RxRPC: Allow key payloads to be passed in XDR form

Allow add_key() and KEYCTL_INSTANTIATE to accept key payloads in XDR form as
described by openafs-1.4.10/src/auth/afs_token.xg.  This provides a way of
passing kaserver, Kerberos 4, Kerberos 5 and GSSAPI keys from userspace, and
allows for future expansion.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/keys/rxrpc-type.h

@@ -21,4 +21,59 @@ extern struct key_type key_type_rxrpc;
 
 extern struct key *rxrpc_get_null_key(const char *);
 
+/*
+ * RxRPC key for Kerberos IV (type-2 security)
+ */
+struct rxkad_key {
+	u32	vice_id;
+	u32	start;			/* time at which ticket starts */
+	u32	expiry;			/* time at which ticket expires */
+	u32	kvno;			/* key version number */
+	u8	primary_flag;		/* T if key for primary cell for this user */
+	u16	ticket_len;		/* length of ticket[] */
+	u8	session_key[8];		/* DES session key */
+	u8	ticket[0];		/* the encrypted ticket */
+};
+
+/*
+ * list of tokens attached to an rxrpc key
+ */
+struct rxrpc_key_token {
+	u16	security_index;		/* RxRPC header security index */
+	struct rxrpc_key_token *next;	/* the next token in the list */
+	union {
+		struct rxkad_key *kad;
+	};
+};
+
+/*
+ * structure of raw payloads passed to add_key() or instantiate key
+ */
+struct rxrpc_key_data_v1 {
+	u32		kif_version;		/* 1 */
+	u16		security_index;
+	u16		ticket_length;
+	u32		expiry;			/* time_t */
+	u32		kvno;
+	u8		session_key[8];
+	u8		ticket[0];
+};
+
+/*
+ * AF_RXRPC key payload derived from XDR format
+ * - based on openafs-1.4.10/src/auth/afs_token.xg
+ */
+#define AFSTOKEN_LENGTH_MAX		16384	/* max payload size */
+#define AFSTOKEN_CELL_MAX		64	/* max cellname length */
+#define AFSTOKEN_MAX			8	/* max tokens per payload */
+#define AFSTOKEN_RK_TIX_MAX		12000	/* max RxKAD ticket size */
+#define AFSTOKEN_GK_KEY_MAX		64	/* max GSSAPI key size */
+#define AFSTOKEN_GK_TOKEN_MAX		16384	/* max GSSAPI token size */
+#define AFSTOKEN_K5_COMPONENTS_MAX	16	/* max K5 components */
+#define AFSTOKEN_K5_NAME_MAX		128	/* max K5 name length */
+#define AFSTOKEN_K5_REALM_MAX		64	/* max K5 realm name length */
+#define AFSTOKEN_K5_TIX_MAX		16384	/* max K5 ticket size */
+#define AFSTOKEN_K5_ADDRESSES_MAX	16	/* max K5 addresses */
+#define AFSTOKEN_K5_AUTHDATA_MAX	16	/* max K5 pieces of auth data */
+
 #endif /* _KEYS_RXRPC_TYPE_H */

net/rxrpc/ar-internal.h

@@ -401,22 +401,6 @@ struct rxrpc_call {
 	__be32			call_id;	/* call ID on connection  */
 };
 
-/*
- * RxRPC key for Kerberos (type-2 security)
- */
-struct rxkad_key {
-	u16	security_index;		/* RxRPC header security index */
-	u16	ticket_len;		/* length of ticket[] */
-	u32	expiry;			/* time at which expires */
-	u32	kvno;			/* key version number */
-	u8	session_key[8];		/* DES session key */
-	u8	ticket[0];		/* the encrypted ticket */
-};
-
-struct rxrpc_key_payload {
-	struct rxkad_key k;
-};
-
 /*
  * locally abort an RxRPC call
  */

net/rxrpc/ar-security.c

@@ -16,6 +16,7 @@
 #include <linux/crypto.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
+#include <keys/rxrpc-type.h>
 #include "ar-internal.h"
 
 static LIST_HEAD(rxrpc_security_methods);
@@ -122,6 +123,7 @@ EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
  */
 int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
 {
+	struct rxrpc_key_token *token;
 	struct rxrpc_security *sec;
 	struct key *key = conn->key;
 	int ret;
@@ -135,7 +137,11 @@ int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
 	if (ret < 0)
 		return ret;
 
-	sec = rxrpc_security_lookup(key->type_data.x[0]);
+	if (!key->payload.data)
+		return -EKEYREJECTED;
+	token = key->payload.data;
+
+	sec = rxrpc_security_lookup(token->security_index);
 	if (!sec)
 		return -EKEYREJECTED;
 	conn->security = sec;

net/rxrpc/rxkad.c

@@ -18,6 +18,7 @@
 #include <linux/ctype.h>
 #include <net/sock.h>
 #include <net/af_rxrpc.h>
+#include <keys/rxrpc-type.h>
 #define rxrpc_debug rxkad_debug
 #include "ar-internal.h"
 
@@ -59,14 +60,14 @@ static DEFINE_MUTEX(rxkad_ci_mutex);
  */
 static int rxkad_init_connection_security(struct rxrpc_connection *conn)
 {
-	struct rxrpc_key_payload *payload;
 	struct crypto_blkcipher *ci;
+	struct rxrpc_key_token *token;
 	int ret;
 
 	_enter("{%d},{%x}", conn->debug_id, key_serial(conn->key));
 
-	payload = conn->key->payload.data;
-	conn->security_ix = payload->k.security_index;
+	token = conn->key->payload.data;
+	conn->security_ix = token->security_index;
 
 	ci = crypto_alloc_blkcipher("pcbc(fcrypt)", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(ci)) {
@@ -75,8 +76,8 @@ static int rxkad_init_connection_security(struct rxrpc_connection *conn)
 		goto error;
 	}
 
-	if (crypto_blkcipher_setkey(ci, payload->k.session_key,
-				    sizeof(payload->k.session_key)) < 0)
+	if (crypto_blkcipher_setkey(ci, token->kad->session_key,
+				    sizeof(token->kad->session_key)) < 0)
 		BUG();
 
 	switch (conn->security_level) {
@@ -110,7 +111,7 @@ error:
  */
 static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
 {
-	struct rxrpc_key_payload *payload;
+	struct rxrpc_key_token *token;
 	struct blkcipher_desc desc;
 	struct scatterlist sg[2];
 	struct rxrpc_crypt iv;
@@ -123,8 +124,8 @@ static void rxkad_prime_packet_security(struct rxrpc_connection *conn)
 	if (!conn->key)
 		return;
 
-	payload = conn->key->payload.data;
-	memcpy(&iv, payload->k.session_key, sizeof(iv));
+	token = conn->key->payload.data;
+	memcpy(&iv, token->kad->session_key, sizeof(iv));
 
 	desc.tfm = conn->cipher;
 	desc.info = iv.x;
@@ -197,7 +198,7 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
 					u32 data_size,
 					void *sechdr)
 {
-	const struct rxrpc_key_payload *payload;
+	const struct rxrpc_key_token *token;
 	struct rxkad_level2_hdr rxkhdr
 		__attribute__((aligned(8))); /* must be all on one page */
 	struct rxrpc_skb_priv *sp;
@@ -219,8 +220,8 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
 	rxkhdr.checksum = 0;
 
 	/* encrypt from the session key */
-	payload = call->conn->key->payload.data;
-	memcpy(&iv, payload->k.session_key, sizeof(iv));
+	token = call->conn->key->payload.data;
+	memcpy(&iv, token->kad->session_key, sizeof(iv));
 	desc.tfm = call->conn->cipher;
 	desc.info = iv.x;
 	desc.flags = 0;
@@ -400,7 +401,7 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
 				       struct sk_buff *skb,
 				       u32 *_abort_code)
 {
-	const struct rxrpc_key_payload *payload;
+	const struct rxrpc_key_token *token;
 	struct rxkad_level2_hdr sechdr;
 	struct rxrpc_skb_priv *sp;
 	struct blkcipher_desc desc;
@@ -431,8 +432,8 @@ static int rxkad_verify_packet_encrypt(const struct rxrpc_call *call,
 	skb_to_sgvec(skb, sg, 0, skb->len);
 
 	/* decrypt from the session key */
-	payload = call->conn->key->payload.data;
-	memcpy(&iv, payload->k.session_key, sizeof(iv));
+	token = call->conn->key->payload.data;
+	memcpy(&iv, token->kad->session_key, sizeof(iv));
 	desc.tfm = call->conn->cipher;
 	desc.info = iv.x;
 	desc.flags = 0;
@@ -737,7 +738,7 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 				      struct sk_buff *skb,
 				      u32 *_abort_code)
 {
-	const struct rxrpc_key_payload *payload;
+	const struct rxrpc_key_token *token;
 	struct rxkad_challenge challenge;
 	struct rxkad_response resp
 		__attribute__((aligned(8))); /* must be aligned for crypto */
@@ -778,7 +779,7 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 	if (conn->security_level < min_level)
 		goto protocol_error;
 
-	payload = conn->key->payload.data;
+	token = conn->key->payload.data;
 
 	/* build the response packet */
 	memset(&resp, 0, sizeof(resp));
@@ -797,13 +798,13 @@ static int rxkad_respond_to_challenge(struct rxrpc_connection *conn,
 		(conn->channels[3] ? conn->channels[3]->call_id : 0);
 	resp.encrypted.inc_nonce = htonl(nonce + 1);
 	resp.encrypted.level = htonl(conn->security_level);
-	resp.kvno = htonl(payload->k.kvno);
-	resp.ticket_len = htonl(payload->k.ticket_len);
+	resp.kvno = htonl(token->kad->kvno);
+	resp.ticket_len = htonl(token->kad->ticket_len);
 
 	/* calculate the response checksum and then do the encryption */
 	rxkad_calc_response_checksum(&resp);
-	rxkad_encrypt_response(conn, &resp, &payload->k);
-	return rxkad_send_response(conn, &sp->hdr, &resp, &payload->k);
+	rxkad_encrypt_response(conn, &resp, token->kad);
+	return rxkad_send_response(conn, &sp->hdr, &resp, token->kad);
 
 protocol_error:
 	*_abort_code = abort_code;