atm: 32-bit ioctl compatibility

We lack compat ioctl support through most of the ATM code. This patch
deals with most of it, and I can now at least use BR2684 and PPPoATM
with 32-bit userspace.

I haven't added a .compat_ioctl method to struct atm_ioctl, because
AFAICT none of the current users need any conversion -- so we can just
call the ->ioctl() method in every case. I looked at br2684, clip, lec,
mpc, pppoatm and atmtcp.

In svc_compat_ioctl() the only mangling which is needed is to change
COMPAT_ATM_ADDPARTY to ATM_ADDPARTY. Although it's defined as
	_IOW('a', ATMIOC_SPECIAL+4,struct atm_iobuf)
it doesn't actually _take_ a struct atm_iobuf as an argument -- it takes
a struct sockaddr_atmsvc, which _is_ the same between 32-bit and 64-bit
code, so doesn't need conversion.

Almost all of vcc_ioctl() would have been identical, so I converted that
into a core do_vcc_ioctl() function with an 'int compat' argument.

I've done the same with atm_dev_ioctl(), where there _are_ a few
differences, but still it's relatively contained and there would
otherwise have been a lot of duplication.

I haven't done any of the actual device-specific ioctls, although I've
added a compat_ioctl method to struct atmdev_ops.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 68 insertions, 20 deletions

diff --git a/net/atm/resources.c b/net/atm/resources.c
index a34ba948af96..56b7322ff461 100644
--- a/net/atm/resources.c
+++ b/net/atm/resources.c
@@ -195,20 +195,39 @@ static int fetch_stats(struct atm_dev *dev, struct atm_dev_stats __user *arg, in
 }
 
 
-int atm_dev_ioctl(unsigned int cmd, void __user *arg)
+int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat)
 {
         void __user *buf;
         int error, len, number, size = 0;
         struct atm_dev *dev;
         struct list_head *p;
         int *tmp_buf, *tmp_p;
-        struct atm_iobuf __user *iobuf = arg;
-        struct atmif_sioc __user *sioc = arg;
+        int __user *sioc_len;
+        int __user *iobuf_len;
+
+#ifndef CONFIG_COMPAT
+        compat = 0; /* Just so the compiler _knows_ */
+#endif
+
         switch (cmd) {
                 case ATM_GETNAMES:
-                        if (get_user(buf, &iobuf->buffer))
-                                return -EFAULT;
-                        if (get_user(len, &iobuf->length))
+
+                        if (compat) {
+#ifdef CONFIG_COMPAT
+                                struct compat_atm_iobuf __user *ciobuf = arg;
+                                compat_uptr_t cbuf;
+                                iobuf_len = &ciobuf->length;
+                                if (get_user(cbuf, &ciobuf->buffer))
+                                        return -EFAULT;
+                                buf = compat_ptr(cbuf);
+#endif
+                        } else {
+                                struct atm_iobuf __user *iobuf = arg;
+                                iobuf_len = &iobuf->length;
+                                if (get_user(buf, &iobuf->buffer))
+                                        return -EFAULT;
+                        }
+                        if (get_user(len, iobuf_len))
                                 return -EFAULT;
                         mutex_lock(&atm_dev_mutex);
                         list_for_each(p, &atm_devs)
@@ -229,7 +248,7 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg)
                         }
                         mutex_unlock(&atm_dev_mutex);
                         error = ((copy_to_user(buf, tmp_buf, size)) ||
-                                        put_user(size, &iobuf->length))
+                                        put_user(size, iobuf_len))
                                                 ? -EFAULT : 0;
                         kfree(tmp_buf);
                         return error;
@@ -237,13 +256,32 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg)
                         break;
         }
 
-        if (get_user(buf, &sioc->arg))
-                return -EFAULT;
-        if (get_user(len, &sioc->length))
-                return -EFAULT;
-        if (get_user(number, &sioc->number))
-                return -EFAULT;
-
+        if (compat) {
+#ifdef CONFIG_COMPAT
+                struct compat_atmif_sioc __user *csioc = arg;
+                compat_uptr_t carg;
+
+                sioc_len = &csioc->length;
+                if (get_user(carg, &csioc->arg))
+                        return -EFAULT;
+                buf = compat_ptr(carg);
+
+                if (get_user(len, &csioc->length))
+                        return -EFAULT;
+                if (get_user(number, &csioc->number))
+                        return -EFAULT;
+#endif
+        } else {
+                struct atmif_sioc __user *sioc = arg;
+
+                sioc_len = &sioc->length;
+                if (get_user(buf, &sioc->arg))
+                        return -EFAULT;
+                if (get_user(len, &sioc->length))
+                        return -EFAULT;
+                if (get_user(number, &sioc->number))
+                        return -EFAULT;
+        }
         if (!(dev = try_then_request_module(atm_dev_lookup(number),
                                             "atm-device-%d", number)))
                 return -ENODEV;
@@ -358,7 +396,7 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg)
                         size = error;
                         /* may return 0, but later on size == 0 means "don't
                            write the length" */
-                        error = put_user(size, &sioc->length)
+                        error = put_user(size, sioc_len)
                                 ? -EFAULT : 0;
                         goto done;
                 case ATM_SETLOOP:
@@ -380,11 +418,21 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg)
                         }
                         /* fall through */
                 default:
-                        if (!dev->ops->ioctl) {
-                                error = -EINVAL;
-                                goto done;
+                        if (compat) {
+#ifdef CONFIG_COMPAT
+                                if (!dev->ops->compat_ioctl) {
+                                        error = -EINVAL;
+                                        goto done;
+                                }
+                                size = dev->ops->compat_ioctl(dev, cmd, buf);
+#endif
+                        } else {
+                                if (!dev->ops->ioctl) {
+                                        error = -EINVAL;
+                                        goto done;
+                                }
+                                size = dev->ops->ioctl(dev, cmd, buf);
                         }
-                        size = dev->ops->ioctl(dev, cmd, buf);
                         if (size < 0) {
                                 error = (size == -ENOIOCTLCMD ? -EINVAL : size);
                                 goto done;
@@ -392,7 +440,7 @@ int atm_dev_ioctl(unsigned int cmd, void __user *arg)
         }
 
         if (size)
-                error = put_user(size, &sioc->length)
+                error = put_user(size, sioc_len)
                         ? -EFAULT : 0;
         else
                 error = 0;