/*
* Decrypt the contents of a NSS_P7_EncryptedData
*/
void P12Coder::encryptedDataDecrypt(
const NSS_P7_EncryptedData &edata,
SecNssCoder &localCdr,
NSS_P12_PBE_Params *pbep, // preparsed
CSSM_DATA &ptext) // result goes here in localCdr space
{
p12DecodeLog("encryptedDataDecrypt");
/* see if we can grok the encr alg */
CSSM_ALGORITHMS keyAlg; // e.g., CSSM_ALGID_DES
CSSM_ALGORITHMS encrAlg; // e.g., CSSM_ALGID_3DES_3KEY_EDE
CSSM_ALGORITHMS pbeHashAlg; // SHA1 or MD5
uint32 keySizeInBits;
uint32 blockSizeInBytes; // for IV, optional
CSSM_PADDING padding; // CSSM_PADDING_PKCS7, etc.
CSSM_ENCRYPT_MODE mode; // CSSM_ALGMODE_CBCPadIV8, etc.
PKCS_Which pkcs;
bool found = pkcsOidToParams(&edata.contentInfo.encrAlg.algorithm,
keyAlg, encrAlg, pbeHashAlg, keySizeInBits, blockSizeInBytes,
padding, mode, pkcs);
if(!found || (pkcs != PW_PKCS12)) {
p12ErrorLog("EncryptedData encrAlg not understood\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
uint32 iterCount;
if(!p12DataToInt(pbep->iterations, iterCount)) {
p12ErrorLog("encryptedDataDecrypt: badly formed iterCount\n");
P12_THROW_DECODE;
}
const CSSM_DATA *pwd = getEncrPassPhrase();
const CSSM_KEY *passKey = getEncrPassKey();
if((pwd == NULL) && (passKey == NULL)) {
p12ErrorLog("no passphrase set\n");
CssmError::throwMe(CSSMERR_CSP_MISSING_ATTR_PASSPHRASE);
}
/* go */
CSSM_RETURN crtn = p12Decrypt(mCspHand,
edata.contentInfo.encrContent,
keyAlg, encrAlg, pbeHashAlg,
keySizeInBits, blockSizeInBytes,
padding, mode,
iterCount, pbep->salt,
pwd,
passKey,
localCdr,
ptext);
if(crtn) {
CssmError::throwMe(crtn);
}
}
/*
* Verify MAC on an existing PFX.
*/
CSSM_RETURN p12VerifyMac(
const NSS_P12_DecodedPFX &pfx,
CSSM_CSP_HANDLE cspHand,
const CSSM_DATA *pwd, // unicode, double null terminated
const CSSM_KEY *passKey,
SecNssCoder &coder) // for temp mallocs
{
if(pfx.macData == NULL) {
return CSSMERR_CSP_INVALID_SIGNATURE;
}
NSS_P12_MacData &macData = *pfx.macData;
NSS_P7_DigestInfo &digestInfo = macData.mac;
CSSM_OID &algOid = digestInfo.digestAlgorithm.algorithm;
CSSM_ALGORITHMS macAlg;
if(!cssmOidToAlg(&algOid, &macAlg)) {
return CSSMERR_CSP_INVALID_ALGORITHM;
}
uint32 iterCount = 0;
CSSM_DATA &citer = macData.iterations;
if(!p12DataToInt(citer, iterCount)) {
return CSSMERR_CSP_INVALID_ATTR_ROUNDS;
}
if(iterCount == 0) {
/* optional, default 1 */
iterCount = 1;
}
/*
* In classic fashion, the PKCS12 spec now says:
*
* When password integrity mode is used to secure a PFX PDU,
* an SHA-1 HMAC is computed on the BER-encoding of the contents
* of the content field of the authSafe field in the PFX PDU.
*
* So here we go.
*/
CSSM_DATA genMac;
CSSM_RETURN crtn = p12GenMac(cspHand, *pfx.authSafe.content.data,
macAlg, iterCount, macData.macSalt, pwd, passKey, coder, genMac);
if(crtn) {
return crtn;
}
if(nssCompareCssmData(&genMac, &digestInfo.digest)) {
return CSSM_OK;
}
else {
return CSSMERR_CSP_VERIFY_FAILED;
}
}
/*
* Generate random label string to allow associating an imported private
* key with a cert.
*/
void p12GenLabel(
CSSM_DATA &label,
SecNssCoder &coder)
{
/* first a random uint32 */
uint8 d[4];
DevRandomGenerator rng;
rng.random(d, 4);
CSSM_DATA cd = {4, d};
uint32 i;
p12DataToInt(cd, i);
/* sprintf that into a real string */
coder.allocItem(label, 9);
memset(label.Data, 0, 9);
sprintf((char *)label.Data, "%08X", (unsigned)i);
}
static int p12VerifyMac(pkcs12_context * context, const NSS_P12_DecodedPFX *pfx)
{
NSS_P12_MacData *macData = pfx->macData;
require(macData, out);
NSS_P7_DigestInfo *digestInfo = &macData->mac;
require(digestInfo, out);
SecAsn1Item *algOid = &digestInfo->digestAlgorithm.algorithm;
require(algOid, out);
/* has to be OID_OIW_SHA1 */
DERItem algOidItem = { algOid->Data, algOid->Length };
require(algOidItem.length && DEROidCompare(&oidSha1, &algOidItem), out);
uint32_t iterCount = 0;
require_noerr_quiet(p12DataToInt(&macData->iterations, &iterCount), out);
if (iterCount == 0) { /* optional, default 1 */
iterCount = 1;
}
/*
* In classic fashion, the PKCS12 spec now says:
*
* When password integrity mode is used to secure a PFX PDU,
* an SHA-1 HMAC is computed on the BER-encoding of the contents
* of the content field of the authSafe field in the PFX PDU.
*
* So here we go.
*/
uint8_t hmac_key[CC_SHA1_DIGEST_LENGTH];
require_noerr_quiet(p12_pbe_gen(context->passphrase,
macData->macSalt.Data, macData->macSalt.Length,
iterCount, PBE_ID_MAC, hmac_key, sizeof(hmac_key)), out);
/* prealloc the mac data */
SecAsn1Item verifyMac;
alloc_item(context, &verifyMac, CC_SHA1_DIGEST_LENGTH);
SecAsn1Item *ptext = pfx->authSafe.content.data;
CCHmac(kCCHmacAlgSHA1, hmac_key, CC_SHA1_DIGEST_LENGTH,
ptext->Data, ptext->Length, verifyMac.Data);
require_quiet(nssCompareSecAsn1Items(&verifyMac, &digestInfo->digest), out);
return 0;
out:
return -1;
}
static int p12Decrypt(pkcs12_context * context, const SecAsn1AlgId *algId,
const SecAsn1Item *cipherText, SecAsn1Item *plainText)
{
NSS_P12_PBE_Params pbep;
// XXX/cs not requiring decoding, but if pbep is uninit this will fail later
algIdParse(context, algId, &pbep);
CCAlgorithm alg = 0;
uint32_t keySizeInBits = 0;
uint32_t blockSizeInBytes = 0; // for IV, optional
CCOptions options = 0;
require_noerr_quiet(pkcsOidToParams(&algId->algorithm, &alg, &keySizeInBits,
&blockSizeInBytes, &options), out);
uint32_t iterCount = 0;
require_noerr(p12DataToInt(&pbep.iterations, &iterCount), out);
/* P12 style key derivation */
SecAsn1Item key = {0, NULL};
if(keySizeInBits)
alloc_item(context, &key, (keySizeInBits+7)/8);
require_noerr(p12_pbe_gen(context->passphrase, pbep.salt.Data, pbep.salt.Length,
iterCount, PBE_ID_Key, key.Data, key.Length), out);
/* P12 style IV derivation, optional */
SecAsn1Item iv = {0, NULL};
if(blockSizeInBytes) {
alloc_item(context, &iv, blockSizeInBytes);
require_noerr(p12_pbe_gen(context->passphrase, pbep.salt.Data, pbep.salt.Length,
iterCount, PBE_ID_IV, iv.Data, iv.Length), out);
}
SecAsn1Item ourPtext = {0, NULL};
alloc_item(context, &ourPtext, cipherText->Length);
require_noerr(CCCrypt(kCCDecrypt, alg, options/*kCCOptionPKCS7Padding*/,
key.Data, key.Length, iv.Data, cipherText->Data, cipherText->Length,
ourPtext.Data, ourPtext.Length, &ourPtext.Length), out);
*plainText = ourPtext;
return 0;
out:
return -1;
}
/*
* ShroudedKeyBag parser w/decrypt
*/
void P12Coder::shroudedKeyBagParse(
const NSS_P12_SafeBag &safeBag,
SecNssCoder &localCdr)
{
p12DecodeLog("Found shrouded key bag");
if(mPrivKeyImportState == PKIS_NoMore) {
CssmError::throwMe(errSecMultiplePrivKeys);
}
const NSS_P12_ShroudedKeyBag *keyBag = safeBag.bagValue.shroudedKeyBag;
const CSSM_X509_ALGORITHM_IDENTIFIER &algId = keyBag->algorithm;
NSS_P12_PBE_Params pbep;
algIdParse(algId, &pbep, localCdr);
/*
* Prepare for decryption
*/
CSSM_ALGORITHMS keyAlg; // e.g., CSSM_ALGID_DES
CSSM_ALGORITHMS encrAlg; // e.g., CSSM_ALGID_3DES_3KEY_EDE
CSSM_ALGORITHMS pbeHashAlg; // SHA1 or MD5
uint32 keySizeInBits;
uint32 blockSizeInBytes; // for IV, optional
CSSM_PADDING padding; // CSSM_PADDING_PKCS7, etc.
CSSM_ENCRYPT_MODE mode; // CSSM_ALGMODE_CBCPadIV8, etc.
PKCS_Which pkcs;
bool found = pkcsOidToParams(&algId.algorithm,
keyAlg, encrAlg, pbeHashAlg, keySizeInBits, blockSizeInBytes,
padding, mode, pkcs);
if(!found || (pkcs != PW_PKCS12)) {
p12ErrorLog("ShroudedKeyBag encrAlg not understood\n");
CssmError::throwMe(CSSMERR_CSP_INVALID_ALGORITHM);
}
uint32 iterCount;
if(!p12DataToInt(pbep.iterations, iterCount)) {
p12ErrorLog("ShroudedKeyBag: badly formed iterCount\n");
P12_THROW_DECODE;
}
const CSSM_DATA *encrPhrase = getEncrPassPhrase();
const CSSM_KEY *passKey = getEncrPassKey();
if((encrPhrase == NULL) && (passKey == NULL)) {
p12ErrorLog("no passphrase set\n");
CssmError::throwMe(CSSMERR_CSP_MISSING_ATTR_PASSPHRASE);
}
/* We'll own the actual CSSM_KEY memory */
CSSM_KEY_PTR privKey = (CSSM_KEY_PTR)mCoder.malloc(sizeof(CSSM_KEY));
memset(privKey, 0, sizeof(CSSM_KEY));
CSSM_DATA labelData;
p12GenLabel(labelData, localCdr);
CSSM_RETURN crtn = p12UnwrapKey(mCspHand,
mDlDbHand.DLHandle ? &mDlDbHand : NULL,
mImportFlags & kSecImportKeys,
keyBag->encryptedData,
keyAlg, encrAlg, pbeHashAlg,
keySizeInBits, blockSizeInBytes,
padding, mode,
iterCount, pbep.salt,
encrPhrase,
passKey,
localCdr,
labelData,
mAccess,
mNoAcl,
mKeyUsage,
mKeyAttrs,
privKey);
if(crtn) {
p12ErrorLog("Error unwrapping private key\n");
CssmError::throwMe(crtn);
}
p12DecodeLog("unwrapped shrouded key bag");
P12KeyBag *p12bag = new P12KeyBag(privKey, mCspHand,
safeBag.bagAttrs, labelData, mCoder);
addKey(p12bag);
if(mPrivKeyImportState == PKIS_AllowOne) {
mPrivKeyImportState = PKIS_NoMore;
}
}
