From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16078374D2 for ; Mon, 16 Oct 2023 20:17:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Dcm2mikn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AE19C433C7; Mon, 16 Oct 2023 20:17:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697487423; bh=sGSPN075c5HoiuRzD54d5Ke/Yq6FhIM7bQMUpCMuEls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dcm2miknVNjoNN2b+GlPWHe7rknh3654wEMK9FOpOXrT7BJq+Mmul+WWVRQQNkMcF VpduJwDwZOqS+ciT0nSEf2/4iQSAGGzAKOkrx++25KUazFJpKJvCCP3KkbOQOKfkOb TJSVoxY/l128DHpkv+/H565qe/cPLXIOwTnsMrkYd7XSET7/hMmVZu1xPoW1BnFS1h lXiol4vfZO4tUWWv8nLA6P/riaFrC1BfthfH0ttJfLui8zEWktMaWq3e/nW36UOKFO +HLfd2UKcQVZgs/PXslYiXDukR1e6fqaHHhY+IImUFyDqCkVEq4y/SjAbnj2STuC+s zP5X882mylxRA== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, Jakub Kicinski , jiri@resnulli.us Subject: [PATCH net 3/5] net: avoid UAF on deleted altname Date: Mon, 16 Oct 2023 13:16:55 -0700 Message-ID: <20231016201657.1754763-4-kuba@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231016201657.1754763-1-kuba@kernel.org> References: <20231016201657.1754763-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Altnames are accessed under RCU (__dev_get_by_name()) but freed by kfree() with no synchronization point. Because the name nodes don't hold a reference on the netdevice either, take the heavier approach of inserting synchronization points. Subsequent patch will remove the one added on device deletion path. Fixes: ff92741270bf ("net: introduce name_node struct to be used in hashlist") Signed-off-by: Jakub Kicinski --- CC: jiri@resnulli.us --- net/core/dev.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index f4fa2692cf6d..7d5107cd5792 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -345,7 +345,6 @@ int netdev_name_node_alt_create(struct net_device *dev, const char *name) static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node) { list_del(&name_node->list); - netdev_name_node_del(name_node); kfree(name_node->name); netdev_name_node_free(name_node); } @@ -364,6 +363,8 @@ int netdev_name_node_alt_destroy(struct net_device *dev, const char *name) if (name_node == dev->name_node || name_node->dev != dev) return -EINVAL; + netdev_name_node_del(name_node); + synchronize_rcu(); __netdev_name_node_alt_destroy(name_node); return 0; @@ -10937,6 +10938,7 @@ void unregister_netdevice_many_notify(struct list_head *head, synchronize_net(); list_for_each_entry(dev, head, unreg_list) { + struct netdev_name_node *name_node; struct sk_buff *skb = NULL; /* Shutdown queueing discipline. */ @@ -10964,6 +10966,9 @@ void unregister_netdevice_many_notify(struct list_head *head, dev_uc_flush(dev); dev_mc_flush(dev); + netdev_for_each_altname(dev, name_node) + netdev_name_node_del(name_node); + synchronize_rcu(); netdev_name_node_alt_flush(dev); netdev_name_node_free(dev->name_node); -- 2.41.0