linux/net/rose/rose_loopback.c
Bernard Pidoux 3c53cd65de rose: check NULL rose_loopback_neigh->loopback
Commit 3b3fd068c5 added NULL check for
`rose_loopback_neigh->dev` in rose_loopback_timer() but omitted to
check rose_loopback_neigh->loopback.

It thus prevents *all* rose connect.

The reason is that a special rose_neigh loopback has a NULL device.

/proc/net/rose_neigh illustrates it via rose_neigh_show() function :
[...]
seq_printf(seq, "%05d %-9s %-4s   %3d %3d  %3s     %3s %3lu %3lu",
	   rose_neigh->number,
	   (rose_neigh->loopback) ? "RSLOOP-0" : ax2asc(buf, &rose_neigh->callsign),
	   rose_neigh->dev ? rose_neigh->dev->name : "???",
	   rose_neigh->count,

/proc/net/rose_neigh displays special rose_loopback_neigh->loopback as
callsign RSLOOP-0:

addr  callsign  dev  count use mode restart  t0  tf digipeaters
00001 RSLOOP-0  ???      1   2  DCE     yes   0   0

By checking rose_loopback_neigh->loopback, rose_rx_call_request() is called
even in case rose_loopback_neigh->dev is NULL. This repairs rose connections.

Verification with rose client application FPAC:

FPAC-Node v 4.1.3 (built Aug  5 2022) for LINUX (help = h)
F6BVP-4 (Commands = ?) : u
Users - AX.25 Level 2 sessions :
Port   Callsign     Callsign  AX.25 state  ROSE state  NetRom status
axudp  F6BVP-5   -> F6BVP-9   Connected    Connected   ---------

Fixes: 3b3fd068c5 ("rose: Fix Null pointer dereference in rose_send_frame()")
Signed-off-by: Bernard Pidoux <f6bvp@free.fr>
Suggested-by: Francois Romieu <romieu@fr.zoreil.com>
Cc: Thomas DL9SAU Osterried <thomas@osterried.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-08-22 14:24:54 +01:00

134 lines
2.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/timer.h>
#include <net/ax25.h>
#include <linux/skbuff.h>
#include <net/rose.h>
#include <linux/init.h>
static struct sk_buff_head loopback_queue;
#define ROSE_LOOPBACK_LIMIT 1000
static struct timer_list loopback_timer;
static void rose_set_loopback_timer(void);
static void rose_loopback_timer(struct timer_list *unused);
void rose_loopback_init(void)
{
skb_queue_head_init(&loopback_queue);
timer_setup(&loopback_timer, rose_loopback_timer, 0);
}
static int rose_loopback_running(void)
{
return timer_pending(&loopback_timer);
}
int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
{
struct sk_buff *skbn = NULL;
if (skb_queue_len(&loopback_queue) < ROSE_LOOPBACK_LIMIT)
skbn = skb_clone(skb, GFP_ATOMIC);
if (skbn) {
consume_skb(skb);
skb_queue_tail(&loopback_queue, skbn);
if (!rose_loopback_running())
rose_set_loopback_timer();
} else {
kfree_skb(skb);
}
return 1;
}
static void rose_set_loopback_timer(void)
{
mod_timer(&loopback_timer, jiffies + 10);
}
static void rose_loopback_timer(struct timer_list *unused)
{
struct sk_buff *skb;
struct net_device *dev;
rose_address *dest;
struct sock *sk;
unsigned short frametype;
unsigned int lci_i, lci_o;
int count;
for (count = 0; count < ROSE_LOOPBACK_LIMIT; count++) {
skb = skb_dequeue(&loopback_queue);
if (!skb)
return;
if (skb->len < ROSE_MIN_LEN) {
kfree_skb(skb);
continue;
}
lci_i = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
frametype = skb->data[2];
if (frametype == ROSE_CALL_REQUEST &&
(skb->len <= ROSE_CALL_REQ_FACILITIES_OFF ||
skb->data[ROSE_CALL_REQ_ADDR_LEN_OFF] !=
ROSE_CALL_REQ_ADDR_LEN_VAL)) {
kfree_skb(skb);
continue;
}
dest = (rose_address *)(skb->data + ROSE_CALL_REQ_DEST_ADDR_OFF);
lci_o = ROSE_DEFAULT_MAXVC + 1 - lci_i;
skb_reset_transport_header(skb);
sk = rose_find_socket(lci_o, rose_loopback_neigh);
if (sk) {
if (rose_process_rx_frame(sk, skb) == 0)
kfree_skb(skb);
continue;
}
if (frametype == ROSE_CALL_REQUEST) {
if (!rose_loopback_neigh->dev &&
!rose_loopback_neigh->loopback) {
kfree_skb(skb);
continue;
}
dev = rose_dev_get(dest);
if (!dev) {
kfree_skb(skb);
continue;
}
if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) {
dev_put(dev);
kfree_skb(skb);
}
} else {
kfree_skb(skb);
}
}
if (!skb_queue_empty(&loopback_queue))
mod_timer(&loopback_timer, jiffies + 1);
}
void __exit rose_loopback_clear(void)
{
struct sk_buff *skb;
del_timer(&loopback_timer);
while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
skb->sk = NULL;
kfree_skb(skb);
}
}