This is a note to let you know that I've just added the patch titled
NET: mkiss: Fix panic
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mkiss-fix-panic.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Jun 15 11:13:01 CEST 2017
From: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Date: Tue, 23 May 2017 21:53:40 -0400
Subject: NET: mkiss: Fix panic
From: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
[ Upstream commit 7ba1b689038726d34e3244c1ac9e2e18c2ea4787 ]
If a USB-to-serial adapter is unplugged, the driver re-initializes, with
dev->hard_header_len and dev->addr_len set to zero, instead of the correct
values. If then a packet is sent through the half-dead interface, the
kernel will panic due to running out of headroom in the skb when pushing
for the AX.25 headers resulting in this panic:
[<c0595468>] (skb_panic) from [<c0401f70>] (skb_push+0x4c/0x50)
[<c0401f70>] (skb_push) from [<bf0bdad4>] (ax25_hard_header+0x34/0xf4 [ax25])
[<bf0bdad4>] (ax25_hard_header [ax25]) from [<bf0d05d4>] (ax_header+0x38/0x40 [mkiss])
[<bf0d05d4>] (ax_header [mkiss]) from [<c041b584>] (neigh_compat_output+0x8c/0xd8)
[<c041b584>] (neigh_compat_output) from [<c043e7a8>] (ip_finish_output+0x2a0/0x914)
[<c043e7a8>] (ip_finish_output) from [<c043f948>] (ip_output+0xd8/0xf0)
[<c043f948>] (ip_output) from [<c043f04c>] (ip_local_out_sk+0x44/0x48)
This patch makes mkiss behave like the 6pack driver. 6pack does not
panic. In 6pack.c sp_setup() (same function name here) the values for
dev->hard_header_len and dev->addr_len are set to the same values as in
my mkiss patch.
[ralf@xxxxxxxxxxxxxx: Massages original submission to conform to the usual
standards for patch submissions.]
Signed-off-by: Thomas Osterried <thomas@xxxxxxxxxxxx>
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/hamradio/mkiss.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -648,8 +648,8 @@ static void ax_setup(struct net_device *
{
/* Finish setting up the DEVICE info. */
dev->mtu = AX_MTU;
- dev->hard_header_len = 0;
- dev->addr_len = 0;
+ dev->hard_header_len = AX25_MAX_HEADER_LEN;
+ dev->addr_len = AX25_ADDR_LEN;
dev->type = ARPHRD_AX25;
dev->tx_queue_len = 10;
dev->header_ops = &ax25_header_ops;
Patches currently in stable-queue which might be from ralf@xxxxxxxxxxxxxx are
queue-4.4/net-fix-proc-net-arp-for-ax.25.patch
queue-4.4/net-mkiss-fix-panic.patch