diff mbox series

[5.13,028/380] soc: aspeed: lpc-ctrl: Fix boundary check for mmap

Message ID 20210916155804.922880193@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

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

commit b49a0e69a7b1a68c8d3f64097d06dabb770fec96 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: 6c4e97678501 ("drivers/misc: Add Aspeed LPC 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-lpc-ctrl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/soc/aspeed/aspeed-lpc-ctrl.c
+++ b/drivers/soc/aspeed/aspeed-lpc-ctrl.c
@@ -51,7 +51,7 @@  static int aspeed_lpc_ctrl_mmap(struct f
 	unsigned long vsize = vma->vm_end - vma->vm_start;
 	pgprot_t prot = vma->vm_page_prot;
 
-	if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size)
+	if (vma->vm_pgoff + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT)
 		return -EINVAL;
 
 	/* ast2400/2500 AHB accesses are not cache coherent */