ipmi: ipmi_devintf: compat_ioctl method fails to take ipmi_mutex

When a 32 bit version of ipmitool is used on a 64 bit kernel, the
ipmi_devintf code fails to correctly acquire ipmi_mutex.  This results in
incomplete data being retrieved in some cases, or other possible failures.
Add a wrapper around compat_ipmi_ioctl() to take ipmi_mutex to fix this.

Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index 9eb360ff8cab..d5a5f020810a 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -837,13 +837,25 @@ static long compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
                 return ipmi_ioctl(filep, cmd, arg);
         }
 }
+
+static long unlocked_compat_ipmi_ioctl(struct file *filep, unsigned int cmd,
+                                       unsigned long arg)
+{
+        int ret;
+
+        mutex_lock(&ipmi_mutex);
+        ret = compat_ipmi_ioctl(filep, cmd, arg);
+        mutex_unlock(&ipmi_mutex);
+
+        return ret;
+}
 #endif
 
 static const struct file_operations ipmi_fops = {
         .owner          = THIS_MODULE,
         .unlocked_ioctl = ipmi_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
-        .compat_ioctl   = compat_ipmi_ioctl,
+        .compat_ioctl   = unlocked_compat_ipmi_ioctl,
 #endif
         .open           = ipmi_open,
         .release        = ipmi_release,