netdev - [PATCH v2 net 0/2] net: Fix race of rtnl_net_lock(dev

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Message-ID: <20250207044251.65421-1-kuniyu@amazon.com>
Date: Fri, 7 Feb 2025 13:42:49 +0900
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, Simon Horman <horms@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
	<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v2 net 0/2] net: Fix race of rtnl_net_lock(dev_net(dev)).

Yael Chemla reported that commit 7fb1073300a2 ("net: Hold rtnl_net_lock()
in (un)?register_netdevice_notifier_dev_net().") started to trigger KASAN's
use-after-free splat.

The problem is that dev_net(dev) fetched before rtnl_net_lock() might be
different after rtnl_net_lock().

The patch 1 fixes the issue by checking dev_net(dev) after rtnl_net_lock(),
and the patch 2 fixes the same potential issue that would emerge once RTNL
is removed.

Changes:
  v2:
    * Use dev_net_rcu()
    * Use msleep(1) instead of cond_resched() after maybe_get_net()
    * Remove cond_resched() after net_eq() check

  v1: https://lore.kernel.org/netdev/20250130232435.43622-1-kuniyu@amazon.com/

Kuniyuki Iwashima (2):
  net: Fix dev_net(dev) race in unregister_netdevice_notifier_dev_net().
  dev: Use rtnl_net_dev_lock() in unregister_netdev().

 net/core/dev.c | 69 +++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 52 insertions(+), 17 deletions(-)

-- 
2.39.5 (Apple Git-154)