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Commit d3cfd5b9 authored by Elena Reshetova's avatar Elena Reshetova Committed by Greg Kroah-Hartman
Browse files

drivers: convert vme_user_vma_priv.refcnt from atomic_t to refcount_t 



refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6a386dd0

drivers/staging/vme/devices/vme_user.c

+5 −5
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/atomic.h>

#include <linux/refcount.h>

#include <linux/cdev.h>

#include <linux/delay.h>

#include <linux/device.h>
@@ -118,7 +118,7 @@ static const int type[VME_DEVS] = { MASTER_MINOR, MASTER_MINOR, 


struct vme_user_vma_priv {

	unsigned int minor;

	atomic_t refcnt;

	refcount_t refcnt;

};



static ssize_t resource_to_user(int minor, char __user *buf, size_t count,
@@ -430,7 +430,7 @@ static void vme_user_vm_open(struct vm_area_struct *vma) 
{

	struct vme_user_vma_priv *vma_priv = vma->vm_private_data;



	atomic_inc(&vma_priv->refcnt);

	refcount_inc(&vma_priv->refcnt);

}



static void vme_user_vm_close(struct vm_area_struct *vma)
@@ -438,7 +438,7 @@ static void vme_user_vm_close(struct vm_area_struct *vma) 
	struct vme_user_vma_priv *vma_priv = vma->vm_private_data;

	unsigned int minor = vma_priv->minor;



	if (!atomic_dec_and_test(&vma_priv->refcnt))

	if (!refcount_dec_and_test(&vma_priv->refcnt))

		return;



	mutex_lock(&image[minor].mutex);
@@ -473,7 +473,7 @@ static int vme_user_master_mmap(unsigned int minor, struct vm_area_struct *vma) 
	}



	vma_priv->minor = minor;

	atomic_set(&vma_priv->refcnt, 1);

	refcount_set(&vma_priv->refcnt, 1);

	vma->vm_ops = &vme_user_vm_ops;

	vma->vm_private_data = vma_priv;