drm/nouveau/device: use snprintf() to replace strncpy() to avoid NUL-terminated strin...

Following warning is found when using W=1 to build kernel:

In function ‘nvkm_udevice_info’,
    inlined from ‘nvkm_udevice_mthd’ at drivers/gpu/drm/nouveau/nvkm/engine/device/user.c:195:10:
drivers/gpu/drm/nouveau/nvkm/engine/device/user.c:164:2: warning: ‘strncpy’ specified bound 16 equals destination size [-Wstringop-truncation]
  164 |  strncpy(args->v0.chip, device->chip->name, sizeof(args->v0.chip));
drivers/gpu/drm/nouveau/nvkm/engine/device/user.c:165:2: warning: ‘strncpy’ specified bound 64 equals destination size [-Wstringop-truncation]
  165 |  strncpy(args->v0.name, device->name, sizeof(args->v0.name));

The reason of this warning is strncpy() does not guarantee that the
destination buffer will be NUL terminated. If the length of source string
is bigger than number we set by third input parameter, only a part of
characters is copied to the destination, and no NUL-terminated string is
automatically added. There are some potential risks.

So use snprintf() to replace strncpy().

Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/10

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c
index f28894fdede94fa1b78174630cb47987104023d1..113ddc103ac263dd86fcfb440cee0196f340af21 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c
@@ -161,8 +161,8 @@ nvkm_udevice_info(struct nvkm_udevice *udev, void *data, u32 size)
        if (imem && args->v0.ram_size > 0)
                args->v0.ram_user = args->v0.ram_user - imem->reserved;
 
-       strncpy(args->v0.chip, device->chip->name, sizeof(args->v0.chip));
-       strncpy(args->v0.name, device->name, sizeof(args->v0.name));
+       snprintf(args->v0.chip, sizeof(args->v0.chip), "%s", device->chip->name);
+       snprintf(args->v0.name, sizeof(args->v0.name), "%s", device->name);
        return 0;
 }