//
// Encode a key blob
//
KeyBlob *DatabaseCryptoCore::encodeKeyCore(const CssmKey &inKey,
const CssmData &publicAcl, const CssmData &privateAcl,
bool inTheClear) const
{
CssmKey key = inKey;
uint8 iv[8];
CssmKey wrappedKey;
if(inTheClear && (privateAcl.Length != 0)) {
/* can't store private ACL component in the clear */
CssmError::throwMe(CSSMERR_DL_INVALID_ACCESS_CREDENTIALS);
}
// extract and hold some header bits the CSP does not want to see
uint32 heldAttributes = key.attributes() & managedAttributes;
key.clearAttribute(managedAttributes);
key.setAttribute(forcedAttributes);
if(inTheClear) {
/* NULL wrap of public key */
WrapKey wrap(Server::csp(), CSSM_ALGID_NONE);
wrap(key, wrappedKey, NULL);
}
else {
assert(isValid()); // need our database secrets
// create new IV
Server::active().random(iv);
// use a CMS wrap to encrypt the key
WrapKey wrap(Server::csp(), CSSM_ALGID_3DES_3KEY_EDE);
wrap.key(mEncryptionKey);
wrap.mode(CSSM_ALGMODE_CBCPadIV8);
wrap.padding(CSSM_PADDING_PKCS1);
CssmData ivd(iv, sizeof(iv)); wrap.initVector(ivd);
wrap.add(CSSM_ATTRIBUTE_WRAPPED_KEY_FORMAT,
uint32(CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM));
wrap(key, wrappedKey, &privateAcl);
}
// stick the held attribute bits back in
key.clearAttribute(forcedAttributes);
key.setAttribute(heldAttributes);
// allocate the final KeyBlob, uh, blob
size_t length = sizeof(KeyBlob) + publicAcl.length() + wrappedKey.length();
KeyBlob *blob = Allocator::standard().malloc<KeyBlob>(length);
// assemble the KeyBlob
memset(blob, 0, sizeof(KeyBlob)); // fill alignment gaps
blob->initialize();
if(!inTheClear) {
memcpy(blob->iv, iv, sizeof(iv));
}
blob->header = key.header();
h2ni(blob->header); // endian-correct the header
blob->wrappedHeader.blobType = wrappedKey.blobType();
blob->wrappedHeader.blobFormat = wrappedKey.blobFormat();
blob->wrappedHeader.wrapAlgorithm = wrappedKey.wrapAlgorithm();
blob->wrappedHeader.wrapMode = wrappedKey.wrapMode();
memcpy(blob->publicAclBlob(), publicAcl, publicAcl.length());
blob->startCryptoBlob = sizeof(KeyBlob) + publicAcl.length();
memcpy(blob->cryptoBlob(), wrappedKey.data(), wrappedKey.length());
blob->totalLength = blob->startCryptoBlob + wrappedKey.length();
if(inTheClear) {
/* indicate that this is cleartext for decoding */
blob->setClearTextSignature();
}
else {
// sign the blob
CssmData signChunk[] = {
CssmData(blob->data(), fieldOffsetOf(&KeyBlob::blobSignature)),
CssmData(blob->publicAclBlob(), blob->publicAclBlobLength() + blob->cryptoBlobLength())
};
CssmData signature(blob->blobSignature, sizeof(blob->blobSignature));
GenerateMac signer(Server::csp(), CSSM_ALGID_SHA1HMAC_LEGACY); //@@@!!! CRUD
signer.key(mSigningKey);
signer.sign(signChunk, 2, signature);
assert(signature.length() == sizeof(blob->blobSignature));
}
// all done. Clean up
Server::csp()->allocator().free(wrappedKey);
return blob;
}
