Commit bd07063d authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

net: don't use input buffer of __dev_alloc_name() as a scratch space 



Callers of __dev_alloc_name() want to pass dev->name as
the output buffer. Make __dev_alloc_name() not clobber
that buffer on failure, and remove the workarounds
in callers.

dev_alloc_name_ns() is now completely unnecessary.

The extra strscpy() added here will be gone by the end
of the patch series.

Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231023152346.3639749-2-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fb1c535b

net/core/dev.c

+8 −25
Original line number Diff line number Diff line
@@ -1057,7 +1057,7 @@ EXPORT_SYMBOL(dev_valid_name); 
 *	__dev_alloc_name - allocate a name for a device

 *	@net: network namespace to allocate the device name in

 *	@name: name format string

 *	@buf:  scratch buffer and result name string

 *	@res: result name string

 *

 *	Passed a format string - eg "lt%d" it will try and find a suitable

 *	id. It scans list of devices to build up a free map, then chooses
@@ -1068,13 +1068,14 @@ EXPORT_SYMBOL(dev_valid_name); 
 *	Returns the number of the unit assigned or a negative errno code.

 */



static int __dev_alloc_name(struct net *net, const char *name, char *buf)

static int __dev_alloc_name(struct net *net, const char *name, char *res)

{

	int i = 0;

	const char *p;

	const int max_netdevices = 8*PAGE_SIZE;

	unsigned long *inuse;

	struct net_device *d;

	char buf[IFNAMSIZ];



	if (!dev_valid_name(name))

		return -EINVAL;
@@ -1124,8 +1125,10 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) 
	}



	snprintf(buf, IFNAMSIZ, name, i);

	if (!netdev_name_in_use(net, buf))

	if (!netdev_name_in_use(net, buf)) {

		strscpy(res, buf, IFNAMSIZ);

		return i;

	}



	/* It is possible to run out of possible slots

	 * when the name is long and there isn't enough space left
@@ -1154,20 +1157,6 @@ static int dev_prep_valid_name(struct net *net, struct net_device *dev, 
	return 0;

}



static int dev_alloc_name_ns(struct net *net,

			     struct net_device *dev,

			     const char *name)

{

	char buf[IFNAMSIZ];

	int ret;



	BUG_ON(!net);

	ret = __dev_alloc_name(net, name, buf);

	if (ret >= 0)

		strscpy(dev->name, buf, IFNAMSIZ);

	return ret;

}



/**

 *	dev_alloc_name - allocate a name for a device

 *	@dev: device
@@ -1184,20 +1173,14 @@ static int dev_alloc_name_ns(struct net *net, 


int dev_alloc_name(struct net_device *dev, const char *name)

{

	return dev_alloc_name_ns(dev_net(dev), dev, name);

	return __dev_alloc_name(dev_net(dev), name, dev->name);

}

EXPORT_SYMBOL(dev_alloc_name);



static int dev_get_valid_name(struct net *net, struct net_device *dev,

			      const char *name)

{

	char buf[IFNAMSIZ];

	int ret;



	ret = dev_prep_valid_name(net, dev, name, buf);

	if (ret >= 0)

		strscpy(dev->name, buf, IFNAMSIZ);

	return ret;

	return dev_prep_valid_name(net, dev, name, dev->name);

}



/**