/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2008 Isilon Inc http://www.isilon.com/ * Authors: Doug Rabson * Developed with Red Inc: Alfred Perlstein * * 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 #include #include #include #include #include #include #include #include #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 };