linux-toradex.git/net/rxrpc/local_object.c, branch v6.8

rxrpc: Fix use of Don't Fragment flag

2024-01-12T00:41:41+00:00

rxrpc normally has the Don't Fragment flag set on the UDP packets it
transmits, except when it has decided that DATA packets aren't getting
through - in which case it turns it off just for the DATA transmissions.
This can be a problem, however, for RESPONSE packets that convey
authentication and crypto data from the client to the server as ticket may
be larger than can fit in the MTU.

In such a case, rxrpc gets itself into an infinite loop as the sendmsg
returns an error (EMSGSIZE), which causes rxkad_send_response() to return
-EAGAIN - and the CHALLENGE packet is put back on the Rx queue to retry,
leading to the I/O thread endlessly attempting to perform the transmission.

Fix this by disabling DF on RESPONSE packets for now.  The use of DF and
best data MTU determination needs reconsidering at some point in the
future.

Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: Marc Dionne 
Signed-off-by: David Howells 
cc: linux-afs@lists.infradead.org
Acked-by: Paolo Abeni 
Link: https://lore.kernel.org/r/1581852.1704813048@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Fix two connection reaping bugs

2023-11-02T05:28:55+00:00

Fix two connection reaping bugs:

 (1) rxrpc_connection_expiry is in units of seconds, so
     rxrpc_disconnect_call() needs to multiply it by HZ when adding it to
     jiffies.

 (2) rxrpc_client_conn_reap_timeout() should set RXRPC_CLIENT_REAP_TIMER if
     local->kill_all_client_conns is clear, not if it is set (in which case
     we don't need the timer).  Without this, old client connections don't
     get cleaned up until the local endpoint is cleaned up.

Fixes: 5040011d073d ("rxrpc: Make the local endpoint hold a ref on a connected call")
Fixes: 0d6bf319bc5a ("rxrpc: Move the client conn cache management to the I/O thread")
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/783911.1698364174@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski

rxrpc: Remove local->defrag_sem

2023-01-31T16:38:35+00:00

We no longer need local->defrag_sem as all DATA packet transmission is now
done from one thread, so remove it.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Allow a delay to be injected into packet reception

2023-01-31T16:38:09+00:00

If CONFIG_AF_RXRPC_DEBUG_RX_DELAY=y, then a delay is injected between
packets and errors being received and them being made available to the
processing code, thereby allowing the RTT to be artificially increased.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Move client call connection to the I/O thread

2023-01-06T09:43:33+00:00

Move the connection setup of client calls to the I/O thread so that a whole
load of locking and barrierage can be eliminated.  This necessitates the
app thread waiting for connection to complete before it can begin
encrypting data.

This also completes the fix for a race that exists between call connection
and call disconnection whereby the data transmission code adds the call to
the peer error distribution list after the call has been disconnected (say
by the rxrpc socket getting closed).

The fix is to complete the process of moving call connection, data
transmission and call disconnection into the I/O thread and thus forcibly
serialising them.

Note that the issue may predate the overhaul to an I/O thread model that
were included in the merge window for v6.2, but the timing is very much
changed by the change given below.

Fixes: cf37b5987508 ("rxrpc: Move DATA transmission into call processor work item")
Reported-by: syzbot+c22650d2844392afdcfd@syzkaller.appspotmail.com
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Move the client conn cache management to the I/O thread

2023-01-06T09:43:33+00:00

Move the management of the client connection cache to the I/O thread rather
than managing it from the namespace as an aggregate across all the local
endpoints within the namespace.

This will allow a load of locking to be got rid of in a future patch as
only the I/O thread will be looking at the this.

The downside is that the total number of cached connections on the system
can get higher because the limit is now per-local rather than per-netns.
We can, however, keep the number of client conns in use across the entire
netfs and use that to reduce the expiration time of idle connection.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Make the set of connection IDs per local endpoint

2023-01-06T09:43:32+00:00

Make the set of connection IDs per local endpoint so that endpoints don't
cause each other's connections to get dismissed.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Implement a mechanism to send an event notification to a connection

2023-01-06T09:43:31+00:00

Provide a means by which an event notification can be sent to a connection
through such that the I/O thread can pick it up and handle it rather than
doing it in a separate workqueue.

This is then used to move the deferred final ACK of a call into the I/O
thread rather than a separate work queue as part of the drive to do all
transmission from the I/O thread.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Stash the network namespace pointer in rxrpc_local

2023-01-06T09:43:31+00:00

Stash the network namespace pointer in the rxrpc_local struct in addition
to a pointer to the rxrpc-specific net namespace info.  Use this to remove
some places where the socket is passed as a parameter.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Fix I/O thread startup getting skipped

2022-12-19T09:51:31+00:00

When starting a kthread, the __kthread_create_on_node() function, as called
from kthread_run(), waits for a completion to indicate that the task_struct
(or failure state) of the new kernel thread is available before continuing.

This does not wait, however, for the thread function to be invoked and,
indeed, will skip it if kthread_stop() gets called before it gets there.

If this happens, though, kthread_run() will have returned successfully,
indicating that the thread was started and returning the task_struct
pointer.  The actual error indication is returned by kthread_stop().

Note that this is ambiguous, as the caller cannot tell whether the -EINTR
error code came from kthread() or from the thread function.

This was encountered in the new rxrpc I/O thread, where if the system is
being pounded hard by, say, syzbot, the check of KTHREAD_SHOULD_STOP can be
delayed long enough for kthread_stop() to get called when rxrpc releases a
socket - and this causes an oops because the I/O thread function doesn't
get started and thus doesn't remove the rxrpc_local struct from the
local_endpoints list.

Fix this by using a completion to wait for the thread to actually enter
rxrpc_io_thread().  This makes sure the thread can't be prematurely
stopped and makes sure the relied-upon cleanup is done.

Fixes: a275da62e8c1 ("rxrpc: Create a per-local endpoint receive queue and I/O thread")
Reported-by: syzbot+3538a6a72efa8b059c38@syzkaller.appspotmail.com
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: Hillf Danton 
Link: https://lore.kernel.org/r/000000000000229f1505ef2b6159@google.com/
Signed-off-by: David S. Miller