rxrpc: Add YFS RxGK (GSSAPI) security class

Add support for the YFS-variant RxGK security class to support
GSSAPI-derived authentication.  This also allows the use of better crypto
over the rxkad security class.

The key payload is XDR encoded of the form:

    typedef int64_t opr_time;

    const AFSTOKEN_RK_TIX_MAX = 12000; 	/* Matches entry in rxkad.h */

    struct token_rxkad {
	afs_int32 viceid;
	afs_int32 kvno;
	afs_int64 key;
	afs_int32 begintime;
	afs_int32 endtime;
	afs_int32 primary_flag;
	opaque ticket<AFSTOKEN_RK_TIX_MAX>;
    };

    struct token_rxgk {
	opr_time begintime;
	opr_time endtime;
	afs_int64 level;
	afs_int64 lifetime;
	afs_int64 bytelife;
	afs_int64 enctype;
	opaque key<>;
	opaque ticket<>;
    };

    const AFSTOKEN_UNION_NOAUTH = 0;
    const AFSTOKEN_UNION_KAD = 2;
    const AFSTOKEN_UNION_YFSGK = 6;

    union ktc_tokenUnion switch (afs_int32 type) {
	case AFSTOKEN_UNION_KAD:
	    token_rxkad kad;
	case AFSTOKEN_UNION_YFSGK:
	    token_rxgk  gk;
    };

    const AFSTOKEN_LENGTH_MAX = 16384;
    typedef opaque token_opaque<AFSTOKEN_LENGTH_MAX>;

    const AFSTOKEN_MAX = 8;
    const AFSTOKEN_CELL_MAX = 64;

    struct ktc_setTokenData {
	afs_int32 flags;
	string cell<AFSTOKEN_CELL_MAX>;
	token_opaque tokens<AFSTOKEN_MAX>;
    };

The parser for the basic token struct is already present, as is the rxkad
token type.  This adds a parser for the rxgk token type.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-7-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/keys/rxrpc-type.h b/include/keys/rxrpc-type.h
index 333c0f49a9cd..0ddbe197a261 100644
--- a/include/keys/rxrpc-type.h
+++ b/include/keys/rxrpc-type.h
@@ -9,6 +9,7 @@
 #define _KEYS_RXRPC_TYPE_H
 
 #include <linux/key.h>
+#include <crypto/krb5.h>
 
 /*
  * key type for AF_RXRPC keys
@@ -32,6 +33,21 @@ struct rxkad_key {
 };
 
 /*
+ * RxRPC key for YFS-RxGK (type-6 security)
+ */
+struct rxgk_key {
+	s64		begintime;	/* Time at which the ticket starts */
+	s64		endtime;	/* Time at which the ticket ends */
+	u64		lifetime;	/* Maximum lifespan of a connection (seconds) */
+	u64		bytelife;	/* Maximum number of bytes on a connection */
+	unsigned int	enctype;	/* Encoding type */
+	s8		level;		/* Negotiated security RXRPC_SECURITY_PLAIN/AUTH/ENCRYPT */
+	struct krb5_buffer key;		/* Master key, K0 */
+	struct krb5_buffer ticket;	/* Ticket to be passed to server */
+	u8		_key[];		/* Key storage */
+};
+
+/*
  * list of tokens attached to an rxrpc key
  */
 struct rxrpc_key_token {
@@ -40,6 +56,7 @@ struct rxrpc_key_token {
 	struct rxrpc_key_token *next;	/* the next token in the list */
 	union {
 		struct rxkad_key *kad;
+		struct rxgk_key *rxgk;
 	};
 };