crypto/krb5: Implement the AES enctypes from rfc3962

Implement the aes128-cts-hmac-sha1-96 and aes256-cts-hmac-sha1-96 enctypes
from rfc3962, using the rfc3961 kerberos 5 simplified crypto scheme.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: "David S. Miller" <davem@davemloft.net>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-crypto@vger.kernel.org
cc: netdev@vger.kernel.org

crypto/krb5/Kconfig

@@ -5,6 +5,7 @@ config CRYPTO_KRB5
 	select CRYPTO_AUTHENC
 	select CRYPTO_SKCIPHER
 	select CRYPTO_HASH_INFO
+	select CRYPTO_HMAC
 	select CRYPTO_SHA1
 	select CRYPTO_CBC
 	select CRYPTO_CTS

crypto/krb5/Makefile

@@ -6,6 +6,7 @@
 krb5-y += \
 	krb5_kdf.o \
 	krb5_api.o \
-	rfc3961_simplified.o
+	rfc3961_simplified.o \
+	rfc3962_aes.o
 
 obj-$(CONFIG_CRYPTO_KRB5) += krb5.o

crypto/krb5/internal.h

@@ -179,3 +179,9 @@ int rfc3961_verify_mic(const struct krb5_enctype *krb5,
 		       const struct krb5_buffer *metadata,
 		       struct scatterlist *sg, unsigned int nr_sg,
 		       size_t *_offset, size_t *_len);
+
+/*
+ * rfc3962_aes.c
+ */
+extern const struct krb5_enctype krb5_aes128_cts_hmac_sha1_96;
+extern const struct krb5_enctype krb5_aes256_cts_hmac_sha1_96;

crypto/krb5/krb5_api.c

@@ -17,6 +17,8 @@ MODULE_AUTHOR("Red Hat, Inc.");
 MODULE_LICENSE("GPL");
 
 static const struct krb5_enctype *const krb5_supported_enctypes[] = {
+	&krb5_aes128_cts_hmac_sha1_96,
+	&krb5_aes256_cts_hmac_sha1_96,
 };
 
 /**

crypto/krb5/rfc3962_aes.c

@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/* rfc3962 Advanced Encryption Standard (AES) Encryption for Kerberos 5
+ *
+ * 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 "internal.h"
+
+const struct krb5_enctype krb5_aes128_cts_hmac_sha1_96 = {
+	.etype		= KRB5_ENCTYPE_AES128_CTS_HMAC_SHA1_96,
+	.ctype		= KRB5_CKSUMTYPE_HMAC_SHA1_96_AES128,
+	.name		= "aes128-cts-hmac-sha1-96",
+	.encrypt_name	= "krb5enc(hmac(sha1),cts(cbc(aes)))",
+	.cksum_name	= "hmac(sha1)",
+	.hash_name	= "sha1",
+	.derivation_enc	= "cts(cbc(aes))",
+	.key_bytes	= 16,
+	.key_len	= 16,
+	.Kc_len		= 16,
+	.Ke_len		= 16,
+	.Ki_len		= 16,
+	.block_len	= 16,
+	.conf_len	= 16,
+	.cksum_len	= 12,
+	.hash_len	= 20,
+	.prf_len	= 16,
+	.keyed_cksum	= true,
+	.random_to_key	= NULL, /* Identity */
+	.profile	= &rfc3961_simplified_profile,
+};
+
+const struct krb5_enctype krb5_aes256_cts_hmac_sha1_96 = {
+	.etype		= KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96,
+	.ctype		= KRB5_CKSUMTYPE_HMAC_SHA1_96_AES256,
+	.name		= "aes256-cts-hmac-sha1-96",
+	.encrypt_name	= "krb5enc(hmac(sha1),cts(cbc(aes)))",
+	.cksum_name	= "hmac(sha1)",
+	.hash_name	= "sha1",
+	.derivation_enc	= "cts(cbc(aes))",
+	.key_bytes	= 32,
+	.key_len	= 32,
+	.Kc_len		= 32,
+	.Ke_len		= 32,
+	.Ki_len		= 32,
+	.block_len	= 16,
+	.conf_len	= 16,
+	.cksum_len	= 12,
+	.hash_len	= 20,
+	.prf_len	= 16,
+	.keyed_cksum	= true,
+	.random_to_key	= NULL, /* Identity */
+	.profile	= &rfc3961_simplified_profile,
+};