diff options
Diffstat (limited to 'crypto/krb5/rfc3961_simplified.c')
| -rw-r--r-- | crypto/krb5/rfc3961_simplified.c | 792 |
1 files changed, 792 insertions, 0 deletions
diff --git a/crypto/krb5/rfc3961_simplified.c b/crypto/krb5/rfc3961_simplified.c new file mode 100644 index 000000000000..79180d28baa9 --- /dev/null +++ b/crypto/krb5/rfc3961_simplified.c @@ -0,0 +1,792 @@ +// SPDX-License-Identifier: BSD-3-Clause +/* rfc3961 Kerberos 5 simplified crypto profile. + * + * Parts borrowed from net/sunrpc/auth_gss/. + */ +/* + * COPYRIGHT (c) 2008 + * The Regents of the University of Michigan + * ALL RIGHTS RESERVED + * + * Permission is granted to use, copy, create derivative works + * and redistribute this software and such derivative works + * for any purpose, so long as the name of The University of + * Michigan is not used in any advertising or publicity + * pertaining to the use of distribution of this software + * without specific, written prior authorization. If the + * above copyright notice or any other identification of the + * University of Michigan is included in any copy of any + * portion of this software, then the disclaimer below must + * also be included. + * + * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION + * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY + * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF + * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING + * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE + * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE + * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR + * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING + * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN + * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGES. + */ + +/* + * Copyright (C) 1998 by the FundsXpress, INC. + * + * All rights reserved. + * + * Export of this software from the United States of America may require + * a specific license from the United States Government. It is the + * responsibility of any person or organization contemplating export to + * obtain such a license before exporting. + * + * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and + * distribute this software and its documentation for any purpose and + * without fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright notice and + * this permission notice appear in supporting documentation, and that + * the name of FundsXpress. not be used in advertising or publicity pertaining + * to distribution of the software without specific, written prior + * permission. FundsXpress makes no representations about the suitability of + * this software for any purpose. It is provided "as is" without express + * or implied warranty. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED + * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. + */ + +/* + * Copyright (C) 2025 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/random.h> +#include <linux/scatterlist.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <linux/lcm.h> +#include <linux/rtnetlink.h> +#include <crypto/authenc.h> +#include <crypto/skcipher.h> +#include <crypto/hash.h> +#include "internal.h" + +/* Maximum blocksize for the supported crypto algorithms */ +#define KRB5_MAX_BLOCKSIZE (16) + +int crypto_shash_update_sg(struct shash_desc *desc, struct scatterlist *sg, + size_t offset, size_t len) +{ + struct sg_mapping_iter miter; + size_t i, n; + int ret = 0; + + sg_miter_start(&miter, sg, sg_nents(sg), + SG_MITER_FROM_SG | SG_MITER_LOCAL); + for (i = 0; i < len; i += n) { + sg_miter_next(&miter); + n = min(miter.length, len - i); + ret = crypto_shash_update(desc, miter.addr, n); + if (ret < 0) + break; + } + sg_miter_stop(&miter); + return ret; +} + +static int rfc3961_do_encrypt(struct crypto_sync_skcipher *tfm, void *iv, + const struct krb5_buffer *in, struct krb5_buffer *out) +{ + struct scatterlist sg[1]; + u8 local_iv[KRB5_MAX_BLOCKSIZE] __aligned(KRB5_MAX_BLOCKSIZE) = {0}; + SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm); + int ret; + + if (WARN_ON(in->len != out->len)) + return -EINVAL; + if (out->len % crypto_sync_skcipher_blocksize(tfm) != 0) + return -EINVAL; + + if (crypto_sync_skcipher_ivsize(tfm) > KRB5_MAX_BLOCKSIZE) + return -EINVAL; + + if (iv) + memcpy(local_iv, iv, crypto_sync_skcipher_ivsize(tfm)); + + memcpy(out->data, in->data, out->len); + sg_init_one(sg, out->data, out->len); + + skcipher_request_set_sync_tfm(req, tfm); + skcipher_request_set_callback(req, 0, NULL, NULL); + skcipher_request_set_crypt(req, sg, sg, out->len, local_iv); + + ret = crypto_skcipher_encrypt(req); + skcipher_request_zero(req); + return ret; +} + +/* + * Calculate an unkeyed basic hash. + */ +static int rfc3961_calc_H(const struct krb5_enctype *krb5, + const struct krb5_buffer *data, + struct krb5_buffer *digest, + gfp_t gfp) +{ + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t desc_size; + int ret = -ENOMEM; + + tfm = crypto_alloc_shash(krb5->hash_name, 0, 0); + if (IS_ERR(tfm)) + return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm); + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + + desc = kzalloc(desc_size, gfp); + if (!desc) + goto error_tfm; + + digest->len = crypto_shash_digestsize(tfm); + digest->data = kzalloc(digest->len, gfp); + if (!digest->data) + goto error_desc; + + desc->tfm = tfm; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error_digest; + + ret = crypto_shash_finup(desc, data->data, data->len, digest->data); + if (ret < 0) + goto error_digest; + + goto error_desc; + +error_digest: + kfree_sensitive(digest->data); +error_desc: + kfree_sensitive(desc); +error_tfm: + crypto_free_shash(tfm); + return ret; +} + +/* + * This is the n-fold function as described in rfc3961, sec 5.1 + * Taken from MIT Kerberos and modified. + */ +static void rfc3961_nfold(const struct krb5_buffer *source, struct krb5_buffer *result) +{ + const u8 *in = source->data; + u8 *out = result->data; + unsigned long ulcm; + unsigned int inbits, outbits; + int byte, i, msbit; + + /* the code below is more readable if I make these bytes instead of bits */ + inbits = source->len; + outbits = result->len; + + /* first compute lcm(n,k) */ + ulcm = lcm(inbits, outbits); + + /* now do the real work */ + memset(out, 0, outbits); + byte = 0; + + /* this will end up cycling through k lcm(k,n)/k times, which + * is correct. + */ + for (i = ulcm-1; i >= 0; i--) { + /* compute the msbit in k which gets added into this byte */ + msbit = ( + /* first, start with the msbit in the first, + * unrotated byte + */ + ((inbits << 3) - 1) + + /* then, for each byte, shift to the right + * for each repetition + */ + (((inbits << 3) + 13) * (i/inbits)) + + /* last, pick out the correct byte within + * that shifted repetition + */ + ((inbits - (i % inbits)) << 3) + ) % (inbits << 3); + + /* pull out the byte value itself */ + byte += (((in[((inbits - 1) - (msbit >> 3)) % inbits] << 8) | + (in[((inbits) - (msbit >> 3)) % inbits])) + >> ((msbit & 7) + 1)) & 0xff; + + /* do the addition */ + byte += out[i % outbits]; + out[i % outbits] = byte & 0xff; + + /* keep around the carry bit, if any */ + byte >>= 8; + } + + /* if there's a carry bit left over, add it back in */ + if (byte) { + for (i = outbits - 1; i >= 0; i--) { + /* do the addition */ + byte += out[i]; + out[i] = byte & 0xff; + + /* keep around the carry bit, if any */ + byte >>= 8; + } + } +} + +/* + * Calculate a derived key, DK(Base Key, Well-Known Constant) + * + * DK(Key, Constant) = random-to-key(DR(Key, Constant)) + * DR(Key, Constant) = k-truncate(E(Key, Constant, initial-cipher-state)) + * K1 = E(Key, n-fold(Constant), initial-cipher-state) + * K2 = E(Key, K1, initial-cipher-state) + * K3 = E(Key, K2, initial-cipher-state) + * K4 = ... + * DR(Key, Constant) = k-truncate(K1 | K2 | K3 | K4 ...) + * [rfc3961 sec 5.1] + */ +static int rfc3961_calc_DK(const struct krb5_enctype *krb5, + const struct krb5_buffer *inkey, + const struct krb5_buffer *in_constant, + struct krb5_buffer *result, + gfp_t gfp) +{ + unsigned int blocksize, keybytes, keylength, n; + struct krb5_buffer inblock, outblock, rawkey; + struct crypto_sync_skcipher *cipher; + int ret = -EINVAL; + + blocksize = krb5->block_len; + keybytes = krb5->key_bytes; + keylength = krb5->key_len; + + if (inkey->len != keylength || result->len != keylength) + return -EINVAL; + if (!krb5->random_to_key && result->len != keybytes) + return -EINVAL; + + cipher = crypto_alloc_sync_skcipher(krb5->derivation_enc, 0, 0); + if (IS_ERR(cipher)) { + ret = (PTR_ERR(cipher) == -ENOENT) ? -ENOPKG : PTR_ERR(cipher); + goto err_return; + } + ret = crypto_sync_skcipher_setkey(cipher, inkey->data, inkey->len); + if (ret < 0) + goto err_free_cipher; + + ret = -ENOMEM; + inblock.data = kzalloc(blocksize * 2 + keybytes, gfp); + if (!inblock.data) + goto err_free_cipher; + + inblock.len = blocksize; + outblock.data = inblock.data + blocksize; + outblock.len = blocksize; + rawkey.data = outblock.data + blocksize; + rawkey.len = keybytes; + + /* initialize the input block */ + + if (in_constant->len == inblock.len) + memcpy(inblock.data, in_constant->data, inblock.len); + else + rfc3961_nfold(in_constant, &inblock); + + /* loop encrypting the blocks until enough key bytes are generated */ + n = 0; + while (n < rawkey.len) { + rfc3961_do_encrypt(cipher, NULL, &inblock, &outblock); + + if (keybytes - n <= outblock.len) { + memcpy(rawkey.data + n, outblock.data, keybytes - n); + break; + } + + memcpy(rawkey.data + n, outblock.data, outblock.len); + memcpy(inblock.data, outblock.data, outblock.len); + n += outblock.len; + } + + /* postprocess the key */ + if (!krb5->random_to_key) { + /* Identity random-to-key function. */ + memcpy(result->data, rawkey.data, rawkey.len); + ret = 0; + } else { + ret = krb5->random_to_key(krb5, &rawkey, result); + } + + kfree_sensitive(inblock.data); +err_free_cipher: + crypto_free_sync_skcipher(cipher); +err_return: + return ret; +} + +/* + * Calculate single encryption, E() + * + * E(Key, octets) + */ +static int rfc3961_calc_E(const struct krb5_enctype *krb5, + const struct krb5_buffer *key, + const struct krb5_buffer *in_data, + struct krb5_buffer *result, + gfp_t gfp) +{ + struct crypto_sync_skcipher *cipher; + int ret; + + cipher = crypto_alloc_sync_skcipher(krb5->derivation_enc, 0, 0); + if (IS_ERR(cipher)) { + ret = (PTR_ERR(cipher) == -ENOENT) ? -ENOPKG : PTR_ERR(cipher); + goto err; + } + + ret = crypto_sync_skcipher_setkey(cipher, key->data, key->len); + if (ret < 0) + goto err_free; + + ret = rfc3961_do_encrypt(cipher, NULL, in_data, result); + +err_free: + crypto_free_sync_skcipher(cipher); +err: + return ret; +} + +/* + * Calculate the pseudo-random function, PRF(). + * + * tmp1 = H(octet-string) + * tmp2 = truncate tmp1 to multiple of m + * PRF = E(DK(protocol-key, prfconstant), tmp2, initial-cipher-state) + * + * The "prfconstant" used in the PRF operation is the three-octet string + * "prf". + * [rfc3961 sec 5.3] + */ +static int rfc3961_calc_PRF(const struct krb5_enctype *krb5, + const struct krb5_buffer *protocol_key, + const struct krb5_buffer *octet_string, + struct krb5_buffer *result, + gfp_t gfp) +{ + static const struct krb5_buffer prfconstant = { 3, "prf" }; + struct krb5_buffer derived_key; + struct krb5_buffer tmp1, tmp2; + unsigned int m = krb5->block_len; + void *buffer; + int ret; + + if (result->len != krb5->prf_len) + return -EINVAL; + + tmp1.len = krb5->hash_len; + derived_key.len = krb5->key_bytes; + buffer = kzalloc(round16(tmp1.len) + round16(derived_key.len), gfp); + if (!buffer) + return -ENOMEM; + + tmp1.data = buffer; + derived_key.data = buffer + round16(tmp1.len); + + ret = rfc3961_calc_H(krb5, octet_string, &tmp1, gfp); + if (ret < 0) + goto err; + + tmp2.len = tmp1.len & ~(m - 1); + tmp2.data = tmp1.data; + + ret = rfc3961_calc_DK(krb5, protocol_key, &prfconstant, &derived_key, gfp); + if (ret < 0) + goto err; + + ret = rfc3961_calc_E(krb5, &derived_key, &tmp2, result, gfp); + +err: + kfree_sensitive(buffer); + return ret; +} + +/* + * Derive the Ke and Ki keys and package them into a key parameter that can be + * given to the setkey of a authenc AEAD crypto object. + */ +int authenc_derive_encrypt_keys(const struct krb5_enctype *krb5, + const struct krb5_buffer *TK, + unsigned int usage, + struct krb5_buffer *setkey, + gfp_t gfp) +{ + struct crypto_authenc_key_param *param; + struct krb5_buffer Ke, Ki; + struct rtattr *rta; + int ret; + + Ke.len = krb5->Ke_len; + Ki.len = krb5->Ki_len; + setkey->len = RTA_LENGTH(sizeof(*param)) + Ke.len + Ki.len; + setkey->data = kzalloc(setkey->len, GFP_KERNEL); + if (!setkey->data) + return -ENOMEM; + + rta = setkey->data; + rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; + rta->rta_len = RTA_LENGTH(sizeof(*param)); + param = RTA_DATA(rta); + param->enckeylen = htonl(Ke.len); + + Ki.data = (void *)(param + 1); + Ke.data = Ki.data + Ki.len; + + ret = krb5_derive_Ke(krb5, TK, usage, &Ke, gfp); + if (ret < 0) { + pr_err("get_Ke failed %d\n", ret); + return ret; + } + ret = krb5_derive_Ki(krb5, TK, usage, &Ki, gfp); + if (ret < 0) + pr_err("get_Ki failed %d\n", ret); + return ret; +} + +/* + * Package predefined Ke and Ki keys and into a key parameter that can be given + * to the setkey of an authenc AEAD crypto object. + */ +int authenc_load_encrypt_keys(const struct krb5_enctype *krb5, + const struct krb5_buffer *Ke, + const struct krb5_buffer *Ki, + struct krb5_buffer *setkey, + gfp_t gfp) +{ + struct crypto_authenc_key_param *param; + struct rtattr *rta; + + setkey->len = RTA_LENGTH(sizeof(*param)) + Ke->len + Ki->len; + setkey->data = kzalloc(setkey->len, GFP_KERNEL); + if (!setkey->data) + return -ENOMEM; + + rta = setkey->data; + rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; + rta->rta_len = RTA_LENGTH(sizeof(*param)); + param = RTA_DATA(rta); + param->enckeylen = htonl(Ke->len); + memcpy((void *)(param + 1), Ki->data, Ki->len); + memcpy((void *)(param + 1) + Ki->len, Ke->data, Ke->len); + return 0; +} + +/* + * Derive the Kc key for checksum-only mode and package it into a key parameter + * that can be given to the setkey of a hash crypto object. + */ +int rfc3961_derive_checksum_key(const struct krb5_enctype *krb5, + const struct krb5_buffer *TK, + unsigned int usage, + struct krb5_buffer *setkey, + gfp_t gfp) +{ + int ret; + + setkey->len = krb5->Kc_len; + setkey->data = kzalloc(setkey->len, GFP_KERNEL); + if (!setkey->data) + return -ENOMEM; + + ret = krb5_derive_Kc(krb5, TK, usage, setkey, gfp); + if (ret < 0) + pr_err("get_Kc failed %d\n", ret); + return ret; +} + +/* + * Package a predefined Kc key for checksum-only mode into a key parameter that + * can be given to the setkey of a hash crypto object. + */ +int rfc3961_load_checksum_key(const struct krb5_enctype *krb5, + const struct krb5_buffer *Kc, + struct krb5_buffer *setkey, + gfp_t gfp) +{ + setkey->len = krb5->Kc_len; + setkey->data = kmemdup(Kc->data, Kc->len, GFP_KERNEL); + if (!setkey->data) + return -ENOMEM; + return 0; +} + +/* + * Apply encryption and checksumming functions to part of a scatterlist. + */ +ssize_t krb5_aead_encrypt(const struct krb5_enctype *krb5, + struct crypto_aead *aead, + struct scatterlist *sg, unsigned int nr_sg, size_t sg_len, + size_t data_offset, size_t data_len, + bool preconfounded) +{ + struct aead_request *req; + ssize_t ret, done; + size_t bsize, base_len, secure_offset, secure_len, pad_len, cksum_offset; + void *buffer; + u8 *iv; + + if (WARN_ON(data_offset != krb5->conf_len)) + return -EINVAL; /* Data is in wrong place */ + + secure_offset = 0; + base_len = krb5->conf_len + data_len; + pad_len = 0; + secure_len = base_len + pad_len; + cksum_offset = secure_len; + if (WARN_ON(cksum_offset + krb5->cksum_len > sg_len)) + return -EFAULT; + + bsize = krb5_aead_size(aead) + + krb5_aead_ivsize(aead); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + /* Insert the confounder into the buffer */ + ret = -EFAULT; + if (!preconfounded) { + get_random_bytes(buffer, krb5->conf_len); + done = sg_pcopy_from_buffer(sg, nr_sg, buffer, krb5->conf_len, + secure_offset); + if (done != krb5->conf_len) + goto error; + } + + /* We may need to pad out to the crypto blocksize. */ + if (pad_len) { + done = sg_zero_buffer(sg, nr_sg, pad_len, data_offset + data_len); + if (done != pad_len) + goto error; + } + + /* Hash and encrypt the message. */ + req = buffer; + iv = buffer + krb5_aead_size(aead); + + aead_request_set_tfm(req, aead); + aead_request_set_callback(req, 0, NULL, NULL); + aead_request_set_crypt(req, sg, sg, secure_len, iv); + ret = crypto_aead_encrypt(req); + if (ret < 0) + goto error; + + ret = secure_len + krb5->cksum_len; + +error: + kfree_sensitive(buffer); + return ret; +} + +/* + * Apply decryption and checksumming functions to a message. The offset and + * length are updated to reflect the actual content of the encrypted region. + */ +int krb5_aead_decrypt(const struct krb5_enctype *krb5, + struct crypto_aead *aead, + struct scatterlist *sg, unsigned int nr_sg, + size_t *_offset, size_t *_len) +{ + struct aead_request *req; + size_t bsize; + void *buffer; + int ret; + u8 *iv; + + if (WARN_ON(*_offset != 0)) + return -EINVAL; /* Can't set offset on aead */ + + if (*_len < krb5->conf_len + krb5->cksum_len) + return -EPROTO; + + bsize = krb5_aead_size(aead) + + krb5_aead_ivsize(aead); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + /* Decrypt the message and verify its checksum. */ + req = buffer; + iv = buffer + krb5_aead_size(aead); + + aead_request_set_tfm(req, aead); + aead_request_set_callback(req, 0, NULL, NULL); + aead_request_set_crypt(req, sg, sg, *_len, iv); + ret = crypto_aead_decrypt(req); + if (ret < 0) + goto error; + + /* Adjust the boundaries of the data. */ + *_offset += krb5->conf_len; + *_len -= krb5->conf_len + krb5->cksum_len; + ret = 0; + +error: + kfree_sensitive(buffer); + return ret; +} + +/* + * Generate a checksum over some metadata and part of an skbuff and insert the + * MIC into the skbuff immediately prior to the data. + */ +ssize_t rfc3961_get_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, size_t sg_len, + size_t data_offset, size_t data_len) +{ + struct shash_desc *desc; + ssize_t ret, done; + size_t bsize; + void *buffer, *digest; + + if (WARN_ON(data_offset != krb5->cksum_len)) + return -EMSGSIZE; + + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + /* Calculate the MIC with key Kc and store it into the skb */ + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + if (metadata) { + ret = crypto_shash_update(desc, metadata->data, metadata->len); + if (ret < 0) + goto error; + } + + ret = crypto_shash_update_sg(desc, sg, data_offset, data_len); + if (ret < 0) + goto error; + + digest = buffer + krb5_shash_size(shash); + ret = crypto_shash_final(desc, digest); + if (ret < 0) + goto error; + + ret = -EFAULT; + done = sg_pcopy_from_buffer(sg, nr_sg, digest, krb5->cksum_len, + data_offset - krb5->cksum_len); + if (done != krb5->cksum_len) + goto error; + + ret = krb5->cksum_len + data_len; + +error: + kfree_sensitive(buffer); + return ret; +} + +/* + * Check the MIC on a region of an skbuff. The offset and length are updated + * to reflect the actual content of the secure region. + */ +int rfc3961_verify_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, + size_t *_offset, size_t *_len) +{ + struct shash_desc *desc; + ssize_t done; + size_t bsize, data_offset, data_len, offset = *_offset, len = *_len; + void *buffer = NULL; + int ret; + u8 *cksum, *cksum2; + + if (len < krb5->cksum_len) + return -EPROTO; + data_offset = offset + krb5->cksum_len; + data_len = len - krb5->cksum_len; + + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash) * 2; + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + cksum = buffer + + krb5_shash_size(shash); + cksum2 = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash); + + /* Calculate the MIC */ + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + if (metadata) { + ret = crypto_shash_update(desc, metadata->data, metadata->len); + if (ret < 0) + goto error; + } + + crypto_shash_update_sg(desc, sg, data_offset, data_len); + crypto_shash_final(desc, cksum); + + ret = -EFAULT; + done = sg_pcopy_to_buffer(sg, nr_sg, cksum2, krb5->cksum_len, offset); + if (done != krb5->cksum_len) + goto error; + + if (memcmp(cksum, cksum2, krb5->cksum_len) != 0) { + ret = -EBADMSG; + goto error; + } + + *_offset += krb5->cksum_len; + *_len -= krb5->cksum_len; + ret = 0; + +error: + kfree_sensitive(buffer); + return ret; +} + +const struct krb5_crypto_profile rfc3961_simplified_profile = { + .calc_PRF = rfc3961_calc_PRF, + .calc_Kc = rfc3961_calc_DK, + .calc_Ke = rfc3961_calc_DK, + .calc_Ki = rfc3961_calc_DK, + .derive_encrypt_keys = authenc_derive_encrypt_keys, + .load_encrypt_keys = authenc_load_encrypt_keys, + .derive_checksum_key = rfc3961_derive_checksum_key, + .load_checksum_key = rfc3961_load_checksum_key, + .encrypt = krb5_aead_encrypt, + .decrypt = krb5_aead_decrypt, + .get_mic = rfc3961_get_mic, + .verify_mic = rfc3961_verify_mic, +}; |