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Support longer (up to RFC maximum) HKDF outputs.

This commit is contained in:
Fedor 2019-11-12 08:48:29 +03:00
parent 86ef42f705
commit 1bbe3e8972
1 changed files with 25 additions and 8 deletions
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33
security/nss/lib/softoken/pkcs11c.c
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@ -7668,9 +7668,11 @@ NSC_DeriveKey(CK_SESSION_HANDLE hSession,
const SECHashObject *rawHash;
unsigned hashLen;
CK_BYTE hashbuf[HASH_LENGTH_MAX];
CK_BYTE *prk; /* psuedo-random key */
CK_BYTE *prk; /* psuedo-random key */
CK_ULONG prkLen;
CK_BYTE *okm; /* output keying material */
CK_BYTE *okm; /* output keying material */
unsigned allocated_space = 0; /* If we need more work space, track it */
unsigned char *key_buf = &key_block[0];
rawHash = HASH_GetRawHashObject(hashType);
if (rawHash == NULL || rawHash->length > sizeof(hashbuf)) {
@ -7686,7 +7688,7 @@ NSC_DeriveKey(CK_SESSION_HANDLE hSession,
crv = CKR_MECHANISM_PARAM_INVALID;
break;
}
if (keySize == 0 || keySize > sizeof key_block ||
if (keySize == 0 ||
(!params->bExpand && keySize > hashLen) ||
(params->bExpand && keySize > 255 * hashLen)) {
crv = CKR_TEMPLATE_INCONSISTENT;
@ -7736,34 +7738,49 @@ NSC_DeriveKey(CK_SESSION_HANDLE hSession,
/* T(1) = HMAC-Hash(prk, "" | info | 0x01)
* T(n) = HMAC-Hash(prk, T(n-1) | info | n
* key material = T(1) | ... | T(n)
*
* If the requested output length does not fit
* within |key_block|, allocate space for expansion.
*/
HMACContext *hmac;
CK_BYTE bi;
unsigned iterations = PR_ROUNDUP(keySize, hashLen) / hashLen;
unsigned n_bytes = PR_ROUNDUP(keySize, hashLen);
unsigned iterations = n_bytes / hashLen;
hmac = HMAC_Create(rawHash, prk, prkLen, isFIPS);
if (hmac == NULL) {
crv = CKR_HOST_MEMORY;
break;
}
for (bi = 1; bi <= iterations; ++bi) {
if (n_bytes > sizeof(key_block)) {
key_buf = PORT_Alloc(n_bytes);
if (key_buf == NULL) {
crv = CKR_HOST_MEMORY;
break;
}
allocated_space = n_bytes;
}
for (bi = 1; bi <= iterations && bi > 0; ++bi) {
unsigned len;
HMAC_Begin(hmac);
if (bi > 1) {
HMAC_Update(hmac, key_block + ((bi - 2) * hashLen), hashLen);
HMAC_Update(hmac, key_buf + ((bi - 2) * hashLen), hashLen);
}
if (params->ulInfoLen != 0) {
HMAC_Update(hmac, params->pInfo, params->ulInfoLen);
}
HMAC_Update(hmac, &bi, 1);
HMAC_Finish(hmac, key_block + ((bi - 1) * hashLen), &len,
HMAC_Finish(hmac, key_buf + ((bi - 1) * hashLen), &len,
hashLen);
PORT_Assert(len == hashLen);
}
HMAC_Destroy(hmac, PR_TRUE);
okm = key_block;
okm = key_buf;
}
/* key material = prk */
crv = sftk_forceAttribute(key, CKA_VALUE, okm, keySize);
if (allocated_space) {
PORT_ZFree(key_buf, allocated_space);
}
break;
} /* end of CKM_NSS_HKDF_* */