[PATCH 6.3 052/246] rxrpc: Make it so that a waiting process can be aborted

[Greg Kroah-Hartman]

From: David Howells <dhowells at redhat.com>

[ Upstream commit 0eb362d254814ce04848730bf32e75b8ee1a4d6c ]

When sendmsg() creates an rxrpc call, it queues it to wait for a connection
and channel to be assigned and then waits before it can start shovelling
data as the encrypted DATA packet content includes a summary of the
connection parameters.

However, sendmsg() may get interrupted before a connection gets assigned
and further sendmsg() calls will fail with EBUSY until an assignment is
made.

Fix this so that the call can at least be aborted without failing on
EBUSY.  We have to be careful here as sendmsg() mustn't be allowed to start
the call timer if the call doesn't yet have a connection assigned as an
oops may follow shortly thereafter.

Fixes: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Reported-by: Marc Dionne <marc.dionne at auristor.com>
Signed-off-by: David Howells <dhowells at redhat.com>
cc: "David S. Miller" <davem at davemloft.net>
cc: Eric Dumazet <edumazet at google.com>
cc: Jakub Kicinski <kuba at kernel.org>
cc: Paolo Abeni <pabeni at redhat.com>
cc: linux-afs at lists.infradead.org
cc: netdev at vger.kernel.org
cc: linux-kernel at vger.kernel.org
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 net/rxrpc/sendmsg.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 7498a77b5d397..c1b074c17b33e 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -656,10 +656,13 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 			goto out_put_unlock;
 	} else {
 		switch (rxrpc_call_state(call)) {
-		case RXRPC_CALL_UNINITIALISED:
 		case RXRPC_CALL_CLIENT_AWAIT_CONN:
-		case RXRPC_CALL_SERVER_PREALLOC:
 		case RXRPC_CALL_SERVER_SECURING:
+			if (p.command == RXRPC_CMD_SEND_ABORT)
+				break;
+			fallthrough;
+		case RXRPC_CALL_UNINITIALISED:
+		case RXRPC_CALL_SERVER_PREALLOC:
 			rxrpc_put_call(call, rxrpc_call_put_sendmsg);
 			ret = -EBUSY;
 			goto error_release_sock;
-- 
2.39.2