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/net/wireless/wext-priv.c

http://github.com/mirrors/linux
C | 249 lines | 158 code | 39 blank | 52 comment | 41 complexity | ccb665a9d042c965c59b87fde705213b MD5 | raw file
  1/*
  2 * This file implement the Wireless Extensions priv API.
  3 *
  4 * Authors :	Jean Tourrilhes - HPL - <jt@hpl.hp.com>
  5 * Copyright (c) 1997-2007 Jean Tourrilhes, All Rights Reserved.
  6 * Copyright	2009 Johannes Berg <johannes@sipsolutions.net>
  7 *
  8 * (As all part of the Linux kernel, this file is GPL)
  9 */
 10#include <linux/slab.h>
 11#include <linux/wireless.h>
 12#include <linux/netdevice.h>
 13#include <net/iw_handler.h>
 14#include <net/wext.h>
 15
 16int iw_handler_get_private(struct net_device *		dev,
 17			   struct iw_request_info *	info,
 18			   union iwreq_data *		wrqu,
 19			   char *			extra)
 20{
 21	/* Check if the driver has something to export */
 22	if ((dev->wireless_handlers->num_private_args == 0) ||
 23	   (dev->wireless_handlers->private_args == NULL))
 24		return -EOPNOTSUPP;
 25
 26	/* Check if there is enough buffer up there */
 27	if (wrqu->data.length < dev->wireless_handlers->num_private_args) {
 28		/* User space can't know in advance how large the buffer
 29		 * needs to be. Give it a hint, so that we can support
 30		 * any size buffer we want somewhat efficiently... */
 31		wrqu->data.length = dev->wireless_handlers->num_private_args;
 32		return -E2BIG;
 33	}
 34
 35	/* Set the number of available ioctls. */
 36	wrqu->data.length = dev->wireless_handlers->num_private_args;
 37
 38	/* Copy structure to the user buffer. */
 39	memcpy(extra, dev->wireless_handlers->private_args,
 40	       sizeof(struct iw_priv_args) * wrqu->data.length);
 41
 42	return 0;
 43}
 44
 45/* Size (in bytes) of the various private data types */
 46static const char iw_priv_type_size[] = {
 47	0,				/* IW_PRIV_TYPE_NONE */
 48	1,				/* IW_PRIV_TYPE_BYTE */
 49	1,				/* IW_PRIV_TYPE_CHAR */
 50	0,				/* Not defined */
 51	sizeof(__u32),			/* IW_PRIV_TYPE_INT */
 52	sizeof(struct iw_freq),		/* IW_PRIV_TYPE_FLOAT */
 53	sizeof(struct sockaddr),	/* IW_PRIV_TYPE_ADDR */
 54	0,				/* Not defined */
 55};
 56
 57static int get_priv_size(__u16 args)
 58{
 59	int	num = args & IW_PRIV_SIZE_MASK;
 60	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;
 61
 62	return num * iw_priv_type_size[type];
 63}
 64
 65static int adjust_priv_size(__u16 args, struct iw_point *iwp)
 66{
 67	int	num = iwp->length;
 68	int	max = args & IW_PRIV_SIZE_MASK;
 69	int	type = (args & IW_PRIV_TYPE_MASK) >> 12;
 70
 71	/* Make sure the driver doesn't goof up */
 72	if (max < num)
 73		num = max;
 74
 75	return num * iw_priv_type_size[type];
 76}
 77
 78/*
 79 * Wrapper to call a private Wireless Extension handler.
 80 * We do various checks and also take care of moving data between
 81 * user space and kernel space.
 82 * It's not as nice and slimline as the standard wrapper. The cause
 83 * is struct iw_priv_args, which was not really designed for the
 84 * job we are going here.
 85 *
 86 * IMPORTANT : This function prevent to set and get data on the same
 87 * IOCTL and enforce the SET/GET convention. Not doing it would be
 88 * far too hairy...
 89 * If you need to set and get data at the same time, please don't use
 90 * a iw_handler but process it in your ioctl handler (i.e. use the
 91 * old driver API).
 92 */
 93static int get_priv_descr_and_size(struct net_device *dev, unsigned int cmd,
 94				   const struct iw_priv_args **descrp)
 95{
 96	const struct iw_priv_args *descr;
 97	int i, extra_size;
 98
 99	descr = NULL;
100	for (i = 0; i < dev->wireless_handlers->num_private_args; i++) {
101		if (cmd == dev->wireless_handlers->private_args[i].cmd) {
102			descr = &dev->wireless_handlers->private_args[i];
103			break;
104		}
105	}
106
107	extra_size = 0;
108	if (descr) {
109		if (IW_IS_SET(cmd)) {
110			int	offset = 0;	/* For sub-ioctls */
111			/* Check for sub-ioctl handler */
112			if (descr->name[0] == '\0')
113				/* Reserve one int for sub-ioctl index */
114				offset = sizeof(__u32);
115
116			/* Size of set arguments */
117			extra_size = get_priv_size(descr->set_args);
118
119			/* Does it fits in iwr ? */
120			if ((descr->set_args & IW_PRIV_SIZE_FIXED) &&
121			   ((extra_size + offset) <= IFNAMSIZ))
122				extra_size = 0;
123		} else {
124			/* Size of get arguments */
125			extra_size = get_priv_size(descr->get_args);
126
127			/* Does it fits in iwr ? */
128			if ((descr->get_args & IW_PRIV_SIZE_FIXED) &&
129			   (extra_size <= IFNAMSIZ))
130				extra_size = 0;
131		}
132	}
133	*descrp = descr;
134	return extra_size;
135}
136
137static int ioctl_private_iw_point(struct iw_point *iwp, unsigned int cmd,
138				  const struct iw_priv_args *descr,
139				  iw_handler handler, struct net_device *dev,
140				  struct iw_request_info *info, int extra_size)
141{
142	char *extra;
143	int err;
144
145	/* Check what user space is giving us */
146	if (IW_IS_SET(cmd)) {
147		if (!iwp->pointer && iwp->length != 0)
148			return -EFAULT;
149
150		if (iwp->length > (descr->set_args & IW_PRIV_SIZE_MASK))
151			return -E2BIG;
152	} else if (!iwp->pointer)
153		return -EFAULT;
154
155	extra = kzalloc(extra_size, GFP_KERNEL);
156	if (!extra)
157		return -ENOMEM;
158
159	/* If it is a SET, get all the extra data in here */
160	if (IW_IS_SET(cmd) && (iwp->length != 0)) {
161		if (copy_from_user(extra, iwp->pointer, extra_size)) {
162			err = -EFAULT;
163			goto out;
164		}
165	}
166
167	/* Call the handler */
168	err = handler(dev, info, (union iwreq_data *) iwp, extra);
169
170	/* If we have something to return to the user */
171	if (!err && IW_IS_GET(cmd)) {
172		/* Adjust for the actual length if it's variable,
173		 * avoid leaking kernel bits outside.
174		 */
175		if (!(descr->get_args & IW_PRIV_SIZE_FIXED))
176			extra_size = adjust_priv_size(descr->get_args, iwp);
177
178		if (copy_to_user(iwp->pointer, extra, extra_size))
179			err =  -EFAULT;
180	}
181
182out:
183	kfree(extra);
184	return err;
185}
186
187int ioctl_private_call(struct net_device *dev, struct iwreq *iwr,
188		       unsigned int cmd, struct iw_request_info *info,
189		       iw_handler handler)
190{
191	int extra_size = 0, ret = -EINVAL;
192	const struct iw_priv_args *descr;
193
194	extra_size = get_priv_descr_and_size(dev, cmd, &descr);
195
196	/* Check if we have a pointer to user space data or not. */
197	if (extra_size == 0) {
198		/* No extra arguments. Trivial to handle */
199		ret = handler(dev, info, &(iwr->u), (char *) &(iwr->u));
200	} else {
201		ret = ioctl_private_iw_point(&iwr->u.data, cmd, descr,
202					     handler, dev, info, extra_size);
203	}
204
205	/* Call commit handler if needed and defined */
206	if (ret == -EIWCOMMIT)
207		ret = call_commit_handler(dev);
208
209	return ret;
210}
211
212#ifdef CONFIG_COMPAT
213int compat_private_call(struct net_device *dev, struct iwreq *iwr,
214			unsigned int cmd, struct iw_request_info *info,
215			iw_handler handler)
216{
217	const struct iw_priv_args *descr;
218	int ret, extra_size;
219
220	extra_size = get_priv_descr_and_size(dev, cmd, &descr);
221
222	/* Check if we have a pointer to user space data or not. */
223	if (extra_size == 0) {
224		/* No extra arguments. Trivial to handle */
225		ret = handler(dev, info, &(iwr->u), (char *) &(iwr->u));
226	} else {
227		struct compat_iw_point *iwp_compat;
228		struct iw_point iwp;
229
230		iwp_compat = (struct compat_iw_point *) &iwr->u.data;
231		iwp.pointer = compat_ptr(iwp_compat->pointer);
232		iwp.length = iwp_compat->length;
233		iwp.flags = iwp_compat->flags;
234
235		ret = ioctl_private_iw_point(&iwp, cmd, descr,
236					     handler, dev, info, extra_size);
237
238		iwp_compat->pointer = ptr_to_compat(iwp.pointer);
239		iwp_compat->length = iwp.length;
240		iwp_compat->flags = iwp.flags;
241	}
242
243	/* Call commit handler if needed and defined */
244	if (ret == -EIWCOMMIT)
245		ret = call_commit_handler(dev);
246
247	return ret;
248}
249#endif