[PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[David Howells]

Fix rxrpc_kernel_send_data() to loop around if it detects a short send.
David Laight suggested doing it here rather than wrapping all the calls in
loops.  Further, remove the len argument and use the iterator count instead
and return 0 on success, not the amount copied.

Note this is also a prerequisite for changing the way rxrpc_send_data()
works to return a short send rather than an error if some data was
buffered.

Fixes: 651350d10f93 ("[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
Suggested-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 Documentation/networking/rxrpc.rst |  6 ++++--
 fs/afs/rxrpc.c                     | 28 ++++++++++----------------
 include/net/af_rxrpc.h             |  5 ++---
 net/rxrpc/rxperf.c                 | 11 +++-------
 net/rxrpc/sendmsg.c                | 32 ++++++++++++++++++++----------
 5 files changed, 42 insertions(+), 40 deletions(-)

diff --git a/Documentation/networking/rxrpc.rst b/Documentation/networking/rxrpc.rst
index 8926dab8e2e6..01ad12fdf305 100644
--- a/Documentation/networking/rxrpc.rst
+++ b/Documentation/networking/rxrpc.rst
@@ -870,7 +870,6 @@ The kernel interface functions are as follows:
 	int rxrpc_kernel_send_data(struct socket *sock,
 				   struct rxrpc_call *call,
 				   struct msghdr *msg,
-				   size_t len,
 				   rxrpc_notify_end_tx_t notify_end_rx);
 
      This is used to supply either the request part of a client call or the
@@ -880,13 +879,16 @@ The kernel interface functions are as follows:
      MSG_MORE if there will be subsequent data sends for this call.
 
      The msg must not specify a destination address, control data or any flags
-     other than MSG_MORE.  len is the total amount of data to transmit.
+     other than MSG_MORE.
 
      notify_end_rx can be NULL or it can be used to specify a function to be
      called when the call changes state to end the Tx phase.  This function is
      called with a spinlock held to prevent the last DATA packet from being
      transmitted until the function returns.
 
+     It returns 0 if all the data is queued and a negative error code on
+     failure.
+
  (#) Receive data from a call::
 
 	int rxrpc_kernel_recv_data(struct socket *sock,
diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index d82916657a3d..09d9da92a1be 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -412,8 +412,7 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
 
-	ret = rxrpc_kernel_send_data(call->net->socket, rxcall,
-				     &msg, call->request_size,
+	ret = rxrpc_kernel_send_data(call->net->socket, rxcall, &msg,
 				     afs_notify_end_request_tx);
 	if (ret < 0)
 		goto error_do_abort;
@@ -425,7 +424,6 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
 
 		ret = rxrpc_kernel_send_data(call->net->socket,
 					     call->rxcall, &msg,
-					     iov_iter_count(&msg.msg_iter),
 					     afs_notify_end_request_tx);
 		*call->write_iter = msg.msg_iter;
 
@@ -871,7 +869,7 @@ void afs_send_empty_reply(struct afs_call *call)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
 
-	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, 0,
+	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
 				       afs_notify_end_reply_tx)) {
 	case 0:
 		_leave(" [replied]");
@@ -912,21 +910,17 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
 
-	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
+	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
 				   afs_notify_end_reply_tx);
-	if (n >= 0) {
-		/* Success */
-		_leave(" [replied]");
-		return;
-	}
-
-	if (n == -ENOMEM) {
-		_debug("oom");
-		rxrpc_kernel_abort_call(net->socket, call->rxcall,
-					RXGEN_SS_MARSHAL, -ENOMEM,
-					afs_abort_oom);
+	if (n < 0) {
+		if (n == -ENOMEM) {
+			_debug("oom");
+			rxrpc_kernel_abort_call(net->socket, call->rxcall,
+						RXGEN_SS_MARSHAL, -ENOMEM,
+						afs_abort_oom);
+		}
+		_leave(" [error]");
 	}
-	_leave(" [error]");
 }
 
 /*
diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
index 0fb4c41c9bbf..f3980348ed34 100644
--- a/include/net/af_rxrpc.h
+++ b/include/net/af_rxrpc.h
@@ -64,9 +64,8 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
 					   bool upgrade,
 					   enum rxrpc_interruptibility interruptibility,
 					   unsigned int debug_id);
-int rxrpc_kernel_send_data(struct socket *, struct rxrpc_call *,
-			   struct msghdr *, size_t,
-			   rxrpc_notify_end_tx_t);
+int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
+			   struct msghdr *msg, rxrpc_notify_end_tx_t notify_end_tx);
 int rxrpc_kernel_recv_data(struct socket *, struct rxrpc_call *,
 			   struct iov_iter *, size_t *, bool, u32 *, u16 *);
 bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *,
diff --git a/net/rxrpc/rxperf.c b/net/rxrpc/rxperf.c
index b8df6d22314d..dad04062213f 100644
--- a/net/rxrpc/rxperf.c
+++ b/net/rxrpc/rxperf.c
@@ -525,12 +525,10 @@ static int rxperf_process_call(struct rxperf_call *call)
 		iov_iter_bvec(&msg.msg_iter, WRITE, &bv, 1, len);
 		msg.msg_flags = MSG_MORE;
 		n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg,
-					   len, rxperf_notify_end_reply_tx);
+					   rxperf_notify_end_reply_tx);
 		if (n < 0)
 			return n;
-		if (n == 0)
-			return -EIO;
-		reply_len -= n;
+		reply_len -= len;
 	}
 
 	len = sizeof(rxperf_magic_cookie);
@@ -538,11 +536,8 @@ static int rxperf_process_call(struct rxperf_call *call)
 	iov[0].iov_len	= len;
 	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
 	msg.msg_flags = 0;
-	n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg, len,
+	n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg,
 				   rxperf_notify_end_reply_tx);
-	if (n >= 0)
-		return 0; /* Success */
-
 	if (n == -ENOMEM)
 		rxrpc_kernel_abort_call(rxperf_socket, call->rxcall,
 					RXGEN_SS_MARSHAL, -ENOMEM,
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index ed2c9a51005a..34aae8e789a4 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -794,7 +794,6 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
  * @sock: The socket the call is on
  * @call: The call to send data through
  * @msg: The data to send
- * @len: The amount of data to send
  * @notify_end_tx: Notification that the last packet is queued.
  *
  * Allow a kernel service to send data on a call.  The call must be in an state
@@ -805,8 +804,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
  * Return: %0 if successful and a negative error code otherwise.
  */
 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len,
-			   rxrpc_notify_end_tx_t notify_end_tx)
+			   struct msghdr *msg, rxrpc_notify_end_tx_t notify_end_tx)
 {
 	bool dropped_lock = false;
 	int ret;
@@ -816,15 +814,29 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 	ASSERTCMP(msg->msg_name, ==, NULL);
 	ASSERTCMP(msg->msg_control, ==, NULL);
 
-	mutex_lock(&call->user_mutex);
+	for (;;) {
+		mutex_lock(&call->user_mutex);
 
-	ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
-			      notify_end_tx, &dropped_lock);
-	if (ret == -ESHUTDOWN)
-		ret = call->error;
+		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg,
+				      msg_data_left(msg),
+				      notify_end_tx, &dropped_lock);
+		if (ret == -ESHUTDOWN)
+			ret = call->error;
+
+		if (!dropped_lock)
+			mutex_unlock(&call->user_mutex);
+		if (ret < 0)
+			break;
+		if (msg_data_left(msg) == 0) {
+			ret = 0;
+			break;
+		}
+		if (ret == 0) {
+			ret = -EIO;
+			break;
+		}
+	}
 
-	if (!dropped_lock)
-		mutex_unlock(&call->user_mutex);
 	_leave(" = %d", ret);
 	return ret;
 }

[PATCH net v10 02/14] afs: Fix afs to abort the rxrpc call on send error

[David Howells]

Fix afs_send_empty_reply() and afs_send_simple_reply() to always try to
abort the rxrpc call rather than just aborting on -ENOMEM and otherwise
abandoning it.  If the call is already complete due to network failure or a
received abort, this will do nothing.

Also make afs_make_call() always abort on send error; again, it does
nothing if the rxrpc call is already dead.

Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 fs/afs/rxrpc.c               | 36 +++++++++++-------------------------
 include/trace/events/rxrpc.h |  2 +-
 2 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 09d9da92a1be..2b241716dae7 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -441,10 +441,8 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
 	return;
 
 error_do_abort:
-	if (ret != -ECONNABORTED)
-		rxrpc_kernel_abort_call(call->net->socket, rxcall,
-					RX_USER_ABORT, ret,
-					afs_abort_send_data_error);
+	rxrpc_kernel_abort_call(call->net->socket, rxcall,
+				RX_USER_ABORT, ret, afs_abort_send_data_error);
 	if (call->async) {
 		afs_see_call(call, afs_call_trace_async_abort);
 		return;
@@ -857,6 +855,7 @@ void afs_send_empty_reply(struct afs_call *call)
 {
 	struct afs_net *net = call->net;
 	struct msghdr msg;
+	int ret;
 
 	_enter("");
 
@@ -869,22 +868,12 @@ void afs_send_empty_reply(struct afs_call *call)
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
 
-	switch (rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
-				       afs_notify_end_reply_tx)) {
-	case 0:
-		_leave(" [replied]");
-		return;
-
-	case -ENOMEM:
-		_debug("oom");
+	ret = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
+				     afs_notify_end_reply_tx);
+	if (ret < 0)
 		rxrpc_kernel_abort_call(net->socket, call->rxcall,
-					RXGEN_SS_MARSHAL, -ENOMEM,
-					afs_abort_oom);
-		fallthrough;
-	default:
-		_leave(" [error]");
-		return;
-	}
+					RXGEN_SS_MARSHAL, ret,
+					afs_abort_send_error);
 }
 
 /*
@@ -913,12 +902,9 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
 	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
 				   afs_notify_end_reply_tx);
 	if (n < 0) {
-		if (n == -ENOMEM) {
-			_debug("oom");
-			rxrpc_kernel_abort_call(net->socket, call->rxcall,
-						RXGEN_SS_MARSHAL, -ENOMEM,
-						afs_abort_oom);
-		}
+		rxrpc_kernel_abort_call(net->socket, call->rxcall,
+					RXGEN_SS_MARSHAL, n,
+					afs_abort_send_error);
 		_leave(" [error]");
 	}
 }
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 704a10de6670..554dfb777b93 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -20,10 +20,10 @@
 	/* AFS errors */						\
 	EM(afs_abort_general_error,		"afs-error")		\
 	EM(afs_abort_interrupted,		"afs-intr")		\
-	EM(afs_abort_oom,			"afs-oom")		\
 	EM(afs_abort_op_not_supported,		"afs-op-notsupp")	\
 	EM(afs_abort_probeuuid_negative,	"afs-probeuuid-neg")	\
 	EM(afs_abort_send_data_error,		"afs-send-data")	\
+	EM(afs_abort_send_error,		"afs-send-error")	\
 	EM(afs_abort_unmarshal_error,		"afs-unmarshal")	\
 	EM(afs_abort_unsupported_sec_class,	"afs-unsup-sec-class")	\
 	/* rxperf errors */						\

[PATCH net v10 05/14] rxrpc: Fix update of call->tx_pending without holding lock

[David Howells]

Currently, rxrpc_send_data() updates call->tx_pending just before it
returns - but it won't be holding the call->user_mutex when it does this if
a wait was interrupted by a signal.  This would allow a parallel sendmsg()
to race.

Further, both the callers of rxrpc_send_data() call it with the lock held,
and then it returns an indication through the parameter list to say whether
it has dropped the lock or not - after which the callers both just drop the
lock if it's still held.

Fix this by:

 (1) Moving the release of call->user_mutex down into rxrpc_send_data() and
     get rid of the indicator parameter.  This makes it easier to see where
     the lock is held.

 (2) After waiting, if the attempt to reacquire the mutex is interrupted,
     just return directly there rather than going to out_unlock

 (3) Restricting the txb variable to inside the buffering loop and leaving
     ->tx_pending set until we've queued the buffer.

Note that there's a slight change in behaviour in that wait_for_space
failure now doesn't check for completion because it doesn't hold the call
user_mutex.  The caller, however, should re-issue the send and pick up any
error at a second attempt.

Fixes: b0f571ecd794 ("rxrpc: Fix locking in rxrpc's sendmsg")
Closes: https://sashiko.dev/#/patchset/20260702144919.172295-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 net/rxrpc/sendmsg.c | 61 ++++++++++++++++++++-------------------------
 1 file changed, 27 insertions(+), 34 deletions(-)

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index bbb39835ef9e..b370e440e2fd 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -320,10 +320,9 @@ static int rxrpc_alloc_txqueue(struct sock *sk, struct rxrpc_call *call)
 static int rxrpc_send_data(struct rxrpc_sock *rx,
 			   struct rxrpc_call *call,
 			   struct msghdr *msg, size_t len,
-			   rxrpc_notify_end_tx_t notify_end_tx,
-			   bool *_dropped_lock)
+			   rxrpc_notify_end_tx_t notify_end_tx)
+	__releases(&call->user_mutex)
 {
-	struct rxrpc_txbuf *txb;
 	struct sock *sk = &rx->sk;
 	enum rxrpc_call_state state;
 	long timeo;
@@ -341,23 +340,18 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 
 	ret = rxrpc_wait_to_be_connected(call, &timeo);
 	if (ret < 0)
-		return ret;
+		goto out_unlock;
 
 	if (call->conn->state == RXRPC_CONN_CLIENT_UNSECURED) {
 		ret = rxrpc_init_client_conn_security(call->conn);
 		if (ret < 0)
-			return ret;
+			goto out_unlock;
 	}
 
 	/* this should be in poll */
 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 reload:
-	txb = call->tx_pending;
-	call->tx_pending = NULL;
-	if (txb)
-		rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
-
 	ret = -EPIPE;
 	if (sk->sk_shutdown & SEND_SHUTDOWN)
 		goto maybe_error;
@@ -386,6 +380,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	}
 
 	do {
+		struct rxrpc_txbuf *txb = call->tx_pending;
+
 		if (!txb) {
 			size_t remain;
 
@@ -411,6 +407,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 				ret = -ENOMEM;
 				goto maybe_error;
 			}
+			call->tx_pending = txb;
+		} else {
+			rxrpc_see_txbuf(txb, rxrpc_txbuf_see_send_more);
 		}
 
 		_debug("append");
@@ -446,9 +445,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 
 			ret = call->security->secure_packet(call, txb);
 			if (ret < 0)
-				goto out;
+				goto out_unlock;
 			rxrpc_queue_packet(rx, call, txb, notify_end_tx);
-			txb = NULL;
+			call->tx_pending = NULL;
 		}
 	} while (len > 0 && msg_data_left(msg) > 0);
 
@@ -457,45 +456,46 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	if (rxrpc_call_is_complete(call) &&
 	    call->error < 0)
 		ret = call->error;
-out:
-	call->tx_pending = txb;
+out_unlock:
+	mutex_unlock(&call->user_mutex);
 	_leave(" = %d", ret);
 	return ret;
 
 call_terminated:
-	rxrpc_put_txbuf(txb, rxrpc_txbuf_put_send_aborted);
-	_leave(" = %d", call->error);
-	return call->error;
+	ret = call->error;
+	goto out_unlock;
 
 maybe_error:
 	if (copied)
 		goto success;
-	goto out;
+	goto out_unlock;
 
 efault:
 	ret = -EFAULT;
-	goto out;
+	goto out_unlock;
 
 wait_for_space:
 	ret = -EAGAIN;
 	if (msg->msg_flags & MSG_DONTWAIT)
 		goto maybe_error;
 	mutex_unlock(&call->user_mutex);
-	*_dropped_lock = true;
+
 	ret = rxrpc_wait_for_tx_window(rx, call, &timeo,
 				       msg->msg_flags & MSG_WAITALL);
 	if (ret < 0)
-		goto maybe_error;
+		goto out_nolock;
 	if (call->interruptibility == RXRPC_INTERRUPTIBLE) {
 		if (mutex_lock_interruptible(&call->user_mutex) < 0) {
 			ret = sock_intr_errno(timeo);
-			goto maybe_error;
+			goto out_nolock;
 		}
 	} else {
 		mutex_lock(&call->user_mutex);
 	}
-	*_dropped_lock = false;
 	goto reload;
+out_nolock:
+	_leave(" = %d [intr]", ret);
+	return copied ?: ret;
 }
 
 /*
@@ -661,7 +661,6 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
 int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 {
 	struct rxrpc_call *call;
-	bool dropped_lock = false;
 	int ret;
 
 	struct rxrpc_send_params p = {
@@ -770,16 +769,15 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		ret = 0;
 		break;
 	case RXRPC_CMD_SEND_DATA:
-		ret = rxrpc_send_data(rx, call, msg, len, NULL, &dropped_lock);
-		break;
+		ret = rxrpc_send_data(rx, call, msg, len, NULL);
+		goto error_put;
 	default:
 		ret = -EINVAL;
 		break;
 	}
 
 out_put_unlock:
-	if (!dropped_lock)
-		mutex_unlock(&call->user_mutex);
+	mutex_unlock(&call->user_mutex);
 error_put:
 	rxrpc_put_call(call, rxrpc_call_put_sendmsg);
 	_leave(" = %d", ret);
@@ -807,7 +805,6 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 			   struct msghdr *msg, rxrpc_notify_end_tx_t notify_end_tx)
 {
-	bool dropped_lock = false;
 	int ret;
 
 	_enter("{%d},", call->debug_id);
@@ -819,13 +816,9 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 		mutex_lock(&call->user_mutex);
 
 		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg,
-				      msg_data_left(msg),
-				      notify_end_tx, &dropped_lock);
+				      msg_data_left(msg), notify_end_tx);
 		if (ret == -ESHUTDOWN)
 			ret = call->error;
-
-		if (!dropped_lock)
-			mutex_unlock(&call->user_mutex);
 		if (ret < 0)
 			break;
 		if (msg_data_left(msg) == 0) {

[PATCH net v10 06/14] rxrpc: Fix error handling in rxrpc_send_data()

[David Howells]

Fix the error handling in rxrpc_send_data() so that it doesn't return an
error if it has successfully queued the last packet of a call, but the call
has seen to have completed after it did that.  Rather, leave it to
recvmsg() to report the completion (which it will do anyway).

The problem with trying to report the error twice is that the caller may
try to clean up the dead call twice.

Further, if we haven't queued the final packet yet, return -ESHUTDOWN if
the call is now marked complete (e.g. it got aborted by the peer) as
there's no point sendmsg() continuing to try to add data to a call if it is
defunct.  The application should abort the call and then call recvmsg() to
pick up the reason.

Fixes: 4ba68c519255 ("rxrpc: Return an error to sendmsg if call failed")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Jeffrey Altman <jaltman@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 fs/afs/rxrpc.c      | 11 +++---
 net/rxrpc/rxperf.c  | 38 +++++++++++++-------
 net/rxrpc/sendmsg.c | 86 +++++++++++++++++++++++++++++++++------------
 3 files changed, 95 insertions(+), 40 deletions(-)

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 2b241716dae7..4694a6fca9b4 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -448,13 +448,14 @@ void afs_make_call(struct afs_call *call, gfp_t gfp)
 		return;
 	}
 
-	if (ret == -ECONNABORTED) {
+	if (ret == -ESHUTDOWN) {
 		len = 0;
 		iov_iter_kvec(&msg.msg_iter, ITER_DEST, NULL, 0, 0);
-		rxrpc_kernel_recv_data(call->net->socket, rxcall,
-				       &msg.msg_iter, &len, false,
-				       &call->abort_code, &call->service_id);
-		call->responded = true;
+		ret = rxrpc_kernel_recv_data(call->net->socket, rxcall,
+					     &msg.msg_iter, &len, false,
+					     &call->abort_code, &call->service_id);
+		if (ret == -ECONNABORTED)
+			call->responded = true;
 	}
 	call->error = ret;
 	trace_afs_call_done(call);
diff --git a/net/rxrpc/rxperf.c b/net/rxrpc/rxperf.c
index 7e9a53615309..83016830e696 100644
--- a/net/rxrpc/rxperf.c
+++ b/net/rxrpc/rxperf.c
@@ -74,7 +74,7 @@ static struct workqueue_struct *rxperf_workqueue;
 static void rxperf_deliver_to_call(struct work_struct *work);
 static int rxperf_deliver_param_block(struct rxperf_call *call);
 static int rxperf_deliver_request(struct rxperf_call *call);
-static int rxperf_process_call(struct rxperf_call *call);
+static void rxperf_process_call(struct rxperf_call *call);
 static void rxperf_charge_preallocation(struct work_struct *work);
 
 static DECLARE_WORK(rxperf_charge_preallocation_work,
@@ -293,18 +293,28 @@ static void rxperf_deliver_to_call(struct work_struct *work)
 	       state == RXPERF_CALL_SV_AWAIT_ACK
 	       ) {
 		if (state == RXPERF_CALL_SV_AWAIT_ACK) {
-			if (!rxrpc_kernel_check_life(rxperf_socket, call->rxcall))
+			size_t len = 0;
+			iov_iter_kvec(&call->iter, ITER_DEST, NULL, 0, 0);
+			ret = rxrpc_kernel_recv_data(rxperf_socket,
+						     call->rxcall, &call->iter,
+						     &len, false, &remote_abort,
+						     &call->service_id);
+
+			if (ret == -EINPROGRESS || ret == -EAGAIN)
+				return;
+			if (ret < 0 || ret == 1) {
+				if (ret == 1)
+					ret = 0;
 				goto call_complete;
+			}
 			return;
 		}
 
 		ret = call->deliver(call);
-		if (ret == 0)
-			ret = rxperf_process_call(call);
-
 		switch (ret) {
 		case 0:
-			continue;
+			rxperf_process_call(call);
+			return;
 		case -EINPROGRESS:
 		case -EAGAIN:
 			return;
@@ -508,7 +518,7 @@ static int rxperf_deliver_request(struct rxperf_call *call)
 /*
  * Process a call for which we've received the request.
  */
-static int rxperf_process_call(struct rxperf_call *call)
+static void rxperf_process_call(struct rxperf_call *call)
 {
 	struct msghdr msg = {};
 	struct bio_vec bv;
@@ -527,7 +537,7 @@ static int rxperf_process_call(struct rxperf_call *call)
 		n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg,
 					   rxperf_notify_end_reply_tx);
 		if (n < 0)
-			return n;
+			goto send_error;
 		reply_len -= len;
 	}
 
@@ -539,10 +549,13 @@ static int rxperf_process_call(struct rxperf_call *call)
 	n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg,
 				   rxperf_notify_end_reply_tx);
 	if (n < 0)
-		rxrpc_kernel_abort_call(rxperf_socket, call->rxcall,
-					RXGEN_SS_MARSHAL, n,
-					rxperf_abort_send_error);
-	return n;
+		goto send_error;
+	return;
+
+send_error:
+	rxrpc_kernel_abort_call(rxperf_socket, call->rxcall,
+				RXGEN_SS_MARSHAL, n,
+				rxperf_abort_send_error);
 }
 
 /*
@@ -695,4 +708,3 @@ static void __exit rxperf_exit(void)
 	rcu_barrier();
 }
 module_exit(rxperf_exit);
-
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index b370e440e2fd..1012d2d337a5 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -329,13 +329,6 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	bool more = msg->msg_flags & MSG_MORE;
 	int ret, copied = 0;
 
-	if (test_bit(RXRPC_CALL_TX_NO_MORE, &call->flags)) {
-		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
-				  call->cid, call->call_id, call->rx_consumed,
-				  0, -EPROTO);
-		return -EPROTO;
-	}
-
 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 
 	ret = rxrpc_wait_to_be_connected(call, &timeo);
@@ -352,13 +345,20 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 
 reload:
+	if (unlikely(test_bit(RXRPC_CALL_TX_NO_MORE, &call->flags))) {
+		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
+				  call->cid, call->call_id, call->rx_consumed,
+				  0, -EPROTO);
+		ret = -EPROTO;
+		goto out_unlock;
+	}
+
 	ret = -EPIPE;
 	if (sk->sk_shutdown & SEND_SHUTDOWN)
-		goto maybe_error;
+		goto out_unlock;
 	state = rxrpc_call_state(call);
-	ret = -ESHUTDOWN;
 	if (state >= RXRPC_CALL_COMPLETE)
-		goto maybe_error;
+		goto call_terminated;
 	ret = -EPROTO;
 	if (state != RXRPC_CALL_CLIENT_PRE_SEND &&
 	    state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
@@ -368,7 +368,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_late_send,
 				  call->cid, call->call_id, call->rx_consumed,
 				  0, -EPROTO);
-		goto maybe_error;
+		goto out_unlock;
 	}
 
 	ret = -EMSGSIZE;
@@ -448,31 +448,73 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 				goto out_unlock;
 			rxrpc_queue_packet(rx, call, txb, notify_end_tx);
 			call->tx_pending = NULL;
+
+			/* At this point, if that was the last packet, it may
+			 * have been transmitted and the reply (client call) or
+			 * final ACK (service call) may have been received,
+			 * completing the call.
+			 */
 		}
 	} while (len > 0 && msg_data_left(msg) > 0);
 
-success:
+	/* Don't check for call completeness here, but leave that to recvmsg or
+	 * a further call to sendmsg().
+	 */
 	ret = copied;
-	if (rxrpc_call_is_complete(call) &&
-	    call->error < 0)
-		ret = call->error;
 out_unlock:
 	mutex_unlock(&call->user_mutex);
+out:
+
+	/* The return value is a bit complicated as we want to avoid returning
+	 * an error if we have queued the final packet.  In descending order of
+	 * preference:
+	 *
+	 * (1) If we queue the last packet: the amount copied (which may be
+	 *     zero).  recvmsg() should be used to collect the result.
+	 *
+	 * (2) If another sendmsg() has already queued the last packet: -EPROTO.
+	 *
+	 * (3) If the send side of the socket is shut down, -EPIPE.
+	 *
+	 * (4) If the call is in the wrong state to transmit: -EPROTO.
+	 *
+	 * (5) If the call has terminated early, likely due to an external
+	 *     event such as being remotely aborted: -ESHUTDOWN.
+	 *
+	 * (6) If some data has been copied by this call: the amount copied
+	 *     (which will be greater than zero).
+	 *
+	 * (7) Any other error.
+	 *
+	 * For (2)-(5), there's no point in continuing with the sendmsg().  The
+	 * app should abort the call (just in case the error came from
+	 * somewhere else) and then use recvmsg() to collect the final result
+	 * of the call.
+	 */
 	_leave(" = %d", ret);
 	return ret;
 
 call_terminated:
-	ret = call->error;
+	ret = -ESHUTDOWN;
 	goto out_unlock;
 
 maybe_error:
-	if (copied)
-		goto success;
+	if (copied) {
+		if (test_bit(RXRPC_CALL_TX_NO_MORE, &call->flags)) {
+			/* If we've get here, we must have slept waiting for space and .
+			 */
+			ret = copied;
+			goto out_unlock;
+		}
+		if (rxrpc_call_is_complete(call))
+			goto call_terminated;
+		ret = copied;
+	}
 	goto out_unlock;
 
 efault:
 	ret = -EFAULT;
-	goto out_unlock;
+	goto maybe_error;
 
 wait_for_space:
 	ret = -EAGAIN;
@@ -495,7 +537,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	goto reload;
 out_nolock:
 	_leave(" = %d [intr]", ret);
-	return copied ?: ret;
+	if (copied)
+		ret = copied;
+	goto out;
 }
 
 /*
@@ -817,8 +861,6 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 
 		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg,
 				      msg_data_left(msg), notify_end_tx);
-		if (ret == -ESHUTDOWN)
-			ret = call->error;
 		if (ret < 0)
 			break;
 		if (msg_data_left(msg) == 0) {

[PATCH net v10 07/14] rxrpc: Fix packet encryption error handling

[David Howells]

In rxrpc_send_data(), if ->secure_packet() returns an error, the code
currently just jumps to out: and returns the error to the app on the
assumption that any error returned by this is automatically fatal for the
call, and may even have corrupted the transmission queue - but leaving it
to userspace to deal with.  Nothing stops the application from retrying the
sendmsg(), which will try to encrypt the buffer again, and might succeed
with a corrupt buffer.

Fix rxrpc_send_data() in the following ways:

 (1) If -ENOMEM is returned, assume we never got as far as the encryption
     and that the operation is retryable.  In which case, jump to
     maybe_error_rewind and, if we've copied all remaining data into the
     last packet, remove some of the bytes from it that we just added so
     that we don't tell the caller that we've completed the transmission
     phase.  The iterator is also correspondingly rewound.

 (2) If any other error occurs, set the TX_ERROR flag on the call and
     return that error directly; on all subsequent attempts to add data to
     the call, return -EIO.  The app must then abort the call to get rid of
     it (this allows the app to choose the abort code to use).

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Closes: https://sashiko.dev/#/patchset/20260702144919.172295-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 Documentation/networking/rxrpc.rst |  6 ++-
 include/trace/events/rxrpc.h       |  1 +
 net/rxrpc/ar-internal.h            |  1 +
 net/rxrpc/sendmsg.c                | 63 +++++++++++++++++++++++++-----
 4 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/Documentation/networking/rxrpc.rst b/Documentation/networking/rxrpc.rst
index 01ad12fdf305..9b7eeae84148 100644
--- a/Documentation/networking/rxrpc.rst
+++ b/Documentation/networking/rxrpc.rst
@@ -878,8 +878,10 @@ The kernel interface functions are as follows:
      exclusively to in-kernel virtual addresses.  msg.msg_flags may be given
      MSG_MORE if there will be subsequent data sends for this call.
 
-     The msg must not specify a destination address, control data or any flags
-     other than MSG_MORE.
+     msg must not specify a destination address, control data or any flags
+     other than MSG_MORE.  The last-packet flag will only be set on the
+     outgoing packet if MSG_MORE is not set and all the data in the iterator is
+     buffered.
 
      notify_end_rx can be NULL or it can be used to specify a function to be
      called when the call changes state to end the Tx phase.  This function is
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 56dc9b614071..a5c92592d8f9 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -148,6 +148,7 @@
 	EM(rxrpc_eproto_wrong_security,		"wrong-sec")		\
 	EM(rxrpc_recvmsg_excess_data,		"recvmsg-excess")	\
 	EM(rxrpc_recvmsg_short_data,		"recvmsg-short")	\
+	EM(rxrpc_sendmsg_tx_error,		"tx-error")		\
 	E_(rxrpc_sendmsg_late_send,		"sendmsg-late")
 
 #define rxrpc_call_poke_traces \
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 865f05fe37ab..a6f830c1621f 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -642,6 +642,7 @@ enum rxrpc_call_flag {
 	RXRPC_CALL_TX_LAST,		/* Last packet in Tx buffer (at rxtx_top) */
 	RXRPC_CALL_TX_ALL_ACKED,	/* Last packet has been hard-acked */
 	RXRPC_CALL_TX_NO_MORE,		/* No more data to transmit (MSG_MORE deasserted) */
+	RXRPC_CALL_TX_ERROR,		/* Terminal error; call needs abort */
 	RXRPC_CALL_SEND_PING,		/* A ping will need to be sent */
 	RXRPC_CALL_RETRANS_TIMEOUT,	/* Retransmission due to timeout occurred */
 	RXRPC_CALL_BEGAN_RX_TIMER,	/* We began the expect_rx_by timer */
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 1012d2d337a5..ed7ff32da184 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -325,6 +325,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 {
 	struct sock *sk = &rx->sk;
 	enum rxrpc_call_state state;
+	unsigned int rewind_by = 0;
 	long timeo;
 	bool more = msg->msg_flags & MSG_MORE;
 	int ret, copied = 0;
@@ -352,6 +353,13 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 		ret = -EPROTO;
 		goto out_unlock;
 	}
+	if (unlikely(test_bit(RXRPC_CALL_TX_ERROR, &call->flags))) {
+		trace_rxrpc_abort(call->debug_id, rxrpc_sendmsg_tx_error,
+				  call->cid, call->call_id, call->rx_consumed,
+				  0, -EIO);
+		ret = -EIO;
+		goto out_unlock;
+	}
 
 	ret = -EPIPE;
 	if (sk->sk_shutdown & SEND_SHUTDOWN)
@@ -423,6 +431,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 						 copy, &msg->msg_iter))
 				goto efault;
 			_debug("added");
+			rewind_by = copy;
 			txb->space -= copy;
 			txb->len += copy;
 			txb->offset += copy;
@@ -440,14 +449,29 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 		/* add the packet to the send queue if it's now full */
 		if (!txb->space ||
 		    (len == 0 && !more)) {
+			/* Do any required crypto.  If this fails, it could
+			 * have corrupted the txbuf content with a partial
+			 * encrypt.  Assume that ENOMEM is retryable, but
+			 * everything else is terminal.
+			 */
+			ret = call->security->secure_packet(call, txb);
+			if (ret < 0) {
+				/* Assume that ENOMEM here means that the
+				 * encryption hasn't happened yet.  The data is
+				 * aligned to avoid the need for slow buffering
+				 * in the crypto walk.
+				 */
+				if (ret == -ENOMEM)
+					goto maybe_error_rewind;
+				set_bit(RXRPC_CALL_TX_ERROR, &call->flags);
+				goto out;
+			}
+
 			if (len == 0 && !more)
 				txb->flags |= RXRPC_LAST_PACKET;
-
-			ret = call->security->secure_packet(call, txb);
-			if (ret < 0)
-				goto out_unlock;
 			rxrpc_queue_packet(rx, call, txb, notify_end_tx);
 			call->tx_pending = NULL;
+			rewind_by = 0;
 
 			/* At this point, if that was the last packet, it may
 			 * have been transmitted and the reply (client call) or
@@ -474,19 +498,22 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	 *
 	 * (2) If another sendmsg() has already queued the last packet: -EPROTO.
 	 *
-	 * (3) If the send side of the socket is shut down, -EPIPE.
+	 * (3) If an error caused it to be impossible to continue with the
+	 *     call: -EIO.
 	 *
-	 * (4) If the call is in the wrong state to transmit: -EPROTO.
+	 * (4) If the send side of the socket is shut down, -EPIPE.
 	 *
-	 * (5) If the call has terminated early, likely due to an external
+	 * (5) If the call is in the wrong state to transmit: -EPROTO.
+	 *
+	 * (6) If the call has terminated early, likely due to an external
 	 *     event such as being remotely aborted: -ESHUTDOWN.
 	 *
-	 * (6) If some data has been copied by this call: the amount copied
+	 * (7) If some data has been copied by this call: the amount copied
 	 *     (which will be greater than zero).
 	 *
-	 * (7) Any other error.
+	 * (8) Any other error.
 	 *
-	 * For (2)-(5), there's no point in continuing with the sendmsg().  The
+	 * For (2)-(6), there's no point in continuing with the sendmsg().  The
 	 * app should abort the call (just in case the error came from
 	 * somewhere else) and then use recvmsg() to collect the final result
 	 * of the call.
@@ -498,6 +525,22 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 	ret = -ESHUTDOWN;
 	goto out_unlock;
 
+maybe_error_rewind:
+	/* If we got a retryable error after copying all the supplied data into
+	 * the last packet, we need to rewind as much as we can so the caller
+	 * knows they need to retry the sendmsg.
+	 */
+	if (rewind_by && !more && !len) {
+		struct rxrpc_txbuf *txb = call->tx_pending;
+
+		txb->space  += rewind_by;
+		txb->len    -= rewind_by;
+		txb->offset -= rewind_by;
+		copied      -= rewind_by;
+		if (call->tx_total_len != -1)
+			call->tx_total_len += rewind_by;
+		iov_iter_revert(&msg->msg_iter, rewind_by);
+	}
 maybe_error:
 	if (copied) {
 		if (test_bit(RXRPC_CALL_TX_NO_MORE, &call->flags)) {

[PATCH net v10 10/14] rxrpc: Fix RxGK key parser to check enctype is supported

[David Howells]

Fix the parser of RxGK keys supplied by userspace to check that the
specified encryption type is supported and check the key length.  Further,
since the checking function isn't necessarily available in CONFIG_RXGK=n,
make the RxGK key wrangling bits conditional.

Fixes: 0ca100ff4df6 ("rxrpc: Add YFS RxGK (GSSAPI) security class")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 net/rxrpc/key.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/net/rxrpc/key.c b/net/rxrpc/key.c
index a0aa78d89289..dc1b3aa51bf3 100644
--- a/net/rxrpc/key.c
+++ b/net/rxrpc/key.c
@@ -129,6 +129,7 @@ static int rxrpc_preparse_xdr_rxkad(struct key_preparsed_payload *prep,
 	return 0;
 }
 
+#ifdef CONFIG_RXGK
 static u64 xdr_dec64(const __be32 *xdr)
 {
 	return (u64)ntohl(xdr[0]) << 32 | (u64)ntohl(xdr[1]);
@@ -166,12 +167,14 @@ static int rxrpc_preparse_xdr_yfs_rxgk(struct key_preparsed_payload *prep,
 				       size_t datalen,
 				       const __be32 *xdr, unsigned int toklen)
 {
+	const struct krb5_enctype *enc;
 	struct rxrpc_key_token *token, **pptoken;
 	time64_t expiry;
 	size_t plen;
 	const __be32 *ticket, *key;
 	s64 tmp;
 	size_t raw_keylen, raw_tktlen, keylen, tktlen;
+	int ret = -EKEYREJECTED;
 
 	_enter(",{%x,%x,%x,%x},%x",
 	       ntohl(xdr[0]), ntohl(xdr[1]), ntohl(xdr[2]), ntohl(xdr[3]),
@@ -229,6 +232,17 @@ static int rxrpc_preparse_xdr_yfs_rxgk(struct key_preparsed_payload *prep,
 	token->rxgk->key.data	= token->rxgk->_key;
 	token->rxgk->ticket.len = raw_tktlen;
 
+	/* Check the enctype is supported. */
+	enc = crypto_krb5_find_enctype(token->rxgk->enctype);
+	if (!enc) {
+		ret = -ENOPKG;
+		goto reject_token;
+	}
+	if (raw_keylen != enc->key_len) {
+		ret = -EKEYREJECTED;
+		goto reject_token;
+	}
+
 	if (token->rxgk->endtime != 0) {
 		expiry = rxrpc_s64_to_time64(token->rxgk->endtime);
 		if (expiry < 0)
@@ -280,12 +294,13 @@ static int rxrpc_preparse_xdr_yfs_rxgk(struct key_preparsed_payload *prep,
 	kfree(token->rxgk);
 	kfree(token);
 reject:
-	return -EKEYREJECTED;
+	return ret;
 expired:
 	kfree(token->rxgk);
 	kfree(token);
 	return -EKEYEXPIRED;
 }
+#endif /* CONFIG_RXGK */
 
 /*
  * attempt to parse the data as the XDR format
@@ -386,9 +401,11 @@ static int rxrpc_preparse_xdr(struct key_preparsed_payload *prep)
 		case RXRPC_SECURITY_RXKAD:
 			ret2 = rxrpc_preparse_xdr_rxkad(prep, datalen, token, toklen);
 			break;
+#ifdef CONFIG_RXGK
 		case RXRPC_SECURITY_YFS_RXGK:
 			ret2 = rxrpc_preparse_xdr_yfs_rxgk(prep, datalen, token, toklen);
 			break;
+#endif
 		default:
 			ret2 = -EPROTONOSUPPORT;
 			break;
@@ -556,10 +573,12 @@ static void rxrpc_free_token_list(struct rxrpc_key_token *token)
 		case RXRPC_SECURITY_RXKAD:
 			kfree(token->kad);
 			break;
+#ifdef CONFIG_RXGK
 		case RXRPC_SECURITY_YFS_RXGK:
 			kfree(token->rxgk->ticket.data);
 			kfree(token->rxgk);
 			break;
+#endif
 		default:
 			pr_err("Unknown token type %x on rxrpc key\n",
 			       token->security_index);
@@ -603,9 +622,11 @@ static void rxrpc_describe(const struct key *key, struct seq_file *m)
 		case RXRPC_SECURITY_RXKAD:
 			seq_puts(m, "ka");
 			break;
+#ifdef CONFIG_RXGK
 		case RXRPC_SECURITY_YFS_RXGK:
 			seq_puts(m, "ygk");
 			break;
+#endif
 		default: /* we have a ticket we can't encode */
 			seq_printf(m, "%u", token->security_index);
 			break;
@@ -770,12 +791,14 @@ static long rxrpc_read(const struct key *key,
 				toksize += RND(token->kad->ticket_len);
 			break;
 
+#ifdef CONFIG_RXGK
 		case RXRPC_SECURITY_YFS_RXGK:
 			toksize += 6 * 8 + 2 * 4;
 			if (!token->no_leak_key)
 				toksize += RND(token->rxgk->key.len);
 			toksize += RND(token->rxgk->ticket.len);
 			break;
+#endif
 
 		default: /* we have a ticket we can't encode */
 			pr_err("Unsupported key token type (%u)\n",
@@ -856,6 +879,7 @@ static long rxrpc_read(const struct key *key,
 				ENCODE_DATA(token->kad->ticket_len, token->kad->ticket);
 			break;
 
+#ifdef CONFIG_RXGK
 		case RXRPC_SECURITY_YFS_RXGK:
 			ENCODE64(token->rxgk->begintime);
 			ENCODE64(token->rxgk->endtime);
@@ -869,6 +893,7 @@ static long rxrpc_read(const struct key *key,
 				ENCODE_DATA(token->rxgk->key.len, token->rxgk->key.data);
 			ENCODE_DATA(token->rxgk->ticket.len, token->rxgk->ticket.data);
 			break;
+#endif
 
 		default:
 			pr_err("Unsupported key token type (%u)\n",

[PATCH net v10 11/14] afs: Fix creation of RxGK CM channel token to have right size

[David Howells]

Fix afs_create_yfs_cm_token() so that it calculates the token size
correctly, remembering to add in the 4 bytes of the level.

As it happens, this bug has no effect because crypto_krb5_how_much_buffer()
rounds encsize up to a multiple of the crypto block size (16 or 32) before
adding on the checksum size - and so there's actually 8 bytes of unused
space allocated within the blob-to-be-encrypted and 4 bytes of that gets
used.

Fixes: d98c317fd9aa ("afs: Use rxgk RESPONSE to pass token for callback channel")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 fs/afs/cm_security.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/afs/cm_security.c b/fs/afs/cm_security.c
index 103168c70dd4..5eeeef761cf3 100644
--- a/fs/afs/cm_security.c
+++ b/fs/afs/cm_security.c
@@ -235,7 +235,7 @@ static int afs_create_yfs_cm_token(struct sk_buff *challenge,
 	 *	struct RXGK_AuthName	identities<>;
 	 * };
 	 */
-	toksize = keysize + 8 + 4 + 4 + 8 + xdr_len_object(authsize);
+	toksize = keysize + 4 + 8 + 4 + 4 + 8 + xdr_len_object(authsize);
 
 	offset = 0;
 	encsize = crypto_krb5_how_much_buffer(token_krb5, KRB5_ENCRYPT_MODE, toksize, &offset);

[PATCH net v10 14/14] rxrpc: fix use-after-free in rxrpc_poke_conn()

[David Howells]

From: Seungwon Bae <qotmddnjs@ajou.ac.kr>

rxrpc_poke_conn() takes a reference on the connection with no liveness
check, unlike its sibling rxrpc_queue_conn() which gates on
atomic_read(&conn->active) >= 0.  The per-connection timer is armed with
no reference held for it, and rxrpc_put_connection() cancels it with a
non-synchronous timer_delete() only after the refcount reaches 0.
refcount_t saturates rather than resurrecting, so the connection can be
kfree()d while still linked in local->conn_attend_q (nothing in teardown
unlinks attend_link).  The rxrpc I/O thread then performs a UAF write
(list_del_init) plus UAF reads and indirect calls through conn->security.

Reproduced on a KASAN + PREEMPT kernel: 56 "refcount_t: addition on 0"
saturations at load, escalating to

  BUG: KASAN: slab-use-after-free in rxrpc_io_thread   Write of size 8

AF_RXRPC socket creation (rxrpc_create) has no capability check, so this
is reachable by an unprivileged user.

Guard rxrpc_poke_conn() with the same liveness/refcount check the sibling
rxrpc_queue_conn() uses before taking the poke reference, so a connection
past its last-active point is not poked/requeued after teardown began.

Verified before/after on KASAN+PREEMPT at equal timer volume: 56
saturations + 15 KASAN reports unpatched vs 0 and 0 patched.

Fixes: f2cce89a074e ("rxrpc: Implement a mechanism to send an event notification to a connection")
Signed-off-by: Seungwon Bae <qotmddnjs@ajou.ac.kr>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
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: stable@vger.kernel.org
---
 net/rxrpc/conn_object.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 0ece717db0f8..1be50e0c9cee 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -34,7 +34,10 @@ void rxrpc_poke_conn(struct rxrpc_connection *conn, enum rxrpc_conn_trace why)
 	spin_lock_irq(&local->lock);
 	busy = !list_empty(&conn->attend_link);
 	if (!busy) {
-		rxrpc_get_connection(conn, why);
+		if (!rxrpc_get_connection_maybe(conn, why)) {
+			spin_unlock_irq(&local->lock);
+			return;
+		}
 		list_add_tail(&conn->attend_link, &local->conn_attend_q);
 	}
 	spin_unlock_irq(&local->lock);

Re: [PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[David Laight]

On Mon, 14 Sep 2026 16:13:25 +0100
David Howells <dhowells@redhat.com> wrote:

> Fix rxrpc_kernel_send_data() to loop around if it detects a short send.
> David Laight suggested doing it here rather than wrapping all the calls in
> loops.  Further, remove the len argument and use the iterator count instead
> and return 0 on success, not the amount copied.
> 
> Note this is also a prerequisite for changing the way rxrpc_send_data()
> works to return a short send rather than an error if some data was
> buffered.
> 
> Fixes: 651350d10f93 ("[AF_RXRPC]: Add an interface to the AF_RXRPC module for the AFS filesystem to use")
> Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824091645.415423-1-dhowells%40redhat.com
> Suggested-by: David Laight <david.laight.linux@gmail.com>
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Marc Dionne <marc.dionne@auristor.com>
> cc: Eric Dumazet <edumazet@google.com>
> cc: "David S. Miller" <davem@davemloft.net>
> 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: stable@vger.kernel.org
> ---
>  Documentation/networking/rxrpc.rst |  6 ++++--
>  fs/afs/rxrpc.c                     | 28 ++++++++++----------------
>  include/net/af_rxrpc.h             |  5 ++---
>  net/rxrpc/rxperf.c                 | 11 +++-------
>  net/rxrpc/sendmsg.c                | 32 ++++++++++++++++++++----------
>  5 files changed, 42 insertions(+), 40 deletions(-)
> 
...
> diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
> index d82916657a3d..09d9da92a1be 100644
> --- a/fs/afs/rxrpc.c
> +++ b/fs/afs/rxrpc.c
...
> @@ -912,21 +910,17 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
>  	msg.msg_controllen	= 0;
>  	msg.msg_flags		= 0;
>  
> -	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
> +	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
>  				   afs_notify_end_reply_tx);

Probably needs s/n/ret/

...
> diff --git a/include/net/af_rxrpc.h b/include/net/af_rxrpc.h
> index 0fb4c41c9bbf..f3980348ed34 100644
> --- a/include/net/af_rxrpc.h
> +++ b/include/net/af_rxrpc.h
> @@ -64,9 +64,8 @@ struct rxrpc_call *rxrpc_kernel_begin_call(struct socket *sock,
>  					   bool upgrade,
>  					   enum rxrpc_interruptibility interruptibility,
>  					   unsigned int debug_id);
> -int rxrpc_kernel_send_data(struct socket *, struct rxrpc_call *,
> -			   struct msghdr *, size_t,
> -			   rxrpc_notify_end_tx_t);
> +int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
> +			   struct msghdr *msg, rxrpc_notify_end_tx_t notify_end_tx);
>  int rxrpc_kernel_recv_data(struct socket *, struct rxrpc_call *,
>  			   struct iov_iter *, size_t *, bool, u32 *, u16 *);
>  bool rxrpc_kernel_abort_call(struct socket *, struct rxrpc_call *,
> diff --git a/net/rxrpc/rxperf.c b/net/rxrpc/rxperf.c
> index b8df6d22314d..dad04062213f 100644
> --- a/net/rxrpc/rxperf.c
> +++ b/net/rxrpc/rxperf.c
> @@ -525,12 +525,10 @@ static int rxperf_process_call(struct rxperf_call *call)
>  		iov_iter_bvec(&msg.msg_iter, WRITE, &bv, 1, len);
>  		msg.msg_flags = MSG_MORE;
>  		n = rxrpc_kernel_send_data(rxperf_socket, call->rxcall, &msg,
> -					   len, rxperf_notify_end_reply_tx);
> +					   rxperf_notify_end_reply_tx);

Ditto

David

Re: [PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[Paolo Abeni]

On 9/14/26 5:13 PM, David Howells wrote:
> @@ -816,15 +814,29 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
>  	ASSERTCMP(msg->msg_name, ==, NULL);
>  	ASSERTCMP(msg->msg_control, ==, NULL);
>  
> -	mutex_lock(&call->user_mutex);
> +	for (;;) {
> +		mutex_lock(&call->user_mutex);

FTR coccinelle can't digest the lock inside the loop:

https://netdev-ctrl.bots.linux.dev/build/cocci/results/823484/stderr

but AFAICS the report is a false positive, and I can't think of an easy
way to avoid it.

/P

Re: [PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[David Howells]

Paolo Abeni <pabeni@redhat.com> wrote:

> > -	mutex_lock(&call->user_mutex);
> > +	for (;;) {
> > +		mutex_lock(&call->user_mutex);
> 
> FTR coccinelle can't digest the lock inside the loop:
> 
> https://netdev-ctrl.bots.linux.dev/build/cocci/results/823484/stderr
> 
> but AFAICS the report is a false positive, and I can't think of an easy
> way to avoid it.

I wonder if I should have a separate lock for sending, once sendmsg() has
decided that that's what it's going to do.  The lock would be held across
sleeps for buffer space, but would need to be interruptible in case the call
is aborted (or some other terminal condition occurs).

David

Re: [PATCH net v10 01/14] rxrpc: Fix lack of short-send handling in rxrpc_kernel_send_data()

[David Howells]

David Laight <david.laight.linux@gmail.com> wrote:

> > -	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg, len,
> > +	n = rxrpc_kernel_send_data(net->socket, call->rxcall, &msg,
> >  				   afs_notify_end_reply_tx);
> 
> Probably needs s/n/ret/

I had decided not to do that to keep the patch smaller, but I can make that
change.  I also want to change it from ssize_t to int.

David