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authorAl Viro <viro@zeniv.linux.org.uk>2017-06-26 13:19:16 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-01-24 19:13:45 -0500
commit36fd633ec98acd2028585c22128fcaa3da6d5770 (patch)
tree1fa77e8bf1662dea936b52107a0d39485110edb1 /net/core
parentbe1b6e8b5470e8311bfa1a3dfd7bd59e85a99759 (diff)
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>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/dev_ioctl.c29
1 files changed, 7 insertions, 22 deletions
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 7e690d0ccd05..5cdec23dd28e 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -66,9 +66,8 @@ 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;
@@ -79,11 +78,8 @@ 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.
@@ -95,10 +91,10 @@ 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;
@@ -109,12 +105,12 @@ 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;
}
/*
@@ -412,17 +408,6 @@ 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);