[21/26] xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()

Greg KH
2011-11-19T00:08:42Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit 21643e69a4c06f7ef155fbc70e3fba13fba4a756 upstream.

On 32 bit systems a high value of op.count could lead to an integer
overflow in the kzalloc() and gref_ids would be smaller than
expected. If the you triggered another integer overflow in
"if (gref_size + op.count > limit)" then you'd probably get memory
corruption inside add_grefs().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/xen/gntalloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/xen/gntalloc.c
+++ b/drivers/xen/gntalloc.c
@@ -280,7 +280,7 @@ static long gntalloc_ioctl_alloc(struct
goto out;
}

- gref_ids = kzalloc(sizeof(gref_ids[0]) * op.count, GFP_TEMPORARY);
+ gref_ids = kcalloc(op.count, sizeof(gref_ids[0]), GFP_TEMPORARY);
if (!gref_ids) {
rc = -ENOMEM;
goto out;