android/android_kernel_asus_sm8350
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

batman-adv: Hold rtnl lock during MTU update via netlink

Browse Source 
commit 987aae75fc1041072941ffb622b45ce2359a99b9 upstream.

The automatic recalculation of the maximum allowed MTU is usually triggered
by code sections which are already rtnl lock protected by callers outside
of batman-adv. But when the fragmentation setting is changed via
batman-adv's own batadv genl family, then the rtnl lock is not yet taken.

But dev_set_mtu requires that the caller holds the rtnl lock because it
uses netdevice notifiers. And this code will then fail the check for this
lock:

  RTNL: assertion failed at net/core/dev.c (1953)

Cc: stable@vger.kernel.org
Reported-by: syzbot+f8812454d9b3ac00d282@syzkaller.appspotmail.com
Fixes: c6a953cce8d0 ("batman-adv: Trigger events for auto adjusted MTU")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230821-batadv-missing-mtu-rtnl-lock-v1-1-1c5a7bfe861e@narfation.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sven Eckelmann 2023-08-21 21:48:48 +02:00 committed by Greg Kroah-Hartman
parent 61b71562be
commit c5f261825f
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/batman-adv/netlink.c
View File

@ -496,7 +496,10 @@ static int batadv_netlink_set_mesh(struct sk_buff *skb, struct genl_info *info)
attr = info->attrs[BATADV_ATTR_FRAGMENTATION_ENABLED];
atomic_set(&bat_priv->fragmentation, !!nla_get_u8(attr));
rtnl_lock();
batadv_update_min_mtu(bat_priv->soft_iface);
rtnl_unlock();
}
if (info->attrs[BATADV_ATTR_GW_BANDWIDTH_DOWN]) {