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linux-next/net/tipc/subscr.c
Erik Hugne a5d0e7c037 tipc: fix spinlock recursion bug for failed subscriptions
If a topology event subscription fails for any reason, such as out
of memory, max number reached or because we received an invalid
request the correct behavior is to terminate the subscribers
connection to the topology server. This is currently broken and
produces the following oops:

[27.953662] tipc: Subscription rejected, illegal request
[27.955329] BUG: spinlock recursion on CPU#1, kworker/u4:0/6
[27.957066]  lock: 0xffff88003c67f408, .magic: dead4ead, .owner: kworker/u4:0/6, .owner_cpu: 1
[27.958054] CPU: 1 PID: 6 Comm: kworker/u4:0 Not tainted 3.14.0-rc6+ #5
[27.960230] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[27.960874] Workqueue: tipc_rcv tipc_recv_work [tipc]
[27.961430]  ffff88003c67f408 ffff88003de27c18 ffffffff815c0207 ffff88003de1c050
[27.962292]  ffff88003de27c38 ffffffff815beec5 ffff88003c67f408 ffffffff817f0a8a
[27.963152]  ffff88003de27c58 ffffffff815beeeb ffff88003c67f408 ffffffffa0013520
[27.964023] Call Trace:
[27.964292]  [<ffffffff815c0207>] dump_stack+0x45/0x56
[27.964874]  [<ffffffff815beec5>] spin_dump+0x8c/0x91
[27.965420]  [<ffffffff815beeeb>] spin_bug+0x21/0x26
[27.965995]  [<ffffffff81083df6>] do_raw_spin_lock+0x116/0x140
[27.966631]  [<ffffffff815c6215>] _raw_spin_lock_bh+0x15/0x20
[27.967256]  [<ffffffffa0008540>] subscr_conn_shutdown_event+0x20/0xa0 [tipc]
[27.968051]  [<ffffffffa000fde4>] tipc_close_conn+0xa4/0xb0 [tipc]
[27.968722]  [<ffffffffa00101ba>] tipc_conn_terminate+0x1a/0x30 [tipc]
[27.969436]  [<ffffffffa00089a2>] subscr_conn_msg_event+0x1f2/0x2f0 [tipc]
[27.970209]  [<ffffffffa0010000>] tipc_receive_from_sock+0x90/0xf0 [tipc]
[27.970972]  [<ffffffffa000fa79>] tipc_recv_work+0x29/0x50 [tipc]
[27.971633]  [<ffffffff8105dbf5>] process_one_work+0x165/0x3e0
[27.972267]  [<ffffffff8105e869>] worker_thread+0x119/0x3a0
[27.972896]  [<ffffffff8105e750>] ? manage_workers.isra.25+0x2a0/0x2a0
[27.973622]  [<ffffffff810648af>] kthread+0xdf/0x100
[27.974168]  [<ffffffff810647d0>] ? kthread_create_on_node+0x1a0/0x1a0
[27.974893]  [<ffffffff815ce13c>] ret_from_fork+0x7c/0xb0
[27.975466]  [<ffffffff810647d0>] ? kthread_create_on_node+0x1a0/0x1a0

The recursion occurs when subscr_terminate tries to grab the
subscriber lock, which is already taken by subscr_conn_msg_event.
We fix this by checking if the request to establish a new
subscription was successful, and if not we initiate termination of
the subscriber after we have released the subscriber lock.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-24 15:36:56 -04:00

376 lines
11 KiB
C

/*
* net/tipc/subscr.c: TIPC network topology service
*
* Copyright (c) 2000-2006, Ericsson AB
* Copyright (c) 2005-2007, 2010-2013, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "core.h"
#include "name_table.h"
#include "port.h"
#include "subscr.h"
/**
* struct tipc_subscriber - TIPC network topology subscriber
* @conid: connection identifier to server connecting to subscriber
* @lock: control access to subscriber
* @subscription_list: list of subscription objects for this subscriber
*/
struct tipc_subscriber {
int conid;
spinlock_t lock;
struct list_head subscription_list;
};
static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
void *usr_data, void *buf, size_t len);
static void *subscr_named_msg_event(int conid);
static void subscr_conn_shutdown_event(int conid, void *usr_data);
static atomic_t subscription_count = ATOMIC_INIT(0);
static struct sockaddr_tipc topsrv_addr __read_mostly = {
.family = AF_TIPC,
.addrtype = TIPC_ADDR_NAMESEQ,
.addr.nameseq.type = TIPC_TOP_SRV,
.addr.nameseq.lower = TIPC_TOP_SRV,
.addr.nameseq.upper = TIPC_TOP_SRV,
.scope = TIPC_NODE_SCOPE
};
static struct tipc_server topsrv __read_mostly = {
.saddr = &topsrv_addr,
.imp = TIPC_CRITICAL_IMPORTANCE,
.type = SOCK_SEQPACKET,
.max_rcvbuf_size = sizeof(struct tipc_subscr),
.name = "topology_server",
.tipc_conn_recvmsg = subscr_conn_msg_event,
.tipc_conn_new = subscr_named_msg_event,
.tipc_conn_shutdown = subscr_conn_shutdown_event,
};
/**
* htohl - convert value to endianness used by destination
* @in: value to convert
* @swap: non-zero if endianness must be reversed
*
* Returns converted value
*/
static u32 htohl(u32 in, int swap)
{
return swap ? swab32(in) : in;
}
static void subscr_send_event(struct tipc_subscription *sub, u32 found_lower,
u32 found_upper, u32 event, u32 port_ref,
u32 node)
{
struct tipc_subscriber *subscriber = sub->subscriber;
struct kvec msg_sect;
msg_sect.iov_base = (void *)&sub->evt;
msg_sect.iov_len = sizeof(struct tipc_event);
sub->evt.event = htohl(event, sub->swap);
sub->evt.found_lower = htohl(found_lower, sub->swap);
sub->evt.found_upper = htohl(found_upper, sub->swap);
sub->evt.port.ref = htohl(port_ref, sub->swap);
sub->evt.port.node = htohl(node, sub->swap);
tipc_conn_sendmsg(&topsrv, subscriber->conid, NULL, msg_sect.iov_base,
msg_sect.iov_len);
}
/**
* tipc_subscr_overlap - test for subscription overlap with the given values
*
* Returns 1 if there is overlap, otherwise 0.
*/
int tipc_subscr_overlap(struct tipc_subscription *sub, u32 found_lower,
u32 found_upper)
{
if (found_lower < sub->seq.lower)
found_lower = sub->seq.lower;
if (found_upper > sub->seq.upper)
found_upper = sub->seq.upper;
if (found_lower > found_upper)
return 0;
return 1;
}
/**
* tipc_subscr_report_overlap - issue event if there is subscription overlap
*
* Protected by nameseq.lock in name_table.c
*/
void tipc_subscr_report_overlap(struct tipc_subscription *sub, u32 found_lower,
u32 found_upper, u32 event, u32 port_ref,
u32 node, int must)
{
if (!tipc_subscr_overlap(sub, found_lower, found_upper))
return;
if (!must && !(sub->filter & TIPC_SUB_PORTS))
return;
subscr_send_event(sub, found_lower, found_upper, event, port_ref, node);
}
static void subscr_timeout(struct tipc_subscription *sub)
{
struct tipc_subscriber *subscriber = sub->subscriber;
/* The spin lock per subscriber is used to protect its members */
spin_lock_bh(&subscriber->lock);
/* Validate timeout (in case subscription is being cancelled) */
if (sub->timeout == TIPC_WAIT_FOREVER) {
spin_unlock_bh(&subscriber->lock);
return;
}
/* Unlink subscription from name table */
tipc_nametbl_unsubscribe(sub);
/* Unlink subscription from subscriber */
list_del(&sub->subscription_list);
spin_unlock_bh(&subscriber->lock);
/* Notify subscriber of timeout */
subscr_send_event(sub, sub->evt.s.seq.lower, sub->evt.s.seq.upper,
TIPC_SUBSCR_TIMEOUT, 0, 0);
/* Now destroy subscription */
k_term_timer(&sub->timer);
kfree(sub);
atomic_dec(&subscription_count);
}
/**
* subscr_del - delete a subscription within a subscription list
*
* Called with subscriber lock held.
*/
static void subscr_del(struct tipc_subscription *sub)
{
tipc_nametbl_unsubscribe(sub);
list_del(&sub->subscription_list);
kfree(sub);
atomic_dec(&subscription_count);
}
/**
* subscr_terminate - terminate communication with a subscriber
*
* Note: Must call it in process context since it might sleep.
*/
static void subscr_terminate(struct tipc_subscriber *subscriber)
{
tipc_conn_terminate(&topsrv, subscriber->conid);
}
static void subscr_release(struct tipc_subscriber *subscriber)
{
struct tipc_subscription *sub;
struct tipc_subscription *sub_temp;
spin_lock_bh(&subscriber->lock);
/* Destroy any existing subscriptions for subscriber */
list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
subscription_list) {
if (sub->timeout != TIPC_WAIT_FOREVER) {
spin_unlock_bh(&subscriber->lock);
k_cancel_timer(&sub->timer);
k_term_timer(&sub->timer);
spin_lock_bh(&subscriber->lock);
}
subscr_del(sub);
}
spin_unlock_bh(&subscriber->lock);
/* Now destroy subscriber */
kfree(subscriber);
}
/**
* subscr_cancel - handle subscription cancellation request
*
* Called with subscriber lock held. Routine must temporarily release lock
* to enable the subscription timeout routine to finish without deadlocking;
* the lock is then reclaimed to allow caller to release it upon return.
*
* Note that fields of 's' use subscriber's endianness!
*/
static void subscr_cancel(struct tipc_subscr *s,
struct tipc_subscriber *subscriber)
{
struct tipc_subscription *sub;
struct tipc_subscription *sub_temp;
int found = 0;
/* Find first matching subscription, exit if not found */
list_for_each_entry_safe(sub, sub_temp, &subscriber->subscription_list,
subscription_list) {
if (!memcmp(s, &sub->evt.s, sizeof(struct tipc_subscr))) {
found = 1;
break;
}
}
if (!found)
return;
/* Cancel subscription timer (if used), then delete subscription */
if (sub->timeout != TIPC_WAIT_FOREVER) {
sub->timeout = TIPC_WAIT_FOREVER;
spin_unlock_bh(&subscriber->lock);
k_cancel_timer(&sub->timer);
k_term_timer(&sub->timer);
spin_lock_bh(&subscriber->lock);
}
subscr_del(sub);
}
/**
* subscr_subscribe - create subscription for subscriber
*
* Called with subscriber lock held.
*/
static int subscr_subscribe(struct tipc_subscr *s,
struct tipc_subscriber *subscriber,
struct tipc_subscription **sub_p) {
struct tipc_subscription *sub;
int swap;
/* Determine subscriber's endianness */
swap = !(s->filter & (TIPC_SUB_PORTS | TIPC_SUB_SERVICE));
/* Detect & process a subscription cancellation request */
if (s->filter & htohl(TIPC_SUB_CANCEL, swap)) {
s->filter &= ~htohl(TIPC_SUB_CANCEL, swap);
subscr_cancel(s, subscriber);
return 0;
}
/* Refuse subscription if global limit exceeded */
if (atomic_read(&subscription_count) >= TIPC_MAX_SUBSCRIPTIONS) {
pr_warn("Subscription rejected, limit reached (%u)\n",
TIPC_MAX_SUBSCRIPTIONS);
return -EINVAL;
}
/* Allocate subscription object */
sub = kmalloc(sizeof(*sub), GFP_ATOMIC);
if (!sub) {
pr_warn("Subscription rejected, no memory\n");
return -ENOMEM;
}
/* Initialize subscription object */
sub->seq.type = htohl(s->seq.type, swap);
sub->seq.lower = htohl(s->seq.lower, swap);
sub->seq.upper = htohl(s->seq.upper, swap);
sub->timeout = htohl(s->timeout, swap);
sub->filter = htohl(s->filter, swap);
if ((!(sub->filter & TIPC_SUB_PORTS) ==
!(sub->filter & TIPC_SUB_SERVICE)) ||
(sub->seq.lower > sub->seq.upper)) {
pr_warn("Subscription rejected, illegal request\n");
kfree(sub);
return -EINVAL;
}
INIT_LIST_HEAD(&sub->nameseq_list);
list_add(&sub->subscription_list, &subscriber->subscription_list);
sub->subscriber = subscriber;
sub->swap = swap;
memcpy(&sub->evt.s, s, sizeof(struct tipc_subscr));
atomic_inc(&subscription_count);
if (sub->timeout != TIPC_WAIT_FOREVER) {
k_init_timer(&sub->timer,
(Handler)subscr_timeout, (unsigned long)sub);
k_start_timer(&sub->timer, sub->timeout);
}
*sub_p = sub;
return 0;
}
/* Handle one termination request for the subscriber */
static void subscr_conn_shutdown_event(int conid, void *usr_data)
{
subscr_release((struct tipc_subscriber *)usr_data);
}
/* Handle one request to create a new subscription for the subscriber */
static void subscr_conn_msg_event(int conid, struct sockaddr_tipc *addr,
void *usr_data, void *buf, size_t len)
{
struct tipc_subscriber *subscriber = usr_data;
struct tipc_subscription *sub = NULL;
spin_lock_bh(&subscriber->lock);
if (subscr_subscribe((struct tipc_subscr *)buf, subscriber, &sub) < 0) {
spin_unlock_bh(&subscriber->lock);
subscr_terminate(subscriber);
return;
}
if (sub)
tipc_nametbl_subscribe(sub);
spin_unlock_bh(&subscriber->lock);
}
/* Handle one request to establish a new subscriber */
static void *subscr_named_msg_event(int conid)
{
struct tipc_subscriber *subscriber;
/* Create subscriber object */
subscriber = kzalloc(sizeof(struct tipc_subscriber), GFP_ATOMIC);
if (subscriber == NULL) {
pr_warn("Subscriber rejected, no memory\n");
return NULL;
}
INIT_LIST_HEAD(&subscriber->subscription_list);
subscriber->conid = conid;
spin_lock_init(&subscriber->lock);
return (void *)subscriber;
}
int tipc_subscr_start(void)
{
return tipc_server_start(&topsrv);
}
void tipc_subscr_stop(void)
{
tipc_server_stop(&topsrv);
}