On Mon, 2018-08-13 at 20:02 +0800, Zhang Yi wrote: > This patch prevents a user mapping an illegal vma range that is larger > than a dax device physical resource. > > When qemu maps the dax device for virtual nvdimm's backend device, the > v-nvdimm label area is defined at the end of mapped range. By using an > illegal size that exceeds the range of the device dax, it will trigger a > fault with qemu. > > Signed-off-by: Zhang Yi <[email protected]> > --- > drivers/dax/device.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) >
Looks good to me: Reviewed-by: Vishal Verma <[email protected]> > diff --git a/drivers/dax/device.c b/drivers/dax/device.c > index 108c37f..6fe8c30 100644 > --- a/drivers/dax/device.c > +++ b/drivers/dax/device.c > @@ -177,6 +177,33 @@ static const struct attribute_group > *dax_attribute_groups[] = { > NULL, > }; > > +static int check_vma_range(struct dev_dax *dev_dax, struct vm_area_struct > *vma, > + const char *func) > +{ > + struct device *dev = &dev_dax->dev; > + struct resource *res; > + unsigned long size; > + int ret, i; > + > + if (!dax_alive(dev_dax->dax_dev)) > + return -ENXIO; > + > + size = vma->vm_end - vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT); > + ret = -EINVAL; > + for (i = 0; i < dev_dax->num_resources; i++) { > + res = &dev_dax->res[i]; > + if (size > resource_size(res)) { > + dev_info_ratelimited(dev, > + "%s: %s: fail, vma range overflow\n", > + current->comm, func); > + ret = -EINVAL; > + continue; > + } else > + return 0; > + } > + return ret; > +} > + > static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma, > const char *func) > { > @@ -469,6 +496,8 @@ static int dax_mmap(struct file *filp, struct > vm_area_struct *vma) > */ > id = dax_read_lock(); > rc = check_vma(dev_dax, vma, __func__); > + if (!rc) > + rc = check_vma_range(dev_dax, vma, __func__); > dax_read_unlock(id); > if (rc) > return rc; _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
