[
This is just an RFC - I'm not asking to apply it at the moment. Are there
any objections in principle to that change?
]
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.
Signed-off-by: Al Viro
---
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9c23bd2efb56..84428fd0c999 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2729,7 +2729,8 @@ 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)
{
@@ -3278,6 +3279,7 @@ 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);
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index b94b1d293506..b98d1860b29a 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -64,9 +64,8 @@ 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;
@@ -77,11 +76,8 @@ 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.
@@ -93,10 +89,10 @@ 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;
@@ -107,12 +103,12 @@ 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;
}
/*
@@ -396,17 +392,6 @@ 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);
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index df14815a3b8c..8f4621591556 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1160,22 +1160,25 @@ int devinet_ioctl(struct net *net, unsigned int cmd,
void __user *arg)
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)
{
s
