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From: Kees Cook <keescook@chromium.org>
To: Leon Romanovsky <leon@kernel.org>
Cc: Kees Cook <keescook@chromium.org>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: [PATCH v2] RDMA/mlx5: Use memset_after() to zero struct mlx5_ib_mr
Date: Tue,  7 Dec 2021 13:20:22 -0800	[thread overview]
Message-ID: <20211207212022.364703-1-keescook@chromium.org> (raw)

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Use memset_after() to zero the end of struct mlx5_ib_mr that should
be initialized.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
v2: rebased, umem moved into the union and is expected to be wiped
    https://lore.kernel.org/lkml/20211207194525.GL6385@nvidia.com
---
 drivers/infiniband/hw/mlx5/mlx5_ib.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 4a7a56ed740b..ded10719b643 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -664,8 +664,8 @@ struct mlx5_ib_mr {
 
 	/* User MR data */
 	struct mlx5_cache_ent *cache_ent;
+	/* Everything after cache_ent is zero'd when MR allocated */
 
-	/* This is zero'd when the MR is allocated */
 	union {
 		/* Used only while the MR is in the cache */
 		struct {
@@ -718,7 +718,7 @@ struct mlx5_ib_mr {
 /* Zero the fields in the mr that are variant depending on usage */
 static inline void mlx5_clear_mr(struct mlx5_ib_mr *mr)
 {
-	memset(mr->out, 0, sizeof(*mr) - offsetof(struct mlx5_ib_mr, out));
+	memset_after(mr, 0, cache_ent);
 }
 
 static inline bool is_odp_mr(struct mlx5_ib_mr *mr)
-- 
2.30.2


             reply	other threads:[~2021-12-07 21:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-07 21:20 Kees Cook [this message]
2021-12-08  8:51 ` [PATCH v2] RDMA/mlx5: Use memset_after() to zero struct mlx5_ib_mr Leon Romanovsky
2021-12-14  0:39 ` Gustavo A. R. Silva

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