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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>
This commit is contained in:
Al Viro 2017-06-26 13:19:16 -04:00
parent be1b6e8b54
commit 36fd633ec9
4 changed files with 42 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/netdevice.h
View File

@ -2761,7 +2761,8 @@ 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)
{
@ -3315,6 +3316,7 @@ 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);

29
net/core/dev_ioctl.c
View File

@ -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);

16
net/ipv4/devinet.c
View File

@ -1188,22 +1188,25 @@ rarok:
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)
{
struct in_device *in_dev = __in_dev_get_rtnl(dev);
struct in_ifaddr *ifa;
struct ifreq ifr;
int done = 0;
if (WARN_ON(size > sizeof(struct ifreq)))
goto out;
if (!in_dev)
goto out;
for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
if (!buf) {
done += sizeof(ifr);
done += size;
continue;
}
if (len < (int) sizeof(ifr))
if (len < size)
break;
memset(&ifr, 0, sizeof(struct ifreq));
strcpy(ifr.ifr_name, ifa->ifa_label);
@ -1212,13 +1215,12 @@ static int inet_gifconf(struct net_device *dev, char __user *buf, int len)
(*(struct sockaddr_in *)&ifr.ifr_addr).sin_addr.s_addr =
ifa->ifa_local;
if (copy_to_user(buf, &ifr, sizeof(struct ifreq))) {
if (copy_to_user(buf + done, &ifr, size)) {
done = -EFAULT;
break;
}
buf += sizeof(struct ifreq);
len -= sizeof(struct ifreq);
done += sizeof(struct ifreq);
len -= size;
done += size;
}
out:
return done;

79
net/socket.c
View File

@ -961,10 +961,22 @@ static long sock_do_ioctl(struct net *net, struct socket *sock,
* 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;
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 @@ static int dev_ifname32(struct net *net, struct compat_ifreq __user *uifr32)
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 @@ static int compat_sock_ioctl_trans(struct file *file, struct socket *sock,
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: