PCI: Obey iomem restrictions for procfs mmap

There's three ways to access PCI BARs from userspace: /dev/mem, sysfs
files, and the old proc interface. Two check against
iomem_is_exclusive, proc never did. And with CONFIG_IO_STRICT_DEVMEM,
this starts to matter, since we don't want random userspace having
access to PCI BARs while a driver is loaded and using it.

Fix this by adding the same iomem_is_exclusive() check we already have
on the sysfs side in pci_mmap_resource().

Acked-by: Bjorn Helgaas <[email protected]>
References: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
Signed-off-by: Daniel Vetter <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Bjorn Helgaas <[email protected]>
Cc: [email protected]
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index d35186b01d98..3a2f90beb4cb 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -274,6 +274,11 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
 		else
 			return -EINVAL;
 	}
+
+	if (dev->resource[i].flags & IORESOURCE_MEM &&
+	    iomem_is_exclusive(dev->resource[i].start))
+		return -EINVAL;
+
 	ret = pci_mmap_page_range(dev, i, vma,
 				  fpriv->mmap_state, write_combine);
 	if (ret < 0)