linux.git/net/rxrpc/sendmsg.c, branch v6.11

rxrpc: Fix error check on ->alloc_txbuf()

2024-03-14T12:09:53+00:00

rxrpc_alloc_*_txbuf() and ->alloc_txbuf() return NULL to indicate no
memory, but rxrpc_send_data() uses IS_ERR().

Fix rxrpc_send_data() to check for NULL only and set -ENOMEM if it sees
that.

Fixes: 49489bb03a50 ("rxrpc: Do zerocopy using MSG_SPLICE_PAGES and page frags")
Signed-off-by: David Howells 
Reported-by: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
Signed-off-by: Paolo Abeni

rxrpc: Use ktimes for call timeout tracking and set the timer lazily

2024-03-05T23:35:25+00:00

Track the call timeouts as ktimes rather than jiffies as the latter's
granularity is too high and only set the timer at the end of the event
handling function.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc: Do zerocopy using MSG_SPLICE_PAGES and page frags

2024-03-05T23:31:43+00:00

Switch from keeping the transmission buffers in the rxrpc_txbuf struct and
allocated from the slab, to allocating them using page fragment allocators
(which uses raw pages), thereby allowing them to be passed to
MSG_SPLICE_PAGES and avoid copying into the UDP buffers.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc: Add a kvec[] to the rxrpc_txbuf struct

2024-02-29T15:49:59+00:00

Add a kvec[] to the rxrpc_txbuf struct to point to the contributory buffers
for a packet.  Start with just a single element for now, but this will be
expanded later.

Make the ACK sending function use it, which means that rxrpc_fill_out_ack()
doesn't need to return the size of the sack table, padding and trailer.

Make the data sending code use it, both in where sendmsg() packages code up
into txbufs and where those txbufs are transmitted.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc: Convert rxrpc_txbuf::flags into a mask and don't use atomics

2024-02-29T15:49:56+00:00

Convert the transmission buffer flags into a mask and use | and & rather
than bitops functions (atomic ops are not required as only the I/O thread
can manipulate them once submitted for transmission).

The bottom byte can then correspond directly to the Rx protocol header
flags.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc, afs: Allow afs to pin rxrpc_peer objects

2023-12-24T15:22:50+00:00

Change rxrpc's API such that:

 (1) A new function, rxrpc_kernel_lookup_peer(), is provided to look up an
     rxrpc_peer record for a remote address and a corresponding function,
     rxrpc_kernel_put_peer(), is provided to dispose of it again.

 (2) When setting up a call, the rxrpc_peer object used during a call is
     now passed in rather than being set up by rxrpc_connect_call().  For
     afs, this meenat passing it to rxrpc_kernel_begin_call() rather than
     the full address (the service ID then has to be passed in as a
     separate parameter).

 (3) A new function, rxrpc_kernel_remote_addr(), is added so that afs can
     get a pointer to the transport address for display purposed, and
     another, rxrpc_kernel_remote_srx(), to gain a pointer to the full
     rxrpc address.

 (4) The function to retrieve the RTT from a call, rxrpc_kernel_get_srtt(),
     is then altered to take a peer.  This now returns the RTT or -1 if
     there are insufficient samples.

 (5) Rename rxrpc_kernel_get_peer() to rxrpc_kernel_call_get_peer().

 (6) Provide a new function, rxrpc_kernel_get_peer(), to get a ref on a
     peer the caller already has.

This allows the afs filesystem to pin the rxrpc_peer records that it is
using, allowing faster lookups and pointer comparisons rather than
comparing sockaddr_rxrpc contents.  It also makes it easier to get hold of
the RTT.  The following changes are made to afs:

 (1) The addr_list struct's addrs[] elements now hold a peer struct pointer
     and a service ID rather than a sockaddr_rxrpc.

 (2) When displaying the transport address, rxrpc_kernel_remote_addr() is
     used.

 (3) The port arg is removed from afs_alloc_addrlist() since it's always
     overridden.

 (4) afs_merge_fs_addr4() and afs_merge_fs_addr6() do peer lookup and may
     now return an error that must be handled.

 (5) afs_find_server() now takes a peer pointer to specify the address.

 (6) afs_find_server(), afs_compare_fs_alists() and afs_merge_fs_addr[46]{}
     now do peer pointer comparison rather than address comparison.

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

rxrpc: Fix timeout of a call that hasn't yet been granted a channel

2023-05-01T06:43:19+00:00

afs_make_call() calls rxrpc_kernel_begin_call() to begin a call (which may
get stalled in the background waiting for a connection to become
available); it then calls rxrpc_kernel_set_max_life() to set the timeouts -
but that starts the call timer so the call timer might then expire before
we get a connection assigned - leading to the following oops if the call
stalled:

	BUG: kernel NULL pointer dereference, address: 0000000000000000
	...
	CPU: 1 PID: 5111 Comm: krxrpcio/0 Not tainted 6.3.0-rc7-build3+ #701
	RIP: 0010:rxrpc_alloc_txbuf+0xc0/0x157
	...
	Call Trace:
	 
	 rxrpc_send_ACK+0x50/0x13b
	 rxrpc_input_call_event+0x16a/0x67d
	 rxrpc_io_thread+0x1b6/0x45f
	 ? _raw_spin_unlock_irqrestore+0x1f/0x35
	 ? rxrpc_input_packet+0x519/0x519
	 kthread+0xe7/0xef
	 ? kthread_complete_and_exit+0x1b/0x1b
	 ret_from_fork+0x22/0x30

Fix this by noting the timeouts in struct rxrpc_call when the call is
created.  The timer will be started when the first packet is transmitted.

It shouldn't be possible to trigger this directly from userspace through
AF_RXRPC as sendmsg() will return EBUSY if the call is in the
waiting-for-conn state if it dropped out of the wait due to a signal.

Fixes: 9d35d880e0e4 ("rxrpc: Move client call connection to the I/O thread")
Reported-by: Marc Dionne 
Signed-off-by: David Howells 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

rxrpc: Make it so that a waiting process can be aborted

2023-05-01T06:43:19+00:00

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 
Signed-off-by: David Howells 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

rxrpc: Fix hard call timeout units

2023-05-01T06:43:19+00:00

The hard call timeout is specified in the RXRPC_SET_CALL_TIMEOUT cmsg in
seconds, so fix the point at which sendmsg() applies it to the call to
convert to jiffies from seconds, not milliseconds.

Fixes: a158bdd3247b ("rxrpc: Fix timeout of a call that hasn't yet been granted a channel")
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org
cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller

rxrpc: Fix potential data race in rxrpc_wait_to_be_connected()

2023-04-27T07:17:41+00:00

Inside the loop in rxrpc_wait_to_be_connected() it checks call->error to
see if it should exit the loop without first checking the call state.  This
is probably safe as if call->error is set, the call is dead anyway, but we
should probably wait for the call state to have been set to completion
first, lest it cause surprise on the way out.

Fix this by only accessing call->error if the call is complete.  We don't
actually need to access the error inside the loop as we'll do that after.

This caused the following report:

    BUG: KCSAN: data-race in rxrpc_send_data / rxrpc_set_call_completion

    write to 0xffff888159cf3c50 of 4 bytes by task 25673 on cpu 1:
     rxrpc_set_call_completion+0x71/0x1c0 net/rxrpc/call_state.c:22
     rxrpc_send_data_packet+0xba9/0x1650 net/rxrpc/output.c:479
     rxrpc_transmit_one+0x1e/0x130 net/rxrpc/output.c:714
     rxrpc_decant_prepared_tx net/rxrpc/call_event.c:326 [inline]
     rxrpc_transmit_some_data+0x496/0x600 net/rxrpc/call_event.c:350
     rxrpc_input_call_event+0x564/0x1220 net/rxrpc/call_event.c:464
     rxrpc_io_thread+0x307/0x1d80 net/rxrpc/io_thread.c:461
     kthread+0x1ac/0x1e0 kernel/kthread.c:376
     ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

    read to 0xffff888159cf3c50 of 4 bytes by task 25672 on cpu 0:
     rxrpc_send_data+0x29e/0x1950 net/rxrpc/sendmsg.c:296
     rxrpc_do_sendmsg+0xb7a/0xc20 net/rxrpc/sendmsg.c:726
     rxrpc_sendmsg+0x413/0x520 net/rxrpc/af_rxrpc.c:565
     sock_sendmsg_nosec net/socket.c:724 [inline]
     sock_sendmsg net/socket.c:747 [inline]
     ____sys_sendmsg+0x375/0x4c0 net/socket.c:2501
     ___sys_sendmsg net/socket.c:2555 [inline]
     __sys_sendmmsg+0x263/0x500 net/socket.c:2641
     __do_sys_sendmmsg net/socket.c:2670 [inline]
     __se_sys_sendmmsg net/socket.c:2667 [inline]
     __x64_sys_sendmmsg+0x57/0x60 net/socket.c:2667
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]
     do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
     entry_SYSCALL_64_after_hwframe+0x63/0xcd

    value changed: 0x00000000 -> 0xffffffea

Fixes: 9d35d880e0e4 ("rxrpc: Move client call connection to the I/O thread")
Reported-by: syzbot+ebc945fdb4acd72cba78@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/000000000000e7c6d205fa10a3cd@google.com/
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: Dmitry Vyukov 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: linux-fsdevel@vger.kernel.org
cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/508133.1682427395@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni