diff options
Diffstat (limited to 'crypto/krb5/rfc6803_camellia.c')
| -rw-r--r-- | crypto/krb5/rfc6803_camellia.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/crypto/krb5/rfc6803_camellia.c b/crypto/krb5/rfc6803_camellia.c new file mode 100644 index 000000000000..77cd4ce023f1 --- /dev/null +++ b/crypto/krb5/rfc6803_camellia.c @@ -0,0 +1,237 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* rfc6803 Camellia Encryption for Kerberos 5 + * + * 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/slab.h> +#include "internal.h" + +/* + * Calculate the key derivation function KDF-FEEDBACK_CMAC(key, constant) + * + * n = ceiling(k / 128) + * K(0) = zeros + * K(i) = CMAC(key, K(i-1) | i | constant | 0x00 | k) + * DR(key, constant) = k-truncate(K(1) | K(2) | ... | K(n)) + * KDF-FEEDBACK-CMAC(key, constant) = random-to-key(DR(key, constant)) + * + * [rfc6803 sec 3] + */ +static int rfc6803_calc_KDF_FEEDBACK_CMAC(const struct krb5_enctype *krb5, + const struct krb5_buffer *key, + const struct krb5_buffer *constant, + struct krb5_buffer *result, + gfp_t gfp) +{ + struct crypto_shash *shash; + struct krb5_buffer K, data; + struct shash_desc *desc; + __be32 tmp; + size_t bsize, offset, seg; + void *buffer; + u32 i = 0, k = result->len * 8; + u8 *p; + int ret = -ENOMEM; + + shash = crypto_alloc_shash(krb5->cksum_name, 0, 0); + if (IS_ERR(shash)) + return (PTR_ERR(shash) == -ENOENT) ? -ENOPKG : PTR_ERR(shash); + ret = crypto_shash_setkey(shash, key->data, key->len); + if (ret < 0) + goto error_shash; + + ret = -ENOMEM; + K.len = crypto_shash_digestsize(shash); + data.len = K.len + 4 + constant->len + 1 + 4; + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash) + + crypto_roundup(K.len) + + crypto_roundup(data.len); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + goto error_shash; + + desc = buffer; + desc->tfm = shash; + + K.data = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash); + data.data = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash) + + crypto_roundup(K.len); + + p = data.data + K.len + 4; + memcpy(p, constant->data, constant->len); + p += constant->len; + *p++ = 0x00; + tmp = htonl(k); + memcpy(p, &tmp, 4); + p += 4; + + ret = -EINVAL; + if (WARN_ON(p - (u8 *)data.data != data.len)) + goto error; + + offset = 0; + do { + i++; + p = data.data; + memcpy(p, K.data, K.len); + p += K.len; + *(__be32 *)p = htonl(i); + + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + ret = crypto_shash_finup(desc, data.data, data.len, K.data); + if (ret < 0) + goto error; + + seg = min_t(size_t, result->len - offset, K.len); + memcpy(result->data + offset, K.data, seg); + offset += seg; + } while (offset < result->len); + +error: + kfree_sensitive(buffer); +error_shash: + crypto_free_shash(shash); + return ret; +} + +/* + * Calculate the pseudo-random function, PRF(). + * + * Kp = KDF-FEEDBACK-CMAC(protocol-key, "prf") + * PRF = CMAC(Kp, octet-string) + * [rfc6803 sec 6] + */ +static int rfc6803_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 crypto_shash *shash; + struct krb5_buffer Kp; + struct shash_desc *desc; + size_t bsize; + void *buffer; + int ret; + + Kp.len = krb5->prf_len; + + shash = crypto_alloc_shash(krb5->cksum_name, 0, 0); + if (IS_ERR(shash)) + return (PTR_ERR(shash) == -ENOENT) ? -ENOPKG : PTR_ERR(shash); + + ret = -EINVAL; + if (result->len != crypto_shash_digestsize(shash)) + goto out_shash; + + ret = -ENOMEM; + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash) + + crypto_roundup(Kp.len); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + goto out_shash; + + Kp.data = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash); + + ret = rfc6803_calc_KDF_FEEDBACK_CMAC(krb5, protocol_key, &prfconstant, + &Kp, gfp); + if (ret < 0) + goto out; + + ret = crypto_shash_setkey(shash, Kp.data, Kp.len); + if (ret < 0) + goto out; + + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto out; + + ret = crypto_shash_finup(desc, octet_string->data, octet_string->len, result->data); + if (ret < 0) + goto out; + +out: + kfree_sensitive(buffer); +out_shash: + crypto_free_shash(shash); + return ret; +} + + +static const struct krb5_crypto_profile rfc6803_crypto_profile = { + .calc_PRF = rfc6803_calc_PRF, + .calc_Kc = rfc6803_calc_KDF_FEEDBACK_CMAC, + .calc_Ke = rfc6803_calc_KDF_FEEDBACK_CMAC, + .calc_Ki = rfc6803_calc_KDF_FEEDBACK_CMAC, + .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, +}; + +const struct krb5_enctype krb5_camellia128_cts_cmac = { + .etype = KRB5_ENCTYPE_CAMELLIA128_CTS_CMAC, + .ctype = KRB5_CKSUMTYPE_CMAC_CAMELLIA128, + .name = "camellia128-cts-cmac", + .encrypt_name = "krb5enc(cmac(camellia),cts(cbc(camellia)))", + .cksum_name = "cmac(camellia)", + .hash_name = NULL, + .derivation_enc = "cts(cbc(camellia))", + .key_bytes = 16, + .key_len = 16, + .Kc_len = 16, + .Ke_len = 16, + .Ki_len = 16, + .block_len = 16, + .conf_len = 16, + .cksum_len = 16, + .hash_len = 16, + .prf_len = 16, + .keyed_cksum = true, + .random_to_key = NULL, /* Identity */ + .profile = &rfc6803_crypto_profile, +}; + +const struct krb5_enctype krb5_camellia256_cts_cmac = { + .etype = KRB5_ENCTYPE_CAMELLIA256_CTS_CMAC, + .ctype = KRB5_CKSUMTYPE_CMAC_CAMELLIA256, + .name = "camellia256-cts-cmac", + .encrypt_name = "krb5enc(cmac(camellia),cts(cbc(camellia)))", + .cksum_name = "cmac(camellia)", + .hash_name = NULL, + .derivation_enc = "cts(cbc(camellia))", + .key_bytes = 32, + .key_len = 32, + .Kc_len = 32, + .Ke_len = 32, + .Ki_len = 32, + .block_len = 16, + .conf_len = 16, + .cksum_len = 16, + .hash_len = 16, + .prf_len = 16, + .keyed_cksum = true, + .random_to_key = NULL, /* Identity */ + .profile = &rfc6803_crypto_profile, +}; |