IB/mlx5: Limit query HCA clock

When PAGE_SIZE is larger than 4K, the user shouldn't be able to query
the HCA core clock. This counter is within 4KB boundary and the
user-space shall not read information that's after this boundary.

Fixes: b368d7cb8ceb7 ('IB/mlx5: Add hca_core_clock_offset to...')
Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 8845f4b..05036db 100644 (file)
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -991,7 +991,14 @@ static struct ib_ucontext *mlx5_ib_alloc_ucontext(struct ib_device *ibdev,
        if (field_avail(typeof(resp), cqe_version, udata->outlen))
                resp.response_length += sizeof(resp.cqe_version);
 
-       if (field_avail(typeof(resp), hca_core_clock_offset, udata->outlen)) {
+       /*
+        * We don't want to expose information from the PCI bar that is located
+        * after 4096 bytes, so if the arch only supports larger pages, let's
+        * pretend we don't support reading the HCA's core clock. This is also
+        * forced by mmap function.
+        */
+       if (PAGE_SIZE <= 4096 &&
+           field_avail(typeof(resp), hca_core_clock_offset, udata->outlen)) {
                resp.comp_mask |=
                        MLX5_IB_ALLOC_UCONTEXT_RESP_MASK_CORE_CLOCK_OFFSET;
                resp.hca_core_clock_offset =