/*
* Given a partially formed DSA public key (with no p, q, or g) and a
* CssmKey representing a supposedly fully-formed DSA key, populate
* the public key's p, g, and q with values from the fully formed key.
*/
CSSM_RETURN dsaGetParamsFromKey(
DSA *partialKey,
const CssmKey ¶mKey,
AppleCSPSession &session)
{
bool allocdKey;
DSA *dsaParamKey = cssmKeyToDsa(paramKey, session, allocdKey);
if(dsaParamKey == NULL) {
errorLog0("dsaGetParamsFromKey: bad paramKey\n");
return CSSMERR_CSP_APPLE_PUBLIC_KEY_INCOMPLETE;
}
CSSM_RETURN crtn = CSSM_OK;
/* require fully formed other key of course... */
if((dsaParamKey->p == NULL) ||
(dsaParamKey->q == NULL) ||
(dsaParamKey->g == NULL)) {
errorLog0("dsaGetParamsFromKey: incomplete paramKey\n");
crtn = CSSMERR_CSP_APPLE_PUBLIC_KEY_INCOMPLETE;
goto abort;
}
rsaMiscDebug("dsaGetParamsFromKey: partialKey %p paramKey %p",
partialKey, dsaParamKey);
partialKey->q = BN_dup(dsaParamKey->q);
partialKey->p = BN_dup(dsaParamKey->p);
partialKey->g = BN_dup(dsaParamKey->g);
abort:
if(allocdKey) {
DSA_free(dsaParamKey);
}
return crtn;
}
//
// Handle various forms of reference key. Symmetric
// keys are stored as SymmetricBinaryKey, with raw key bytes
// in keyData. Our asymmetric keys are stored as BSafeBinaryKeys,
// with an embedded ready-to-use B_KEY_OBJ.
//
void BSafe::BSafeContext::setRefKey(CssmKey &key)
{
bool isPubKey = false;
switch(key.keyClass()) {
case CSSM_KEYCLASS_SESSION_KEY:
{
assert(key.blobFormat() ==
CSSM_KEYBLOB_REF_FORMAT_INTEGER);
BinaryKey &binKey = session().lookupRefKey(key);
// fails if this is not a SymmetricBinaryKey
SymmetricBinaryKey *symBinKey =
dynamic_cast<SymmetricBinaryKey *>(&binKey);
if(symBinKey == NULL) {
errorLog0("BSafe::setRefKey(1): wrong BinaryKey subclass\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY);
}
setKeyFromCssmData(KI_Item, symBinKey->mKeyData);
return;
}
case CSSM_KEYCLASS_PUBLIC_KEY:
isPubKey = true; // and fall thru
case CSSM_KEYCLASS_PRIVATE_KEY:
{
BinaryKey &binKey = session().lookupRefKey(key);
destroyBsKey();
bsBinKey = dynamic_cast<BSafeBinaryKey *>(&binKey);
/* this cast failing means that this is some other
* kind of binary key */
if(bsBinKey == NULL) {
errorLog0("BSafe::setRefKey(2): wrong BinaryKey subclass\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY);
}
assert(bsBinKey->bsKey() != NULL);
bsKey = bsBinKey->bsKey();
if(key.algorithm() == CSSM_ALGID_RSA) {
setRsaOutSize(isPubKey);
}
return;
}
default:
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
}
static void checkExclusiveUsage(
uint32 keyUsage, // requested usage word
uint32 checkBits, // if any of these are set
uint32 otherBits, // these are the only other bits which can be set
const char *errMsg)
{
if(keyUsage & checkBits) {
if(keyUsage & ~otherBits) {
errorLog0((char *)errMsg);
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
}
}
/*
* CSPKeyInfoProvider for symmetric keys.
*/
CSPKeyInfoProvider *SymmetricKeyInfoProvider::provider(
const CssmKey &cssmKey,
AppleCSPSession &session)
{
if(cssmKey.blobType() != CSSM_KEYBLOB_RAW) {
errorLog0("KeyInfoProvider deals only with RAW keys!\n");
CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
}
if(cssmKey.keyClass() != CSSM_KEYCLASS_SESSION_KEY) {
/* that's all we need to know */
return NULL;
}
return new SymmetricKeyInfoProvider(cssmKey, session);
}
void DeriveKey_DH (
const Context &context,
const CssmData &Param, // other's public key. may be empty
CSSM_DATA *keyData, // mallocd by caller
// we fill in keyData->Length bytes
AppleCSPSession &session)
{
bool mallocdPrivKey;
size_t privSize;
/* private DH key from context - required */
DH *privKey = contextToDhKey(context, session, CSSM_ATTRIBUTE_KEY,
CSSM_KEYCLASS_PRIVATE_KEY, CSSM_KEYUSE_DERIVE, mallocdPrivKey);
if(privKey == NULL) {
CssmError::throwMe(CSSMERR_CSP_MISSING_ATTR_KEY);
}
cspDhDebug("DeriveKey_DH, privKey %p", privKey);
privSize = DH_size(privKey);
if(privSize < keyData->Length) {
/* we've been asked for more bits than this key can generate */
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEY_SIZE);
}
/*
* Public key ("their" key) can come from two places:
* -- in the context as a CSSM_ATTRIBUTE_PUBLIC_KEY. This is how
* public keys in X509 format must be used in this function
* -- in the incoming Param, the raw unformatted (PKCS3) form
*/
bool mallocdPubKey = false;
BIGNUM *pubKeyBn = NULL;
bool allocdPubKeyBn = false;
DH *pubKey = contextToDhKey(context, session, CSSM_ATTRIBUTE_PUBLIC_KEY,
CSSM_KEYCLASS_PUBLIC_KEY, CSSM_KEYUSE_DERIVE, mallocdPubKey);
if(pubKey != NULL) {
if(pubKey->pub_key == NULL) {
errorLog0("DeriveKey_DH: public key in context with no pub_key\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY);
}
pubKeyBn = pubKey->pub_key;
cspDhDebug("DeriveKey_DH, pubKey from context %p", pubKey);
}
else {
if((Param.Data == NULL) || (Param.Length == 0)) {
errorLog0("DeriveKey_DH: no pub_key, no Param\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY);
}
pubKeyBn = BN_bin2bn(Param.Data, Param.Length, NULL);
if(pubKeyBn == NULL) {
CssmError::throwMe(CSSMERR_CSP_MEMORY_ERROR);
}
allocdPubKeyBn = true;
cspDhDebug("DeriveKey_DH, no pubKey in context");
}
unsigned char *buf = (unsigned char *)session.malloc(privSize);
int rtn = DH_compute_key(buf, pubKeyBn, privKey);
if(rtn > 0) {
/*
* FIXME : I have not found a specification describing *which*
* bytes of the value we just computed we are supposed to
* use as the actual key bytes. We use the M.S. bytes.
*
* Note that due to modulo arithmetic, we may have gotten fewer
* bytes than we asked for. If so, the caller will have
* to deal with that if they really need privSize bytes.
*/
assert((uint32)rtn <= privSize);
uint32 toMove = keyData->Length;
if((uint32)rtn < toMove) {
toMove = (uint32)rtn;
}
memmove(keyData->Data, buf, toMove);
keyData->Length = toMove;
}
if(mallocdPrivKey) {
DH_free(privKey);
}
if(mallocdPubKey) {
DH_free(pubKey);
}
if(allocdPubKeyBn) {
BN_free(pubKeyBn);
}
session.free(buf);
if(rtn <= 0) {
throwRsaDsa("DH_compute_key");
}
}
/*
* Perform sanity check of incoming key attribute bits for a given
* key type, and return a cspKeyStorage value.
*
* Called from any routine which generates a new key. This specifically
* excludes WrapKey().
*/
cspKeyStorage cspParseKeyAttr(
cspKeyType keyType,
uint32 keyAttr)
{
uint32 sensitiveBit = (keyAttr & CSSM_KEYATTR_SENSITIVE) ? 1 : 0;
uint32 rtnDataBit = (keyAttr & CSSM_KEYATTR_RETURN_DATA) ? 1 : 0;
uint32 rtnRefBit = (keyAttr & CSSM_KEYATTR_RETURN_REF) ? 1 : 0;
uint32 extractBit = (keyAttr & CSSM_KEYATTR_EXTRACTABLE) ? 1 : 0;
cspKeyStorage rtn;
/* first general CDSA-wide checks */
if(keyAttr & (CSSM_KEYATTR_ALWAYS_SENSITIVE |
CSSM_KEYATTR_NEVER_EXTRACTABLE)) {
//errorLog0("ALWAYS_SENSITIVE, NEVER_EXTRACTABLE illegal at SPI\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
switch(keyAttr & KEY_ATTR_RETURN_MASK) {
/* ensure only one bit is set */
case CSSM_KEYATTR_RETURN_DATA:
rtn = CKS_Data;
break;
case CSSM_KEYATTR_RETURN_REF:
rtn = CKS_Ref;
break;
case CSSM_KEYATTR_RETURN_NONE:
rtn = CKS_None;
break;
case CSSM_KEYATTR_RETURN_DEFAULT:
/* CSP default */
rtnRefBit = 1;
rtn = CKS_Ref;
break;
default:
//errorLog0("Multiple KEYATTR_RETURN bits set\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
/* now CSP-wide checks for all key types */
if(keyType != CKT_Session) {
/* session keys modifiable, no others are */
if(keyAttr & CSSM_KEYATTR_MODIFIABLE) {
//errorLog0("CSSM_KEYATTR_MODIFIABLE not supported\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
}
if(rtnDataBit) {
if(!extractBit) {
//errorLog0("RETURN_DATA and !EXTRACTABLE not supported\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
if(sensitiveBit) {
//errorLog0("RETURN_DATA and SENSITIVE not supported\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
}
/* now check per keyType. We're ust checking for things specific
* to KEYATTR_RETURN_xxx; cspValidateKeyAttr will check other fields. */
#if 0
// nothing for now
switch(keyType) {
case CKT_Session:
break;
case MKT_Public:
break;
case MKT_Private:
if(rtnDataBit) {
errorLog0("Private keys must be generated by ref\n");
goto errorOut;
}
/*
* One more restriction - EXTRACTABLE - caller must check since
* that involves KEYUSE bits.
*/
break;
default:
CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
}
#endif // 0
/* validate other common static attributes */
cspValidateKeyAttr(keyType, (keyAttr & ~KEY_ATTR_RETURN_MASK));
return rtn;
}
/*
* Validate key usage bits for specified key type.
*/
void cspValidateKeyUsageBits (
cspKeyType keyType,
uint32 keyUsage)
{
/* general restrictions */
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_ANY,
CSSM_KEYUSE_ANY,
"CSSM_KEYUSE_ANY overload");
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_DERIVE,
CSSM_KEYUSE_DERIVE,
"CSSM_KEYUSE_DERIVE overload\n");
/* brute force per key type. */
switch(keyType) {
case CKT_Session:
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_ENCRYPT | CSSM_KEYUSE_DECRYPT,
CSSM_KEYUSE_ENCRYPT | CSSM_KEYUSE_DECRYPT,
"session key usage: encrypt/decrypt overload\n");
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_SIGN | CSSM_KEYUSE_VERIFY |
CSSM_KEYUSE_SIGN_RECOVER | CSSM_KEYUSE_VERIFY_RECOVER,
CSSM_KEYUSE_SIGN | CSSM_KEYUSE_VERIFY |
CSSM_KEYUSE_SIGN_RECOVER | CSSM_KEYUSE_VERIFY_RECOVER,
"session key usage: sign/verify overload\n");
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_WRAP | CSSM_KEYUSE_UNWRAP,
CSSM_KEYUSE_WRAP | CSSM_KEYUSE_UNWRAP,
"session key usage: wrap/unwrap overload\n");
break;
case CKT_Public:
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_ENCRYPT,
CSSM_KEYUSE_ENCRYPT,
"public key usage: encrypt overload\n");
if(keyUsage & CSSM_KEYUSE_DECRYPT) {
errorLog0("public key usage: DECRYPT illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
if(keyUsage & (CSSM_KEYUSE_SIGN | CSSM_KEYUSE_SIGN_RECOVER)) {
errorLog0("public key usage: SIGN illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_VERIFY | CSSM_KEYUSE_VERIFY_RECOVER,
CSSM_KEYUSE_VERIFY | CSSM_KEYUSE_VERIFY_RECOVER,
"public key usage: verify overload\n");
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_WRAP,
CSSM_KEYUSE_WRAP,
"public key usage: wrap overload\n");
if(keyUsage & CSSM_KEYUSE_UNWRAP) {
errorLog0("public key usage: UNWRAP illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
break;
case CKT_Private:
if(keyUsage & CSSM_KEYUSE_ENCRYPT) {
errorLog0("private key usage: ENCRYPT illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_DECRYPT,
CSSM_KEYUSE_DECRYPT,
"private key usage: decrypt overload\n");
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_SIGN | CSSM_KEYUSE_SIGN_RECOVER,
CSSM_KEYUSE_SIGN | CSSM_KEYUSE_SIGN_RECOVER,
"private key usage: sign overload\n");
if(keyUsage & (CSSM_KEYUSE_VERIFY | CSSM_KEYUSE_VERIFY_RECOVER)) {
errorLog0("private key usage: VERIFY illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
if(keyUsage & CSSM_KEYUSE_WRAP) {
errorLog0("private key usage: WRAP illegal\n");
CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEYUSAGE_MASK);
}
checkExclusiveUsage(keyUsage,
CSSM_KEYUSE_UNWRAP,
CSSM_KEYUSE_UNWRAP,
"private key usage: unwrap overload\n");
break;
default:
CssmError::throwMe(CSSMERR_CSP_INTERNAL_ERROR);
}
}
void AppleCSPSession::WrapKey(
CSSM_CC_HANDLE CCHandle,
const Context &Context,
const AccessCredentials &AccessCred,
const CssmKey &UnwrappedKey,
const CssmData *DescriptiveData,
CssmKey &WrappedKey,
CSSM_PRIVILEGE Privilege)
{
CssmKey::Header &wrappedHdr = WrappedKey.header();
bool isNullWrap = false;
CssmKey *wrappingKey = NULL;
CSSM_KEYBLOB_FORMAT wrapFormat;
switch(UnwrappedKey.keyClass()) {
case CSSM_KEYCLASS_PUBLIC_KEY:
case CSSM_KEYCLASS_PRIVATE_KEY:
case CSSM_KEYCLASS_SESSION_KEY:
break;
default:
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
/* wrapping key only required for non-NULL wrap */
wrappingKey = Context.get<CssmKey>(CSSM_ATTRIBUTE_KEY);
if(wrappingKey == NULL) {
if((Context.algorithm() == CSSM_ALGID_NONE) &&
(Context.type() == CSSM_ALGCLASS_SYMMETRIC)) {
// NULL wrap, OK
isNullWrap = true;
}
else {
errorLog0("WrapKey: missing wrapping key\n");
CssmError::throwMe(CSSMERR_CSP_MISSING_ATTR_KEY);
}
}
/*
* Validate misc. params as best we can
*/
if(isNullWrap) {
wrapFormat = CSSM_KEYBLOB_WRAPPED_FORMAT_NONE;
}
else {
/*
* Can only wrap session and private keys.
*/
#if !ALLOW_PUB_KEY_WRAP
if(UnwrappedKey.keyClass() == CSSM_KEYCLASS_PUBLIC_KEY) {
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
#endif /* ALLOW_PUB_KEY_WRAP */
cspValidateIntendedKeyUsage(&wrappingKey->KeyHeader, CSSM_KEYUSE_WRAP);
cspVerifyKeyTimes(wrappingKey->KeyHeader);
/*
* make sure wrapping key type matches context
*/
CSSM_CONTEXT_TYPE wrapType;
switch(wrappingKey->KeyHeader.KeyClass) {
case CSSM_KEYCLASS_PUBLIC_KEY:
case CSSM_KEYCLASS_PRIVATE_KEY:
wrapType = CSSM_ALGCLASS_ASYMMETRIC;
break;
case CSSM_KEYCLASS_SESSION_KEY:
wrapType = CSSM_ALGCLASS_SYMMETRIC;
break;
default:
errorLog0("WrapKey: bad class of wrappingKey\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_KEY);
}
if(wrapType != Context.type()) {
errorLog0("WrapKey: mismatch wrappingKey/contextType\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_CONTEXT);
}
if(Context.algorithm() == CSSM_ALGID_NONE) {
errorLog0("WrapKey: null wrap alg, non-null key\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
/*
* Get optional wrap format, set default per incoming keys
* Note: no such atrribute ==> 0 ==> FORMAT_NONE, which we
* take to mean "use the default".
*/
wrapFormat = Context.getInt(CSSM_ATTRIBUTE_WRAPPED_KEY_FORMAT);
if(wrapFormat == CSSM_KEYBLOB_WRAPPED_FORMAT_NONE) {
/* figure out a default based on unwrapped key */
switch(UnwrappedKey.keyClass()) {
case CSSM_KEYCLASS_SESSION_KEY:
wrapFormat = CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS7;
break;
case CSSM_KEYCLASS_PUBLIC_KEY:
wrapFormat = CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM;
break;
case CSSM_KEYCLASS_PRIVATE_KEY:
switch(UnwrappedKey.algorithm()) {
case CSSM_ALGID_FEE:
wrapFormat = CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM;
break;
default:
wrapFormat = CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS8;
break;
}
break;
default:
/* NOT REACHED - checked above */
break;
}
} /* no format present or FORMAT_NONE */
}
/* make sure we have a valid format here */
switch(wrapFormat) {
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS7:
if(UnwrappedKey.keyClass() != CSSM_KEYCLASS_SESSION_KEY) {
/* this wrapping style only for symmetric keys */
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS8:
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSL:
if(UnwrappedKey.keyClass() != CSSM_KEYCLASS_PRIVATE_KEY) {
/* these wrapping styles only for private keys */
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM:
/* no restrictions (well AES can't be the wrap alg but that will
* be caught later */
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1:
/* RSA private key, reference format, only */
if(UnwrappedKey.keyClass() != CSSM_KEYCLASS_PRIVATE_KEY) {
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
if(UnwrappedKey.algorithm() != CSSM_ALGID_RSA) {
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
if(UnwrappedKey.blobType() != CSSM_KEYBLOB_REFERENCE) {
CssmError::throwMe(CSSMERR_CSP_KEY_BLOB_TYPE_INCORRECT);
}
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_NONE:
if(isNullWrap) {
/* only time this is OK */
break;
}
/* else fall thru */
default:
dprintf1("KeyWrap: invalid wrapFormat (%d)\n", (int)wrapFormat);
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_WRAPPED_KEY_FORMAT);
}
/* get the blob to be wrappped */
CssmData rawBlob;
bool allocdRawBlob = false;
CSSM_KEYBLOB_FORMAT rawFormat;
/*
* Outgoing same as incoming unless a partial key is completed during
* generateKeyBlob()
*/
const CssmKey::Header &unwrappedHdr = UnwrappedKey.header();
CSSM_KEYATTR_FLAGS unwrappedKeyAttrFlags = unwrappedHdr.KeyAttr;
switch(UnwrappedKey.blobType()) {
case CSSM_KEYBLOB_RAW:
/*
* Trivial case - we already have the blob.
* This op - wrapping a raw key - is not supported for the
* CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1 format since that doesn't
* operate on a key blob.
*/
rawBlob = CssmData::overlay(UnwrappedKey.KeyData);
rawFormat = UnwrappedKey.blobFormat();
break;
case CSSM_KEYBLOB_REFERENCE:
/* get binary key, then get blob from it */
{
BinaryKey &binKey = lookupRefKey(UnwrappedKey);
/*
* Subsequent tests for extractability: don't trust the
* caller's header; use the one in the BinaryKey.
*/
CSSM_KEYATTR_FLAGS keyAttr = binKey.mKeyHeader.KeyAttr;
if(!(keyAttr & CSSM_KEYATTR_EXTRACTABLE)) {
/* this key not extractable in any form */
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
/*
* CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1: we're ready to roll;
* all we need is the reference key.
*/
if(wrapFormat == CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1) {
break;
}
/*
* Null wrap - prevent caller from obtaining
* clear bits if CSSM_KEYATTR_SENSITIVE
*/
if(isNullWrap && (keyAttr & CSSM_KEYATTR_SENSITIVE)) {
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
/*
* Special case for PKCS8 and openssl: need to get blob of a specific
* algorithm-dependent format. Caller can override our
* preference with a
* CSSM_ATTRIBUTE_{PRIVATE,PUBLIC,SESSION}_KEY_FORMAT
* context attribute.
*/
rawFormat = requestedKeyFormat(Context, UnwrappedKey);
if(rawFormat == CSSM_KEYBLOB_RAW_FORMAT_NONE) {
CSSM_ALGORITHMS keyAlg = binKey.mKeyHeader.AlgorithmId;
switch(wrapFormat) {
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS8:
rawFormat = pkcs8RawKeyFormat(keyAlg);
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSL:
rawFormat = opensslRawKeyFormat(keyAlg);
break;
default:
/* punt and take default for key type */
break;
}
}
/*
* DescriptiveData for encoding, currently only used for
* SSH1 keys.
*/
if((DescriptiveData != NULL) && (DescriptiveData->Length != 0)) {
binKey.descData(*DescriptiveData);
}
/* optional parameter-bearing key */
CssmKey *paramKey = Context.get<CssmKey>(CSSM_ATTRIBUTE_PARAM_KEY);
binKey.generateKeyBlob(privAllocator,
rawBlob,
rawFormat,
*this,
paramKey,
unwrappedKeyAttrFlags);
}
allocdRawBlob = true; // remember - we need to free
break;
default:
errorLog0("WrapKey: bad unwrappedKey BlobType\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY);
}
/*
* Prepare outgoing header.
*/
setKeyHeader(wrappedHdr,
plugin.myGuid(),
unwrappedHdr.algorithm(), // same as incoming
unwrappedHdr.keyClass(), // same as incoming
unwrappedKeyAttrFlags,
unwrappedHdr.KeyUsage);
wrappedHdr.LogicalKeySizeInBits = unwrappedHdr.LogicalKeySizeInBits;
wrappedHdr.WrapAlgorithmId = Context.algorithm(); // true for null
// and non-Null
wrappedHdr.StartDate = unwrappedHdr.StartDate;
wrappedHdr.EndDate = unwrappedHdr.EndDate;
wrappedHdr.Format = wrapFormat;
if(isNullWrap) {
wrappedHdr.BlobType = CSSM_KEYBLOB_RAW;
}
else {
wrappedHdr.BlobType = CSSM_KEYBLOB_WRAPPED;
}
/*
* special cases - break out here for Apple Custom and OpenSSHv1
*/
if(!isNullWrap) {
switch(wrapFormat) {
case CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM:
try {
WrapKeyCms(CCHandle,
Context,
AccessCred,
UnwrappedKey,
rawBlob,
allocdRawBlob,
DescriptiveData,
WrappedKey,
Privilege);
}
catch(...) {
if(allocdRawBlob) {
freeCssmData(rawBlob, privAllocator);
}
throw;
}
if(allocdRawBlob) {
freeCssmData(rawBlob, privAllocator);
}
return;
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1:
{
/*
* 1. We don't have to worry about allocdRawBlob since this
* operation only works on reference keys and we did not
* obtain the raw blob from the BinaryKey.
* 2. This is a redundant lookupRefKey, I know, but since
* that returns a reference, it would just be too messy to have
* the previous call be in the same scope as this.
*/
BinaryKey &binKey = lookupRefKey(UnwrappedKey);
WrapKeyOpenSSH1(CCHandle,
Context,
AccessCred,
binKey,
rawBlob,
allocdRawBlob,
DescriptiveData,
WrappedKey,
Privilege);
return;
}
default:
/* proceed to encrypt blob */
break;
}
} /* !isNullWrap */
/*
* Generate wrapped blob. Careful, we need to conditionally free
* rawBlob on error.
*/
CssmData encryptedBlob;
CssmData remData;
WrappedKey.KeyData.Data = NULL; // ignore possible incoming KeyData
WrappedKey.KeyData.Length = 0;
try {
if(isNullWrap) {
/* copy raw blob to caller's wrappedKey */
copyCssmData(rawBlob,
CssmData::overlay(WrappedKey.KeyData),
normAllocator);
wrappedHdr.Format = rawFormat;
}
else {
/* encrypt rawBlob using caller's context, then encode to
* WrappedKey.KeyData */
CSSM_SIZE bytesEncrypted;
EncryptData(CCHandle,
Context,
&rawBlob, // ClearBufs[]
1, // ClearBufCount
&encryptedBlob, // CipherBufs[],
1, // CipherBufCount,
bytesEncrypted,
remData,
Privilege);
// I'm not 100% sure about this....
assert(remData.Length == 0);
encryptedBlob.Length = bytesEncrypted;
WrappedKey.KeyData = encryptedBlob;
wrappedHdr.BlobType = CSSM_KEYBLOB_WRAPPED;
// OK to be zero or not present
wrappedHdr.WrapMode = Context.getInt(
CSSM_ATTRIBUTE_MODE);
}
}
catch (...) {
errorLog0("WrapKey: EncryptData() threw exception\n");
if(allocdRawBlob) {
freeCssmData(rawBlob, privAllocator);
}
freeCssmData(remData,normAllocator);
throw;
}
if(allocdRawBlob) {
freeCssmData(rawBlob, privAllocator);
}
freeCssmData(remData, normAllocator);
}
/*
* Unwrap key function. Used for:
*
* -- Given key of BlobType CSSM_KEYBLOB_WRAPPED, decode and decrypt
* it, yielding a key in either raw or reference format. Unwrapping
* key may be either raw or reference. The context must match
* the unwrapping key (ALGCLASS_SYMMETRIC or ALGCLASS_ASYMMETRIC).
*
* Private keys are assumed to be PKCS8 encoded; session keys
* are assumed to be PKCS7 encoded.
*
* -- Convert a Raw key to a reference key (with no decrypting).
* This is called a NULL unwrap; no unwrapping key need be present in
* the context, but the context must be of class
* ALGCLASS_SYMMETRIC and algorithm ALGID_NONE.
*/
void AppleCSPSession::UnwrapKey(
CSSM_CC_HANDLE CCHandle,
const Context &Context,
const CssmKey *PublicKey,
const CssmKey &WrappedKey,
uint32 KeyUsage,
uint32 KeyAttr,
const CssmData *KeyLabel,
const CSSM_RESOURCE_CONTROL_CONTEXT *CredAndAclEntry,
CssmKey &UnwrappedKey,
CssmData &DescriptiveData,
CSSM_PRIVILEGE Privilege)
{
bool isNullUnwrap = false;
CssmKey *unwrappingKey = NULL;
cspKeyType keyType; // CKT_Public, etc.
CSSM_KEYBLOB_FORMAT wrapFormat = WrappedKey.blobFormat();
/* obtain unwrapping key if present */
unwrappingKey = Context.get<CssmKey>(CSSM_ATTRIBUTE_KEY);
if(unwrappingKey == NULL) {
if((Context.algorithm() == CSSM_ALGID_NONE) &&
(Context.type() == CSSM_ALGCLASS_SYMMETRIC)) {
// NULL unwrap, OK
isNullUnwrap = true;
}
else {
errorLog0("UnwrapKey: missing wrapping key\n");
CssmError::throwMe(CSSMERR_CSP_MISSING_ATTR_KEY);
}
}
/*
* validate unwrappingKey
*/
if(!isNullUnwrap) {
/* make sure unwrapping key type matches context */
CSSM_CONTEXT_TYPE unwrapType;
switch(unwrappingKey->KeyHeader.KeyClass) {
case CSSM_KEYCLASS_PUBLIC_KEY:
case CSSM_KEYCLASS_PRIVATE_KEY:
unwrapType = CSSM_ALGCLASS_ASYMMETRIC;
break;
case CSSM_KEYCLASS_SESSION_KEY:
unwrapType = CSSM_ALGCLASS_SYMMETRIC;
break;
default:
errorLog0("UnwrapKey: bad class of wrappingKey\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_KEY);
}
if(unwrapType != Context.type()) {
errorLog0("UnwrapKey: mismatch unwrappingKey/contextType\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_CONTEXT);
}
if(Context.algorithm() == CSSM_ALGID_NONE) {
errorLog0("UnwrapKey: null wrap alg, non-null key\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
cspValidateIntendedKeyUsage(&unwrappingKey->KeyHeader, CSSM_KEYUSE_UNWRAP);
cspVerifyKeyTimes(unwrappingKey->KeyHeader);
}
/* validate WrappedKey */
switch(WrappedKey.keyClass()) {
case CSSM_KEYCLASS_PUBLIC_KEY:
#if !ALLOW_PUB_KEY_WRAP
if(!isNullUnwrap) {
errorLog0("UnwrapKey: unwrap of public key illegal\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
#endif /* ALLOW_PUB_KEY_WRAP */
keyType = CKT_Public;
break;
case CSSM_KEYCLASS_PRIVATE_KEY:
keyType = CKT_Private;
break;
case CSSM_KEYCLASS_SESSION_KEY:
keyType = CKT_Session;
break;
default:
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
if(isNullUnwrap) {
if(WrappedKey.blobType() != CSSM_KEYBLOB_RAW) {
errorLog0("UnwrapKey: expected raw blobType\n");
CssmError::throwMe(CSSMERR_CSP_KEY_BLOB_TYPE_INCORRECT);
}
}
else {
if(WrappedKey.blobType() != CSSM_KEYBLOB_WRAPPED) {
errorLog0("UnwrapKey: expected wrapped blobType\n");
CssmError::throwMe(CSSMERR_CSP_KEY_BLOB_TYPE_INCORRECT);
}
}
/* validate requested storage and usage */
cspKeyStorage keyStorage = cspParseKeyAttr(keyType, KeyAttr);
switch(keyStorage) {
case CKS_Ref:
case CKS_Data:
break; // OK
default:
CssmError::throwMe(CSSMERR_CSP_INVALID_KEYATTR_MASK);
}
cspValidateKeyUsageBits(keyType, KeyUsage);
/* prepare outgoing header */
CssmKey::Header &unwrappedHdr = UnwrappedKey.header();
const CssmKey::Header &wrappedHdr = WrappedKey.header();
setKeyHeader(unwrappedHdr,
plugin.myGuid(),
wrappedHdr.algorithm(), // same as incoming
wrappedHdr.keyClass(), // same as incoming
KeyAttr & ~KEY_ATTR_RETURN_MASK,
KeyUsage);
unwrappedHdr.LogicalKeySizeInBits = wrappedHdr.LogicalKeySizeInBits;
unwrappedHdr.StartDate = wrappedHdr.StartDate;
unwrappedHdr.EndDate = wrappedHdr.EndDate;
UnwrappedKey.KeyData.Data = NULL; // ignore possible incoming KeyData
UnwrappedKey.KeyData.Length = 0;
/* validate wrappedKey format */
if(!isNullUnwrap) {
switch(wrapFormat) {
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS7:
if(WrappedKey.keyClass() != CSSM_KEYCLASS_SESSION_KEY) {
/* this unwrapping style only for symmetric keys */
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS8:
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSL:
if(WrappedKey.keyClass() != CSSM_KEYCLASS_PRIVATE_KEY) {
/* these unwrapping styles only for private keys */
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_APPLE_CUSTOM:
UnwrapKeyCms(CCHandle,
Context,
WrappedKey,
CredAndAclEntry,
UnwrappedKey,
DescriptiveData,
Privilege,
keyStorage);
return;
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSH1:
/* RSA private key, unwrap to ref key only */
if(WrappedKey.keyClass() != CSSM_KEYCLASS_PRIVATE_KEY) {
CssmError::throwMe(CSSMERR_CSP_INVALID_KEY_CLASS);
}
if(WrappedKey.algorithm() != CSSM_ALGID_RSA) {
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
if(keyStorage != CKS_Ref) {
errorLog0("UNwrapKey: OPENSSH1 only wraps to reference key\n");
CssmError::throwMe(CSSMERR_CSP_KEY_BLOB_TYPE_INCORRECT);
}
UnwrapKeyOpenSSH1(CCHandle,
Context,
WrappedKey,
CredAndAclEntry,
UnwrappedKey,
DescriptiveData,
Privilege,
keyStorage);
return;
default:
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_WRAPPED_KEY_FORMAT);
}
}
/* Get key blob, decoding and decrypting if necessary */
CssmData decodedBlob;
CssmData remData;
try {
if(isNullUnwrap) {
/* simple copy of raw blob */
copyData(WrappedKey.KeyData,
UnwrappedKey.KeyData,
normAllocator);
unwrappedHdr.BlobType = CSSM_KEYBLOB_RAW;
unwrappedHdr.Format = wrapFormat;
}
else {
decodedBlob = CssmData::overlay(WrappedKey.KeyData);
CSSM_SIZE bytesDecrypted;
CssmData *unwrapData =
CssmData::overlay(&UnwrappedKey.KeyData);
DecryptData(CCHandle,
Context,
&decodedBlob, // CipherBufs[],
1, // CipherBufCount,
unwrapData, // ClearBufs[]
1, // ClearBufCount
bytesDecrypted,
remData,
Privilege);
// I'm not 100% sure about this....
assert(remData.Length == 0);
UnwrappedKey.KeyData.Length = bytesDecrypted;
unwrappedHdr.BlobType = CSSM_KEYBLOB_RAW;
/*
* Figure out various header fields from resulting blob
*/
switch(wrapFormat) {
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS7:
unwrappedHdr.Format =
CSSM_KEYBLOB_RAW_FORMAT_OCTET_STRING;
if(unwrappedHdr.LogicalKeySizeInBits == 0) {
unwrappedHdr.LogicalKeySizeInBits =
(unsigned)(bytesDecrypted * 8);
}
/* app has to infer/know algorithm */
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_PKCS8:
pkcs8InferKeyHeader(UnwrappedKey);
break;
case CSSM_KEYBLOB_WRAPPED_FORMAT_OPENSSL:
/*
* App told us key algorithm (in WrappedKey).
* Infer format and key size.
*/
opensslInferKeyHeader(UnwrappedKey);
break;
}
}
}
catch (...) {
errorLog0("UnwrapKey: DecryptData() threw exception\n");
freeCssmData(remData, normAllocator);
throw;
}
freeCssmData(remData, normAllocator);
/*
* One more thing: cook up a BinaryKey if caller wants a
* reference key.
*/
if(keyStorage == CKS_Ref) {
/*
* We have a key in raw format; convert to BinaryKey.
*/
BinaryKey *binKey = NULL;
CSPKeyInfoProvider *provider = infoProvider(UnwrappedKey);
/* optional parameter-bearing key */
CssmKey *paramKey = Context.get<CssmKey>(CSSM_ATTRIBUTE_PARAM_KEY);
provider->CssmKeyToBinary(paramKey, UnwrappedKey.KeyHeader.KeyAttr, &binKey);
addRefKey(*binKey, UnwrappedKey);
delete provider;
}
}
void AppleCSPSession::DeriveKey_PBKDF2(
const Context &context,
const CssmData &Param,
CSSM_DATA *keyData)
{
/* validate algorithm-specific arguments */
/* Param must point to a CSSM_PKCS5_PBKDF2_PARAMS */
if(Param.Length != sizeof(CSSM_PKCS5_PBKDF2_PARAMS)) {
errorLog0("DeriveKey_PBKDF2: Param wrong size\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_INPUT_POINTER);
}
const CSSM_PKCS5_PBKDF2_PARAMS *pbkdf2Params =
reinterpret_cast<const CSSM_PKCS5_PBKDF2_PARAMS *>(Param.Data);
if(pbkdf2Params == NULL) {
errorLog0("DeriveKey_PBKDF2: null Param.Data\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_DATA);
}
/* Get passphrase from either baseKey or from CSSM_PKCS5_PBKDF2_PARAMS */
CssmKey *passKey = context.get<CssmKey>(CSSM_ATTRIBUTE_KEY);
CSSM_SIZE passphraseLen = 0;
uint8 *passphrase = NULL;
if(passKey != NULL) {
AppleCSPContext::symmetricKeyBits(context, *this,
CSSM_ALGID_SECURE_PASSPHRASE, CSSM_KEYUSE_DERIVE,
passphrase, passphraseLen);
}
else {
passphraseLen = pbkdf2Params->Passphrase.Length;
passphrase = pbkdf2Params->Passphrase.Data;
}
#if !ALLOW_ZERO_PASSWORD
/* passphrase required */
if(passphrase == NULL) {
errorLog0("DeriveKey_PBKDF2: null Passphrase\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_DATA);
}
if(passphraseLen == 0) {
/* FIXME - enforce minimum length? */
errorLog0("DeriveKey_PBKDF2: zero length passphrase\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_INPUT_POINTER);
}
#endif /* ALLOW_ZERO_PASSWORD */
if(pbkdf2Params->PseudoRandomFunction !=
CSSM_PKCS5_PBKDF2_PRF_HMAC_SHA1) {
errorLog0("DeriveKey_PBKDF2: invalid PRF\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
/* salt, from context, required */
CssmData salt = context.get<CssmData>(CSSM_ATTRIBUTE_SALT,
CSSMERR_CSP_MISSING_ATTR_SALT);
if((salt.Data == NULL) || (salt.Length < PBKDF2_MIN_SALT)) {
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_SALT);
}
/* iteration count, from context, required */
uint32 iterCount = context.getInt(CSSM_ATTRIBUTE_ITERATION_COUNT,
CSSMERR_CSP_MISSING_ATTR_ITERATION_COUNT);
if(iterCount < PBKDF2_MIN_ITER_CNT) {
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_ITERATION_COUNT);
}
/*
* allocate a temp buffer, length
* = MAX (hLen, saltLen + 4) + 2 * hLen
* = MAX (kSHA1DigestSize, saltLen + 4) + 2 * kSHA1DigestSize
*/
size_t tempLen = salt.Length + 4;
if(tempLen < kSHA1DigestSize) {
tempLen = kSHA1DigestSize;
}
tempLen += (2 * kSHA1DigestSize);
CSSM_DATA tempData = {0, NULL};
setUpData(tempData, tempLen, privAllocator);
/* go */
pbkdf2 (hmacsha1,
kSHA1DigestSize,
passphrase, (uint32)passphraseLen,
salt.Data, (uint32)salt.Length,
iterCount,
keyData->Data, (uint32)keyData->Length,
tempData.Data);
freeData(&tempData, privAllocator, false);
}
/*
* PKCS5 v1.5 key derivation. Also used for traditional openssl key
* derivation, which is mighty similar to PKCS5 v1.5, with the addition
* of the ability to generate more than (keysize + ivsize) bytes.
*/
void AppleCSPSession::DeriveKey_PKCS5_V1_5(
const Context &context,
CSSM_ALGORITHMS algId,
const CssmData &Param, // IV optional, mallocd by app to indicate
// size
CSSM_DATA *keyData) // mallocd by caller to indicate size
{
CSSM_DATA pwd = {0, NULL};
/* password from either Seed.Param or from base key */
CssmCryptoData *cryptData =
context.get<CssmCryptoData>(CSSM_ATTRIBUTE_SEED);
if((cryptData != NULL) && (cryptData->Param.Length != 0)) {
pwd = cryptData->Param;
}
else {
/* Get secure passphrase from base key */
CssmKey *passKey = context.get<CssmKey>(CSSM_ATTRIBUTE_KEY);
if (passKey != NULL) {
AppleCSPContext::symmetricKeyBits(context, *this,
CSSM_ALGID_SECURE_PASSPHRASE, CSSM_KEYUSE_DERIVE,
pwd.Data, pwd.Length);
}
}
if(pwd.Data == NULL) {
errorLog0("DeriveKey_PKCS5_V1_5: null Passphrase\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_DATA);
}
if(pwd.Length == 0) {
errorLog0("DeriveKey_PKCS5_V1_5: zero length passphrase\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_INPUT_POINTER);
}
CSSM_ALGORITHMS hashAlg;
unsigned digestLen;
bool opensslAlg = false;
switch(algId) {
case CSSM_ALGID_PKCS5_PBKDF1_MD5:
hashAlg = CSSM_ALGID_MD5;
digestLen = kMD5DigestSize;
break;
case CSSM_ALGID_PKCS5_PBKDF1_MD2:
hashAlg = CSSM_ALGID_MD2;
digestLen = kMD2DigestSize;
break;
case CSSM_ALGID_PKCS5_PBKDF1_SHA1:
hashAlg = CSSM_ALGID_SHA1;
digestLen = kSHA1DigestSize;
break;
case CSSM_ALGID_PBE_OPENSSL_MD5:
hashAlg = CSSM_ALGID_MD5;
digestLen = kMD5DigestSize;
opensslAlg = true;
break;
default:
/* should not have been called */
assert(0);
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
/* IV optional */
CSSM_DATA iv = Param;
/* total requested length can't exceed digest size for struct PKCS5 v1.5*/
if(!opensslAlg && ((keyData->Length + iv.Length) > digestLen)) {
errorLog0("DeriveKey_PKCS5_V1_5: requested length larger than digest\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_KEY_LENGTH);
}
/* salt, from context, required */
CssmData salt = context.get<CssmData>(CSSM_ATTRIBUTE_SALT,
CSSMERR_CSP_MISSING_ATTR_SALT);
if(salt.Data == NULL) {
CssmError::throwMe(CSSMERR_CSP_INVALID_ATTR_SALT);
}
/* iteration count, from context, required */
uint32 iterCount = context.getInt(CSSM_ATTRIBUTE_ITERATION_COUNT,
CSSMERR_CSP_MISSING_ATTR_ITERATION_COUNT);
/*
* Apply the underlying hash function Hash for c iterations to
* the concatenation of the password P and the salt S, then
* extract the first dkLen octets to produce a derived key DK:
*
* T1 = Hash (P || S) ,
* T2 = Hash (T1) ,
* ...
* Tc = Hash (Tc-1) ,
* DK = Tc<0..dkLen-1> .
*/
DigestCtx ctx;
uint8 *keyDataP = keyData->Data;
size_t keyBytesToGo = keyData->Length;
uint8 *ivDataP = iv.Data;
size_t ivBytesToGo = iv.Length;
bool looping = false; // true for additional bytes for openssl
unsigned char digestOut[kMaxDigestSize];
for(;;) {
/* this loop guaranteed to only run once if !opensslAlg */
DigestCtxInit(&ctx, hashAlg);
if(looping) {
/* openssl addition: re-digest the digest here */
DigestCtxUpdate(&ctx, digestOut, digestLen);
}
/* digest password then salt */
DigestCtxUpdate(&ctx, pwd.Data, (uint32)pwd.Length);
DigestCtxUpdate(&ctx, salt.Data, (uint32)salt.Length);
DigestCtxFinal(&ctx, digestOut);
/* now iterCount-1 more iterations */
for(unsigned dex=1; dex<iterCount; dex++) {
DigestCtxInit(&ctx, hashAlg);
DigestCtxUpdate(&ctx, digestOut, digestLen);
DigestCtxFinal(&ctx, digestOut);
}
/* first n bytes to the key */
uint32 bytesAvail = digestLen;
size_t toMove = (keyBytesToGo > bytesAvail) ? bytesAvail : keyBytesToGo;
memmove(keyDataP, digestOut, toMove);
uint8 *remainder = digestOut + toMove;
bytesAvail -= toMove;
keyDataP += toMove;
keyBytesToGo -= toMove;
/* then optionally some to IV */
if(ivBytesToGo && bytesAvail) {
toMove = (ivBytesToGo > bytesAvail) ? bytesAvail : ivBytesToGo;
memmove(ivDataP, remainder, toMove);
ivDataP += toMove;
ivBytesToGo -= toMove;
}
if((keyBytesToGo == 0) && (ivBytesToGo == 0)) {
/* guaranteed true for PKCS5 v1.5 */
break;
}
assert(opensslAlg == true);
looping = true;
}
DigestCtxFree(&ctx);
}