Dan Carpenter
2011-Nov-04 18:24 UTC
[patch 1/2] xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
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 at oracle.com> 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;
Konrad Rzeszutek Wilk
2011-Nov-04 18:35 UTC
[patch 1/2] xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
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 <dan.carpenter at oracle.com>Great! Keep them coming! Will push for stable and 3.2.> > 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;
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