b.a.t.m.a.n.lists.open-mesh.org archive mirror
 help / color / mirror / Atom feed
From: Sven Eckelmann <sven@narfation.org>
To: b.a.t.m.a.n@lists.open-mesh.org
Cc: Sven Eckelmann <sven@narfation.org>
Subject: [RFC PATCH 2/4] batman-adv: Request iflink once in batadv_get_real_netdevice
Date: Mon, 28 Feb 2022 00:52:55 +0100	[thread overview]
Message-ID: <20220227235257.1324636-2-sven@narfation.org> (raw)
In-Reply-To: <20220227235257.1324636-1-sven@narfation.org>

There is no need to call dev_get_iflink multiple times for the same
net_device in batadv_get_real_netdevice. And since some of the
ndo_get_iflink callbacks are dynamic (for example via RCUs like in
vxcan_get_iflink), it could easily happen that the returned values are not
stable. The pre-checks before __dev_get_by_index are then of course bogus.

Fixes: 2b45bb6c3aad ("batman-adv: additional checks for virtual interfaces on top of WiFi")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
 net/batman-adv/hard-interface.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 774a26c5..8ed128bb 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -215,14 +215,16 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
 	struct net_device *real_netdev = NULL;
 	struct net *real_net;
 	struct net *net;
-	int ifindex;
+	int iflink;
 	if (!netdev)
 		return NULL;
-	if (netdev->ifindex == dev_get_iflink(netdev)) {
+	iflink = dev_get_iflink(netdev);
+	if (netdev->ifindex == iflink) {
 		return netdev;
@@ -232,9 +234,8 @@ static struct net_device *batadv_get_real_netdevice(struct net_device *netdev)
 		goto out;
 	net = dev_net(hard_iface->soft_iface);
-	ifindex = dev_get_iflink(netdev);
 	real_net = batadv_getlink_net(netdev, net);
-	real_netdev = dev_get_by_index(real_net, ifindex);
+	real_netdev = dev_get_by_index(real_net, iflink);

  reply	other threads:[~2022-02-27 23:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-27 23:52 [RFC PATCH 1/4] batman-adv: Request iflink once in batadv-on-batadv check Sven Eckelmann
2022-02-27 23:52 ` Sven Eckelmann [this message]
2022-02-27 23:52 ` [RFC PATCH 3/4] batman-adv: Don't expect inter-netns unique iflink indices Sven Eckelmann
2022-02-27 23:52 ` [RFC PATCH 4/4] batman-adv: Demote batadv-on-batadv skip error message Sven Eckelmann
     [not found]   ` <CAHhjh1P1WvsEP3zo7KGPmexiHCiZrOUrxA_7RR17_wZapUupqQ@mail.gmail.com>
2022-02-28  0:30     ` Sven Eckelmann

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220227235257.1324636-2-sven@narfation.org \
    --to=sven@narfation.org \
    --cc=b.a.t.m.a.n@lists.open-mesh.org \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).