From 75ea27d0d62281c31ee259c872dfdeb072cf5e39 Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Thu, 7 Oct 2021 18:16:50 +0200 Subject: [PATCH 1/3] net: introduce a function to check if a netdev name is in use __dev_get_by_name is currently used to either retrieve a net device reference using its name or to check if a name is already used by a registered net device (per ns). In the later case there is no need to return a reference to a net device. Introduce a new helper, netdev_name_in_use, to check if a name is currently used by a registered net device without leaking a reference the corresponding net device. This helper uses netdev_name_node_lookup instead of __dev_get_by_name as we don't need the extra logic retrieving a reference to the corresponding net device. Signed-off-by: Antoine Tenart Signed-off-by: David S. Miller --- include/linux/netdevice.h | 1 + net/core/dev.c | 14 ++++++++++---- 2 files changed, 11 insertions(+), 4 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index d79163208dfd..15f4a658e436 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2955,6 +2955,7 @@ struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags, struct net_device *dev_get_by_name(struct net *net, const char *name); struct net_device *dev_get_by_name_rcu(struct net *net, const char *name); struct net_device *__dev_get_by_name(struct net *net, const char *name); +bool netdev_name_in_use(struct net *net, const char *name); int dev_alloc_name(struct net_device *dev, const char *name); int dev_open(struct net_device *dev, struct netlink_ext_ack *extack); void dev_close(struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index 16ab09b6a7f8..1594cd2955ba 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -303,6 +303,12 @@ static struct netdev_name_node *netdev_name_node_lookup_rcu(struct net *net, return NULL; } +bool netdev_name_in_use(struct net *net, const char *name) +{ + return netdev_name_node_lookup(net, name); +} +EXPORT_SYMBOL(netdev_name_in_use); + int netdev_name_node_alt_create(struct net_device *dev, const char *name) { struct netdev_name_node *name_node; @@ -1133,7 +1139,7 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) } snprintf(buf, IFNAMSIZ, name, i); - if (!__dev_get_by_name(net, buf)) + if (!netdev_name_in_use(net, buf)) return i; /* It is possible to run out of possible slots @@ -1187,7 +1193,7 @@ static int dev_get_valid_name(struct net *net, struct net_device *dev, if (strchr(name, '%')) return dev_alloc_name_ns(net, dev, name); - else if (__dev_get_by_name(net, name)) + else if (netdev_name_in_use(net, name)) return -EEXIST; else if (dev->name != name) strlcpy(dev->name, name, IFNAMSIZ); @@ -11153,7 +11159,7 @@ int __dev_change_net_namespace(struct net_device *dev, struct net *net, * we can use it in the destination network namespace. */ err = -EEXIST; - if (__dev_get_by_name(net, dev->name)) { + if (netdev_name_in_use(net, dev->name)) { /* We get here if we can't use the current device name */ if (!pat) goto out; @@ -11506,7 +11512,7 @@ static void __net_exit default_device_exit(struct net *net) /* Push remaining network devices to init_net */ snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex); - if (__dev_get_by_name(&init_net, fb_name)) + if (netdev_name_in_use(&init_net, fb_name)) snprintf(fb_name, IFNAMSIZ, "dev%%d"); err = dev_change_net_namespace(dev, &init_net, fb_name); if (err) { From caa9b35fadff57e6ee7499f2fb26f8abd83a133b Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Thu, 7 Oct 2021 18:16:51 +0200 Subject: [PATCH 2/3] bonding: use the correct function to check for netdev name collision A new helper to detect if a net device name is in use was added. Use it here as the return reference from __dev_get_by_name was discarded. Signed-off-by: Antoine Tenart Signed-off-by: David S. Miller --- drivers/net/bonding/bond_sysfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c index b9e9842fed94..c48b77167fab 100644 --- a/drivers/net/bonding/bond_sysfs.c +++ b/drivers/net/bonding/bond_sysfs.c @@ -811,8 +811,8 @@ int bond_create_sysfs(struct bond_net *bn) */ if (ret == -EEXIST) { /* Is someone being kinky and naming a device bonding_master? */ - if (__dev_get_by_name(bn->net, - class_attr_bonding_masters.attr.name)) + if (netdev_name_in_use(bn->net, + class_attr_bonding_masters.attr.name)) pr_err("network device named %s already exists in sysfs\n", class_attr_bonding_masters.attr.name); ret = 0; From d03eb9787d3aa74da0379cd34345686227580000 Mon Sep 17 00:00:00 2001 From: Antoine Tenart Date: Thu, 7 Oct 2021 18:16:52 +0200 Subject: [PATCH 3/3] ppp: use the correct function to check if a netdev name is in use A new helper to detect if a net device name is in use was added. Use it here as the return reference from __dev_get_by_name was discarded. Signed-off-by: Antoine Tenart Signed-off-by: David S. Miller --- drivers/net/ppp/ppp_generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index fb52cd175b45..1180a0e2445f 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -1161,7 +1161,7 @@ static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set) if (!ifname_is_set) { while (1) { snprintf(ppp->dev->name, IFNAMSIZ, "ppp%i", ret); - if (!__dev_get_by_name(ppp->ppp_net, ppp->dev->name)) + if (!netdev_name_in_use(ppp->ppp_net, ppp->dev->name)) break; unit_put(&pn->units_idr, ret); ret = unit_get(&pn->units_idr, ppp, ret + 1);