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Subject: [PATCH v1 23/41] SUNRPC: Add gk5e definitions for RFC 8009 encryption
 types
From:   Chuck Lever <cel@kernel.org>
To:     linux-nfs@vger.kernel.org
Cc:     dhowells@redhat.com, simo@redhat.com
Date:   Fri, 13 Jan 2023 10:23:53 -0500
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From: Chuck Lever <chuck.lever@oracle.com>

Fill in entries in the supported_gss_krb5_enctypes array for the
encryption types defined in RFC 8009. These new enctypes use the
SHA-256 and SHA-384 message digest algorithms (as defined in
FIPS-180) instead of the deprecated SHA-1 algorithm, and are thus
more secure.

Note that NIST has scheduled SHA-1 for deprecation:

https://www.nist.gov/news-events/news/2022/12/nist-retires-sha-1-cryptographic-algorithm

Thus these new encryption types are placed under a separate CONFIG
option to enable distributors to separately introduce support for
the AES-SHA2 enctypes and deprecate support for the current set of
AES-SHA1 encryption types as their user space allows.

As this implementation is still a "beta", the default is to not
build it automatically.

Tested-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/gss_krb5.h     |   19 ++++++++++++-
 net/sunrpc/Kconfig                  |   14 ++++++++++
 net/sunrpc/auth_gss/gss_krb5_mech.c |   51 +++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index 48e82397132b..be2fa13ef0f8 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -56,8 +56,8 @@
 /* Maximum key length (in bytes) for the supported crypto algorithms */
 #define GSS_KRB5_MAX_KEYLEN (32)
 
-/* Maximum checksum function output for the supported crypto algorithms */
-#define GSS_KRB5_MAX_CKSUM_LEN  (20)
+/* Maximum checksum function output for the supported enctypes */
+#define GSS_KRB5_MAX_CKSUM_LEN  (24)
 
 /* Maximum blocksize for the supported crypto algorithms */
 #define GSS_KRB5_MAX_BLOCKSIZE  (16)
@@ -164,6 +164,12 @@ enum seal_alg {
 	SEAL_ALG_DES3KD = 0x0002
 };
 
+/*
+ * These values are assigned by IANA and published via the
+ * subregistry at the link below:
+ *
+ * https://www.iana.org/assignments/kerberos-parameters/kerberos-parameters.xhtml#kerberos-parameters-2
+ */
 #define CKSUMTYPE_CRC32			0x0001
 #define CKSUMTYPE_RSA_MD4		0x0002
 #define CKSUMTYPE_RSA_MD4_DES		0x0003
@@ -174,6 +180,8 @@ enum seal_alg {
 #define CKSUMTYPE_HMAC_SHA1_DES3	0x000c
 #define CKSUMTYPE_HMAC_SHA1_96_AES128   0x000f
 #define CKSUMTYPE_HMAC_SHA1_96_AES256   0x0010
+#define CKSUMTYPE_HMAC_SHA256_128_AES128	0x0013
+#define CKSUMTYPE_HMAC_SHA384_192_AES256	0x0014
 #define CKSUMTYPE_HMAC_MD5_ARCFOUR      -138 /* Microsoft md5 hmac cksumtype */
 
 /* from gssapi_err_krb5.h */
@@ -194,6 +202,11 @@ enum seal_alg {
 
 /* per Kerberos v5 protocol spec crypto types from the wire. 
  * these get mapped to linux kernel crypto routines.  
+ *
+ * These values are assigned by IANA and published via the
+ * subregistry at the link below:
+ *
+ * https://www.iana.org/assignments/kerberos-parameters/kerberos-parameters.xhtml#kerberos-parameters-1
  */
 #define ENCTYPE_NULL            0x0000
 #define ENCTYPE_DES_CBC_CRC     0x0001	/* DES cbc mode with CRC-32 */
@@ -207,6 +220,8 @@ enum seal_alg {
 #define ENCTYPE_DES3_CBC_SHA1   0x0010
 #define ENCTYPE_AES128_CTS_HMAC_SHA1_96 0x0011
 #define ENCTYPE_AES256_CTS_HMAC_SHA1_96 0x0012
+#define ENCTYPE_AES128_CTS_HMAC_SHA256_128	0x0013
+#define ENCTYPE_AES256_CTS_HMAC_SHA384_192	0x0014
 #define ENCTYPE_ARCFOUR_HMAC            0x0017
 #define ENCTYPE_ARCFOUR_HMAC_EXP        0x0018
 #define ENCTYPE_UNKNOWN         0x01ff
diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig
index 1135ff362132..b1aa2318e1dc 100644
--- a/net/sunrpc/Kconfig
+++ b/net/sunrpc/Kconfig
@@ -76,6 +76,20 @@ config RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA1
 	  SHA-1 digests. These include aes128-cts-hmac-sha1-96 and
 	  aes256-cts-hmac-sha1-96.
 
+config RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2
+	bool "Enable Kerberos enctypes based on AES and SHA-2"
+	depends on RPCSEC_GSS_KRB5
+	depends on CRYPTO_CBC && CRYPTO_CTS
+	depends on CRYPTO_HMAC && CRYPTO_SHA256 && CRYPTO_SHA512
+	depends on CRYPTO_AES
+	default n
+	select RPCSEC_GSS_KRB5_CRYPTOSYSTEM
+	help
+	  Choose Y to enable the use of Kerberos 5 encryption types
+	  that utilize Advanced Encryption Standard (AES) ciphers and
+	  SHA-2 digests. These include aes128-cts-hmac-sha256-128 and
+	  aes256-cts-hmac-sha384-192.
+
 config SUNRPC_DEBUG
 	bool "RPC: Enable dprintk debugging"
 	depends on SUNRPC && SYSCTL
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index 03725f2dd28f..bfcd13e6eb18 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -146,6 +146,57 @@ static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
 	  .keyed_cksum = 1,
 	},
 #endif
+
+#if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2)
+	/*
+	 * AES-128 with SHA-256 (RFC 8009)
+	 */
+	{
+		.etype		= ENCTYPE_AES128_CTS_HMAC_SHA256_128,
+		.ctype		= CKSUMTYPE_HMAC_SHA256_128_AES128,
+		.name		= "aes128-cts-hmac-sha256-128",
+		.encrypt_name	= "cts(cbc(aes))",
+		.aux_cipher	= "cbc(aes)",
+		.cksum_name	= "hmac(sha256)",
+		.cksumlength	= BITS2OCTETS(128),
+		.keyed_cksum	= 1,
+		.keylength	= BITS2OCTETS(128),
+		.Kc_length	= BITS2OCTETS(128),
+		.Ke_length	= BITS2OCTETS(128),
+		.Ki_length	= BITS2OCTETS(128),
+
+		.import_ctx	= gss_krb5_import_ctx_v2,
+
+		.get_mic	= gss_krb5_get_mic_v2,
+		.verify_mic	= gss_krb5_verify_mic_v2,
+		.wrap		= gss_krb5_wrap_v2,
+		.unwrap		= gss_krb5_unwrap_v2,
+	},
+	/*
+	 * AES-256 with SHA-384 (RFC 8009)
+	 */
+	{
+		.etype		= ENCTYPE_AES256_CTS_HMAC_SHA384_192,
+		.ctype		= CKSUMTYPE_HMAC_SHA384_192_AES256,
+		.name		= "aes256-cts-hmac-sha384-192",
+		.encrypt_name	= "cts(cbc(aes))",
+		.aux_cipher	= "cbc(aes)",
+		.cksum_name	= "hmac(sha384)",
+		.cksumlength	= BITS2OCTETS(192),
+		.keyed_cksum	= 1,
+		.keylength	= BITS2OCTETS(256),
+		.Kc_length	= BITS2OCTETS(192),
+		.Ke_length	= BITS2OCTETS(256),
+		.Ki_length	= BITS2OCTETS(192),
+
+		.import_ctx	= gss_krb5_import_ctx_v2,
+
+		.get_mic	= gss_krb5_get_mic_v2,
+		.verify_mic	= gss_krb5_verify_mic_v2,
+		.wrap		= gss_krb5_wrap_v2,
+		.unwrap		= gss_krb5_unwrap_v2,
+	},
+#endif
 };
 
 /*