Michael S. Tsirkin
2022-Nov-26 23:22 UTC
[PATCH] vduse: Fix a possible warning in vduse_create_dev()
On Fri, Nov 25, 2022 at 07:59:58PM -0800, Harshit Mogalapalli wrote:> As 'dev->vq_num' is user-controlled data, if user tries to allocate > memory larger than(>=) MAX_ORDER, then kcalloc() will fail, it > creates a stack trace and messes up dmesg with a warning. > > Call trace: > -> vduse_ioctl > --> vduse_create_dev > 'config->vq_num' is user data as it comes from ioctl, which is > assigned to 'dev->vq_num'. > > Add __GFP_NOWARN in order to avoid too large allocation warning. > This is detected by static analysis using smatch. > > Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace") > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli at oracle.com> > --- > drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c > index 35dceee3ed56..5e9546b16165 100644 > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > @@ -1512,7 +1512,8 @@ static int vduse_create_dev(struct vduse_dev_config *config, > dev->config_size = config->config_size; > dev->vq_align = config->vq_align; > dev->vq_num = config->vq_num; > - dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL); > + dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), > + GFP_KERNEL | __GFP_NOWARN); > if (!dev->vqs) > goto err_vqs;This is insufficient - the real source of the problem is that vq_num is not validated. The thing to do is to validate config and limit vq_num to 0xffff;> -- > 2.38.1