From: Jason Gunthorpe <j...@mellanox.com>

commit c660133c339f9ab684fdf568c0d51b9ae5e86002 upstream.

The intent of this VMA was to be read-only from user space, but the
VM_MAYWRITE masking was missed, so mprotect could make it writable.

Cc: sta...@vger.kernel.org
Fixes: 5c99eaecb1fc ("IB/mlx5: Mmap the HCA's clock info to user-space")
Signed-off-by: Jason Gunthorpe <j...@mellanox.com>
Reviewed-by: Haggai Eran <hagg...@mellanox.com>
Signed-off-by: Leon Romanovsky <leo...@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/infiniband/hw/mlx5/main.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1982,6 +1982,7 @@ static int mlx5_ib_mmap_clock_info_page(
 
        if (vma->vm_flags & VM_WRITE)
                return -EPERM;
+       vma->vm_flags &= ~VM_MAYWRITE;
 
        if (!dev->mdev->clock_info_page)
                return -EOPNOTSUPP;
@@ -2147,6 +2148,7 @@ static int mlx5_ib_mmap(struct ib_uconte
 
                if (vma->vm_flags & VM_WRITE)
                        return -EPERM;
+               vma->vm_flags &= ~VM_MAYWRITE;
 
                /* Don't expose to user-space information it shouldn't have */
                if (PAGE_SIZE > 4096)


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