fix(coding-agent): harden git package install paths

packages/coding-agent/src/core/package-manager.ts

@@ -1952,10 +1952,11 @@ export class DefaultPackageManager implements PackageManager {
 		if (scope === "temporary") {
 			return this.getTemporaryDir(`git-${source.host}`, source.path);
 		}
-		if (scope === "project") {
-			return join(this.cwd, CONFIG_DIR_NAME, "git", source.host, source.path);
+		const installRoot = this.getGitInstallRoot(scope);
+		if (!installRoot) {
+			throw new Error("Missing git install root");
 		}
-		return join(this.agentDir, "git", source.host, source.path);
+		return this.resolveManagedPath(installRoot, source.host, source.path);
 	}
 
 	private getGitInstallRoot(scope: SourceScope): string | undefined {
@@ -1969,11 +1970,21 @@ export class DefaultPackageManager implements PackageManager {
 	}
 
 	private getTemporaryDir(prefix: string, suffix?: string): string {
+		const root = this.resolveManagedPath(join(tmpdir(), "pi-extensions"), prefix);
 		const hash = createHash("sha256")
 			.update(`${prefix}-${suffix ?? ""}`)
 			.digest("hex")
 			.slice(0, 8);
-		return join(tmpdir(), "pi-extensions", prefix, hash, suffix ?? "");
+		return this.resolveManagedPath(root, hash, suffix ?? "");
+	}
+
+	private resolveManagedPath(root: string, ...parts: string[]): string {
+		const resolvedRoot = resolve(root);
+		const resolvedPath = resolve(resolvedRoot, ...parts);
+		if (resolvedPath !== resolvedRoot && !resolvedPath.startsWith(`${resolvedRoot}${sep}`)) {
+			throw new Error(`Refusing to use path outside package install root: ${resolvedPath}`);
+		}
+		return resolvedPath;
 	}
 
 	private getBaseDirForScope(scope: SourceScope): string {

packages/coding-agent/src/utils/git.ts

@@ -73,6 +73,56 @@ function splitRef(url: string): { repo: string; ref?: string } {
 	};
 }
 
+function decodeForValidation(value: string): string | null {
+	try {
+		return decodeURIComponent(value);
+	} catch {
+		return null;
+	}
+}
+
+function hasUnsafeGitInstallPart(value: string, allowSlash: boolean): boolean {
+	const decoded = decodeForValidation(value);
+	if (decoded === null) {
+		return true;
+	}
+	const candidates = [value, decoded];
+	for (const candidate of candidates) {
+		if (candidate.includes("\0") || candidate.includes("\\") || candidate.startsWith("/")) {
+			return true;
+		}
+		if (!allowSlash && candidate.includes("/")) {
+			return true;
+		}
+		if (candidate.split("/").includes("..")) {
+			return true;
+		}
+	}
+	return false;
+}
+
+function buildGitSource(args: { repo: string; host: string; path: string; ref?: string }): GitSource | null {
+	if (args.path.startsWith("/")) {
+		return null;
+	}
+	const normalizedPath = args.path.replace(/\.git$/, "").replace(/^\/+/, "");
+	if (!args.host || !normalizedPath || normalizedPath.split("/").length < 2) {
+		return null;
+	}
+	if (hasUnsafeGitInstallPart(args.host, false) || hasUnsafeGitInstallPart(normalizedPath, true)) {
+		return null;
+	}
+
+	return {
+		type: "git",
+		repo: args.repo,
+		host: args.host,
+		path: normalizedPath,
+		ref: args.ref,
+		pinned: Boolean(args.ref),
+	};
+}
+
 function parseGenericGitUrl(url: string): GitSource | null {
 	const { repo: repoWithoutRef, ref } = splitRef(url);
 	let repo = repoWithoutRef;
@@ -109,19 +159,7 @@ function parseGenericGitUrl(url: string): GitSource | null {
 		repo = `https://${repoWithoutRef}`;
 	}
 
-	const normalizedPath = path.replace(/\.git$/, "").replace(/^\/+/, "");
-	if (!host || !normalizedPath || normalizedPath.split("/").length < 2) {
-		return null;
-	}
-
-	return {
-		type: "git",
-		repo,
-		host,
-		path: normalizedPath,
-		ref,
-		pinned: Boolean(ref),
-	};
+	return buildGitSource({ repo, host, path, ref });
 }
 
 /**
@@ -157,14 +195,12 @@ export function parseGitUrl(source: string): GitSource | null {
 				!split.repo.startsWith("ssh://") &&
 				!split.repo.startsWith("git://") &&
 				!split.repo.startsWith("git@");
-			return {
-				type: "git",
+			return buildGitSource({
 				repo: useHttpsPrefix ? `https://${split.repo}` : split.repo,
 				host: info.domain || "",
-				path: `${info.user}/${info.project}`.replace(/\.git$/, ""),
+				path: `${info.user}/${info.project}`,
 				ref: info.committish || split.ref || undefined,
-				pinned: Boolean(info.committish || split.ref),
-			};
+			});
 		}
 	}
 
@@ -177,14 +213,12 @@ export function parseGitUrl(source: string): GitSource | null {
 			if (split.ref && info.project?.includes("@")) {
 				continue;
 			}
-			return {
-				type: "git",
+			return buildGitSource({
 				repo: `https://${split.repo}`,
 				host: info.domain || "",
-				path: `${info.user}/${info.project}`.replace(/\.git$/, ""),
+				path: `${info.user}/${info.project}`,
 				ref: info.committish || split.ref || undefined,
-				pinned: Boolean(info.committish || split.ref),
-			};
+			});
 		}
 	}