diff mbox series

[5.13,029/380] soc: aspeed: p2a-ctrl: Fix boundary check for mmap

Message ID 20210916155804.954500417@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg KH Sept. 16, 2021, 3:56 p.m. UTC 
From: Iwona Winiarska <iwona.winiarska@intel.com>

commit 8b07e990fb254fcbaa919616ac77f981cb48c73d upstream.

The check mixes pages (vm_pgoff) with bytes (vm_start, vm_end) on one
side of the comparison, and uses resource address (rather than just the
resource size) on the other side of the comparison.
This can allow malicious userspace to easily bypass the boundary check and
map pages that are located outside memory-region reserved by the driver.

Fixes: 01c60dcea9f7 ("drivers/misc: Add Aspeed P2A control driver")
Cc: stable@vger.kernel.org
Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/soc/aspeed/aspeed-p2a-ctrl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/soc/aspeed/aspeed-p2a-ctrl.c
+++ b/drivers/soc/aspeed/aspeed-p2a-ctrl.c
@@ -110,7 +110,7 @@  static int aspeed_p2a_mmap(struct file *
 	vsize = vma->vm_end - vma->vm_start;
 	prot = vma->vm_page_prot;
 
-	if (vma->vm_pgoff + vsize > ctrl->mem_base + ctrl->mem_size)
+	if (vma->vm_pgoff + vma_pages(vma) > ctrl->mem_size >> PAGE_SHIFT)
 		return -EINVAL;
 
 	/* ast2400/2500 AHB accesses are not cache coherent */