Bernard Pidoux 9197ca40fd rose: check NULL rose_loopback_neigh->loopback
[ Upstream commit 3c53cd65dece47dd1f9d3a809f32e59d1d87b2b8 ]

Commit 3b3fd068c56e3fbea30090859216a368398e39bf 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: 3b3fd068c56e ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31 17:18:02 +02:00
2022-08-31 17:18:02 +02:00
2022-07-27 09:43:07 -07:00
2022-08-29 11:18:05 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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