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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/socket.c b/net/socket.c
index 1536515b..96e5b23 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -961,10 +961,22 @@
* 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;
- 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);
}
/*
@@ -2673,70 +2685,25 @@
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 @@
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: