/// <summary>
/// Checks the hashes and signatures for this PKG.
/// </summary>
/// <returns>Returns a list of failed hashes. If the list is empty then the PKG is valid.</returns>
public List <string> Validate(Stream pkgStream)
{
var errors = new List <string>();
Action <string> onError = e => { errors.Add(e); errorHandler?.Invoke(e); };
// Check general digests
var generalDigests = pkg_.CalcGeneralDigests();
foreach (var d in generalDigests)
{
if (!d.Value.SequenceEqual(pkg_.GeneralDigests.Digests[d.Key]))
{
onError(d.Key.ToString());
}
}
// Check PFS Signed digest
var pfsSignedDigest = Crypto.Sha256(pkgStream, (long)pkg_.Header.pfs_image_offset, 0x10000);
if (!pfsSignedDigest.SequenceEqual(pkg_.Header.pfs_signed_digest))
{
onError(nameof(pkg_.Header.pfs_signed_digest));
}
// Check PFS Image digest
var pfsImageDigest = Crypto.Sha256(pkgStream, (long)pkg_.Header.pfs_image_offset, (long)pkg_.Header.pfs_image_size);
if (!pfsImageDigest.SequenceEqual(pkg_.Header.pfs_image_digest))
{
onError(nameof(pkg_.Header.pfs_image_digest));
}
return(errors);
}
/// <summary>
/// Computes the final digests and writes them to the PKG
/// </summary>
/// <param name="pkgStream">PKG file stream</param>
private void FinishPkg(Stream pkgStream)
{
Logger("Calculating SHA256 of finished outer PFS...");
// Set PFS Image 1st block and full SHA256 hashes (mount image)
pkg.Header.pfs_signed_digest = Crypto.Sha256(pkgStream, (long)pkg.Header.pfs_image_offset, 0x10000);
pkg.Header.pfs_image_digest = Crypto.Sha256(pkgStream, (long)pkg.Header.pfs_image_offset, (long)pkg.Header.pfs_image_size);
foreach (var a in pkg.CalcGeneralDigests())
{
pkg.GeneralDigests.Set(a.Key, a.Value);
}
// Write body now because it will make calculating hashes easier.
var writer = new PkgWriter(pkgStream);
writer.WriteBody(pkg, project.ContentId, project.Passcode);
CalcBodyDigests(pkg, pkgStream);
// Now write header
pkgStream.Position = 0;
writer.WriteHeader(pkg.Header);
// Final Pkg digest and signature
pkg.HeaderDigest = Crypto.Sha256(pkgStream, 0, 0xFE0);
pkgStream.Position = 0xFE0;
pkgStream.Write(pkg.HeaderDigest, 0, pkg.HeaderDigest.Length);
byte[] header_sha256 = Crypto.Sha256(pkgStream, 0, 0x1000);
pkgStream.Position = 0x1000;
pkgStream.Write(pkg.HeaderSignature = Crypto.RSA2048EncryptKey(Keys.PkgSignKey, header_sha256), 0, 256);
}