rxrpc: Allow CHALLENGEs to the passed to the app for a RESPONSE

Allow the app to request that CHALLENGEs be passed to it through an
out-of-band queue that allows recvmsg() to pick it up so that the app can
add data to it with sendmsg().

This will allow the application (AFS or userspace) to interact with the
process if it wants to and put values into user-defined fields.  This will
be used by AFS when talking to a fileserver to supply that fileserver with
a crypto key by which callback RPCs can be encrypted (ie. notifications
from the fileserver to the client).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Simon Horman <horms@kernel.org>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20250411095303.2316168-5-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 75 insertions, 13 deletions

diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index ebb6092c488b..0b209f703ffc 100644
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -16,6 +16,7 @@ struct sock;
 struct socket;
 struct rxrpc_call;
 struct rxrpc_peer;
+struct krb5_buffer;
 enum rxrpc_abort_reason;
 
 enum rxrpc_interruptibility {
@@ -24,6 +25,10 @@ enum rxrpc_interruptibility {
 	RXRPC_UNINTERRUPTIBLE,	/* Call should not be interruptible at all */
 };
 
+enum rxrpc_oob_type {
+	RXRPC_OOB_CHALLENGE,	/* Security challenge for a connection */
+};
+
 /*
  * Debug ID counter for tracing.
  */
@@ -37,6 +42,7 @@ struct rxrpc_kernel_ops {
 				unsigned long user_call_ID);
 	void (*discard_new_call)(struct rxrpc_call *call, unsigned long user_call_ID);
 	void (*user_attach_call)(struct rxrpc_call *call, unsigned long user_call_ID);
+	void (*notify_oob)(struct sock *sk, struct sk_buff *oob);
 };
 
 typedef void (*rxrpc_notify_rx_t)(struct sock *, struct rxrpc_call *,
@@ -88,5 +94,23 @@ void rxrpc_kernel_set_max_life(struct socket *, struct rxrpc_call *,
 
 int rxrpc_sock_set_min_security_level(struct sock *sk, unsigned int val);
 int rxrpc_sock_set_security_keyring(struct sock *, struct key *);
+int rxrpc_sock_set_manage_response(struct sock *sk, bool set);
+
+enum rxrpc_oob_type rxrpc_kernel_query_oob(struct sk_buff *oob,
+					   struct rxrpc_peer **_peer,
+					   unsigned long *_peer_appdata);
+struct sk_buff *rxrpc_kernel_dequeue_oob(struct socket *sock,
+					 enum rxrpc_oob_type *_type);
+void rxrpc_kernel_free_oob(struct sk_buff *oob);
+void rxrpc_kernel_query_challenge(struct sk_buff *challenge,
+				  struct rxrpc_peer **_peer,
+				  unsigned long *_peer_appdata,
+				  u16 *_service_id, u8 *_security_index);
+int rxrpc_kernel_reject_challenge(struct sk_buff *challenge, u32 abort_code,
+				  int error, enum rxrpc_abort_reason why);
+int rxkad_kernel_respond_to_challenge(struct sk_buff *challenge);
+u32 rxgk_kernel_query_challenge(struct sk_buff *challenge);
+int rxgk_kernel_respond_to_challenge(struct sk_buff *challenge,
+				     struct krb5_buffer *appdata);
 
 #endif /* _NET_RXRPC_H */
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index cad50d91077e..08ecebd90595 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -25,6 +25,7 @@
 	EM(afs_abort_probeuuid_negative,	"afs-probeuuid-neg")	\
 	EM(afs_abort_send_data_error,		"afs-send-data")	\
 	EM(afs_abort_unmarshal_error,		"afs-unmarshal")	\
+	EM(afs_abort_unsupported_sec_class,	"afs-unsup-sec-class")	\
 	/* rxperf errors */						\
 	EM(rxperf_abort_general_error,		"rxperf-error")		\
 	EM(rxperf_abort_oom,			"rxperf-oom")		\
@@ -77,6 +78,7 @@
 	EM(rxrpc_abort_call_timeout,		"call-timeout")		\
 	EM(rxrpc_abort_no_service_key,		"no-serv-key")		\
 	EM(rxrpc_abort_nomem,			"nomem")		\
+	EM(rxrpc_abort_response_sendmsg,	"resp-sendmsg")		\
 	EM(rxrpc_abort_service_not_offered,	"serv-not-offered")	\
 	EM(rxrpc_abort_shut_down,		"shut-down")		\
 	EM(rxrpc_abort_unsupported_security,	"unsup-sec")		\
@@ -133,24 +135,33 @@
 	EM(rxrpc_skb_get_conn_secured,		"GET conn-secd") \
 	EM(rxrpc_skb_get_conn_work,		"GET conn-work") \
 	EM(rxrpc_skb_get_local_work,		"GET locl-work") \
+	EM(rxrpc_skb_get_post_oob,		"GET post-oob ") \
 	EM(rxrpc_skb_get_reject_work,		"GET rej-work ") \
 	EM(rxrpc_skb_get_to_recvmsg,		"GET to-recv  ") \
 	EM(rxrpc_skb_get_to_recvmsg_oos,	"GET to-recv-o") \
 	EM(rxrpc_skb_new_encap_rcv,		"NEW encap-rcv") \
 	EM(rxrpc_skb_new_error_report,		"NEW error-rpt") \
 	EM(rxrpc_skb_new_jumbo_subpacket,	"NEW jumbo-sub") \
+	EM(rxrpc_skb_new_response_rxgk,		"NEW resp-rxgk") \
+	EM(rxrpc_skb_new_response_rxkad,	"NEW resp-rxkd") \
 	EM(rxrpc_skb_new_unshared,		"NEW unshared ") \
 	EM(rxrpc_skb_put_call_rx,		"PUT call-rx  ") \
+	EM(rxrpc_skb_put_challenge,		"PUT challenge") \
 	EM(rxrpc_skb_put_conn_secured,		"PUT conn-secd") \
 	EM(rxrpc_skb_put_conn_work,		"PUT conn-work") \
 	EM(rxrpc_skb_put_error_report,		"PUT error-rep") \
 	EM(rxrpc_skb_put_input,			"PUT input    ") \
 	EM(rxrpc_skb_put_jumbo_subpacket,	"PUT jumbo-sub") \
+	EM(rxrpc_skb_put_oob,			"PUT oob      ") \
 	EM(rxrpc_skb_put_purge,			"PUT purge    ") \
+	EM(rxrpc_skb_put_purge_oob,		"PUT purge-oob") \
+	EM(rxrpc_skb_put_response,		"PUT response ") \
 	EM(rxrpc_skb_put_rotate,		"PUT rotate   ") \
 	EM(rxrpc_skb_put_unknown,		"PUT unknown  ") \
 	EM(rxrpc_skb_see_conn_work,		"SEE conn-work") \
+	EM(rxrpc_skb_see_oob_challenge,		"SEE oob-chall") \
 	EM(rxrpc_skb_see_recvmsg,		"SEE recvmsg  ") \
+	EM(rxrpc_skb_see_recvmsg_oob,		"SEE recvm-oob") \
 	EM(rxrpc_skb_see_reject,		"SEE reject   ") \
 	EM(rxrpc_skb_see_rotate,		"SEE rotate   ") \
 	E_(rxrpc_skb_see_version,		"SEE version  ")
@@ -216,9 +227,11 @@
 	EM(rxrpc_conn_free,			"FREE        ") \
 	EM(rxrpc_conn_get_activate_call,	"GET act-call") \
 	EM(rxrpc_conn_get_call_input,		"GET inp-call") \
+	EM(rxrpc_conn_get_challenge_input,	"GET inp-chal") \
 	EM(rxrpc_conn_get_conn_input,		"GET inp-conn") \
 	EM(rxrpc_conn_get_idle,			"GET idle    ") \
 	EM(rxrpc_conn_get_poke_abort,		"GET pk-abort") \
+	EM(rxrpc_conn_get_poke_response,	"GET response") \
 	EM(rxrpc_conn_get_poke_secured,		"GET secured ") \
 	EM(rxrpc_conn_get_poke_timer,		"GET poke    ") \
 	EM(rxrpc_conn_get_service_conn,		"GET svc-conn") \
@@ -226,10 +239,12 @@
 	EM(rxrpc_conn_new_service,		"NEW service ") \
 	EM(rxrpc_conn_put_call,			"PUT call    ") \
 	EM(rxrpc_conn_put_call_input,		"PUT inp-call") \
+	EM(rxrpc_conn_put_challenge_input,	"PUT inp-chal") \
 	EM(rxrpc_conn_put_conn_input,		"PUT inp-conn") \
 	EM(rxrpc_conn_put_discard_idle,		"PUT disc-idl") \
 	EM(rxrpc_conn_put_local_dead,		"PUT loc-dead") \
 	EM(rxrpc_conn_put_noreuse,		"PUT noreuse ") \
+	EM(rxrpc_conn_put_oob,			"PUT oob     ") \
 	EM(rxrpc_conn_put_poke,			"PUT poke    ") \
 	EM(rxrpc_conn_put_service_reaped,	"PUT svc-reap") \
 	EM(rxrpc_conn_put_unbundle,		"PUT unbundle") \
@@ -331,6 +346,7 @@
 	EM(rxrpc_recvmsg_full,			"FULL") \
 	EM(rxrpc_recvmsg_hole,			"HOLE") \
 	EM(rxrpc_recvmsg_next,			"NEXT") \
+	EM(rxrpc_recvmsg_oobq,			"OOBQ") \
 	EM(rxrpc_recvmsg_requeue,		"REQU") \
 	EM(rxrpc_recvmsg_return,		"RETN") \
 	EM(rxrpc_recvmsg_terminal,		"TERM") \
@@ -456,7 +472,7 @@
 	EM(rxrpc_tx_point_conn_abort,		"ConnAbort") \
 	EM(rxrpc_tx_point_reject,		"Reject") \
 	EM(rxrpc_tx_point_rxkad_challenge,	"RxkadChall") \
-	EM(rxrpc_tx_point_rxkad_response,	"RxkadResp") \
+	EM(rxrpc_tx_point_response,		"Response") \
 	EM(rxrpc_tx_point_version_keepalive,	"VerKeepalive") \
 	E_(rxrpc_tx_point_version_reply,	"VerReply")
 
diff --git a/include/uapi/linux/rxrpc.h b/include/uapi/linux/rxrpc.h
index 8f8dc7a937a4..c4e9833b0a12 100644
--- a/include/uapi/linux/rxrpc.h
+++ b/include/uapi/linux/rxrpc.h
@@ -36,26 +36,33 @@ struct sockaddr_rxrpc {
 #define RXRPC_MIN_SECURITY_LEVEL	4	/* minimum security level */
 #define RXRPC_UPGRADEABLE_SERVICE	5	/* Upgrade service[0] -> service[1] */
 #define RXRPC_SUPPORTED_CMSG		6	/* Get highest supported control message type */
+#define RXRPC_MANAGE_RESPONSE		7	/* [clnt] Want to manage RESPONSE packets */
 
 /*
  * RxRPC control messages
  * - If neither abort or accept are specified, the message is a data message.
  * - terminal messages mean that a user call ID tag can be recycled
+ * - C/S/- indicate whether these are applicable to client, server or both
  * - s/r/- indicate whether these are applicable to sendmsg() and/or recvmsg()
  */
 enum rxrpc_cmsg_type {
-	RXRPC_USER_CALL_ID	= 1,	/* sr: user call ID specifier */
-	RXRPC_ABORT		= 2,	/* sr: abort request / notification [terminal] */
-	RXRPC_ACK		= 3,	/* -r: [Service] RPC op final ACK received [terminal] */
-	RXRPC_NET_ERROR		= 5,	/* -r: network error received [terminal] */
-	RXRPC_BUSY		= 6,	/* -r: server busy received [terminal] */
-	RXRPC_LOCAL_ERROR	= 7,	/* -r: local error generated [terminal] */
-	RXRPC_NEW_CALL		= 8,	/* -r: [Service] new incoming call notification */
-	RXRPC_EXCLUSIVE_CALL	= 10,	/* s-: Call should be on exclusive connection */
-	RXRPC_UPGRADE_SERVICE	= 11,	/* s-: Request service upgrade for client call */
-	RXRPC_TX_LENGTH		= 12,	/* s-: Total length of Tx data */
-	RXRPC_SET_CALL_TIMEOUT	= 13,	/* s-: Set one or more call timeouts */
-	RXRPC_CHARGE_ACCEPT	= 14,	/* s-: Charge the accept pool with a user call ID */
+	RXRPC_USER_CALL_ID	= 1,	/* -sr: User call ID specifier */
+	RXRPC_ABORT		= 2,	/* -sr: Abort request / notification [terminal] */
+	RXRPC_ACK		= 3,	/* S-r: RPC op final ACK received [terminal] */
+	RXRPC_NET_ERROR		= 5,	/* --r: Network error received [terminal] */
+	RXRPC_BUSY		= 6,	/* C-r: Server busy received [terminal] */
+	RXRPC_LOCAL_ERROR	= 7,	/* --r: Local error generated [terminal] */
+	RXRPC_NEW_CALL		= 8,	/* S-r: New incoming call notification */
+	RXRPC_EXCLUSIVE_CALL	= 10,	/* Cs-: Call should be on exclusive connection */
+	RXRPC_UPGRADE_SERVICE	= 11,	/* Cs-: Request service upgrade for client call */
+	RXRPC_TX_LENGTH		= 12,	/* -s-: Total length of Tx data */
+	RXRPC_SET_CALL_TIMEOUT	= 13,	/* -s-: Set one or more call timeouts */
+	RXRPC_CHARGE_ACCEPT	= 14,	/* Ss-: Charge the accept pool with a user call ID */
+	RXRPC_OOB_ID		= 15,	/* -sr: OOB message ID */
+	RXRPC_CHALLENGED	= 16,	/* C-r: Info on a received CHALLENGE */
+	RXRPC_RESPOND		= 17,	/* Cs-: Respond to a challenge */
+	RXRPC_RESPONDED		= 18,	/* S-r: Data received in RESPONSE */
+	RXRPC_RESP_RXGK_APPDATA	= 19,	/* Cs-: RESPONSE: RxGK app data to include */
 	RXRPC__SUPPORTED
 };
 
@@ -118,4 +125,19 @@ enum rxrpc_cmsg_type {
 #define RXKADDATALEN		19270411	/* user data too long */
 #define RXKADILLEGALLEVEL	19270412	/* caller not authorised to use encrypted conns */
 
+/*
+ * Challenge information in the RXRPC_CHALLENGED control message.
+ */
+struct rxrpc_challenge {
+	__u16		service_id;	/* The service ID of the connection (may be upgraded) */
+	__u8		security_index;	/* The security index of the connection */
+	__u8		pad;		/* Round out to a multiple of 4 bytes. */
+	/* ... The security class gets to append extra information ... */
+};
+
+struct rxgk_challenge {
+	struct rxrpc_challenge	base;
+	__u32			enctype;	/* Krb5 encoding type */
+};
+
 #endif /* _UAPI_LINUX_RXRPC_H */