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Date:   Thu, 14 Sep 2023 21:30:37 +0000
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Message-ID: <20230914-strncpy-drivers-gpu-drm-nouveau-nvif-client-c-v1-1-dc3b3719fcb4@google.com>
Subject: [PATCH] drm/nouveau/nvif: refactor deprecated strncpy
From:   Justin Stitt <justinstitt@google.com>
To:     Ben Skeggs <bskeggs@redhat.com>, Karol Herbst <kherbst@redhat.com>,
        Lyude Paul <lyude@redhat.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
        Justin Stitt <justinstitt@google.com>
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Precedence: bulk

`strncpy` is deprecated and as such we should prefer more robust and
less ambiguous string interfaces.

A suitable replacement is `strscpy_pad` due to the fact that it
guarantees NUL-termination on the destination buffer whilst also
maintaining the NUL-padding behavior that `strncpy` provides. I am not
sure whether NUL-padding is strictly needed but I see in
`nvif_object_ctor()` args is memcpy'd elsewhere so I figured we'd keep
the same functionality.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only.
---
 drivers/gpu/drm/nouveau/nvif/client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvif/client.c b/drivers/gpu/drm/nouveau/nvif/client.c
index a3264a0e933a..3a27245f467f 100644
--- a/drivers/gpu/drm/nouveau/nvif/client.c
+++ b/drivers/gpu/drm/nouveau/nvif/client.c
@@ -69,7 +69,7 @@ nvif_client_ctor(struct nvif_client *parent, const char *name, u64 device,
 	} nop = {};
 	int ret;
 
-	strncpy(args.name, name, sizeof(args.name));
+	strscpy_pad(args.name, name, sizeof(args.name));
 	ret = nvif_object_ctor(parent != client ? &parent->object : NULL,
 			       name ? name : "nvifClient", 0,
 			       NVIF_CLASS_CLIENT, &args, sizeof(args),

---
base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
change-id: 20230914-strncpy-drivers-gpu-drm-nouveau-nvif-client-c-82b023c36953

Best regards,
--
Justin Stitt <justinstitt@google.com>