Implement the aes128-cts-hmac-sha256-128 and aes256-cts-hmac-sha384-192 enctypes from rfc8009, overriding the rfc3961 kerberos 5 simplified crypto scheme.
Signed-off-by: David Howells <dhowe...@redhat.com> --- crypto/krb5/Kconfig | 2 crypto/krb5/Makefile | 3 - crypto/krb5/internal.h | 6 + crypto/krb5/main.c | 2 crypto/krb5/rfc8009_aes2.c | 239 ++++++++++++++++++++++++++++++++++++++++++++ include/crypto/krb5.h | 4 + 6 files changed, 255 insertions(+), 1 deletion(-) create mode 100644 crypto/krb5/rfc8009_aes2.c diff --git a/crypto/krb5/Kconfig b/crypto/krb5/Kconfig index e2eba1d689ab..5607c0c81049 100644 --- a/crypto/krb5/Kconfig +++ b/crypto/krb5/Kconfig @@ -4,6 +4,8 @@ config CRYPTO_KRB5 select CRYPTO_SKCIPHER select CRYPTO_HASH_INFO select CRYPTO_SHA1 + select CRYPTO_SHA256 + select CRYPTO_SHA512 select CRYPTO_CBC select CRYPTO_CTS select CRYPTO_AES diff --git a/crypto/krb5/Makefile b/crypto/krb5/Makefile index b7da03cae6d1..85763131f7b6 100644 --- a/crypto/krb5/Makefile +++ b/crypto/krb5/Makefile @@ -7,7 +7,8 @@ krb5-y += \ kdf.o \ main.o \ rfc3961_simplified.o \ - rfc3962_aes.o + rfc3962_aes.o \ + rfc8009_aes2.o krb5-$(CONFIG_CRYPTO_KRB5_SELFTESTS) += \ selftest.o \ diff --git a/crypto/krb5/internal.h b/crypto/krb5/internal.h index 47424b433778..e64f5e58199f 100644 --- a/crypto/krb5/internal.h +++ b/crypto/krb5/internal.h @@ -158,6 +158,12 @@ int rfc3961_verify_mic(const struct krb5_enctype *krb5, extern const struct krb5_enctype krb5_aes128_cts_hmac_sha1_96; extern const struct krb5_enctype krb5_aes256_cts_hmac_sha1_96; +/* + * rfc8009_aes2.c + */ +extern const struct krb5_enctype krb5_aes128_cts_hmac_sha256_128; +extern const struct krb5_enctype krb5_aes256_cts_hmac_sha384_192; + /* * selftest.c */ diff --git a/crypto/krb5/main.c b/crypto/krb5/main.c index b79127027551..9914d3417c21 100644 --- a/crypto/krb5/main.c +++ b/crypto/krb5/main.c @@ -20,6 +20,8 @@ MODULE_LICENSE("GPL"); static const struct krb5_enctype *const krb5_supported_enctypes[] = { &krb5_aes128_cts_hmac_sha1_96, &krb5_aes256_cts_hmac_sha1_96, + &krb5_aes128_cts_hmac_sha256_128, + &krb5_aes256_cts_hmac_sha384_192, }; /** diff --git a/crypto/krb5/rfc8009_aes2.c b/crypto/krb5/rfc8009_aes2.c new file mode 100644 index 000000000000..9f0f0f410d91 --- /dev/null +++ b/crypto/krb5/rfc8009_aes2.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* rfc8009 AES Encryption with HMAC-SHA2 for Kerberos 5 + * + * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowe...@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <crypto/skcipher.h> +#include <crypto/hash.h> +#include <linux/slab.h> +#include "internal.h" + +static const struct krb5_buffer rfc8009_no_context = { .len = 0, .data = "" }; + +/* + * Calculate the key derivation function KDF-HMAC-SHA2(key, label, [context,] k) + * + * KDF-HMAC-SHA2(key, label, [context,] k) = k-truncate(K1) + * + * Using the appropriate one of: + * K1 = HMAC-SHA-256(key, 0x00000001 | label | 0x00 | k) + * K1 = HMAC-SHA-384(key, 0x00000001 | label | 0x00 | k) + * K1 = HMAC-SHA-256(key, 0x00000001 | label | 0x00 | context | k) + * K1 = HMAC-SHA-384(key, 0x00000001 | label | 0x00 | context | k) + * [rfc8009 sec 3] + */ +static int rfc8009_calc_KDF_HMAC_SHA2(const struct krb5_enctype *krb5, + const struct krb5_buffer *key, + const struct krb5_buffer *label, + const struct krb5_buffer *context, + unsigned int k, + struct krb5_buffer *result, + gfp_t gfp) +{ + struct crypto_shash *shash; + struct krb5_buffer K1, data; + struct shash_desc *desc; + __be32 tmp; + size_t bsize; + void *buffer; + u8 *p; + int ret = -ENOMEM; + + if (WARN_ON(result->len != k / 8)) + return -EINVAL; + + 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 = -EINVAL; + if (WARN_ON(crypto_shash_digestsize(shash) * 8 < k)) + goto error_shash; + + ret = -ENOMEM; + data.len = 4 + label->len + 1 + context->len + 4; + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash) + + crypto_roundup(data.len); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + goto error_shash; + + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + p = data.data = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash); + *(__be32 *)p = htonl(0x00000001); + p += 4; + memcpy(p, label->data, label->len); + p += label->len; + *p++ = 0; + memcpy(p, context->data, context->len); + p += context->len; + tmp = htonl(k); + memcpy(p, &tmp, 4); + p += 4; + + ret = -EINVAL; + if (WARN_ON(p - (u8 *)data.data != data.len)) + goto error; + + K1.len = crypto_shash_digestsize(shash); + K1.data = buffer + + krb5_shash_size(shash); + + ret = crypto_shash_finup(desc, data.data, data.len, K1.data); + if (ret < 0) + goto error; + + memcpy(result->data, K1.data, result->len); + +error: + kfree_sensitive(buffer); +error_shash: + crypto_free_shash(shash); + return ret; +} + +/* + * Calculate the pseudo-random function, PRF(). + * + * PRF = KDF-HMAC-SHA2(input-key, "prf", octet-string, 256) + * PRF = KDF-HMAC-SHA2(input-key, "prf", octet-string, 384) + * + * The "prfconstant" used in the PRF operation is the three-octet string + * "prf". + * [rfc8009 sec 5] + */ +static int rfc8009_calc_PRF(const struct krb5_enctype *krb5, + const struct krb5_buffer *input_key, + const struct krb5_buffer *octet_string, + struct krb5_buffer *result, + gfp_t gfp) +{ + static const struct krb5_buffer prfconstant = { 3, "prf" }; + + return rfc8009_calc_KDF_HMAC_SHA2(krb5, input_key, &prfconstant, + octet_string, krb5->prf_len * 8, + result, gfp); +} + +/* + * Derive Ke. + * Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA, 128) + * Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA, 256) + * [rfc8009 sec 5] + */ +static int rfc8009_calc_Ke(const struct krb5_enctype *krb5, + const struct krb5_buffer *base_key, + const struct krb5_buffer *usage_constant, + struct krb5_buffer *result, + gfp_t gfp) +{ + return rfc8009_calc_KDF_HMAC_SHA2(krb5, base_key, usage_constant, + &rfc8009_no_context, krb5->key_bytes * 8, + result, gfp); +} + +/* + * Derive Kc/Ki + * Kc = KDF-HMAC-SHA2(base-key, usage | 0x99, 128) + * Ki = KDF-HMAC-SHA2(base-key, usage | 0x55, 128) + * Kc = KDF-HMAC-SHA2(base-key, usage | 0x99, 192) + * Ki = KDF-HMAC-SHA2(base-key, usage | 0x55, 192) + * [rfc8009 sec 5] + */ +static int rfc8009_calc_Ki(const struct krb5_enctype *krb5, + const struct krb5_buffer *base_key, + const struct krb5_buffer *usage_constant, + struct krb5_buffer *result, + gfp_t gfp) +{ + return rfc8009_calc_KDF_HMAC_SHA2(krb5, base_key, usage_constant, + &rfc8009_no_context, krb5->cksum_len * 8, + result, gfp); +} + +/* + * AES random-to-key function. For AES, this is an identity operation. + */ +static int rfc8009_random_to_key(const struct krb5_enctype *krb5, + const struct krb5_buffer *randombits, + struct krb5_buffer *result) +{ + if (randombits->len != 16 && randombits->len != 32) + return -EINVAL; + + if (result->len != randombits->len) + return -EINVAL; + + memcpy(result->data, randombits->data, randombits->len); + return 0; +} + +static const struct krb5_crypto_profile rfc8009_crypto_profile = { + .calc_PRF = rfc8009_calc_PRF, + .calc_Kc = rfc8009_calc_Ki, + .calc_Ke = rfc8009_calc_Ke, + .calc_Ki = rfc8009_calc_Ki, + .encrypt = NULL, //rfc8009_encrypt, + .decrypt = NULL, //rfc8009_decrypt, + .get_mic = rfc3961_get_mic, + .verify_mic = rfc3961_verify_mic, +}; + +const struct krb5_enctype krb5_aes128_cts_hmac_sha256_128 = { + .etype = KRB5_ENCTYPE_AES128_CTS_HMAC_SHA256_128, + .ctype = KRB5_CKSUMTYPE_HMAC_SHA256_128_AES128, + .name = "aes128-cts-hmac-sha256-128", + .encrypt_name = "cts(cbc(aes))", + .cksum_name = "hmac(sha256)", + .hash_name = "sha256", + .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 = 20, + .prf_len = 32, + .keyed_cksum = true, + .random_to_key = rfc8009_random_to_key, + .profile = &rfc8009_crypto_profile, +}; + +const struct krb5_enctype krb5_aes256_cts_hmac_sha384_192 = { + .etype = KRB5_ENCTYPE_AES256_CTS_HMAC_SHA384_192, + .ctype = KRB5_CKSUMTYPE_HMAC_SHA384_192_AES256, + .name = "aes256-cts-hmac-sha384-192", + .encrypt_name = "cts(cbc(aes))", + .cksum_name = "hmac(sha384)", + .hash_name = "sha384", + .key_bytes = 32, + .key_len = 32, + .Kc_len = 24, + .Ke_len = 32, + .Ki_len = 24, + .block_len = 16, + .conf_len = 16, + .cksum_len = 24, + .hash_len = 20, + .prf_len = 48, + .keyed_cksum = true, + .random_to_key = rfc8009_random_to_key, + .profile = &rfc8009_crypto_profile, +}; diff --git a/include/crypto/krb5.h b/include/crypto/krb5.h index b83d3d487753..f38a5b4d97ee 100644 --- a/include/crypto/krb5.h +++ b/include/crypto/krb5.h @@ -32,6 +32,8 @@ struct scatterlist; #define KRB5_ENCTYPE_DES3_CBC_SHA1 0x0010 #define KRB5_ENCTYPE_AES128_CTS_HMAC_SHA1_96 0x0011 #define KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96 0x0012 +#define KRB5_ENCTYPE_AES128_CTS_HMAC_SHA256_128 0x0013 +#define KRB5_ENCTYPE_AES256_CTS_HMAC_SHA384_192 0x0014 #define KRB5_ENCTYPE_ARCFOUR_HMAC 0x0017 #define KRB5_ENCTYPE_ARCFOUR_HMAC_EXP 0x0018 #define KRB5_ENCTYPE_UNKNOWN 0x01ff @@ -46,6 +48,8 @@ struct scatterlist; #define KRB5_CKSUMTYPE_HMAC_SHA1_DES3 0x000c #define KRB5_CKSUMTYPE_HMAC_SHA1_96_AES128 0x000f #define KRB5_CKSUMTYPE_HMAC_SHA1_96_AES256 0x0010 +#define KRB5_CKSUMTYPE_HMAC_SHA256_128_AES128 0x0013 +#define KRB5_CKSUMTYPE_HMAC_SHA384_192_AES256 0x0014 #define KRB5_CKSUMTYPE_HMAC_MD5_ARCFOUR -138 /* Microsoft md5 hmac cksumtype */ /*