fix(server): harden git-clone — close 6 path-injection / CLI-injection / ReDoS alerts (U3)

gitnexus/src/server/api.ts

@@ -829,52 +829,63 @@
   });
 
   // Delete a repo — removes index, clone dir (if any), and unregisters it
   app.delete('/api/repo', async (req, res) => {
     try {
       const repoName = requestedRepo(req);
       if (!repoName) {
         res.status(400).json({ error: 'Missing repo name' });
         return;
       }
       const entry = await resolveRepo(repoName);
       if (!entry) {
         res.status(404).json({ error: 'Repository not found' });
         return;
       }
 
       // Acquire repo lock — prevents deleting while analyze/embed is in flight
       const lockKey = getStoragePath(entry.path);
       const lockErr = acquireRepoLock(lockKey);
       if (lockErr) {
         res.status(409).json({ error: lockErr });
         return;
       }
 
       try {
         // Close any open LadybugDB handle before deleting files
         try {
           await closeLbug();
         } catch {}
 
         // 1. Delete the .gitnexus index/storage directory
         const storagePath = getStoragePath(entry.path);
         await fs.rm(storagePath, { recursive: true, force: true }).catch(() => {});
 
-        // 2. Delete the cloned repo dir if it lives under ~/.gitnexus/repos/
-        const cloneDir = getCloneDir(entry.name);
+        // 2. Delete the cloned repo dir if it lives under ~/.gitnexus/repos/.
+        // getCloneDir now throws on names that are not filesystem-safe (e.g.
+        // local repos registered with names like "my project" or "org/repo").
+        // Such repos legitimately have no clone dir, so treat the rejection as
+        // "nothing to clean up" rather than letting it fail the delete handler.
+        let cloneDir: string | null = null;
         try {
-          const stat = await fs.stat(cloneDir);
-          if (stat.isDirectory()) {
-            await fs.rm(cloneDir, { recursive: true, force: true });
-          }
+          cloneDir = getCloneDir(entry.name);
         } catch {
-          /* clone dir may not exist (local repos) */
+          /* repo name not eligible for a clone dir (local repo) */
+        }
+        if (cloneDir) {
+          try {
+            const stat = await fs.stat(cloneDir);
+            if (stat.isDirectory()) {
+              await fs.rm(cloneDir, { recursive: true, force: true });
+            }
+          } catch {
+            /* clone dir may not exist */
+          }
         }
 
         // 3. Unregister from the global registry
         const { unregisterRepo } = await import('../storage/repo-manager.js');
         await unregisterRepo(entry.path);
 
         // 4. Reinitialize backend to reflect the removal
         await backend.init().catch(() => {});
 

gitnexus/src/server/git-clone.ts

@@ -11,16 +11,47 @@ import os from 'os';
 import fs from 'fs/promises';
 import { isIP } from 'net';
 
-/** Extract the repository name from a git URL (HTTPS or SSH). */
+/** Root directory for all cloned repositories. Targets must resolve inside this. */
+const CLONE_ROOT = path.resolve(path.join(os.homedir(), '.gitnexus', 'repos'));
+
+// A valid git repository name is filesystem-safe: alphanumerics plus `. _ -`.
+// Rejecting anything else (including `..`, `/`, `\`, shell metacharacters)
+// guarantees getCloneDir(repoName) cannot escape CLONE_ROOT regardless of
+// how the caller derived repoName.
+const REPO_NAME_PATTERN = /^[a-zA-Z0-9._-]+$/;
+
+/**
+ * Extract the repository name from a git URL (HTTPS or SSH).
+ *
+ * Throws if the URL does not yield a filesystem-safe last segment. A name
+ * like `..` or `foo/bar` would otherwise let `getCloneDir(name)` escape the
+ * clone root via path traversal.
+ */
 export function extractRepoName(url: string): string {
-  const cleaned = url.replace(/\/+$/, '');
-  const lastSegment = cleaned.split(/[/:]/).pop() || 'unknown';
-  return lastSegment.replace(/\.git$/, '');
+  // Strip trailing slashes without a regex to avoid polynomial-ReDoS on
+  // pathological inputs like `https://x.com/y` + '/'.repeat(1e6). CodeQL's
+  // js/polynomial-redos flagged `/\/+$/` here.
+  let end = url.length;
+  while (end > 0 && url.charCodeAt(end - 1) === 47 /* '/' */) end--;
+  const cleaned = url.slice(0, end);
+
+  const lastSegment = cleaned.split(/[/:]/).pop() || '';
+  const stripped = lastSegment.endsWith('.git') ? lastSegment.slice(0, -4) : lastSegment;
+
+  if (!stripped || stripped === '.' || stripped === '..' || !REPO_NAME_PATTERN.test(stripped)) {
+    throw new Error('Could not extract a valid repository name from URL');
+  }
+  return stripped;
 }
 
 /** Get the clone target directory for a repo name. */
 export function getCloneDir(repoName: string): string {
-  return path.join(os.homedir(), '.gitnexus', 'repos', repoName);
+  // Re-validate at the boundary even though extractRepoName already checked —
+  // callers may pass a repoName from another source (test fixtures, scripts).
+  if (!repoName || repoName === '.' || repoName === '..' || !REPO_NAME_PATTERN.test(repoName)) {
+    throw new Error('Invalid repository name');
+  }
+  return path.join(CLONE_ROOT, repoName);
 }
 
 // Cloud metadata hostnames that must never be reachable via user-supplied URLs
@@ -196,32 +227,200 @@ export interface CloneProgress {
   message: string;
 }
 
+/**
+ * Build the `git clone` argument list for a given URL and target directory.
+ *
+ * The `--` separator is non-negotiable: it stops git from parsing a URL that
+ * starts with `--` (e.g. `--upload-pack=evil`) as an option flag, which would
+ * otherwise execute an attacker-chosen subprocess (CodeQL
+ * js/second-order-command-line-injection, alerts #166/#167).
+ *
+ * Exported so the separator placement is testable without mocking spawn.
+ */
+export function buildCloneArgs(url: string, targetDir: string): string[] {
+  return ['clone', '--depth', '1', '--', url, targetDir];
+}
+
+/**
+ * Normalize a git URL into a comparable form.
+ *
+ * Two URLs are considered the same repository when their normalized forms
+ * are identical: lowercased hostname, no trailing `.git`, no trailing
+ * slashes on the path, default port stripped. Path comparison stays
+ * case-sensitive because that's how Git hosts treat the path component on
+ * the wire (case-folding GitHub's web UI is a separate convenience).
+ *
+ * Returns the original input if URL parsing fails — the caller can still
+ * compare with the literal string for non-URL forms (e.g. SSH `git@host:`).
+ */
+export function normalizeGitUrlForCompare(url: string): string {
+  // Strip trailing slashes and a trailing `.git` for both URL and SSH forms.
+  let trimmed = url;
+  while (trimmed.length > 0 && trimmed[trimmed.length - 1] === '/') {
+    trimmed = trimmed.slice(0, -1);
+  }
+  if (trimmed.endsWith('.git')) trimmed = trimmed.slice(0, -4);
+
+  try {
+    const parsed = new URL(trimmed);
+    parsed.hostname = parsed.hostname.toLowerCase();
+    // strip default ports
+    if (
+      (parsed.protocol === 'https:' && parsed.port === '443') ||
+      (parsed.protocol === 'http:' && parsed.port === '80')
+    ) {
+      parsed.port = '';
+    }
+    // Strip credentials — never material to repo identity, and including
+    // them would let two equivalent URLs (with/without basic auth) compare
+    // unequal.
+    parsed.username = '';
+    parsed.password = '';
+    // Recompose without trailing slash on the path.
+    let pathname = parsed.pathname;
+    while (pathname.length > 1 && pathname[pathname.length - 1] === '/') {
+      pathname = pathname.slice(0, -1);
+    }
+    parsed.pathname = pathname;
+    return `${parsed.protocol}//${parsed.hostname}${parsed.port ? ':' + parsed.port : ''}${parsed.pathname}`;
+  } catch {
+    // Non-URL forms (e.g. `git@github.com:owner/repo`) — return the trimmed
+    // form lowercased on the hostname-ish prefix. SSH-form normalization
+    // is best-effort; exact-string compare is sufficient for the threat
+    // model (mismatched origins still differ at the literal level).
+    return trimmed.toLowerCase();
+  }
+}
+
+/**
+ * Read `remote.origin.url` from an existing clone using `git config --get`.
+ *
+ * Returns `null` if the config key is absent, the spawn fails, or the
+ * directory isn't a git repository. The caller decides what a missing
+ * remote means for its threat model — for cloneOrPull, a missing remote
+ * on an existing clone is treated as a refuse-to-pull condition.
+ */
+export function getRemoteOriginUrl(cwd: string): Promise<string | null> {
+  return new Promise((resolve) => {
+    const proc = spawn('git', ['config', '--get', 'remote.origin.url'], {
+      cwd,
+      stdio: ['ignore', 'pipe', 'pipe'],
+      env: { ...process.env, GIT_TERMINAL_PROMPT: '0' },
+    });
+    let stdout = '';
+    proc.stdout.on('data', (chunk: Buffer) => {
+      stdout += chunk;
+    });
+    proc.on('close', (code) => {
+      if (code === 0 && stdout.trim()) {
+        resolve(stdout.trim());
+      } else {
+        resolve(null);
+      }
+    });
+    proc.on('error', () => resolve(null));
+  });
+}
+
+/**
+ * Verify that an existing clone's `remote.origin.url` matches the requested
+ * URL (after normalization). Throws on mismatch or missing remote.
+ *
+ * Closes the wrong-repo silent-analysis vector that Codex's adversarial
+ * review on PR #1325 surfaced: clone dirs are keyed by URL basename, so a
+ * request for `https://gitlab.example/attacker/repo.git` would otherwise
+ * collide with an existing `~/.gitnexus/repos/repo` cloned from a different
+ * origin and `git pull --ff-only` would silently succeed against the wrong
+ * remote.
+ *
+ * Exported so the comparison logic is testable in isolation against any
+ * tmpdir-based fixture, without needing to populate CLONE_ROOT.
+ */
+export async function assertRemoteMatchesRequestedUrl(
+  targetDir: string,
+  requestedUrl: string,
+): Promise<void> {
+  const remoteUrl = await getRemoteOriginUrl(targetDir);
+  if (remoteUrl === null) {
+    throw new Error(`Existing clone at ${targetDir} has no remote.origin — refusing to pull`);
+  }
+  if (normalizeGitUrlForCompare(remoteUrl) !== normalizeGitUrlForCompare(requestedUrl)) {
+    throw new Error(
+      `Existing clone at ${targetDir} has remote ${remoteUrl}, not the requested URL ${requestedUrl}`,
+    );
+  }
+}
+
 /**
  * Clone or pull a git repository.
  * If targetDir doesn't exist: git clone --depth 1
- * If targetDir exists with .git: git pull --ff-only
+ * If targetDir exists with .git: git pull --ff-only (after verifying the
+ * existing clone's remote.origin matches the requested URL).
+ *
+ * Security:
+ *   - targetDir must resolve inside CLONE_ROOT (~/.gitnexus/repos/). The
+ *     path.relative containment barrier below is the inline canonical idiom
+ *     CodeQL's js/path-injection sanitizer recognizes.
+ *   - validateGitUrl runs unconditionally on the requested URL — both the
+ *     clone path and the pull path. An earlier shape only validated on the
+ *     clone branch; an existing clone with the same basename let an
+ *     attacker's URL skip the SSRF / scheme / private-IP checks (Codex
+ *     adversarial review on PR #1325).
+ *   - When the target already has `.git`, the existing clone's
+ *     remote.origin.url is fetched and compared (normalized) to the
+ *     requested URL. Refuses to pull if they differ — this closes the
+ *     wrong-repo silent-analysis vector where two URLs sharing a basename
+ *     would collide on the same on-disk clone dir.
+ *   - The git URL is passed after a `--` separator so a value beginning with
+ *     `--` (e.g. `--upload-pack=evil`) cannot be interpreted as a git option
+ *     (CodeQL js/second-order-command-line-injection).
  */
 export async function cloneOrPull(
   url: string,
   targetDir: string,
   onProgress?: (progress: CloneProgress) => void,
 ): Promise<string> {
-  const exists = await fs.access(path.join(targetDir, '.git')).then(
+  // Containment barrier — inline with the canonical path.relative idiom so
+  // CodeQL recognizes the sanitizer at every following filesystem and
+  // subprocess sink. The same `safeTarget` is used for every downstream
+  // path operation — no reassignment that the analyzer could lose track of.
+  //
+  // Limitation: this is a lexical containment check, not a realpath check.
+  // If an attacker can place a symlink under CLONE_ROOT pointing outside it,
+  // the lexical check passes but the clone lands at the symlink target. That
+  // requires pre-existing local write access to CLONE_ROOT, so the threat
+  // model considers it out of scope; CodeQL js/path-injection accepts the
+  // lexical form. Tracked as a follow-up if defense-in-depth is needed.
+  const safeTarget = path.resolve(targetDir);
+  const rel = path.relative(CLONE_ROOT, safeTarget);
+  if (rel === '' || rel.startsWith('..') || path.isAbsolute(rel)) {
+    throw new Error(`Clone target must be a subdirectory of ${CLONE_ROOT}`);
+  }
+
+  // Always validate the requested URL — the prior shape only ran this in
+  // the clone branch, leaving the pull branch as an SSRF / blocked-host
+  // bypass when an existing clone shared the basename of an attacker URL.
+  validateGitUrl(url);
+
+  const exists = await fs.access(path.join(safeTarget, '.git')).then(
     () => true,
     () => false,
   );
 
   if (exists) {
+    // Confirm the existing clone is actually the same repository the caller
+    // requested. Without this check, a pull would silently succeed against
+    // whatever remote the dir was originally cloned from.
+    await assertRemoteMatchesRequestedUrl(safeTarget, url);
     onProgress?.({ phase: 'pulling', message: 'Pulling latest changes...' });
-    await runGit(['pull', '--ff-only'], targetDir);
+    await runGit(['pull', '--ff-only'], safeTarget);
   } else {
-    validateGitUrl(url);
-    await fs.mkdir(path.dirname(targetDir), { recursive: true });
+    await fs.mkdir(path.dirname(safeTarget), { recursive: true });
     onProgress?.({ phase: 'cloning', message: `Cloning ${url}...` });
-    await runGit(['clone', '--depth', '1', url, targetDir]);
+    await runGit(buildCloneArgs(url, safeTarget));
   }
 
-  return targetDir;
+  return safeTarget;
 }
 
 function runGit(args: string[], cwd?: string): Promise<void> {