Messages in this thread | | | Subject | Re: [PATCH V2 1/1] device-dax: check for vma range while dax_mmap. | From | Dave Jiang <> | Date | Mon, 20 Aug 2018 12:50:31 -0700 |
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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.
> >> 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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