crypto.X509Certificate.toLegacyObject doesn't propagate internal OpenSSL errors

[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?

For context, consider this JavaScript code as an illustrative example:

const { X509Certificate } = require('crypto');
const fs = require('fs');
console.log((new X509Certificate(fs.readFileSync('test/fixtures/x509-escaping/alt-28-cert.pem'))).toLegacyObject());

Various values are fetched from a certificate to put into an object here:

node/src/crypto/crypto_x509.cc

Lines 774 to 794 in 6009d93

	MaybeLocal<Value> values[] = {
	GetX509NameObject(env, cert.getSubjectName()),
	GetX509NameObject(env, cert.getIssuerName()),
	GetSubjectAltNameString(env, cert),
	GetInfoAccessString(env, cert),
	Boolean::New(env->isolate(), cert.isCA()),
	Undefined(env->isolate()), // modulus
	Undefined(env->isolate()), // exponent
	Undefined(env->isolate()), // pubkey
	Undefined(env->isolate()), // bits
	GetValidFrom(env, cert),
	GetValidTo(env, cert),
	GetFingerprintDigest(env, Digest::SHA1, cert),
	GetFingerprintDigest(env, Digest::SHA256, cert),
	GetFingerprintDigest(env, Digest::SHA512, cert),
	GetKeyUsage(env, cert),
	GetSerialNumber(env, cert),
	GetDer(env, cert),
	Undefined(env->isolate()), // asn1curve
	Undefined(env->isolate()), // nistcurve
	};

Various of these functions can actually fail internally in OpenSSL, but this isn't propagated via an exception. So it is impossible to distinguish between a certificate that doesn't have a certain value or a failure.
For example, a failure somewhere in this code for example will cause the absence of the subjectaltname property of the returned object:

node/deps/ncrypto/ncrypto.cc

Lines 1086 to 1097 in 6009d93

	BIOPointer X509View::getSubjectAltName() const {
	ClearErrorOnReturn clearErrorOnReturn;
	if (cert_ == nullptr) return {};
	BIOPointer bio(BIO_new(BIO_s_mem()));
	if (!bio) return {};
	int index = X509_get_ext_by_NID(cert_, NID_subject_alt_name, -1);
	if (index < 0 ||
	!SafeX509SubjectAltNamePrint(bio, X509_get_ext(cert_, index))) {
	return {};
	}
	return bio;
	}

More specifically, our testing framework reported these concerns specifically for the following OpenSSL calls that can fail:

`OBJ_obj2nid` via `ncrypto::X509Name::Iterator::operator*[abi:cxx11]() const+0x5ad` with return value `0`
`BN_bn2hex` via `ncrypto::BignumPointer::toHex() const+0x58` with return value `0`
`ASN1_INTEGER_to_BN` via `ncrypto::X509View::getSerialNumber() const+0x180` with return value `0`
`BIO_new` via `ncrypto::X509View::getInfoAccess() const+0x14f` with return value `0`
`BIO_new` via `ncrypto::X509View::getValidFrom() const+0x14f` with return value `0`
`BIO_new` via `ncrypto::X509View::getSubjectAltName() const+0x14f` with return value `0`
`BIO_new` via `ncrypto::X509View::getValidTo() const+0x14f` with return value `0`
`X509_get_ext_by_NID` via `ncrypto::X509View::getInfoAccess() const+0x1bd` with return value `0`
`X509_get_ext_by_NID` via `ncrypto::X509View::getSubjectAltName() const+0x1bd` with return value `0`
`i2d_X509_bio` via `ncrypto::X509View::toDER() const+0x1c4` with return value `0`
`ASN1_TIME_print` via `ncrypto::X509View::getValidFrom() const+0x1cc`  with return value `0`
`ASN1_TIME_print` via `ncrypto::X509View::getValidTo() const+0x1cc`  with return value `0`

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.

What do you see instead?

The property will not be added to the object, making it impossible to detect whether a property is absent from the certificate or if there was an internal error in OpenSSL.

Additional information

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