Re: [PATCH v1 1/2] RDMA/i40iw: Address an mmap handler exploit in i40iw

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Nov 24, 2020 at 05:51:02PM -0600, Shiraz Saleem wrote:
> i40iw_mmap manipulates the vma->vm_pgoff to differentiate a push page
> mmap vs a doorbell mmap, and uses it to compute the pfn in remap_pfn_range
> without any validation. This is vulnerable to an mmap exploit as
> described in [1].
> 
> Push feature is disabled in the driver currently and therefore no push
> mmaps are issued from user-space. The feature does not work as expected
> in the x722 product.
> 
> Remove the push module parameter and all VMA attribute manipulations
> for this feature in i40iw_mmap. Update i40iw_mmap to only allow DB
> user mmapings at offset = 0. Check vm_pgoff for zero and if the mmaps
> are bound to a single page.
> 
> [1] https://lore.kernel.org/linux-rdma/20201119093523.7588-1-zhudi21@huawei.com/raw
> 
> Fixes: d37498417947 ("i40iw: add files for iwarp interface")
> Cc: stable@kernel.org
> Reported-by: Di Zhu <zhudi21@huawei.com>
> Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
>  drivers/infiniband/hw/i40iw/i40iw_main.c  |    4 ---
>  drivers/infiniband/hw/i40iw/i40iw_verbs.c |   37 +++++-----------------------
>  2 files changed, 7 insertions(+), 34 deletions(-)

Please compile your patches:

drivers/infiniband/hw/i40iw/i40iw_main.c: In function ‘i40iw_setup_init_state’:
drivers/infiniband/hw/i40iw/i40iw_main.c:1579:21: error: ‘push_mode’ undeclared (first use in this function); did you mean ‘user_mode’?
 1579 |  iwdev->push_mode = push_mode;
      |                     ^~~~~~~~~
      |                     user_mode
drivers/infiniband/hw/i40iw/i40iw_main.c:1579:21: note: each undeclared identifier is reported only once for each function it appears in

Jason