK = function(username, pubKey, cbSign) {

buf[p += 9] = (cbSign ? 1 : 0);

writeUInt32BE(buf, algoLen, ++p);
buf.write(keyType, p += 4, algoLen, 'ascii');
writeUInt32BE(buf, pubKeyTypeLen, ++p);
buf.write(pubKeyType, p += 4, pubKeyTypeLen, 'ascii');

writeUInt32BE(buf, pubKeyLen, p += algoLen);
writeUInt32BE(buf, pubKeyLen, p += pubKeyTypeLen);
pubKey.copy(buf, p += 4);

if (!cbSign) {
Expand All @@ -1638,20 +1638,24 @@ SSH2Stream.prototype.authPK = function(username, pubKey, cbSign) {
}

cbSign(buf, function(signature) {
signature = convertSignature(signature, keyType);
if (signature === false)
var converted = convertSignature(signature, pubKeyType);

if (converted === false)
throw new Error('Error while converting handshake signature');
signature = converted.signature;
var signatureType = converted.keyType;
var signatureTypeLen = Buffer.byteLength(signatureType);

var sigLen = signature.length;
var sigbuf = Buffer.allocUnsafe(1
+ 4 + userLen
+ 4 + 14 // "ssh-connection"
+ 4 + 9 // "publickey"
+ 1
+ 4 + algoLen
+ 4 + pubKeyTypeLen
+ 4 + pubKeyLen
+ 4 // 4 + algoLen + 4 + sigLen
+ 4 + algoLen
+ 4 // 4 + signatureTypeLen + 4 + sigLen
+ 4 + signatureTypeLen
+ 4 + sigLen);

p = 0;
Expand All @@ -1669,15 +1673,15 @@ SSH2Stream.prototype.authPK = function(username, pubKey, cbSign) {

sigbuf[p += 9] = 1;

writeUInt32BE(sigbuf, algoLen, ++p);
sigbuf.write(keyType, p += 4, algoLen, 'ascii');
writeUInt32BE(sigbuf, pubKeyTypeLen, ++p);
sigbuf.write(pubKeyType, p += 4, pubKeyTypeLen, 'ascii');

writeUInt32BE(sigbuf, pubKeyLen, p += algoLen);
writeUInt32BE(sigbuf, pubKeyLen, p += pubKeyTypeLen);
pubKey.copy(sigbuf, p += 4);
writeUInt32BE(sigbuf, 4 + algoLen + 4 + sigLen, p += pubKeyLen);
writeUInt32BE(sigbuf, algoLen, p += 4);
sigbuf.write(keyType, p += 4, algoLen, 'ascii');
writeUInt32BE(sigbuf, sigLen, p += algoLen);
writeUInt32BE(sigbuf, 4 + signatureTypeLen + 4 + sigLen, p += pubKeyLen);
writeUInt32BE(sigbuf, signatureTypeLen, p += 4);
sigbuf.write(signatureType, p += 4, signatureTypeLen, 'ascii');
writeUInt32BE(sigbuf, sigLen, p += signatureTypeLen);
signature.copy(sigbuf, p += 4);

// Servers shouldn't send packet type 60 in response to signed publickey
Expand Down Expand Up @@ -1753,10 +1757,11 @@ SSH2Stream.prototype.authHostbased = function(username, pubKey, hostname,
buf.write(userlocal, p += 4, userlocalLen, 'utf8');

cbSign(buf, function(signature) {
signature = convertSignature(signature, keyType);
var converted = convertSignature(signature, keyType);
if (signature === false)
throw new Error('Error while converting handshake signature');

signature = converted.signature;
var sigLen = signature.length;
var sigbuf = Buffer.allocUnsafe((buf.length - sesLen) + sigLen);

Expand Down Expand Up @@ -5000,14 +5005,16 @@ function KEXDH_REPLY(self, e) { // Server
return false;
}

signature = convertSignature(signature, hostkeyAlgo);
var converted = convertSignature(signature, hostkeyAlgo);
if (signature === false) {
signature.message = 'Error while converting handshake signature';
signature.level = 'handshake';
self.emit('error', signature);
self.disconnect(DISCONNECT_REASON.KEY_EXCHANGE_FAILED);
return false;
}
signature = converted.signature;
hostKeyAlgo = converted.keyType;

/*
byte SSH_MSG_KEXDH_REPLY
Expand Down Expand Up @@ -5250,16 +5257,35 @@ function tryComputeSecret(dh, e) {
}

function convertSignature(signature, keyType) {
switch (keyType) {
case 'ssh-rsa-cert-v01@openssh.com':
case 'ssh-dss-cert-v01@openssh.com':
case 'ecdsa-sha2-nistp256':
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@dhensby dhensby Mar 25, 2021

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I'd suggest this entire switch statement is unnecessary and you could just perform the replace blind. But this particular case statement seems redundant as it doesn't end in the appropriate string to qualify for the replace call?

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@TimWolla TimWolla Mar 26, 2021

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In fact the two cases below are also identical. These should've been ecdsa-sha2-nistp256-cert-v01@openssh.com, ecdsa-sha2-nistp384-cert-v01@openssh.com, and ecdsa-sha2-nistp521-cert-v01@openssh.com.

Not going to fix it, because this PR realistically is not going to be merged due to the planned rewrite of this library.

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@GitMensch GitMensch Mar 4, 2022

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Not going to fix it, because this PR realistically is not going to be merged due to the planned rewrite of this library.

Are this issues the same in mscdex/ssh2#808 (which also "primarily awaits an updated PR")?

case 'ecdsa-sha2-nistp256-cert-v01@openssh.com':
case 'ecdsa-sha2-nistp256-cert-v01@openssh.com':
case 'ssh-ed25519-cert-v01@openssh.com':
keyType = keyType.replace(/-cert-v01@openssh.com$/, '');
}

switch (keyType) {
case 'ssh-dss':
return DSASigBERToBare(signature);
signature = DSASigBERToBare(signature);
break;
case 'ecdsa-sha2-nistp256':
case 'ecdsa-sha2-nistp384':
case 'ecdsa-sha2-nistp521':
return ECDSASigASN1ToSSH(signature);
signature = ECDSASigASN1ToSSH(signature);
break;
}

return signature;
if (signature === false) {
return false;
}

return {
signature: signature,
keyType: keyType
}
}

var timingSafeEqual = (function() {
Expand Down
1 change: 1 addition & 0 deletions test/fixtures/openssh_cert_rsa-cert.pub
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
ssh-rsa-cert-v01@openssh.com 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 ssh certificate
7 changes: 7 additions & 0 deletions test/fixtures/openssh_cert_rsa-cert.pub.result
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@@ -0,0 +1,7 @@
{
"type": "ssh-rsa-cert-v01@openssh.com",
"comment": "ssh certificate",
"public": "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAttxjF19t0FshMtBi1L0e\nHyF4csasnxX6CRv2wSIuG6/Ak5LwKpLenTLjhzjykZQ8KzI3DNHyLkpvOyw62dWr\ndc9MbblYxwaAV36dRchnynNqhbalZyF+qatjxaFX/HXC/8Ufzj/VTKsejvjzL/4x\nF5BDcOoRMtD7V7sGA4PVSyNOEA7a8er+OAVG1L7vEKvX/Buc3BQcTK/AXWjz+rHc\nlhlZNOTEWu4/rguc0tykvHRldDyDhHlJnFboSbEUUlYAc81KtpgNXaLotxlgO7zE\nDsp+MfPXzIt4F34zPFzGQOynP9+TXNBsarU2EE/Bv2sadlnQO78iNbs/uJZNvSE1\nvwIDAQAB\n-----END PUBLIC KEY-----",
"publicSSH": "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",
"private": null
}