linux-hardening - [PATCH v2] RDMA/mlx5: Use memset_after() to zero struct mlx5_ib

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

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

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@...omium.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