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Date: Fri, 6 Nov 2009 19:09:04 +0100
From: Arnd Bergmann <arnd@...db.de>
To: linux-kernel@...r.kernel.org
Cc: David Miller <davem@...emloft.net>, Christoph Hellwig <hch@....de>,
netdev@...r.kernel.org, Arnd Bergmann <arnd@...db.de>
Subject: [PATCH 2/7] 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@...db.de>
---
drivers/net/tun.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++------
fs/compat_ioctl.c | 20 -------------------
2 files changed, 48 insertions(+), 27 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 4fdfa2a..c132c8e 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -54,6 +54,7 @@
#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>
@@ -1110,8 +1111,8 @@ 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;
@@ -1121,7 +1122,7 @@ 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) {
@@ -1144,7 +1145,7 @@ 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;
}
@@ -1162,7 +1163,7 @@ 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;
@@ -1236,7 +1237,7 @@ 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;
@@ -1275,6 +1276,43 @@ 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)
+{
+ int ret;
+
+ 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);
@@ -1359,7 +1397,10 @@ 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
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index f91fd51..c562e9a 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -539,12 +539,6 @@ static int dev_ifsioc(unsigned int fd, unsigned int cmd, unsigned long arg)
set_fs (old_fs);
if (!err) {
switch (cmd) {
- /* TUNSETIFF is defined as _IOW, it should be _IORW
- * as the data is copied back to user space, but that
- * cannot be fixed without breaking all existing apps.
- */
- case TUNSETIFF:
- case TUNGETIFF:
case SIOCGIFFLAGS:
case SIOCGIFMETRIC:
case SIOCGIFMTU:
@@ -1979,18 +1973,6 @@ COMPATIBLE_IOCTL(SCSI_IOCTL_SEND_COMMAND)
COMPATIBLE_IOCTL(SCSI_IOCTL_PROBE_HOST)
COMPATIBLE_IOCTL(SCSI_IOCTL_GET_PCI)
#endif
-/* Big T */
-COMPATIBLE_IOCTL(TUNSETNOCSUM)
-COMPATIBLE_IOCTL(TUNSETDEBUG)
-COMPATIBLE_IOCTL(TUNSETPERSIST)
-COMPATIBLE_IOCTL(TUNSETOWNER)
-COMPATIBLE_IOCTL(TUNSETLINK)
-COMPATIBLE_IOCTL(TUNSETGROUP)
-COMPATIBLE_IOCTL(TUNGETFEATURES)
-COMPATIBLE_IOCTL(TUNSETOFFLOAD)
-COMPATIBLE_IOCTL(TUNSETTXFILTER)
-COMPATIBLE_IOCTL(TUNGETSNDBUF)
-COMPATIBLE_IOCTL(TUNSETSNDBUF)
/* Big V */
COMPATIBLE_IOCTL(VT_SETMODE)
COMPATIBLE_IOCTL(VT_GETMODE)
@@ -2571,8 +2553,6 @@ HANDLE_IOCTL(SIOCSIFPFLAGS, dev_ifsioc)
HANDLE_IOCTL(SIOCGIFPFLAGS, dev_ifsioc)
HANDLE_IOCTL(SIOCGIFTXQLEN, dev_ifsioc)
HANDLE_IOCTL(SIOCSIFTXQLEN, dev_ifsioc)
-HANDLE_IOCTL(TUNSETIFF, dev_ifsioc)
-HANDLE_IOCTL(TUNGETIFF, dev_ifsioc)
HANDLE_IOCTL(SIOCETHTOOL, ethtool_ioctl)
HANDLE_IOCTL(SIOCBONDENSLAVE, bond_ioctl)
HANDLE_IOCTL(SIOCBONDRELEASE, bond_ioctl)
--
1.6.3.3
--
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