Files
ThothII/backend/src/auth/principal.ts
T

91 lines
3.6 KiB
TypeScript

import { chmodSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";
import { randomUUID } from "node:crypto";
export interface PrincipalContext {
issuer: string;
subject: string;
displayName?: string;
isAdmin: boolean;
}
const principalEnvKeys = [
"THT_PRINCIPAL_ISSUER", "THT_PRINCIPAL_SUBJECT", "THT_PRINCIPAL_DISPLAY_NAME", "THT_PRINCIPAL_IS_ADMIN",
] as const;
export function clearPrincipalEnvironment(env: NodeJS.ProcessEnv): void {
for (const key of principalEnvKeys) delete env[key];
}
export function expandLocalHome(path: string, home = homedir()): string {
if (path === "~") return home;
if (path.startsWith("~/")) return join(home, path.slice(2));
return path;
}
function harden(path: string, mode: number): void {
if (process.platform === "win32") return;
try { chmodSync(path, mode); } catch { /* best-effort parity with harness local storage */ }
}
const invalid = (value: string) => value.length === 0 || value.length > 512 || /[\u0000-\u001f\u007f]/.test(value);
function required(value: unknown): string | undefined {
if (typeof value !== "string") return undefined;
const normalized = value.trim();
return invalid(normalized) ? undefined : normalized;
}
function optional(value: unknown): string | undefined {
if (value === undefined) return undefined;
return required(value);
}
export function upstreamPrincipal(headers: Record<string, unknown>): PrincipalContext | undefined {
const issuer = required(headers["x-thoth-principal-issuer"]);
const subject = required(headers["x-thoth-principal-subject"]);
const displayName = optional(headers["x-thoth-principal-display-name"]);
const adminHeader = headers["x-thoth-is-admin"];
if (!issuer || !subject || (headers["x-thoth-principal-display-name"] !== undefined && !displayName)) return undefined;
if (adminHeader !== "0" && adminHeader !== "1" && adminHeader !== "true" && adminHeader !== "false") return undefined;
return { issuer, subject, displayName, isAdmin: adminHeader === "1" || adminHeader === "true" };
}
export function localPrincipal(): PrincipalContext {
const home = expandLocalHome(process.env.THT_HOME ?? join(homedir(), ".thothii"));
const identityPath = join(home, "identity.json");
mkdirSync(home, { recursive: true, mode: 0o700 });
harden(home, 0o700);
try {
const stored = JSON.parse(readFileSync(identityPath, "utf8"));
if (stored?.issuer === "local" && typeof stored.subject === "string" && /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i.test(stored.subject)) {
harden(identityPath, 0o600);
return { issuer: "local", subject: stored.subject, isAdmin: false };
}
throw new Error("invalid local identity");
} catch (error: any) {
if (error?.code !== "ENOENT") throw error;
const principal = { issuer: "local", subject: randomUUID() };
try {
writeFileSync(identityPath, JSON.stringify(principal) + "\n", { mode: 0o600, flag: "wx" });
harden(identityPath, 0o600);
return { ...principal, isAdmin: false };
} catch (writeError: any) {
// Another local request won the identity creation race; always converge on its UUID.
if (writeError?.code === "EEXIST") return localPrincipal();
throw writeError;
}
}
}
export function principalEnvironment(principal: PrincipalContext): NodeJS.ProcessEnv {
const env: NodeJS.ProcessEnv = {
THT_PRINCIPAL_ISSUER: principal.issuer,
THT_PRINCIPAL_SUBJECT: principal.subject,
THT_PRINCIPAL_IS_ADMIN: principal.isAdmin ? "true" : "false",
};
if (principal.displayName) env.THT_PRINCIPAL_DISPLAY_NAME = principal.displayName;
return env;
}