/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2008 Isilon Inc http://www.isilon.com/
* Authors: Doug Rabson <dfr@rabson.org>
* Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/kobj.h>
#include <sys/mbuf.h>
#include <opencrypto/cryptodev.h>
#include <kgssapi/gssapi.h>
#include <kgssapi/gssapi_impl.h>
#include "kcrypto.h"
struct aes_state {
struct mtx as_lock;
crypto_session_t as_session_aes;
crypto_session_t as_session_sha1;
};
static void
aes_init(struct krb5_key_state *ks)
{
struct aes_state *as;
as = malloc(sizeof(struct aes_state), M_GSSAPI, M_WAITOK|M_ZERO);
mtx_init(&as->as_lock, "gss aes lock", NULL, MTX_DEF);
ks->ks_priv = as;
}
static void
aes_destroy(struct krb5_key_state *ks)
{
struct aes_state *as = ks->ks_priv;
if (as->as_session_aes != 0)
crypto_freesession(as->as_session_aes);
if (as->as_session_sha1 != 0)
crypto_freesession(as->as_session_sha1);
mtx_destroy(&as->as_lock);
free(ks->ks_priv, M_GSSAPI);
}
static void
aes_set_key(struct krb5_key_state *ks, const void *in)
{
void *kp = ks->ks_key;
struct aes_state *as = ks->ks_priv;
struct crypto_session_params csp;
if (kp != in)
bcopy(in, kp, ks->ks_class->ec_keylen);
if (as->as_session_aes != 0)
crypto_freesession(as->as_session_aes);
if (as->as_session_sha1 != 0)
crypto_freesession(as->as_session_sha1);
/*
* We only want the first 96 bits of the HMAC.
*/
memset(&csp, 0, sizeof(csp));
csp.csp_mode = CSP_MODE_DIGEST;
csp.csp_auth_alg = CRYPTO_SHA1_HMAC;
csp.csp_auth_klen = ks->ks_class->ec_keybits / 8;
csp.csp_auth_mlen = 12;
csp.csp_auth_key = ks->ks_key;
crypto_newsession(&as->as_session_sha1, &csp,
CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE);
memset(&csp, 0, sizeof(csp));
csp.csp_mode = CSP_MODE_CIPHER;
csp.csp_cipher_alg = CRYPTO_AES_CBC;
csp.csp_cipher_klen = ks->ks_class->ec_keybits / 8;
csp.csp_cipher_key = ks->ks_key;
csp.csp_ivlen = 16;
crypto_newsession(&as->as_session_aes, &csp,
CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE);
}
static void
aes_random_to_key(struct krb5_key_state *ks, const void *in)
{
aes_set_key(ks, in);
}
static int
aes_crypto_cb(struct cryptop *crp)
{
int error;
struct aes_state *as = (struct aes_state *) crp->crp_opaque;
if (CRYPTO_SESS_SYNC(crp->crp_session))
return (0);
error = crp->crp_etype;
if (error == EAGAIN)
error = crypto_dispatch(crp);
mtx_lock(&as->as_lock);
if (error || (crp->crp_flags & CRYPTO_F_DONE))
wakeup(crp);
mtx_unlock(&as->as_lock);
return (0);
}
static void
aes_encrypt_1(const struct krb5_key_state *ks, int buftype, void *buf,
size_t skip, size_t len, void *ivec, bool encrypt)
{
struct aes_state *as = ks->ks_priv;
struct cryptop *crp;
int error;
crp = crypto_getreq(as->as_session_aes, M_WAITOK);
crp->crp_payload_start = skip;
crp->crp_payload_length = len;
crp->crp_op = encrypt ? CRYPTO_OP_ENCRYPT : CRYPTO_OP_DECRYPT;
crp->crp_flags = CRYPTO_F_CBIFSYNC | CRYPTO_F_IV_SEPARATE;
if (ivec) {
memcpy(crp->crp_iv, ivec, 16);
} else {
memset(crp->crp_iv, 0, 16);
}
if (buftype == CRYPTO_BUF_MBUF)
crypto_use_mbuf(crp, buf);
else
crypto_use_buf(crp, buf, skip + len);
crp->crp_opaque = as;
crp->crp_callback = aes_crypto_cb;
error = crypto_dispatch(crp);
if (!CRYPTO_SESS_SYNC(as->as_session_aes)) {
mtx_lock(&as->as_lock);
if (!error && !(crp->crp_flags & CRYPTO_F_DONE))
error = msleep(crp, &as->as_lock, 0, "gssaes", 0);
mtx_unlock(&as->as_lock);
}
crypto_freereq(crp);
}
static void
aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout,
size_t skip, size_t len, void *ivec, size_t ivlen)
{
size_t blocklen = 16, plen;
struct {
uint8_t cn_1[16], cn[16];
} last2;
int i, off;
/*
* AES encryption with cyphertext stealing:
*
* CTSencrypt(P[0], ..., P[n], IV, K):
* len = length(P[n])
* (C[0], ..., C[n-2], E[n-1]) =
* CBCencrypt(P[0], ..., P[n-1], IV, K)
* P = pad(P[n], 0, blocksize)
* E[n] = CBCencrypt(P, E[n-1], K);
* C[n-1] = E[n]
* C[n] = E[n-1]{0..len-1}
*/
plen = len % blocklen;
if (len == blocklen) {
/*
* Note: caller will ensure len >= blocklen.
*/
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec,
true);
} else if (plen == 0) {
/*
* This is equivalent to CBC mode followed by swapping
* the last two blocks. We assume that neither of the
* last two blocks cross iov boundaries.
*/
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec,
true);
off = skip + len - 2 * blocklen;
m_copydata(inout, off, 2 * blocklen, (void*) &last2);
m_copyback(inout, off, blocklen, last2.cn);
m_copyback(inout, off + blocklen, blocklen, last2.cn_1);
} else {
/*
* This is the difficult case. We encrypt all but the
* last partial block first. We then create a padded
* copy of the last block and encrypt that using the
* second to last encrypted block as IV. Once we have
* the encrypted versions of the last two blocks, we
* reshuffle to create the final result.
*/
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen,
ivec, true);
/*
* Copy out the last two blocks, pad the last block
* and encrypt it. Rearrange to get the final
* result. The cyphertext for cn_1 is in cn. The
* cyphertext for cn is the first plen bytes of what
* is in cn_1 now.
*/
off = skip + len - blocklen - plen;
m_copydata(inout, off, blocklen + plen, (void*) &last2);
for (i = plen; i < blocklen; i++)
last2.cn[i] = 0;
aes_encrypt_1(ks, CRYPTO_BUF_CONTIG, last2.cn, 0, blocklen,
last2.cn_1, true);
m_copyback(inout, off, blocklen, last2.cn);
m_copyback(inout, off + blocklen, plen, last2.cn_1);
}
}
static void
aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout,
size_t skip, size_t len, void *ivec, size_t ivlen)
{
size_t blocklen = 16, plen;
struct {
uint8_t cn_1[16], cn[16];
} last2;
int i, off, t;
/*
* AES decryption with cyphertext stealing:
*
* CTSencrypt(C[0], ..., C[n], IV, K):
* len = length(C[n])
* E[n] = C[n-1]
* X = decrypt(E[n], K)
* P[n] = (X ^ C[n]){0..len-1}
* E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]}
* (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K)
*/
plen = len % blocklen;
if (len == blocklen) {
/*
* Note: caller will ensure len >= blocklen.
*/
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec,
false);
} else if (plen == 0) {
/*
* This is equivalent to CBC mode followed by swapping
* the last two blocks.
*/
off = skip + len - 2 * blocklen;
m_copydata(inout, off, 2 * blocklen, (void*) &last2);
m_copyback(inout, off, blocklen, last2.cn);
m_copyback(inout, off + blocklen, blocklen, last2.cn_1);
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec,
false);
} else {
/*
* This is the difficult case. We first decrypt the
* second to last block with a zero IV to make X. The
* plaintext for the last block is the XOR of X and
* the last cyphertext block.
*
* We derive a new cypher text for the second to last
* block by mixing the unused bytes of X with the last
* cyphertext block. The result of that can be
* decrypted with the rest in CBC mode.
*/
off = skip + len - plen - blocklen;
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, off, blocklen,
NULL, false);
m_copydata(inout, off, blocklen + plen, (void*) &last2);
for (i = 0; i < plen; i++) {
t = last2.cn[i];
last2.cn[i] ^= last2.cn_1[i];
last2.cn_1[i] = t;
}
m_copyback(inout, off, blocklen + plen, (void*) &last2);
aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen,
ivec, false);
}
}
static void
aes_checksum(const struct krb5_key_state *ks, int usage,
struct mbuf *inout, size_t skip, size_t inlen, size_t outlen)
{
struct aes_state *as = ks->ks_priv;
struct cryptop *crp;
int error;
crp = crypto_getreq(as->as_session_sha1, M_WAITOK);
crp->crp_payload_start = skip;
crp->crp_payload_length = inlen;
crp->crp_digest_start = skip + inlen;
crp->crp_flags = CRYPTO_F_CBIFSYNC;
crypto_use_mbuf(crp, inout);
crp->crp_opaque = as;
crp->crp_callback = aes_crypto_cb;
error = crypto_dispatch(crp);
if (!CRYPTO_SESS_SYNC(as->as_session_sha1)) {
mtx_lock(&as->as_lock);
if (!error && !(crp->crp_flags & CRYPTO_F_DONE))
error = msleep(crp, &as->as_lock, 0, "gssaes", 0);
mtx_unlock(&as->as_lock);
}
crypto_freereq(crp);
}
struct krb5_encryption_class krb5_aes128_encryption_class = {
"aes128-cts-hmac-sha1-96", /* name */
ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */
EC_DERIVED_KEYS, /* flags */
16, /* blocklen */
1, /* msgblocklen */
12, /* checksumlen */
128, /* keybits */
16, /* keylen */
aes_init,
aes_destroy,
aes_set_key,
aes_random_to_key,
aes_encrypt,
aes_decrypt,
aes_checksum
};
struct krb5_encryption_class krb5_aes256_encryption_class = {
"aes256-cts-hmac-sha1-96", /* name */
ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */
EC_DERIVED_KEYS, /* flags */
16, /* blocklen */
1, /* msgblocklen */
12, /* checksumlen */
256, /* keybits */
32, /* keylen */
aes_init,
aes_destroy,
aes_set_key,
aes_random_to_key,
aes_encrypt,
aes_decrypt,
aes_checksum
};
