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authorArnd Bergmann <arnd@arndb.de>2009-11-06 22:52:32 -0800
committerDavid S. Miller <davem@davemloft.net>2009-11-06 22:52:32 -0800
commit50857e2a59d8beddc6bb76137df026d67f30d5ca (patch)
tree7b6d244ad6fa07ff199c7d1436750d535b6b8dcd /drivers/net/tun.c
parent2dceba14ef0e62738d58777a1bd4018130d47a74 (diff)
net/tun: handle compat_ioctl directly
The tun driver is the only code in the kernel that operates on a character device with struct ifreq. Change the driver to handle the conversion itself so we can contain the remaining ifreq handling in the socket layer. This also fixes a bug in the handling of invalid ioctl numbers on an unbound tun device. The driver treats this as a TUNSETIFF in native mode, but there is no way for the generic compat_ioctl() function to emulate this behaviour. Possibly the driver was only doing this accidentally anyway, but if any code relies on this misfeature, it now also works in compat mode. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r--drivers/net/tun.c53
1 files changed, 46 insertions, 7 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9c59a82784d..01e99f22210 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -53,6 +53,7 @@
#include <linux/miscdevice.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
+#include <linux/compat.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
@@ -1109,8 +1110,8 @@ static int set_offload(struct net_device *dev, unsigned long arg)
return 0;
}
-static long tun_chr_ioctl(struct file *file, unsigned int cmd,
- unsigned long arg)
+static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg, int ifreq_len)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun;
@@ -1120,7 +1121,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd,
int ret;
if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
- if (copy_from_user(&ifr, argp, sizeof ifr))
+ if (copy_from_user(&ifr, argp, ifreq_len))
return -EFAULT;
if (cmd == TUNGETFEATURES) {
@@ -1143,7 +1144,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd,
if (ret)
goto unlock;
- if (copy_to_user(argp, &ifr, sizeof(ifr)))
+ if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
goto unlock;
}
@@ -1161,7 +1162,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd,
if (ret)
break;
- if (copy_to_user(argp, &ifr, sizeof(ifr)))
+ if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
break;
@@ -1235,7 +1236,7 @@ static long tun_chr_ioctl(struct file *file, unsigned int cmd,
/* Get hw addres */
memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
ifr.ifr_hwaddr.sa_family = tun->dev->type;
- if (copy_to_user(argp, &ifr, sizeof ifr))
+ if (copy_to_user(argp, &ifr, ifreq_len))
ret = -EFAULT;
break;
@@ -1274,6 +1275,41 @@ unlock:
return ret;
}
+static long tun_chr_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
+}
+
+#ifdef CONFIG_COMPAT
+static long tun_chr_compat_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ case TUNSETIFF:
+ case TUNGETIFF:
+ case TUNSETTXFILTER:
+ case TUNGETSNDBUF:
+ case TUNSETSNDBUF:
+ case SIOCGIFHWADDR:
+ case SIOCSIFHWADDR:
+ arg = (unsigned long)compat_ptr(arg);
+ break;
+ default:
+ arg = (compat_ulong_t)arg;
+ break;
+ }
+
+ /*
+ * compat_ifreq is shorter than ifreq, so we must not access beyond
+ * the end of that structure. All fields that are used in this
+ * driver are compatible though, we don't need to convert the
+ * contents.
+ */
+ return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
+}
+#endif /* CONFIG_COMPAT */
+
static int tun_chr_fasync(int fd, struct file *file, int on)
{
struct tun_struct *tun = tun_get(file);
@@ -1356,7 +1392,10 @@ static const struct file_operations tun_fops = {
.write = do_sync_write,
.aio_write = tun_chr_aio_write,
.poll = tun_chr_poll,
- .unlocked_ioctl = tun_chr_ioctl,
+ .unlocked_ioctl = tun_chr_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = tun_chr_compat_ioctl,
+#endif
.open = tun_chr_open,
.release = tun_chr_close,
.fasync = tun_chr_fasync