PCI: check mmap range of /proc/bus/pci files too

/proc/bus/pci allows you to mmap resource ranges too, so we should probably be
checking to make sure the mapping is somewhat valid.  Uses the same code as the recent sysfs mmap range checking patch from Linus.
Acked-by: NDavid Miller <davem@davemloft.net>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/pci-sysfs.c

@@ -569,7 +569,7 @@ void pci_remove_legacy_files(struct pci_bus *b)
 
 #ifdef HAVE_PCI_MMAP
 
-static int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma)
+int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma)
 {
 	unsigned long nr, start, size;
 

drivers/pci/pci.h

@@ -10,6 +10,10 @@ extern int pci_uevent(struct device *dev, struct kobj_uevent_env *env);
 extern int pci_create_sysfs_dev_files(struct pci_dev *pdev);
 extern void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
 extern void pci_cleanup_rom(struct pci_dev *dev);
+#ifdef HAVE_PCI_MMAP
+extern int pci_mmap_fits(struct pci_dev *pdev, int resno,
+			 struct vm_area_struct *vma);
+#endif
 
 /**
  * Firmware PM callbacks

drivers/pci/proc.c

@@ -252,11 +252,20 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
 	const struct proc_dir_entry *dp = PDE(inode);
 	struct pci_dev *dev = dp->data;
 	struct pci_filp_private *fpriv = file->private_data;
-	int ret;
+	int i, ret;
 
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
+	/* Make sure the caller is mapping a real resource for this device */
+	for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+		if (pci_mmap_fits(dev, i, vma))
+			break;
+	}
+
+	if (i >= PCI_ROM_RESOURCE)
+		return -ENODEV;
+
 	ret = pci_mmap_page_range(dev, vma,
 				  fpriv->mmap_state,
 				  fpriv->write_combine);