Merge branch 'net-various-compat-ioctl-fixes'

Johannes Berg says:

====================
various compat ioctl fixes

Back a long time ago, I already fixed a few of these by passing
the size of the struct ifreq to do_sock_ioctl(). However, Robert
found more cases, and now it won't be as simple because we'd have
to pass that down all the way to e.g. bond_do_ioctl() which isn't
really feasible.

Therefore, restore the old code.

While looking at why SIOCGIFNAME was broken, I realized that Al
had removed that case - which had been handled in an explicit
separate function - as well, and looking through his work at the
time I saw that bond ioctls were also affected by the erroneous
removal.

I've restored SIOCGIFNAME and bond ioctls by going through the
(now renamed) dev_ifsioc() instead of reintroducing their own
helper functions, which I hope is correct but have only tested
with SIOCGIFNAME.
====================
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/socket.c

@@ -941,8 +941,7 @@ void dlci_ioctl_set(int (*hook) (unsigned int, void __user *))
 EXPORT_SYMBOL(dlci_ioctl_set);
 
 static long sock_do_ioctl(struct net *net, struct socket *sock,
-			  unsigned int cmd, unsigned long arg,
-			  unsigned int ifreq_size)
+			  unsigned int cmd, unsigned long arg)
 {
 	int err;
 	void __user *argp = (void __user *)arg;
@@ -968,11 +967,11 @@ static long sock_do_ioctl(struct net *net, struct socket *sock,
 	} else {
 		struct ifreq ifr;
 		bool need_copyout;
-		if (copy_from_user(&ifr, argp, ifreq_size))
+		if (copy_from_user(&ifr, argp, sizeof(struct ifreq)))
 			return -EFAULT;
 		err = dev_ioctl(net, cmd, &ifr, &need_copyout);
 		if (!err && need_copyout)
-			if (copy_to_user(argp, &ifr, ifreq_size))
+			if (copy_to_user(argp, &ifr, sizeof(struct ifreq)))
 				return -EFAULT;
 	}
 	return err;
@@ -1071,8 +1070,7 @@ static long sock_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 			err = open_related_ns(&net->ns, get_net_ns);
 			break;
 		default:
-			err = sock_do_ioctl(net, sock, cmd, arg,
-					    sizeof(struct ifreq));
+			err = sock_do_ioctl(net, sock, cmd, arg);
 			break;
 		}
 	return err;
@@ -2780,8 +2778,7 @@ static int do_siocgstamp(struct net *net, struct socket *sock,
 	int err;
 
 	set_fs(KERNEL_DS);
-	err = sock_do_ioctl(net, sock, cmd, (unsigned long)&ktv,
-			    sizeof(struct compat_ifreq));
+	err = sock_do_ioctl(net, sock, cmd, (unsigned long)&ktv);
 	set_fs(old_fs);
 	if (!err)
 		err = compat_put_timeval(&ktv, up);
@@ -2797,8 +2794,7 @@ static int do_siocgstampns(struct net *net, struct socket *sock,
 	int err;
 
 	set_fs(KERNEL_DS);
-	err = sock_do_ioctl(net, sock, cmd, (unsigned long)&kts,
-			    sizeof(struct compat_ifreq));
+	err = sock_do_ioctl(net, sock, cmd, (unsigned long)&kts);
 	set_fs(old_fs);
 	if (!err)
 		err = compat_put_timespec(&kts, up);
@@ -2994,6 +2990,54 @@ 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:
+		case SIOCGIFNAME:
+			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)
 {
@@ -3109,8 +3153,7 @@ static int routing_ioctl(struct net *net, struct socket *sock,
 	}
 
 	set_fs(KERNEL_DS);
-	ret = sock_do_ioctl(net, sock, cmd, (unsigned long) r,
-			    sizeof(struct compat_ifreq));
+	ret = sock_do_ioctl(net, sock, cmd, (unsigned long) r);
 	set_fs(old_fs);
 
 out:
@@ -3210,21 +3253,22 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock,
 	case SIOCSIFTXQLEN:
 	case SIOCBRADDIF:
 	case SIOCBRDELIF:
+	case SIOCGIFNAME:
 	case SIOCSIFNAME:
 	case SIOCGMIIPHY:
 	case SIOCGMIIREG:
 	case SIOCSMIIREG:
-	case SIOCSARP:
-	case SIOCGARP:
-	case SIOCDARP:
-	case SIOCATMARK:
 	case SIOCBONDENSLAVE:
 	case SIOCBONDRELEASE:
 	case SIOCBONDSETHWADDR:
 	case SIOCBONDCHANGEACTIVE:
-	case SIOCGIFNAME:
-		return sock_do_ioctl(net, sock, cmd, arg,
-				     sizeof(struct compat_ifreq));
+		return compat_ifreq_ioctl(net, sock, cmd, argp);
+
+	case SIOCSARP:
+	case SIOCGARP:
+	case SIOCDARP:
+	case SIOCATMARK:
+		return sock_do_ioctl(net, sock, cmd, arg);
 	}
 
 	return -ENOIOCTLCMD;