Commit 36fd633e authored by Al Viro's avatar Al Viro
Browse files

net: separate SIOCGIFCONF handling from dev_ioctl() 



Only two of dev_ioctl() callers may pass SIOCGIFCONF to it.
Separating that codepath from the rest of dev_ioctl() allows both
to simplify dev_ioctl() itself (all other cases work with struct ifreq *)
*and* seriously simplify the compat side of that beast: all it takes
is passing to inet_gifconf() an extra argument - the size of individual
records (sizeof(struct ifreq) or sizeof(struct compat_ifreq)).  With
dev_ifconf() called directly from sock_do_ioctl()/compat_dev_ifconf()
that's easy to arrange.

As the result, compat side of SIOCGIFCONF doesn't need any
allocations, copy_in_user() back and forth, etc.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent be1b6e8b

include/linux/netdevice.h

+3 −1
Original line number Diff line number Diff line
@@ -2761,7 +2761,8 @@ static inline bool dev_validate_header(const struct net_device *dev, 
	return false;

}



typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr, int len);

typedef int gifconf_func_t(struct net_device * dev, char __user * bufptr,

			   int len, int size);

int register_gifconf(unsigned int family, gifconf_func_t *gifconf);

static inline int unregister_gifconf(unsigned int family)

{
@@ -3315,6 +3316,7 @@ void netdev_rx_handler_unregister(struct net_device *dev); 


bool dev_valid_name(const char *name);

int dev_ioctl(struct net *net, unsigned int cmd, void __user *);

int dev_ifconf(struct net *net, struct ifconf *, int);

int dev_ethtool(struct net *net, struct ifreq *);

unsigned int dev_get_flags(const struct net_device *);

int __dev_change_flags(struct net_device *, unsigned int flags);

net/core/dev_ioctl.c

+7 −22
Original line number Diff line number Diff line
@@ -66,9 +66,8 @@ EXPORT_SYMBOL(register_gifconf); 
 *	Thus we will need a 'compatibility mode'.

 */



static int dev_ifconf(struct net *net, char __user *arg)

int dev_ifconf(struct net *net, struct ifconf *ifc, int size)

{

	struct ifconf ifc;

	struct net_device *dev;

	char __user *pos;

	int len;
@@ -79,11 +78,8 @@ static int dev_ifconf(struct net *net, char __user *arg) 
	 *	Fetch the caller's info block.

	 */



	if (copy_from_user(&ifc, arg, sizeof(struct ifconf)))

		return -EFAULT;



	pos = ifc.ifc_buf;

	len = ifc.ifc_len;

	pos = ifc->ifc_buf;

	len = ifc->ifc_len;



	/*

	 *	Loop over the interfaces, and write an info block for each.
@@ -95,10 +91,10 @@ static int dev_ifconf(struct net *net, char __user *arg) 
			if (gifconf_list[i]) {

				int done;

				if (!pos)

					done = gifconf_list[i](dev, NULL, 0);

					done = gifconf_list[i](dev, NULL, 0, size);

				else

					done = gifconf_list[i](dev, pos + total,

							       len - total);

							       len - total, size);

				if (done < 0)

					return -EFAULT;

				total += done;
@@ -109,12 +105,12 @@ static int dev_ifconf(struct net *net, char __user *arg) 
	/*

	 *	All done.  Write the updated control block back to the caller.

	 */

	ifc.ifc_len = total;

	ifc->ifc_len = total;



	/*

	 * 	Both BSD and Solaris return 0 here, so we do too.

	 */

	return copy_to_user(arg, &ifc, sizeof(struct ifconf)) ? -EFAULT : 0;

	return 0;

}



/*
@@ -412,17 +408,6 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg) 
	int ret;

	char *colon;



	/* One special case: SIOCGIFCONF takes ifconf argument

	   and requires shared lock, because it sleeps writing

	   to user space.

	 */



	if (cmd == SIOCGIFCONF) {

		rtnl_lock();

		ret = dev_ifconf(net, (char __user *) arg);

		rtnl_unlock();

		return ret;

	}

	if (cmd == SIOCGIFNAME)

		return dev_ifname(net, (struct ifreq __user *)arg);

net/ipv4/devinet.c

+9 −7
Original line number Diff line number Diff line
@@ -1188,22 +1188,25 @@ rarok: 
	goto out;

}



static int inet_gifconf(struct net_device *dev, char __user *buf, int len)

static int inet_gifconf(struct net_device *dev, char __user *buf, int len, int size)

{

	struct in_device *in_dev = __in_dev_get_rtnl(dev);

	struct in_ifaddr *ifa;

	struct ifreq ifr;

	int done = 0;



	if (WARN_ON(size > sizeof(struct ifreq)))

		goto out;



	if (!in_dev)

		goto out;



	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {

		if (!buf) {

			done += sizeof(ifr);

			done += size;

			continue;

		}

		if (len < (int) sizeof(ifr))

		if (len < size)

			break;

		memset(&ifr, 0, sizeof(struct ifreq));

		strcpy(ifr.ifr_name, ifa->ifa_label);
@@ -1212,13 +1215,12 @@ static int inet_gifconf(struct net_device *dev, char __user *buf, int len) 
		(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr =

								ifa->ifa_local;



		if (copy_to_user(buf, &ifr, sizeof(struct ifreq))) {

		if (copy_to_user(buf + done, &ifr, size)) {

			done = -EFAULT;

			break;

		}

		buf  += sizeof(struct ifreq);

		len  -= sizeof(struct ifreq);

		done += sizeof(struct ifreq);

		len  -= size;

		done += size;

	}

out:

	return done;

net/socket.c

+23 −56
Original line number Diff line number Diff line
@@ -961,12 +961,24 @@ static long sock_do_ioctl(struct net *net, struct socket *sock, 
	 * If this ioctl is unknown try to hand it down

	 * to the NIC driver.

	 */

	if (err == -ENOIOCTLCMD)

		err = dev_ioctl(net, cmd, argp);

	if (err != -ENOIOCTLCMD)

		return err;



	if (cmd == SIOCGIFCONF) {

		struct ifconf ifc;

		if (copy_from_user(&ifc, argp, sizeof(struct ifconf)))

			return -EFAULT;

		rtnl_lock();

		err = dev_ifconf(net, &ifc, sizeof(struct ifreq));

		rtnl_unlock();

		if (!err && copy_to_user(argp, &ifc, sizeof(struct ifconf)))

			err = -EFAULT;

		return err;

	}



	return dev_ioctl(net, cmd, argp);

}



/*

 *	With an ioctl, arg may well be a user mode pointer, but we don't know

 *	what to do with it - that's up to the protocol still.
@@ -2673,70 +2685,25 @@ static int dev_ifname32(struct net *net, struct compat_ifreq __user *uifr32) 
	return 0;

}



static int dev_ifconf(struct net *net, struct compat_ifconf __user *uifc32)

static int compat_dev_ifconf(struct net *net, struct compat_ifconf __user *uifc32)

{

	struct compat_ifconf ifc32;

	struct ifconf ifc;

	struct ifconf __user *uifc;

	struct compat_ifreq __user *ifr32;

	struct ifreq __user *ifr;

	unsigned int i, j;

	int err;



	if (copy_from_user(&ifc32, uifc32, sizeof(struct compat_ifconf)))

		return -EFAULT;



	memset(&ifc, 0, sizeof(ifc));

	if (ifc32.ifcbuf == 0) {

		ifc32.ifc_len = 0;

		ifc.ifc_len = 0;

		ifc.ifc_req = NULL;

		uifc = compat_alloc_user_space(sizeof(struct ifconf));

	} else {

		size_t len = ((ifc32.ifc_len / sizeof(struct compat_ifreq)) + 1) *

			sizeof(struct ifreq);

		uifc = compat_alloc_user_space(sizeof(struct ifconf) + len);

		ifc.ifc_len = len;

		ifr = ifc.ifc_req = (void __user *)(uifc + 1);

		ifr32 = compat_ptr(ifc32.ifcbuf);

		for (i = 0; i < ifc32.ifc_len; i += sizeof(struct compat_ifreq)) {

			if (copy_in_user(ifr, ifr32, sizeof(struct compat_ifreq)))

				return -EFAULT;

			ifr++;

			ifr32++;

		}

	}

	if (copy_to_user(uifc, &ifc, sizeof(struct ifconf)))

		return -EFAULT;

	ifc.ifc_len = ifc32.ifc_len;

	ifc.ifc_req = compat_ptr(ifc32.ifcbuf);



	err = dev_ioctl(net, SIOCGIFCONF, uifc);

	rtnl_lock();

	err = dev_ifconf(net, &ifc, sizeof(struct compat_ifreq));

	rtnl_unlock();

	if (err)

		return err;



	if (copy_from_user(&ifc, uifc, sizeof(struct ifconf)))

		return -EFAULT;



	ifr = ifc.ifc_req;

	ifr32 = compat_ptr(ifc32.ifcbuf);

	for (i = 0, j = 0;

	     i + sizeof(struct compat_ifreq) <= ifc32.ifc_len && j < ifc.ifc_len;

	     i += sizeof(struct compat_ifreq), j += sizeof(struct ifreq)) {

		if (copy_in_user(ifr32, ifr, sizeof(struct compat_ifreq)))

			return -EFAULT;

		ifr32++;

		ifr++;

	}



	if (ifc32.ifcbuf == 0) {

		/* Translate from 64-bit structure multiple to

		 * a 32-bit one.

		 */

		i = ifc.ifc_len;

		i = ((i / sizeof(struct ifreq)) * sizeof(struct compat_ifreq));

		ifc32.ifc_len = i;

	} else {

		ifc32.ifc_len = i;

	}

	ifc32.ifc_len = ifc.ifc_len;

	if (copy_to_user(uifc32, &ifc32, sizeof(struct compat_ifconf)))

		return -EFAULT;
@@ -3133,7 +3100,7 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock, 
	case SIOCGIFNAME:

		return dev_ifname32(net, argp);

	case SIOCGIFCONF:

		return dev_ifconf(net, argp);

		return compat_dev_ifconf(net, argp);

	case SIOCETHTOOL:

		return ethtool_ioctl(net, argp);

	case SIOCWANDEV:

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