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improved parsing ssh-config #198

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45 changes: 35 additions & 10 deletions src/authResolver.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ import type { ParsedKey } from 'ssh2-streams';
import Log from './common/logger';
import SSHDestination from './ssh/sshDestination';
import SSHConnection, { SSHTunnelConfig } from './ssh/sshConnection';
import SSHConfiguration from './ssh/sshConfig';
import SSHConfiguration, { HostConfiguration } from './ssh/sshConfig';
import { gatherIdentityFiles } from './ssh/identityFiles';
import { untildify, exists as fileExists } from './common/files';
import { findRandomPort } from './common/ports';
Expand Down Expand Up @@ -95,40 +95,59 @@ export class RemoteSSHResolver implements vscode.RemoteAuthorityResolver, vscode
try {
const sshconfig = await SSHConfiguration.loadFromFS();
const sshHostConfig = sshconfig.getHostConfiguration(sshDest.hostname);
const sshHostName = sshHostConfig['HostName'] ? sshHostConfig['HostName'].replace('%h', sshDest.hostname) : sshDest.hostname;
const sshHostName = sshHostConfig['HostName'] ? SSHConfiguration.interpolate(sshHostConfig['HostName'], { '%': '%', 'h': sshDest.hostname }) : sshDest.hostname;
const sshUser = sshHostConfig['User'] || sshDest.user || os.userInfo().username || ''; // https://github.com/openssh/openssh-portable/blob/5ec5504f1d328d5bfa64280cd617c3efec4f78f3/sshconnect.c#L1561-L1562
const sshPort = sshHostConfig['Port'] ? parseInt(sshHostConfig['Port'], 10) : (sshDest.port || 22);

this.sshAgentSock = sshHostConfig['IdentityAgent'] || process.env['SSH_AUTH_SOCK'] || (isWindows ? '\\\\.\\pipe\\openssh-ssh-agent' : undefined);
const valuesToInterpolate = {
'%': '%',
'd': os.homedir(),
'h': sshHostName,
'i': os.userInfo().uid.toString(),
'k': sshHostConfig['HostKeyAlias'] || sshDest.hostname,
'L': os.hostname(),
'l': os.hostname(),
'n': sshDest.hostname,
'p': (sshDest.port || 22).toString(),
'r': sshUser,
'u': os.userInfo().username || ''
};
const interpolatePath = (value: string) => {
return SSHConfiguration.interpolate(
value, valuesToInterpolate);
};

const identityAgent = sshHostConfig['IdentityAgent'] ? interpolatePath(sshHostConfig['IdentityAgent']) : undefined;
this.sshAgentSock = identityAgent || process.env['SSH_AUTH_SOCK'] || (isWindows ? '\\\\.\\pipe\\openssh-ssh-agent' : undefined);
this.sshAgentSock = this.sshAgentSock ? untildify(this.sshAgentSock) : undefined;
const agentForward = enableAgentForwarding && (sshHostConfig['ForwardAgent'] || 'no').toLowerCase() === 'yes';
const agent = agentForward && this.sshAgentSock ? new ssh2.OpenSSHAgent(this.sshAgentSock) : undefined;

const preferredAuthentications = sshHostConfig['PreferredAuthentications'] ? sshHostConfig['PreferredAuthentications'].split(',').map(s => s.trim()) : ['publickey', 'password', 'keyboard-interactive'];

const identityFiles: string[] = (sshHostConfig['IdentityFile'] as unknown as string[]) || [];
const identityFiles: string[] = (sshHostConfig['IdentityFile']?.map(f => untildify(interpolatePath(f)))) || [];
const identitiesOnly = (sshHostConfig['IdentitiesOnly'] || 'no').toLowerCase() === 'yes';
const identityKeys = await gatherIdentityFiles(identityFiles, this.sshAgentSock, identitiesOnly, this.logger);

// Create proxy jump connections if any
let proxyStream: ssh2.ClientChannel | stream.Duplex | undefined;
if (sshHostConfig['ProxyJump']) {
const proxyJumps = sshHostConfig['ProxyJump'].split(',').filter(i => !!i.trim())
.map(i => {
.map((i): [SSHDestination, HostConfiguration] => {
const proxy = SSHDestination.parse(i);
const proxyHostConfig = sshconfig.getHostConfiguration(proxy.hostname);
return [proxy, proxyHostConfig] as [SSHDestination, Record<string, string>];
return [proxy, proxyHostConfig];
});
for (let i = 0; i < proxyJumps.length; i++) {
const [proxy, proxyHostConfig] = proxyJumps[i];
const proxyHostName = proxyHostConfig['HostName'] || proxy.hostname;
const proxyHostName = proxyHostConfig['HostName'] ? SSHConfiguration.interpolate(sshHostConfig['HostName'], { '%': '%', 'h': proxy.hostname }) : proxy.hostname;
const proxyUser = proxyHostConfig['User'] || proxy.user || sshUser;
const proxyPort = proxyHostConfig['Port'] ? parseInt(proxyHostConfig['Port'], 10) : (proxy.port || sshPort);

const proxyAgentForward = enableAgentForwarding && (proxyHostConfig['ForwardAgent'] || 'no').toLowerCase() === 'yes';
const proxyAgent = proxyAgentForward && this.sshAgentSock ? new ssh2.OpenSSHAgent(this.sshAgentSock) : undefined;

const proxyIdentityFiles: string[] = (proxyHostConfig['IdentityFile'] as unknown as string[]) || [];
const proxyIdentityFiles: string[] = (proxyHostConfig['IdentityFile']?.map(f => untildify(interpolatePath(f)))) || [];
const proxyIdentitiesOnly = (proxyHostConfig['IdentitiesOnly'] || 'no').toLowerCase() === 'yes';
const proxyIdentityKeys = await gatherIdentityFiles(proxyIdentityFiles, this.sshAgentSock, proxyIdentitiesOnly, this.logger);

Expand All @@ -152,8 +171,14 @@ export class RemoteSSHResolver implements vscode.RemoteAuthorityResolver, vscode
proxyStream = await proxyConnection.forwardOut('127.0.0.1', 0, destIP, destPort);
}
} else if (sshHostConfig['ProxyCommand']) {
let proxyArgs = (sshHostConfig['ProxyCommand'] as unknown as string[])
.map((arg) => arg.replace('%h', sshHostName).replace('%n', sshDest.hostname).replace('%p', sshPort.toString()).replace('%r', sshUser));
let proxyArgs = (sshHostConfig['ProxyCommand'])
.map((arg) => SSHConfiguration.interpolate(arg, {
'%': '%',
'h': sshHostName,
'n': sshDest.hostname,
'p': sshPort.toString(),
'r': sshUser,
}));
let proxyCommand = proxyArgs.shift()!;

let options = {};
Expand Down
52 changes: 44 additions & 8 deletions src/ssh/sshConfig.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ function isIncludeDirective(line: Line): line is Section {
const SSH_CONFIG_PROPERTIES: Record<string, string> = {
'host': 'Host',
'hostname': 'HostName',
'hostkeyalias': 'HostKeyAlias',
'user': 'User',
'port': 'Port',
'identityagent': 'IdentityAgent',
Expand Down Expand Up @@ -90,6 +91,25 @@ async function parseSSHConfigFromFile(filePath: string, userConfig: boolean) {
return config;
}

export type HostConfiguration = {
// https://github.com/jeanp413/ssh-config/blob/8d187bb8f1d83a51ff2b1d127e6b6269d24092b5/src/ssh-config.ts#L9
GlobalKnownHostsFile?: string[];
Host?: string[];
IPQoS?: string[];
SendEnv?: string[];
UserKnownHostsFile?: string[];
ProxyCommand?: string[];
Match?: string[];
// https://github.com/jeanp413/ssh-config/blob/8d187bb8f1d83a51ff2b1d127e6b6269d24092b5/src/ssh-config.ts#L72-L78
IdentityFile?: string[];
LocalForward?: string[];
RemoteForward?: string[];
DynamicForward?: string[];
CertificateFile?: string[];
} & {
[key: string]: string;
};

export default class SSHConfiguration {

static async loadFromFS(): Promise<SSHConfiguration> {
Expand All @@ -106,20 +126,36 @@ export default class SSHConfiguration {
const hosts = new Set<string>();
for (const line of this.sshConfig) {
if (isHostSection(line)) {
const value = Array.isArray(line.value) ? line.value[0] : line.value;
const isPattern = /^!/.test(value) || /[?*]/.test(value);
if (!isPattern) {
hosts.add(value);
const values = Array.isArray(line.value) ? line.value : [line.value];
for (const value of values) {
const isPattern = /^!/.test(value) || /[?*]/.test(value);
if (!isPattern) {
hosts.add(value);
}
}
}
}

return [...hosts.keys()];
}

getHostConfiguration(host: string): Record<string, string> {
// Only a few directives return an array
// https://github.com/jeanp413/ssh-config/blob/8d187bb8f1d83a51ff2b1d127e6b6269d24092b5/src/ssh-config.ts#L9C1-L9C118
return this.sshConfig.compute(host) as Record<string, string>;
getHostConfiguration(host: string): HostConfiguration {
return this.sshConfig.compute(host) as HostConfiguration;
}

static interpolate(str: string, values: Record<string, string>): string {
const results: string[] = [];
for (let i = 0; i < str.length; i++) {
if (str[i] === '%' && i + 1 < str.length) {
const next = str[i + 1];
if (next in values) {
results.push(values[next]);
i++;
continue;
}
}
results.push(str[i]);
}
return results.join('');
}
}