[Bug 60486] New: crypt32: PFXExportCertStoreEx() and PFXImportCertStore() do not support ECDSA (CNG) keys

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60486

            Bug ID: 60486
           Summary: crypt32: PFXExportCertStoreEx() and
                    PFXImportCertStore() do not support ECDSA (CNG) keys
           Product: Wine
           Version: 11.19
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: crypt32
          Assignee: [e-mail]
          Reporter: [e-mail]
  Target Milestone: ---
      Distribution: ---

Exporting or importing a PFX whose private key is an ECDSA key fails.

1. Export: X509Certificate2.Export(X509ContentType.Pfx) in .NET Framework 4.8
for a
   certificate with a CNG ECDSA P-256 key crashes. PFXExportCertStoreEx()
always asks NCrypt
   for BCRYPT_RSAFULLPRIVATE_BLOB, which ends in bcrypt's RSA export code with
an EC key
   (page fault inside the RSA key accessor).

2. Import: new X509Certificate2(pfxBytes, password, flags) with an EC key fails
with
   CRYPT_E_BAD_ENCODE (0x80092002). The unix side (open_cert_store) rejects
every key that is
   not GNUTLS_PK_RSA, and the PE side only knows how to import RSA keys into a
CAPI provider.

Steps (any .NET 4.8 program, 32- or 64-bit):
  var ec = ECDsa.Create(ECCurve.NamedCurves.nistP256);
  var req = new CertificateRequest("CN=test", ec, HashAlgorithmName.SHA256);
  var cert = req.CreateSelfSigned(DateTimeOffset.Now,
DateTimeOffset.Now.AddYears(1));
  var pfx = cert.Export(X509ContentType.Pfx, "pw");                  // crash
  var back = new X509Certificate2(pfx, "pw", X509KeyStorageFlags.Exportable);
// 0x80092002
(CreateSelfSigned itself needs the ncrypt changes from bug 60443.)

A suggested patch is attached (tested on Wine 11.19, applies to master too):
- PFXExportCertStoreEx(): read NCRYPT_ALGORITHM_GROUP_PROPERTY and export
  BCRYPT_ECCPRIVATE_BLOB for ECDSA/ECDH; unix export_cert_store builds the key
with
  gnutls_x509_privkey_import_ecc_raw(GNUTLS_ECC_CURVE_SECP256R1).
- open_cert_store accepts GNUTLS_PK_ECDSA; import returns a
BCRYPT_ECCPRIVATE_BLOB built with
  gnutls_x509_privkey_export_ecc_raw().
- PFXImportCertStore(): ECC blobs are imported with
NCryptOpenStorageProvider(MS_KEY_STORAGE_PROVIDER)
  + NCryptImportKey() and attached with CERT_NCRYPT_KEY_HANDLE_PROP_ID plus a
CNG
  CERT_KEY_PROV_INFO, so HasPrivateKey is true and
CryptAcquireCertificatePrivateKey() returns
  the NCrypt handle. RSA keeps the existing CAPI path.

With it, export/import round trip and signing with the imported key work (32-
and 64-bit);
crypt32 conformance tests are unchanged.

Limitations, why this is a suggestion rather than a finished patch: P-256 only;
the
CERT_KEY_PROV_INFO names a container that does not exist (Wine has no persisted
NCrypt keys);
PKCS12_ALWAYS_CNG_KSP is still ignored; no new tests yet. Possibly related: bug
59038.

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[Bug 60486] crypt32: PFXExportCertStoreEx() and PFXImportCertStore() do not support ECDSA (CNG) keys

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60486

--- Comment #1 from [e-mail] ---
Created attachment 82338
  --> http://bugs.winehq.org/attachment.cgi?id=82338
Suggested patch (tested on Wine 11.19, not upstream-ready)

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[Bug 60486] crypt32: PFXExportCertStoreEx() and PFXImportCertStore() do not support ECDSA (CNG) keys

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60486

--- Comment #2 from Nikolay Sivov <[e-mail]> ---
Do you know which applications depend on this?

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[Bug 60486] crypt32: PFXExportCertStoreEx() and PFXImportCertStore() do not support ECDSA (CNG) keys

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60486

--- Comment #3 from [e-mail] ---
SALTO ProAccess Space 6.14 (access control server, .NET Framework 4.8). Its
service creates a
self-signed ECDSA P-256 certificate (CertificateRequest.CreateSelfSigned),
exports it as a PFX
and loads it back with new X509Certificate2(pfx, password, flags). Without the
attached changes
(and the ncrypt ones from bug 60443) the export crashes and the import fails
with 0x80092002,
and the service logs certificate errors.

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