[PATCH rdma-rc 04/10] IB/mlx5: Limit query HCA clock

Leon Romanovsky
2016-06-04T12:15:31Z

From: Noa Osherovich <noaos-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

When PAGE_SIZE is larger then 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-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Noa Osherovich <noaos-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
drivers/infiniband/hw/mlx5/main.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 8845f4b..05036db 100644
--- 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 =