The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 311cca40661f428b7aa114fb5af578cfdbe3e8b6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023102026-cruelly-untaken-8b7c@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 311cca40661f428b7aa114fb5af578cfdbe3e8b6 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski kuba@kernel.org Date: Tue, 17 Oct 2023 18:38:13 -0700 Subject: [PATCH] net: fix ifname in netlink ntf during netns move
dev_get_valid_name() overwrites the netdev's name on success. This makes it hard to use in prepare-commit-like fashion, where we do validation first, and "commit" to the change later.
Factor out a helper which lets us save the new name to a buffer. Use it to fix the problem of notification on netns move having incorrect name:
5: eth0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default link/ether be:4d:58:f9:d5:40 brd ff:ff:ff:ff:ff:ff 6: eth1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default link/ether 1e:4a:34:36:e3:cd brd ff:ff:ff:ff:ff:ff
[ ~]# ip link set dev eth0 netns 1 name eth1
ip monitor inside netns: Deleted inet eth0 Deleted inet6 eth0 Deleted 5: eth1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default link/ether be:4d:58:f9:d5:40 brd ff:ff:ff:ff:ff:ff new-netnsid 0 new-ifindex 7
Name is reported as eth1 in old netns for ifindex 5, already renamed.
Fixes: d90310243fd7 ("net: device name allocation cleanups") Signed-off-by: Jakub Kicinski kuba@kernel.org Reviewed-by: Jiri Pirko jiri@nvidia.com Signed-off-by: Paolo Abeni pabeni@redhat.com
diff --git a/net/core/dev.c b/net/core/dev.c index 5aaf5753d4e4..f109ad34d660 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1123,6 +1123,26 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) return -ENFILE; }
+static int dev_prep_valid_name(struct net *net, struct net_device *dev, + const char *want_name, char *out_name) +{ + int ret; + + if (!dev_valid_name(want_name)) + return -EINVAL; + + if (strchr(want_name, '%')) { + ret = __dev_alloc_name(net, want_name, out_name); + return ret < 0 ? ret : 0; + } else if (netdev_name_in_use(net, want_name)) { + return -EEXIST; + } else if (out_name != want_name) { + strscpy(out_name, want_name, IFNAMSIZ); + } + + return 0; +} + static int dev_alloc_name_ns(struct net *net, struct net_device *dev, const char *name) @@ -1160,19 +1180,13 @@ EXPORT_SYMBOL(dev_alloc_name); static int dev_get_valid_name(struct net *net, struct net_device *dev, const char *name) { - BUG_ON(!net); - - if (!dev_valid_name(name)) - return -EINVAL; - - if (strchr(name, '%')) - return dev_alloc_name_ns(net, dev, name); - else if (netdev_name_in_use(net, name)) - return -EEXIST; - else if (dev->name != name) - strscpy(dev->name, name, IFNAMSIZ); + char buf[IFNAMSIZ]; + int ret;
- return 0; + ret = dev_prep_valid_name(net, dev, name, buf); + if (ret >= 0) + strscpy(dev->name, buf, IFNAMSIZ); + return ret; }
/** @@ -11038,6 +11052,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat, int new_ifindex) { struct net *net_old = dev_net(dev); + char new_name[IFNAMSIZ] = {}; int err, new_nsid;
ASSERT_RTNL(); @@ -11064,7 +11079,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, /* We get here if we can't use the current device name */ if (!pat) goto out; - err = dev_get_valid_name(net, dev, pat); + err = dev_prep_valid_name(net, dev, pat, new_name); if (err < 0) goto out; } @@ -11135,6 +11150,9 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, kobject_uevent(&dev->dev.kobj, KOBJ_ADD); netdev_adjacent_add_links(dev);
+ if (new_name[0]) /* Rename the netdev to prepared name */ + strscpy(dev->name, new_name, IFNAMSIZ); + /* Fixup kobjects */ err = device_rename(&dev->dev, dev->name); WARN_ON(err);