![David Howells](/assets/img/avatar_default.png)
The introduction of a split between the reference count on rxrpc_local
objects and the usage count didn't quite go far enough. A number of kernel
work items need to make use of the socket to perform transmission. These
also need to get an active count on the local object to prevent the socket
from being closed.
Fix this by getting the active count in those places.
Also split out the raw active count get/put functions as these places tend
to hold refs on the rxrpc_local object already, so getting and putting an
extra object ref is just a waste of time.
The problem can lead to symptoms like:
BUG: kernel NULL pointer dereference, address: 0000000000000018
..
CPU: 2 PID: 818 Comm: kworker/u9:0 Not tainted 5.5.0-fscache+ #51
...
RIP: 0010:selinux_socket_sendmsg+0x5/0x13
...
Call Trace:
security_socket_sendmsg+0x2c/0x3e
sock_sendmsg+0x1a/0x46
rxrpc_send_keepalive+0x131/0x1ae
rxrpc_peer_keepalive_worker+0x219/0x34b
process_one_work+0x18e/0x271
worker_thread+0x1a3/0x247
kthread+0xe6/0xeb
ret_from_fork+0x1f/0x30
Fixes: 730c5fd42c
("rxrpc: Fix local endpoint refcounting")
Signed-off-by: David Howells <dhowells@redhat.com>
503 lines
12 KiB
C
503 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* connection-level event handling
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <linux/errqueue.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include <net/ip.h>
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#include "ar-internal.h"
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/*
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* Retransmit terminal ACK or ABORT of the previous call.
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*/
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static void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
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struct sk_buff *skb,
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unsigned int channel)
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{
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struct rxrpc_skb_priv *sp = skb ? rxrpc_skb(skb) : NULL;
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struct rxrpc_channel *chan;
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struct msghdr msg;
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struct kvec iov[3];
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struct {
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struct rxrpc_wire_header whdr;
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union {
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__be32 abort_code;
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struct rxrpc_ackpacket ack;
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};
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} __attribute__((packed)) pkt;
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struct rxrpc_ackinfo ack_info;
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size_t len;
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int ret, ioc;
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u32 serial, mtu, call_id, padding;
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_enter("%d", conn->debug_id);
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chan = &conn->channels[channel];
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/* If the last call got moved on whilst we were waiting to run, just
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* ignore this packet.
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*/
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call_id = READ_ONCE(chan->last_call);
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/* Sync with __rxrpc_disconnect_call() */
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smp_rmb();
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if (skb && call_id != sp->hdr.callNumber)
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return;
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msg.msg_name = &conn->params.peer->srx.transport;
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msg.msg_namelen = conn->params.peer->srx.transport_len;
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msg.msg_control = NULL;
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msg.msg_controllen = 0;
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msg.msg_flags = 0;
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iov[0].iov_base = &pkt;
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iov[0].iov_len = sizeof(pkt.whdr);
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iov[1].iov_base = &padding;
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iov[1].iov_len = 3;
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iov[2].iov_base = &ack_info;
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iov[2].iov_len = sizeof(ack_info);
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pkt.whdr.epoch = htonl(conn->proto.epoch);
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pkt.whdr.cid = htonl(conn->proto.cid | channel);
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pkt.whdr.callNumber = htonl(call_id);
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pkt.whdr.seq = 0;
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pkt.whdr.type = chan->last_type;
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pkt.whdr.flags = conn->out_clientflag;
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pkt.whdr.userStatus = 0;
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pkt.whdr.securityIndex = conn->security_ix;
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pkt.whdr._rsvd = 0;
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pkt.whdr.serviceId = htons(conn->service_id);
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len = sizeof(pkt.whdr);
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switch (chan->last_type) {
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case RXRPC_PACKET_TYPE_ABORT:
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pkt.abort_code = htonl(chan->last_abort);
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iov[0].iov_len += sizeof(pkt.abort_code);
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len += sizeof(pkt.abort_code);
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ioc = 1;
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break;
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case RXRPC_PACKET_TYPE_ACK:
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mtu = conn->params.peer->if_mtu;
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mtu -= conn->params.peer->hdrsize;
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pkt.ack.bufferSpace = 0;
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pkt.ack.maxSkew = htons(skb ? skb->priority : 0);
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pkt.ack.firstPacket = htonl(chan->last_seq + 1);
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pkt.ack.previousPacket = htonl(chan->last_seq);
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pkt.ack.serial = htonl(skb ? sp->hdr.serial : 0);
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pkt.ack.reason = skb ? RXRPC_ACK_DUPLICATE : RXRPC_ACK_IDLE;
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pkt.ack.nAcks = 0;
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ack_info.rxMTU = htonl(rxrpc_rx_mtu);
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ack_info.maxMTU = htonl(mtu);
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ack_info.rwind = htonl(rxrpc_rx_window_size);
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ack_info.jumbo_max = htonl(rxrpc_rx_jumbo_max);
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pkt.whdr.flags |= RXRPC_SLOW_START_OK;
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padding = 0;
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iov[0].iov_len += sizeof(pkt.ack);
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len += sizeof(pkt.ack) + 3 + sizeof(ack_info);
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ioc = 3;
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break;
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default:
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return;
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}
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/* Resync with __rxrpc_disconnect_call() and check that the last call
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* didn't get advanced whilst we were filling out the packets.
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*/
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smp_rmb();
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if (READ_ONCE(chan->last_call) != call_id)
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return;
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serial = atomic_inc_return(&conn->serial);
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pkt.whdr.serial = htonl(serial);
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switch (chan->last_type) {
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case RXRPC_PACKET_TYPE_ABORT:
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_proto("Tx ABORT %%%u { %d } [re]", serial, conn->abort_code);
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break;
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case RXRPC_PACKET_TYPE_ACK:
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trace_rxrpc_tx_ack(chan->call_debug_id, serial,
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ntohl(pkt.ack.firstPacket),
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ntohl(pkt.ack.serial),
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pkt.ack.reason, 0);
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_proto("Tx ACK %%%u [re]", serial);
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break;
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}
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ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, ioc, len);
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conn->params.peer->last_tx_at = ktime_get_seconds();
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if (ret < 0)
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trace_rxrpc_tx_fail(chan->call_debug_id, serial, ret,
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rxrpc_tx_point_call_final_resend);
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else
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trace_rxrpc_tx_packet(chan->call_debug_id, &pkt.whdr,
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rxrpc_tx_point_call_final_resend);
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_leave("");
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}
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/*
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* pass a connection-level abort onto all calls on that connection
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*/
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static void rxrpc_abort_calls(struct rxrpc_connection *conn,
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enum rxrpc_call_completion compl,
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rxrpc_serial_t serial)
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{
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struct rxrpc_call *call;
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int i;
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_enter("{%d},%x", conn->debug_id, conn->abort_code);
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spin_lock(&conn->channel_lock);
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for (i = 0; i < RXRPC_MAXCALLS; i++) {
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call = rcu_dereference_protected(
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conn->channels[i].call,
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lockdep_is_held(&conn->channel_lock));
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if (call) {
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if (compl == RXRPC_CALL_LOCALLY_ABORTED)
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trace_rxrpc_abort(call->debug_id,
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"CON", call->cid,
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call->call_id, 0,
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conn->abort_code,
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conn->error);
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else
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trace_rxrpc_rx_abort(call, serial,
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conn->abort_code);
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if (rxrpc_set_call_completion(call, compl,
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conn->abort_code,
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conn->error))
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rxrpc_notify_socket(call);
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}
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}
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spin_unlock(&conn->channel_lock);
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_leave("");
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}
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/*
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* generate a connection-level abort
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*/
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static int rxrpc_abort_connection(struct rxrpc_connection *conn,
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int error, u32 abort_code)
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{
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struct rxrpc_wire_header whdr;
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struct msghdr msg;
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struct kvec iov[2];
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__be32 word;
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size_t len;
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u32 serial;
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int ret;
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_enter("%d,,%u,%u", conn->debug_id, error, abort_code);
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/* generate a connection-level abort */
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spin_lock_bh(&conn->state_lock);
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if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
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spin_unlock_bh(&conn->state_lock);
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_leave(" = 0 [already dead]");
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return 0;
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}
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conn->error = error;
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conn->abort_code = abort_code;
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conn->state = RXRPC_CONN_LOCALLY_ABORTED;
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spin_unlock_bh(&conn->state_lock);
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msg.msg_name = &conn->params.peer->srx.transport;
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msg.msg_namelen = conn->params.peer->srx.transport_len;
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msg.msg_control = NULL;
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msg.msg_controllen = 0;
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msg.msg_flags = 0;
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whdr.epoch = htonl(conn->proto.epoch);
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whdr.cid = htonl(conn->proto.cid);
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whdr.callNumber = 0;
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whdr.seq = 0;
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whdr.type = RXRPC_PACKET_TYPE_ABORT;
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whdr.flags = conn->out_clientflag;
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whdr.userStatus = 0;
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whdr.securityIndex = conn->security_ix;
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whdr._rsvd = 0;
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whdr.serviceId = htons(conn->service_id);
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word = htonl(conn->abort_code);
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iov[0].iov_base = &whdr;
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iov[0].iov_len = sizeof(whdr);
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iov[1].iov_base = &word;
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iov[1].iov_len = sizeof(word);
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len = iov[0].iov_len + iov[1].iov_len;
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serial = atomic_inc_return(&conn->serial);
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rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, serial);
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whdr.serial = htonl(serial);
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_proto("Tx CONN ABORT %%%u { %d }", serial, conn->abort_code);
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ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
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if (ret < 0) {
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trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
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rxrpc_tx_point_conn_abort);
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_debug("sendmsg failed: %d", ret);
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return -EAGAIN;
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}
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trace_rxrpc_tx_packet(conn->debug_id, &whdr, rxrpc_tx_point_conn_abort);
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conn->params.peer->last_tx_at = ktime_get_seconds();
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_leave(" = 0");
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return 0;
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}
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/*
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* mark a call as being on a now-secured channel
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* - must be called with BH's disabled.
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*/
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static void rxrpc_call_is_secure(struct rxrpc_call *call)
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{
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_enter("%p", call);
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if (call) {
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write_lock_bh(&call->state_lock);
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if (call->state == RXRPC_CALL_SERVER_SECURING) {
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call->state = RXRPC_CALL_SERVER_ACCEPTING;
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rxrpc_notify_socket(call);
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}
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write_unlock_bh(&call->state_lock);
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}
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}
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/*
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* connection-level Rx packet processor
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*/
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static int rxrpc_process_event(struct rxrpc_connection *conn,
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struct sk_buff *skb,
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u32 *_abort_code)
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{
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struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
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__be32 wtmp;
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u32 abort_code;
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int loop, ret;
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if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
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_leave(" = -ECONNABORTED [%u]", conn->state);
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return -ECONNABORTED;
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}
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_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
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switch (sp->hdr.type) {
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case RXRPC_PACKET_TYPE_DATA:
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case RXRPC_PACKET_TYPE_ACK:
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rxrpc_conn_retransmit_call(conn, skb,
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sp->hdr.cid & RXRPC_CHANNELMASK);
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return 0;
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case RXRPC_PACKET_TYPE_BUSY:
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/* Just ignore BUSY packets for now. */
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return 0;
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case RXRPC_PACKET_TYPE_ABORT:
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if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
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&wtmp, sizeof(wtmp)) < 0) {
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trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
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tracepoint_string("bad_abort"));
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return -EPROTO;
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}
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abort_code = ntohl(wtmp);
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_proto("Rx ABORT %%%u { ac=%d }", sp->hdr.serial, abort_code);
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conn->error = -ECONNABORTED;
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conn->abort_code = abort_code;
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conn->state = RXRPC_CONN_REMOTELY_ABORTED;
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rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED, sp->hdr.serial);
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return -ECONNABORTED;
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case RXRPC_PACKET_TYPE_CHALLENGE:
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return conn->security->respond_to_challenge(conn, skb,
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_abort_code);
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case RXRPC_PACKET_TYPE_RESPONSE:
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ret = conn->security->verify_response(conn, skb, _abort_code);
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if (ret < 0)
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return ret;
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ret = conn->security->init_connection_security(conn);
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if (ret < 0)
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return ret;
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ret = conn->security->prime_packet_security(conn);
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if (ret < 0)
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return ret;
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spin_lock(&conn->channel_lock);
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spin_lock(&conn->state_lock);
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if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
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conn->state = RXRPC_CONN_SERVICE;
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spin_unlock(&conn->state_lock);
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for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
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rxrpc_call_is_secure(
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rcu_dereference_protected(
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conn->channels[loop].call,
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lockdep_is_held(&conn->channel_lock)));
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} else {
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spin_unlock(&conn->state_lock);
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}
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spin_unlock(&conn->channel_lock);
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return 0;
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default:
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trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
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tracepoint_string("bad_conn_pkt"));
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return -EPROTO;
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}
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}
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/*
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* set up security and issue a challenge
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*/
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static void rxrpc_secure_connection(struct rxrpc_connection *conn)
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{
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u32 abort_code;
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int ret;
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_enter("{%d}", conn->debug_id);
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ASSERT(conn->security_ix != 0);
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ASSERT(conn->server_key);
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if (conn->security->issue_challenge(conn) < 0) {
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abort_code = RX_CALL_DEAD;
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ret = -ENOMEM;
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goto abort;
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}
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_leave("");
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return;
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abort:
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_debug("abort %d, %d", ret, abort_code);
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rxrpc_abort_connection(conn, ret, abort_code);
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_leave(" [aborted]");
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}
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/*
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* Process delayed final ACKs that we haven't subsumed into a subsequent call.
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*/
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static void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn)
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{
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unsigned long j = jiffies, next_j;
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unsigned int channel;
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bool set;
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again:
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next_j = j + LONG_MAX;
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set = false;
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for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
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struct rxrpc_channel *chan = &conn->channels[channel];
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unsigned long ack_at;
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if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
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continue;
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smp_rmb(); /* vs rxrpc_disconnect_client_call */
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ack_at = READ_ONCE(chan->final_ack_at);
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if (time_before(j, ack_at)) {
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if (time_before(ack_at, next_j)) {
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next_j = ack_at;
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set = true;
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}
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continue;
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}
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if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
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&conn->flags))
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rxrpc_conn_retransmit_call(conn, NULL, channel);
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}
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j = jiffies;
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if (time_before_eq(next_j, j))
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goto again;
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if (set)
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rxrpc_reduce_conn_timer(conn, next_j);
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}
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/*
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* connection-level event processor
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*/
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static void rxrpc_do_process_connection(struct rxrpc_connection *conn)
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{
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struct sk_buff *skb;
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u32 abort_code = RX_PROTOCOL_ERROR;
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int ret;
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if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
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rxrpc_secure_connection(conn);
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/* Process delayed ACKs whose time has come. */
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if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
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rxrpc_process_delayed_final_acks(conn);
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/* go through the conn-level event packets, releasing the ref on this
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* connection that each one has when we've finished with it */
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while ((skb = skb_dequeue(&conn->rx_queue))) {
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rxrpc_see_skb(skb, rxrpc_skb_seen);
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ret = rxrpc_process_event(conn, skb, &abort_code);
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switch (ret) {
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case -EPROTO:
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case -EKEYEXPIRED:
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case -EKEYREJECTED:
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goto protocol_error;
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case -ENOMEM:
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case -EAGAIN:
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goto requeue_and_leave;
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case -ECONNABORTED:
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default:
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|
rxrpc_free_skb(skb, rxrpc_skb_freed);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return;
|
|
|
|
requeue_and_leave:
|
|
skb_queue_head(&conn->rx_queue, skb);
|
|
return;
|
|
|
|
protocol_error:
|
|
if (rxrpc_abort_connection(conn, ret, abort_code) < 0)
|
|
goto requeue_and_leave;
|
|
rxrpc_free_skb(skb, rxrpc_skb_freed);
|
|
return;
|
|
}
|
|
|
|
void rxrpc_process_connection(struct work_struct *work)
|
|
{
|
|
struct rxrpc_connection *conn =
|
|
container_of(work, struct rxrpc_connection, processor);
|
|
|
|
rxrpc_see_connection(conn);
|
|
|
|
if (__rxrpc_use_local(conn->params.local)) {
|
|
rxrpc_do_process_connection(conn);
|
|
rxrpc_unuse_local(conn->params.local);
|
|
}
|
|
|
|
rxrpc_put_connection(conn);
|
|
_leave("");
|
|
return;
|
|
}
|