Messages in this thread |  | | Date | Wed, 22 Aug 2018 00:16:57 +0800 | From | Yi Zhang <> | Subject | Re: [PATCH V2 1/1] device-dax: check for vma range while dax_mmap. |
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On 2018-08-20 at 12:50:31 -0700, Dave Jiang wrote: > > > On 08/20/2018 10:53 AM, Verma, Vishal L wrote: > > > > 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 <yi.z.zhang@linux.intel.com> > >> --- > >> drivers/dax/device.c | 29 +++++++++++++++++++++++++++++ > >> 1 file changed, 29 insertions(+) > >> > > > > Looks good to me: > > Reviewed-by: Vishal Verma <vishal.l.verma@intel.com> > > Applied. Thanks Dava and Vishal's kindly review. Thank you. > > > > >> 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;
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