fix(ci): bound the release evidence subprocess capture

scripts/verify-release-evidence.test.ts

@@ -1,4 +1,5 @@
 import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
 import { describe, it } from "node:test";
 
 import {
@@ -164,6 +165,18 @@ void describe("release evidence manifest", () => {
 	});
 });
 
+void describe("subprocess capture", () => {
+	void it("bounds every captured subprocess above Node's 1 MiB default", () => {
+		// A cosign attestation carries the whole SPDX SBOM base64-encoded. Under the default cap the
+		// capture raises ENOBUFS, which failed a release after the images were already tagged.
+		const source = readFileSync(new URL("./verify-release-evidence.ts", import.meta.url), "utf8");
+		assert.match(source, /maxBuffer: CAPTURE_LIMIT_BYTES/);
+		const limit = /const CAPTURE_LIMIT_BYTES = (\d+) \* 1024 \* 1024;/.exec(source);
+		assert.ok(limit, "CAPTURE_LIMIT_BYTES must be declared in MiB");
+		assert.ok(Number(limit[1]) >= 64, "an SBOM attestation needs far more than the 1 MiB default");
+	});
+});
+
 void describe("release evidence bindings", () => {
 	void it("binds license and OCI index evidence to the immutable subject", () => {
 		const amd64 = subject("linux/amd64");

scripts/verify-release-evidence.ts

@@ -182,10 +182,19 @@ export function validateManifest(
 	return { schemaVersion: 1, subjects };
 }
 
+/**
+ * Node caps a captured subprocess at 1 MiB and raises ENOBUFS past it. A `cosign verify-attestation`
+ * envelope carries the whole SPDX SBOM base64-encoded, so the webapp's exceeds that cap and failed a
+ * release mid-verification. The bound belongs here rather than at a call site: every capture in this
+ * file reads an SBOM, an attestation or an image index, and none of them has a useful size limit.
+ */
+const CAPTURE_LIMIT_BYTES = 256 * 1024 * 1024;
+
 function command(commandName: string, args: string[], capture = false): string {
 	const result = spawnSync(commandName, args, {
 		encoding: "utf8",
 		stdio: capture ? "pipe" : "inherit",
+		maxBuffer: CAPTURE_LIMIT_BYTES,
 	});
 	if (result.error) throw result.error;
 	if (result.status !== 0) {