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

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
This commit is contained in:
Luo Jiaxing 2021-03-08 16:32:52 +08:00 committed by Karol Herbst
parent bd6e07e72f
commit 22da19f900

View File

@ -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;
}