On Mon, Jun 24, 2019 at 04:32:56PM +0200, Andrey Konovalov wrote: > This patch is a part of a series that extends kernel ABI to allow to pass > tagged user pointers (with the top byte set to something else other than > 0x00) as syscall arguments. > > mlx4_get_umem_mr() uses provided user pointers for vma lookups, which can > only by done with untagged pointers. > > Untag user pointers in this function. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees > --- > drivers/infiniband/hw/mlx4/mr.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c > index 355205a28544..13d9f917f249 100644 > --- a/drivers/infiniband/hw/mlx4/mr.c > +++ b/drivers/infiniband/hw/mlx4/mr.c > @@ -378,6 +378,7 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, > * again > */ > if (!ib_access_writable(access_flags)) { > + unsigned long untagged_start = untagged_addr(start); > struct vm_area_struct *vma; > > down_read(¤t->mm->mmap_sem); > @@ -386,9 +387,9 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start, > * cover the memory, but for now it requires a single vma to > * entirely cover the MR to support RO mappings. > */ > - vma = find_vma(current->mm, start); > - if (vma && vma->vm_end >= start + length && > - vma->vm_start <= start) { > + vma = find_vma(current->mm, untagged_start); > + if (vma && vma->vm_end >= untagged_start + length && > + vma->vm_start <= untagged_start) { > if (vma->vm_flags & VM_WRITE) > access_flags |= IB_ACCESS_LOCAL_WRITE; > } else { > -- > 2.22.0.410.gd8fdbe21b5-goog > -- Kees Cook _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx