Re: [patch 1/2] xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
From: Konrad Rzeszutek Wilk <hidden>
Date: 2011-11-04 18:35:54
Also in:
kernel-janitors, xen-devel
On Fri, Nov 04, 2011 at 09:24:08PM +0300, Dan Carpenter wrote:
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 <redacted>
Great! Keep them coming! Will push for stable and 3.2.
quoted hunk
diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c index f6832f4..23c60cf 100644 --- a/drivers/xen/gntalloc.c +++ b/drivers/xen/gntalloc.c@@ -280,7 +280,7 @@ static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv, 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;