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Commit 37ac39bd authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
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Revert "kill dev_ifsioc()" 

This reverts commit bf440573 ("kill dev_ifsioc()").

This wasn't really unused as implied by the original commit,
it still handles the copy to/from user differently, and the
commit thus caused issues such as
  https://bugzilla.kernel.org/show_bug.cgi?id=199469
and
  https://bugzilla.kernel.org/show_bug.cgi?id=202273



However, deviating from a strict revert, rename dev_ifsioc()
to compat_ifreq_ioctl() to be clearer as to its purpose and
add a comment.

Cc: stable@vger.kernel.org
Fixes: bf440573 ("kill dev_ifsioc()")
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 63ff03ab

net/socket.c

+49 −0
Original line number Diff line number Diff line
@@ -2990,6 +2990,53 @@ static int compat_ifr_data_ioctl(struct net *net, unsigned int cmd, 
	return dev_ioctl(net, cmd, &ifreq, NULL);

}



static int compat_ifreq_ioctl(struct net *net, struct socket *sock,

			      unsigned int cmd,

			      struct compat_ifreq __user *uifr32)

{

	struct ifreq __user *uifr;

	int err;



	/* Handle the fact that while struct ifreq has the same *layout* on

	 * 32/64 for everything but ifreq::ifru_ifmap and ifreq::ifru_data,

	 * which are handled elsewhere, it still has different *size* due to

	 * ifreq::ifru_ifmap (which is 16 bytes on 32 bit, 24 bytes on 64-bit,

	 * resulting in struct ifreq being 32 and 40 bytes respectively).

	 * As a result, if the struct happens to be at the end of a page and

	 * the next page isn't readable/writable, we get a fault. To prevent

	 * that, copy back and forth to the full size.

	 */



	uifr = compat_alloc_user_space(sizeof(*uifr));

	if (copy_in_user(uifr, uifr32, sizeof(*uifr32)))

		return -EFAULT;



	err = sock_do_ioctl(net, sock, cmd, (unsigned long)uifr);



	if (!err) {

		switch (cmd) {

		case SIOCGIFFLAGS:

		case SIOCGIFMETRIC:

		case SIOCGIFMTU:

		case SIOCGIFMEM:

		case SIOCGIFHWADDR:

		case SIOCGIFINDEX:

		case SIOCGIFADDR:

		case SIOCGIFBRDADDR:

		case SIOCGIFDSTADDR:

		case SIOCGIFNETMASK:

		case SIOCGIFPFLAGS:

		case SIOCGIFTXQLEN:

		case SIOCGMIIPHY:

		case SIOCGMIIREG:

			if (copy_in_user(uifr32, uifr, sizeof(*uifr32)))

				err = -EFAULT;

			break;

		}

	}

	return err;

}



static int compat_sioc_ifmap(struct net *net, unsigned int cmd,

			struct compat_ifreq __user *uifr32)

{
@@ -3209,6 +3256,8 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock, 
	case SIOCGMIIPHY:

	case SIOCGMIIREG:

	case SIOCSMIIREG:

		return compat_ifreq_ioctl(net, sock, cmd, argp);



	case SIOCSARP:

	case SIOCGARP:

	case SIOCDARP: