Commit 100c7a8e authored by Andy Strohman's avatar Andy Strohman Committed by Zicheng Qu
Browse files

batman-adv: fix panic during interface removal 

mainline inclusion
from mainline-v6.14-rc3
commit ccb7276a6d26d6f8416e315b43b45e15ee7f29e2
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPLJA
CVE: CVE-2025-21823

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ccb7276a6d26d6f8416e315b43b45e15ee7f29e2



--------------------------------

Reference counting is used to ensure that
batadv_hardif_neigh_node and batadv_hard_iface
are not freed before/during
batadv_v_elp_throughput_metric_update work is
finished.

But there isn't a guarantee that the hard if will
remain associated with a soft interface up until
the work is finished.

This fixes a crash triggered by reboot that looks
like this:

Call trace:
 batadv_v_mesh_free+0xd0/0x4dc [batman_adv]
 batadv_v_elp_throughput_metric_update+0x1c/0xa4
 process_one_work+0x178/0x398
 worker_thread+0x2e8/0x4d0
 kthread+0xd8/0xdc
 ret_from_fork+0x10/0x20

(the batadv_v_mesh_free call is misleading,
and does not actually happen)

I was able to make the issue happen more reliably
by changing hardif_neigh->bat_v.metric_work work
to be delayed work. This allowed me to track down
and confirm the fix.

Cc: stable@vger.kernel.org
Fixes: c833484e ("batman-adv: ELP - compute the metric based on the estimated throughput")
Signed-off-by: default avatarAndy Strohman <andrew@andrewstrohman.com>
[sven@narfation.org: prevent entering batadv_v_elp_get_throughput without
 soft_iface]
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: default avatarZicheng Qu <quzicheng@huawei.com>
parent d3bcf062

net/batman-adv/bat_v_elp.c

+8 −1
Original line number Diff line number Diff line
@@ -67,12 +67,19 @@ static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) 
static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)

{

	struct batadv_hard_iface *hard_iface = neigh->if_incoming;

	struct net_device *soft_iface = hard_iface->soft_iface;

	struct ethtool_link_ksettings link_settings;

	struct net_device *real_netdev;

	struct station_info sinfo;

	u32 throughput;

	int ret;



	/* don't query throughput when no longer associated with any

	 * batman-adv interface

	 */

	if (!soft_iface)

		return BATADV_THROUGHPUT_DEFAULT_VALUE;



	/* if the user specified a customised value for this interface, then

	 * return it directly

	 */
@@ -142,7 +149,7 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) 


default_throughput:

	if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {

		batadv_info(hard_iface->soft_iface,

		batadv_info(soft_iface,

			    "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n",

			    hard_iface->net_dev->name,

			    BATADV_THROUGHPUT_DEFAULT_VALUE / 10,