fix rawctl compat ioctls breakage on amd64 and itanic

RAW_SETBIND and RAW_GETBIND 32bit versions are fscked in interesting ways.

1) fs/compat_ioctl.c has COMPATIBLE_IOCTL(RAW_SETBIND) followed by
HANDLE_IOCTL(RAW_SETBIND, raw_ioctl).  The latter is ignored.

2) on amd64 (and itanic) the damn thing is broken - we have int + u64 + u64
and layouts on i386 and amd64 are _not_ the same.  raw_ioctl() would
work there, but it's never called due to (1).  As it is, i386 /sbin/raw
definitely doesn't work on amd64 boxen.

3) switching to raw_ioctl() as is would *not* work on e.g. sparc64 and ppc64,
which would be rather sad, seeing that normal userland there is 32bit.
The thing is, slapping __packed on the struct in question does not DTRT -
it eliminates *all* padding.  The real solution is to use compat_u64.

4) of course, all that stuff has no business being outside of raw.c in the
first place - there should be ->compat_ioctl() for /dev/rawctl instead of
messing with compat_ioctl.c.

[akpm@linux-foundation.org: coding-style fixes]
[arnd@arndb.de: port to 2.6.36]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 140 insertions, 103 deletions

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index b38942f6bf31..24b2b9160aa6 100644
--- a/drivers/char/raw.c
+++ b/drivers/char/raw.c
@@ -19,8 +19,8 @@
 #include <linux/cdev.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
-#include <linux/smp_lock.h>
 #include <linux/gfp.h>
+#include <linux/compat.h>
 
 #include <asm/uaccess.h>
 
@@ -55,7 +55,6 @@ static int raw_open(struct inode *inode, struct file *filp)
                 return 0;
         }
 
-        lock_kernel();
         mutex_lock(&raw_mutex);
 
         /*
@@ -82,7 +81,6 @@ static int raw_open(struct inode *inode, struct file *filp)
                         bdev->bd_inode->i_mapping;
         filp->private_data = bdev;
         mutex_unlock(&raw_mutex);
-        unlock_kernel();
         return 0;
 
 out2:
@@ -91,7 +89,6 @@ out1:
         blkdev_put(bdev, filp->f_mode);
 out:
         mutex_unlock(&raw_mutex);
-        unlock_kernel();
         return err;
 }
 
@@ -125,20 +122,84 @@ static long
 raw_ioctl(struct file *filp, unsigned int command, unsigned long arg)
 {
         struct block_device *bdev = filp->private_data;
-        int ret;
+        return blkdev_ioctl(bdev, 0, command, arg);
+}
+
+static int bind_set(int number, u64 major, u64 minor)
+{
+        dev_t dev = MKDEV(major, minor);
+        struct raw_device_data *rawdev;
+        int err = 0;
 
-        lock_kernel();
-        ret = blkdev_ioctl(bdev, 0, command, arg);
-        unlock_kernel();
+        if (number <= 0 || number >= MAX_RAW_MINORS)
+                return -EINVAL;
 
-        return ret;
+        if (MAJOR(dev) != major || MINOR(dev) != minor)
+                return -EINVAL;
+
+        rawdev = &raw_devices[number];
+
+        /*
+         * This is like making block devices, so demand the
+         * same capability
+         */
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        /*
+         * For now, we don't need to check that the underlying
+         * block device is present or not: we can do that when
+         * the raw device is opened.  Just check that the
+         * major/minor numbers make sense.
+         */
+
+        if (MAJOR(dev) == 0 && dev != 0)
+                return -EINVAL;
+
+        mutex_lock(&raw_mutex);
+        if (rawdev->inuse) {
+                mutex_unlock(&raw_mutex);
+                return -EBUSY;
+        }
+        if (rawdev->binding) {
+                bdput(rawdev->binding);
+                module_put(THIS_MODULE);
+        }
+        if (!dev) {
+                /* unbind */
+                rawdev->binding = NULL;
+                device_destroy(raw_class, MKDEV(RAW_MAJOR, number));
+        } else {
+                rawdev->binding = bdget(dev);
+                if (rawdev->binding == NULL) {
+                        err = -ENOMEM;
+                } else {
+                        dev_t raw = MKDEV(RAW_MAJOR, number);
+                        __module_get(THIS_MODULE);
+                        device_destroy(raw_class, raw);
+                        device_create(raw_class, NULL, raw, NULL,
+                                      "raw%d", number);
+                }
+        }
+        mutex_unlock(&raw_mutex);
+        return err;
 }
 
-static void bind_device(struct raw_config_request *rq)
+static int bind_get(int number, dev_t *dev)
 {
-        device_destroy(raw_class, MKDEV(RAW_MAJOR, rq->raw_minor));
-        device_create(raw_class, NULL, MKDEV(RAW_MAJOR, rq->raw_minor), NULL,
-                      "raw%d", rq->raw_minor);
+        struct raw_device_data *rawdev;
+        struct block_device *bdev;
+
+        if (number <= 0 || number >= MAX_RAW_MINORS)
+                return -EINVAL;
+
+        rawdev = &raw_devices[number];
+
+        mutex_lock(&raw_mutex);
+        bdev = rawdev->binding;
+        *dev = bdev ? bdev->bd_dev : 0;
+        mutex_unlock(&raw_mutex);
+        return 0;
 }
 
 /*
@@ -149,105 +210,78 @@ static long raw_ctl_ioctl(struct file *filp, unsigned int command,
                           unsigned long arg)
 {
         struct raw_config_request rq;
-        struct raw_device_data *rawdev;
-        int err = 0;
+        dev_t dev;
+        int err;
 
-        lock_kernel();
         switch (command) {
         case RAW_SETBIND:
+                if (copy_from_user(&rq, (void __user *) arg, sizeof(rq)))
+                        return -EFAULT;
+
+                return bind_set(rq.raw_minor, rq.block_major, rq.block_minor);
+
         case RAW_GETBIND:
+                if (copy_from_user(&rq, (void __user *) arg, sizeof(rq)))
+                        return -EFAULT;
 
-                /* First, find out which raw minor we want */
+                err = bind_get(rq.raw_minor, &dev);
+                if (err)
+                        return err;
 
-                if (copy_from_user(&rq, (void __user *) arg, sizeof(rq))) {
-                        err = -EFAULT;
-                        goto out;
-                }
+                rq.block_major = MAJOR(dev);
+                rq.block_minor = MINOR(dev);
 
-                if (rq.raw_minor <= 0 || rq.raw_minor >= MAX_RAW_MINORS) {
-                        err = -EINVAL;
-                        goto out;
-                }
-                rawdev = &raw_devices[rq.raw_minor];
-
-                if (command == RAW_SETBIND) {
-                        dev_t dev;
-
-                        /*
-                         * This is like making block devices, so demand the
-                         * same capability
-                         */
-                        if (!capable(CAP_SYS_ADMIN)) {
-                                err = -EPERM;
-                                goto out;
-                        }
-
-                        /*
-                         * For now, we don't need to check that the underlying
-                         * block device is present or not: we can do that when
-                         * the raw device is opened.  Just check that the
-                         * major/minor numbers make sense.
-                         */
-
-                        dev = MKDEV(rq.block_major, rq.block_minor);
-                        if ((rq.block_major == 0 && rq.block_minor != 0) ||
-                                        MAJOR(dev) != rq.block_major ||
-                                        MINOR(dev) != rq.block_minor) {
-                                err = -EINVAL;
-                                goto out;
-                        }
-
-                        mutex_lock(&raw_mutex);
-                        if (rawdev->inuse) {
-                                mutex_unlock(&raw_mutex);
-                                err = -EBUSY;
-                                goto out;
-                        }
-                        if (rawdev->binding) {
-                                bdput(rawdev->binding);
-                                module_put(THIS_MODULE);
-                        }
-                        if (rq.block_major == 0 && rq.block_minor == 0) {
-                                /* unbind */
-                                rawdev->binding = NULL;
-                                device_destroy(raw_class,
-                                                MKDEV(RAW_MAJOR, rq.raw_minor));
-                        } else {
-                                rawdev->binding = bdget(dev);
-                                if (rawdev->binding == NULL)
-                                        err = -ENOMEM;
-                                else {
-                                        __module_get(THIS_MODULE);
-                                        bind_device(&rq);
-                                }
-                        }
-                        mutex_unlock(&raw_mutex);
-                } else {
-                        struct block_device *bdev;
-
-                        mutex_lock(&raw_mutex);
-                        bdev = rawdev->binding;
-                        if (bdev) {
-                                rq.block_major = MAJOR(bdev->bd_dev);
-                                rq.block_minor = MINOR(bdev->bd_dev);
-                        } else {
-                                rq.block_major = rq.block_minor = 0;
-                        }
-                        mutex_unlock(&raw_mutex);
-                        if (copy_to_user((void __user *)arg, &rq, sizeof(rq))) {
-                                err = -EFAULT;
-                                goto out;
-                        }
-                }
-                break;
-        default:
-                err = -EINVAL;
-                break;
+                if (copy_to_user((void __user *)arg, &rq, sizeof(rq)))
+                        return -EFAULT;
+
+                return 0;
         }
-out:
-        unlock_kernel();
-        return err;
+
+        return -EINVAL;
+}
+
+#ifdef CONFIG_COMPAT
+struct raw32_config_request {
+        compat_int_t    raw_minor;
+        compat_u64      block_major;
+        compat_u64      block_minor;
+};
+
+static long raw_ctl_compat_ioctl(struct file *file, unsigned int cmd,
+                                unsigned long arg)
+{
+        struct raw32_config_request __user *user_req = compat_ptr(arg);
+        struct raw32_config_request rq;
+        dev_t dev;
+        int err = 0;
+
+        switch (cmd) {
+        case RAW_SETBIND:
+                if (copy_from_user(&rq, user_req, sizeof(rq)))
+                        return -EFAULT;
+
+                return bind_set(rq.raw_minor, rq.block_major, rq.block_minor);
+
+        case RAW_GETBIND:
+                if (copy_from_user(&rq, user_req, sizeof(rq)))
+                        return -EFAULT;
+
+                err = bind_get(rq.raw_minor, &dev);
+                if (err)
+                        return err;
+
+                rq.block_major = MAJOR(dev);
+                rq.block_minor = MINOR(dev);
+
+                if (copy_to_user(user_req, &rq, sizeof(rq)))
+                        return -EFAULT;
+
+                return 0;
+        }
+
+        return -EINVAL;
 }
+#endif
 
 static const struct file_operations raw_fops = {
         .read           = do_sync_read,
@@ -263,6 +297,9 @@ static const struct file_operations raw_fops = {
 
 static const struct file_operations raw_ctl_fops = {
         .unlocked_ioctl = raw_ctl_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl   = raw_ctl_compat_ioctl,
+#endif
         .open           = raw_open,
         .owner          = THIS_MODULE,
 };