spkac exportPublicKey cannot distinguish between internal failure vs invalid input

[ndossche]

Version

v25.9.0

Platform

Linux 749dbb0e74fd 6.8.0-106-generic #106-Ubuntu SMP PREEMPT_DYNAMIC Fri Mar  6 07:58:08 UTC 2026 x86_64 x86_64 x86_64 GNU/Linux

Subsystem

crypto

What steps will reproduce the bug?

The following code will serve as an example to sketch the scenario:

const { Certificate } = require('crypto');
const spkacString = '...';
console.log(Certificate.exportPublicKey(spkacString));

This will hit the following code path, causing an empty string to be returned:

node/src/crypto/crypto_spkac.cc

Lines 43 to 44 in 349d226

	BIOPointer bio = ncrypto::ExportPublicKey(input.data(), input.size());
	if (!bio) return args.GetReturnValue().SetEmptyString();

Note that in the case of a valid spkac but with an internal OpenSSL failure (e.g. allocation failure), it behaves the same as an invalid spkac string. This makes distinguishing between an invalid spkac and an internal failure conditions not possible at the call site.
Furthermore, returning an empty string seems inconsistent with how other similar APIs work, e.g.:

node/src/crypto/crypto_keys.cc

Lines 141 to 143 in 349d226

	ThrowCryptoError(
	env, res.openssl_error.value_or(0), "Failed to encode public key");
	return MaybeLocal<Value>();

How often does it reproduce? Is there a required condition?

When an allocation failure happens or unspecified other type of failure happens inside OpenSSL, it will reproduce.

What is the expected behavior? Why is that the expected behavior?

I would expect an exception at least in the case of an internal OpenSSL failure. Besides that, it's unexpected that there's an inconsistency in the API design between different export functions. I'd expect the failure handling to be done in a consistent manner.

What do you see instead?

An empty string is returned. At least something to distinguish invalid spkac vs internal failure would be welcome.

Additional information

Found by an experimental static-hybrid analyzer I'm working on.