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linux/net/ax25/ax25_route.c
Duoming Zhou 87563a043c ax25: fix reference count leaks of ax25_dev 
The previous commit d01ffb9eee ("ax25: add refcount in ax25_dev
to avoid UAF bugs") introduces refcount into ax25_dev, but there
are reference leak paths in ax25_ctl_ioctl(), ax25_fwd_ioctl(),
ax25_rt_add(), ax25_rt_del() and ax25_rt_opt().

This patch uses ax25_dev_put() and adjusts the position of
ax25_addr_ax25dev() to fix reference cout leaks of ax25_dev.

Fixes: d01ffb9eee ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20220203150811.42256-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-03 14:20:36 -08:00

490 lines
11 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
* Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
* Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
* Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
*/
#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/timer.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/slab.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/export.h>
static ax25_route *ax25_route_list;
DEFINE_RWLOCK(ax25_route_lock);
void ax25_rt_device_down(struct net_device *dev)
{
ax25_route *s, *t, *ax25_rt;
write_lock_bh(&ax25_route_lock);
ax25_rt = ax25_route_list;
while (ax25_rt != NULL) {
s = ax25_rt;
ax25_rt = ax25_rt->next;
if (s->dev == dev) {
if (ax25_route_list == s) {
ax25_route_list = s->next;
kfree(s->digipeat);
kfree(s);
} else {
for (t = ax25_route_list; t != NULL; t = t->next) {
if (t->next == s) {
t->next = s->next;
kfree(s->digipeat);
kfree(s);
break;
}
}
}
}
}
write_unlock_bh(&ax25_route_lock);
}
static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
{
ax25_route *ax25_rt;
ax25_dev *ax25_dev;
int i;
if (route->digi_count > AX25_MAX_DIGIS)
return -EINVAL;
ax25_dev = ax25_addr_ax25dev(&route->port_addr);
if (!ax25_dev)
return -EINVAL;
write_lock_bh(&ax25_route_lock);
ax25_rt = ax25_route_list;
while (ax25_rt != NULL) {
if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
ax25_rt->dev == ax25_dev->dev) {
kfree(ax25_rt->digipeat);
ax25_rt->digipeat = NULL;
if (route->digi_count != 0) {
if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return -ENOMEM;
}
ax25_rt->digipeat->lastrepeat = -1;
ax25_rt->digipeat->ndigi = route->digi_count;
for (i = 0; i < route->digi_count; i++) {
ax25_rt->digipeat->repeated[i] = 0;
ax25_rt->digipeat->calls[i] = route->digi_addr[i];
}
}
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return 0;
}
ax25_rt = ax25_rt->next;
}
if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return -ENOMEM;
}
refcount_set(&ax25_rt->refcount, 1);
ax25_rt->callsign = route->dest_addr;
ax25_rt->dev = ax25_dev->dev;
ax25_rt->digipeat = NULL;
ax25_rt->ip_mode = ' ';
if (route->digi_count != 0) {
if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
write_unlock_bh(&ax25_route_lock);
kfree(ax25_rt);
ax25_dev_put(ax25_dev);
return -ENOMEM;
}
ax25_rt->digipeat->lastrepeat = -1;
ax25_rt->digipeat->ndigi = route->digi_count;
for (i = 0; i < route->digi_count; i++) {
ax25_rt->digipeat->repeated[i] = 0;
ax25_rt->digipeat->calls[i] = route->digi_addr[i];
}
}
ax25_rt->next = ax25_route_list;
ax25_route_list = ax25_rt;
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return 0;
}
void __ax25_put_route(ax25_route *ax25_rt)
{
kfree(ax25_rt->digipeat);
kfree(ax25_rt);
}
static int ax25_rt_del(struct ax25_routes_struct *route)
{
ax25_route *s, *t, *ax25_rt;
ax25_dev *ax25_dev;
if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
return -EINVAL;
write_lock_bh(&ax25_route_lock);
ax25_rt = ax25_route_list;
while (ax25_rt != NULL) {
s = ax25_rt;
ax25_rt = ax25_rt->next;
if (s->dev == ax25_dev->dev &&
ax25cmp(&route->dest_addr, &s->callsign) == 0) {
if (ax25_route_list == s) {
ax25_route_list = s->next;
ax25_put_route(s);
} else {
for (t = ax25_route_list; t != NULL; t = t->next) {
if (t->next == s) {
t->next = s->next;
ax25_put_route(s);
break;
}
}
}
}
}
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return 0;
}
static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
{
ax25_route *ax25_rt;
ax25_dev *ax25_dev;
int err = 0;
if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
return -EINVAL;
write_lock_bh(&ax25_route_lock);
ax25_rt = ax25_route_list;
while (ax25_rt != NULL) {
if (ax25_rt->dev == ax25_dev->dev &&
ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
switch (rt_option->cmd) {
case AX25_SET_RT_IPMODE:
switch (rt_option->arg) {
case ' ':
case 'D':
case 'V':
ax25_rt->ip_mode = rt_option->arg;
break;
default:
err = -EINVAL;
goto out;
}
break;
default:
err = -EINVAL;
goto out;
}
}
ax25_rt = ax25_rt->next;
}
out:
write_unlock_bh(&ax25_route_lock);
ax25_dev_put(ax25_dev);
return err;
}
int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
{
struct ax25_route_opt_struct rt_option;
struct ax25_routes_struct route;
switch (cmd) {
case SIOCADDRT:
if (copy_from_user(&route, arg, sizeof(route)))
return -EFAULT;
return ax25_rt_add(&route);
case SIOCDELRT:
if (copy_from_user(&route, arg, sizeof(route)))
return -EFAULT;
return ax25_rt_del(&route);
case SIOCAX25OPTRT:
if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
return -EFAULT;
return ax25_rt_opt(&rt_option);
default:
return -EINVAL;
}
}
#ifdef CONFIG_PROC_FS
static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(ax25_route_lock)
{
struct ax25_route *ax25_rt;
int i = 1;
read_lock(&ax25_route_lock);
if (*pos == 0)
return SEQ_START_TOKEN;
for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
if (i == *pos)
return ax25_rt;
++i;
}
return NULL;
}
static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
return (v == SEQ_START_TOKEN) ? ax25_route_list :
((struct ax25_route *) v)->next;
}
static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
__releases(ax25_route_lock)
{
read_unlock(&ax25_route_lock);
}
static int ax25_rt_seq_show(struct seq_file *seq, void *v)
{
char buf[11];
if (v == SEQ_START_TOKEN)
seq_puts(seq, "callsign dev mode digipeaters\n");
else {
struct ax25_route *ax25_rt = v;
const char *callsign;
int i;
if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
callsign = "default";
else
callsign = ax2asc(buf, &ax25_rt->callsign);
seq_printf(seq, "%-9s %-4s",
callsign,
ax25_rt->dev ? ax25_rt->dev->name : "???");
switch (ax25_rt->ip_mode) {
case 'V':
seq_puts(seq, " vc");
break;
case 'D':
seq_puts(seq, " dg");
break;
default:
seq_puts(seq, " *");
break;
}
if (ax25_rt->digipeat != NULL)
for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
seq_printf(seq, " %s",
ax2asc(buf, &ax25_rt->digipeat->calls[i]));
seq_puts(seq, "\n");
}
return 0;
}
const struct seq_operations ax25_rt_seqops = {
.start = ax25_rt_seq_start,
.next = ax25_rt_seq_next,
.stop = ax25_rt_seq_stop,
.show = ax25_rt_seq_show,
};
#endif
/*
* Find AX.25 route
*
* Only routes with a reference count of zero can be destroyed.
* Must be called with ax25_route_lock read locked.
*/
ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
{
ax25_route *ax25_spe_rt = NULL;
ax25_route *ax25_def_rt = NULL;
ax25_route *ax25_rt;
/*
* Bind to the physical interface we heard them on, or the default
* route if none is found;
*/
for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
if (dev == NULL) {
if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
ax25_spe_rt = ax25_rt;
if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
ax25_def_rt = ax25_rt;
} else {
if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
ax25_spe_rt = ax25_rt;
if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
ax25_def_rt = ax25_rt;
}
}
ax25_rt = ax25_def_rt;
if (ax25_spe_rt != NULL)
ax25_rt = ax25_spe_rt;
return ax25_rt;
}
/*
* Adjust path: If you specify a default route and want to connect
* a target on the digipeater path but w/o having a special route
* set before, the path has to be truncated from your target on.
*/
static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
{
int k;
for (k = 0; k < digipeat->ndigi; k++) {
if (ax25cmp(addr, &digipeat->calls[k]) == 0)
break;
}
digipeat->ndigi = k;
}
/*
* Find which interface to use.
*/
int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
{
ax25_uid_assoc *user;
ax25_route *ax25_rt;
int err = 0;
ax25_route_lock_use();
ax25_rt = ax25_get_route(addr, NULL);
if (!ax25_rt) {
ax25_route_lock_unuse();
return -EHOSTUNREACH;
}
if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
err = -EHOSTUNREACH;
goto put;
}
user = ax25_findbyuid(current_euid());
if (user) {
ax25->source_addr = user->call;
ax25_uid_put(user);
} else {
if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
err = -EPERM;
goto put;
}
ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
}
if (ax25_rt->digipeat != NULL) {
ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
GFP_ATOMIC);
if (ax25->digipeat == NULL) {
err = -ENOMEM;
goto put;
}
ax25_adjust_path(addr, ax25->digipeat);
}
if (ax25->sk != NULL) {
local_bh_disable();
bh_lock_sock(ax25->sk);
sock_reset_flag(ax25->sk, SOCK_ZAPPED);
bh_unlock_sock(ax25->sk);
local_bh_enable();
}
put:
ax25_route_lock_unuse();
return err;
}
struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
ax25_address *dest, ax25_digi *digi)
{
unsigned char *bp;
int len;
len = digi->ndigi * AX25_ADDR_LEN;
if (unlikely(skb_headroom(skb) < len)) {
skb = skb_expand_head(skb, len);
if (!skb) {
printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
return NULL;
}
}
bp = skb_push(skb, len);
ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
return skb;
}
/*
* Free all memory associated with routing structures.
*/
void __exit ax25_rt_free(void)
{
ax25_route *s, *ax25_rt = ax25_route_list;
write_lock_bh(&ax25_route_lock);
while (ax25_rt != NULL) {
s = ax25_rt;
ax25_rt = ax25_rt->next;
kfree(s->digipeat);
kfree(s);
}
write_unlock_bh(&ax25_route_lock);
}
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