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linux/net/ax25/sysctl_net_ax25.c
Ralf Baechle DL5RB c7c694d196 [AX.25]: Fix potencial memory hole. 
If the AX.25 dialect chosen by the sysadmin is set to DAMA master / 3
(or DAMA slave / 2, if CONFIG_AX25_DAMA_SLAVE=n) ax25_kick() will fall
through the switch statement without calling ax25_send_iframe() or any
other function that would eventually free skbn thus leaking the packet.

Fix by restricting the sysctl inferface to allow only actually supported
AX.25 dialects.

The system administration mistake needed for this to happen is rather
unlikely, so this is an uncritical hole.

Coverity #651.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-19 13:20:06 -08:00

263 lines
6.6 KiB
C
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/*
* This program 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.
*
* Copyright (C) 1996 Mike Shaver (shaver@zeroknowledge.com)
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/sysctl.h>
#include <linux/spinlock.h>
#include <net/ax25.h>
static int min_ipdefmode[1], max_ipdefmode[] = {1};
static int min_axdefmode[1], max_axdefmode[] = {1};
static int min_backoff[1], max_backoff[] = {2};
static int min_conmode[1], max_conmode[] = {2};
static int min_window[] = {1}, max_window[] = {7};
static int min_ewindow[] = {1}, max_ewindow[] = {63};
static int min_t1[] = {1}, max_t1[] = {30 * HZ};
static int min_t2[] = {1}, max_t2[] = {20 * HZ};
static int min_t3[1], max_t3[] = {3600 * HZ};
static int min_idle[1], max_idle[] = {65535 * HZ};
static int min_n2[] = {1}, max_n2[] = {31};
static int min_paclen[] = {1}, max_paclen[] = {512};
static int min_proto[1], max_proto[] = { AX25_PROTO_MAX };
static int min_ds_timeout[1], max_ds_timeout[] = {65535 * HZ};
static struct ctl_table_header *ax25_table_header;
static ctl_table *ax25_table;
static int ax25_table_size;
static ctl_table ax25_dir_table[] = {
{
.ctl_name = NET_AX25,
.procname = "ax25",
.mode = 0555,
},
{ .ctl_name = 0 }
};
static ctl_table ax25_root_table[] = {
{
.ctl_name = CTL_NET,
.procname = "net",
.mode = 0555,
.child = ax25_dir_table
},
{ .ctl_name = 0 }
};
static const ctl_table ax25_param_table[] = {
{
.ctl_name = NET_AX25_IP_DEFAULT_MODE,
.procname = "ip_default_mode",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_ipdefmode,
.extra2 = &max_ipdefmode
},
{
.ctl_name = NET_AX25_DEFAULT_MODE,
.procname = "ax25_default_mode",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_axdefmode,
.extra2 = &max_axdefmode
},
{
.ctl_name = NET_AX25_BACKOFF_TYPE,
.procname = "backoff_type",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_backoff,
.extra2 = &max_backoff
},
{
.ctl_name = NET_AX25_CONNECT_MODE,
.procname = "connect_mode",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_conmode,
.extra2 = &max_conmode
},
{
.ctl_name = NET_AX25_STANDARD_WINDOW,
.procname = "standard_window_size",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_window,
.extra2 = &max_window
},
{
.ctl_name = NET_AX25_EXTENDED_WINDOW,
.procname = "extended_window_size",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_ewindow,
.extra2 = &max_ewindow
},
{
.ctl_name = NET_AX25_T1_TIMEOUT,
.procname = "t1_timeout",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_t1,
.extra2 = &max_t1
},
{
.ctl_name = NET_AX25_T2_TIMEOUT,
.procname = "t2_timeout",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_t2,
.extra2 = &max_t2
},
{
.ctl_name = NET_AX25_T3_TIMEOUT,
.procname = "t3_timeout",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_t3,
.extra2 = &max_t3
},
{
.ctl_name = NET_AX25_IDLE_TIMEOUT,
.procname = "idle_timeout",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_idle,
.extra2 = &max_idle
},
{
.ctl_name = NET_AX25_N2,
.procname = "maximum_retry_count",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_n2,
.extra2 = &max_n2
},
{
.ctl_name = NET_AX25_PACLEN,
.procname = "maximum_packet_length",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_paclen,
.extra2 = &max_paclen
},
{
.ctl_name = NET_AX25_PROTOCOL,
.procname = "protocol",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_proto,
.extra2 = &max_proto
},
{
.ctl_name = NET_AX25_DAMA_SLAVE_TIMEOUT,
.procname = "dama_slave_timeout",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.strategy = &sysctl_intvec,
.extra1 = &min_ds_timeout,
.extra2 = &max_ds_timeout
},
{ .ctl_name = 0 } /* that's all, folks! */
};
void ax25_register_sysctl(void)
{
ax25_dev *ax25_dev;
int n, k;
spin_lock_bh(&ax25_dev_lock);
for (ax25_table_size = sizeof(ctl_table), ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
ax25_table_size += sizeof(ctl_table);
if ((ax25_table = kmalloc(ax25_table_size, GFP_ATOMIC)) == NULL) {
spin_unlock_bh(&ax25_dev_lock);
return;
}
memset(ax25_table, 0x00, ax25_table_size);
for (n = 0, ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next) {
ctl_table *child = kmalloc(sizeof(ax25_param_table), GFP_ATOMIC);
if (!child) {
while (n--)
kfree(ax25_table[n].child);
kfree(ax25_table);
spin_unlock_bh(&ax25_dev_lock);
return;
}
memcpy(child, ax25_param_table, sizeof(ax25_param_table));
ax25_table[n].child = ax25_dev->systable = child;
ax25_table[n].ctl_name = n + 1;
ax25_table[n].procname = ax25_dev->dev->name;
ax25_table[n].mode = 0555;
#ifndef CONFIG_AX25_DAMA_SLAVE
/*
* We do not wish to have a representation of this parameter
* in /proc/sys/ when configured *not* to include the
* AX.25 DAMA slave code, do we?
*/
child[AX25_VALUES_DS_TIMEOUT].procname = NULL;
#endif
child[AX25_MAX_VALUES].ctl_name = 0; /* just in case... */
for (k = 0; k < AX25_MAX_VALUES; k++)
child[k].data = &ax25_dev->values[k];
n++;
}
spin_unlock_bh(&ax25_dev_lock);
ax25_dir_table[0].child = ax25_table;
ax25_table_header = register_sysctl_table(ax25_root_table, 1);
}
void ax25_unregister_sysctl(void)
{
ctl_table *p;
unregister_sysctl_table(ax25_table_header);
ax25_dir_table[0].child = NULL;
for (p = ax25_table; p->ctl_name; p++)
kfree(p->child);
kfree(ax25_table);
}
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