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linux-next/net/lapb/lapb_iface.c
Diego Calleja 558e10a57d [LAPB]: Fix windowsize check 
In bug #6954, Norbert Reinartz reported the following issue:

"Function lapb_setparms() in file net/lapb/lapb_iface.c checks if the given
parameters are valid. If the given window size is in the range of 8 .. 127,
lapb_setparms() fails and returns an error value of LAPB_INVALUE, even if bit
LAPB_EXTENDED in parms->mode is set.
If bit LAPB_EXTENDED in parms->mode is set and the window size is in the range
of 8 .. 127, the first check "(parms->mode & LAPB_EXTENDED)" results true  and
the second check "(parms->window < 1 || parms->window > 127)" results false.
Both checks in conjunction result to false, thus the third check "(parms->window
< 1 || parms->window > 7)" is done by fault.
This third check results true, so that we leave lapb_setparms() by 'goto out_put'.
Seems that this bug doesn't cause any problems, because lapb_setparms() isn't
used to change the default values of LAPB. We are using kernel lapb in our
software project and also change the default parameters of lapb, so we found
this bug"

He also pasted a fix, that I've transformated into a patch:

Signed-off-by: Diego Calleja <diegocg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-05 21:15:58 -07:00

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/*
* LAPB release 002
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* This module:
* This module is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* History
* LAPB 001 Jonathan Naylor Started Coding
* LAPB 002 Jonathan Naylor New timer architecture.
* 2000-10-29 Henner Eisen lapb_data_indication() return status.
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <net/lapb.h>
static struct list_head lapb_list = LIST_HEAD_INIT(lapb_list);
static DEFINE_RWLOCK(lapb_list_lock);
/*
* Free an allocated lapb control block.
*/
static void lapb_free_cb(struct lapb_cb *lapb)
{
kfree(lapb);
}
static __inline__ void lapb_hold(struct lapb_cb *lapb)
{
atomic_inc(&lapb->refcnt);
}
static __inline__ void lapb_put(struct lapb_cb *lapb)
{
if (atomic_dec_and_test(&lapb->refcnt))
lapb_free_cb(lapb);
}
/*
* Socket removal during an interrupt is now safe.
*/
static void __lapb_remove_cb(struct lapb_cb *lapb)
{
if (lapb->node.next) {
list_del(&lapb->node);
lapb_put(lapb);
}
}
/*
* Add a socket to the bound sockets list.
*/
static void __lapb_insert_cb(struct lapb_cb *lapb)
{
list_add(&lapb->node, &lapb_list);
lapb_hold(lapb);
}
static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
{
struct list_head *entry;
struct lapb_cb *lapb, *use = NULL;
list_for_each(entry, &lapb_list) {
lapb = list_entry(entry, struct lapb_cb, node);
if (lapb->dev == dev) {
use = lapb;
break;
}
}
if (use)
lapb_hold(use);
return use;
}
static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
{
struct lapb_cb *rc;
read_lock_bh(&lapb_list_lock);
rc = __lapb_devtostruct(dev);
read_unlock_bh(&lapb_list_lock);
return rc;
}
/*
* Create an empty LAPB control block.
*/
static struct lapb_cb *lapb_create_cb(void)
{
struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
if (!lapb)
goto out;
skb_queue_head_init(&lapb->write_queue);
skb_queue_head_init(&lapb->ack_queue);
init_timer(&lapb->t1timer);
init_timer(&lapb->t2timer);
lapb->t1 = LAPB_DEFAULT_T1;
lapb->t2 = LAPB_DEFAULT_T2;
lapb->n2 = LAPB_DEFAULT_N2;
lapb->mode = LAPB_DEFAULT_MODE;
lapb->window = LAPB_DEFAULT_WINDOW;
lapb->state = LAPB_STATE_0;
atomic_set(&lapb->refcnt, 1);
out:
return lapb;
}
int lapb_register(struct net_device *dev, struct lapb_register_struct *callbacks)
{
struct lapb_cb *lapb;
int rc = LAPB_BADTOKEN;
write_lock_bh(&lapb_list_lock);
lapb = __lapb_devtostruct(dev);
if (lapb) {
lapb_put(lapb);
goto out;
}
lapb = lapb_create_cb();
rc = LAPB_NOMEM;
if (!lapb)
goto out;
lapb->dev = dev;
lapb->callbacks = *callbacks;
__lapb_insert_cb(lapb);
lapb_start_t1timer(lapb);
rc = LAPB_OK;
out:
write_unlock_bh(&lapb_list_lock);
return rc;
}
int lapb_unregister(struct net_device *dev)
{
struct lapb_cb *lapb;
int rc = LAPB_BADTOKEN;
write_lock_bh(&lapb_list_lock);
lapb = __lapb_devtostruct(dev);
if (!lapb)
goto out;
lapb_stop_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb_clear_queues(lapb);
__lapb_remove_cb(lapb);
lapb_put(lapb);
rc = LAPB_OK;
out:
write_unlock_bh(&lapb_list_lock);
return rc;
}
int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
int rc = LAPB_BADTOKEN;
struct lapb_cb *lapb = lapb_devtostruct(dev);
if (!lapb)
goto out;
parms->t1 = lapb->t1 / HZ;
parms->t2 = lapb->t2 / HZ;
parms->n2 = lapb->n2;
parms->n2count = lapb->n2count;
parms->state = lapb->state;
parms->window = lapb->window;
parms->mode = lapb->mode;
if (!timer_pending(&lapb->t1timer))
parms->t1timer = 0;
else
parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
if (!timer_pending(&lapb->t2timer))
parms->t2timer = 0;
else
parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
lapb_put(lapb);
rc = LAPB_OK;
out:
return rc;
}
int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
{
int rc = LAPB_BADTOKEN;
struct lapb_cb *lapb = lapb_devtostruct(dev);
if (!lapb)
goto out;
rc = LAPB_INVALUE;
if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
goto out_put;
if (lapb->state == LAPB_STATE_0) {
if (parms->mode & LAPB_EXTENDED) {
if (parms->window < 1 || parms->window > 127)
goto out_put;
} else {
if (parms->window < 1 || parms->window > 7)
goto out_put;
}
lapb->mode = parms->mode;
lapb->window = parms->window;
}
lapb->t1 = parms->t1 * HZ;
lapb->t2 = parms->t2 * HZ;
lapb->n2 = parms->n2;
rc = LAPB_OK;
out_put:
lapb_put(lapb);
out:
return rc;
}
int lapb_connect_request(struct net_device *dev)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
rc = LAPB_OK;
if (lapb->state == LAPB_STATE_1)
goto out_put;
rc = LAPB_CONNECTED;
if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
goto out_put;
lapb_establish_data_link(lapb);
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S0 -> S1\n", lapb->dev);
#endif
lapb->state = LAPB_STATE_1;
rc = LAPB_OK;
out_put:
lapb_put(lapb);
out:
return rc;
}
int lapb_disconnect_request(struct net_device *dev)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
switch (lapb->state) {
case LAPB_STATE_0:
rc = LAPB_NOTCONNECTED;
goto out_put;
case LAPB_STATE_1:
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S1 TX DISC(1)\n", lapb->dev);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S1 -> S0\n", lapb->dev);
#endif
lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
lapb->state = LAPB_STATE_0;
lapb_start_t1timer(lapb);
rc = LAPB_NOTCONNECTED;
goto out_put;
case LAPB_STATE_2:
rc = LAPB_OK;
goto out_put;
}
lapb_clear_queues(lapb);
lapb->n2count = 0;
lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
lapb_start_t1timer(lapb);
lapb_stop_t2timer(lapb);
lapb->state = LAPB_STATE_2;
#if LAPB_DEBUG > 1
printk(KERN_DEBUG "lapb: (%p) S3 DISC(1)\n", lapb->dev);
#endif
#if LAPB_DEBUG > 0
printk(KERN_DEBUG "lapb: (%p) S3 -> S2\n", lapb->dev);
#endif
rc = LAPB_OK;
out_put:
lapb_put(lapb);
out:
return rc;
}
int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (!lapb)
goto out;
rc = LAPB_NOTCONNECTED;
if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
goto out_put;
skb_queue_tail(&lapb->write_queue, skb);
lapb_kick(lapb);
rc = LAPB_OK;
out_put:
lapb_put(lapb);
out:
return rc;
}
int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
{
struct lapb_cb *lapb = lapb_devtostruct(dev);
int rc = LAPB_BADTOKEN;
if (lapb) {
lapb_data_input(lapb, skb);
lapb_put(lapb);
rc = LAPB_OK;
}
return rc;
}
void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks.connect_confirmation)
lapb->callbacks.connect_confirmation(lapb->dev, reason);
}
void lapb_connect_indication(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks.connect_indication)
lapb->callbacks.connect_indication(lapb->dev, reason);
}
void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks.disconnect_confirmation)
lapb->callbacks.disconnect_confirmation(lapb->dev, reason);
}
void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
{
if (lapb->callbacks.disconnect_indication)
lapb->callbacks.disconnect_indication(lapb->dev, reason);
}
int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
{
if (lapb->callbacks.data_indication)
return lapb->callbacks.data_indication(lapb->dev, skb);
kfree_skb(skb);
return NET_RX_CN_HIGH; /* For now; must be != NET_RX_DROP */
}
int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
{
int used = 0;
if (lapb->callbacks.data_transmit) {
lapb->callbacks.data_transmit(lapb->dev, skb);
used = 1;
}
return used;
}
EXPORT_SYMBOL(lapb_register);
EXPORT_SYMBOL(lapb_unregister);
EXPORT_SYMBOL(lapb_getparms);
EXPORT_SYMBOL(lapb_setparms);
EXPORT_SYMBOL(lapb_connect_request);
EXPORT_SYMBOL(lapb_disconnect_request);
EXPORT_SYMBOL(lapb_data_request);
EXPORT_SYMBOL(lapb_data_received);
static int __init lapb_init(void)
{
return 0;
}
static void __exit lapb_exit(void)
{
WARN_ON(!list_empty(&lapb_list));
}
MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
MODULE_LICENSE("GPL");
module_init(lapb_init);
module_exit(lapb_exit);
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