From: Luo Jiaxing Date: Mon, 8 Mar 2021 08:32:52 +0000 (+0800) Subject: drm/nouveau/device: use snprintf() to replace strncpy() to avoid NUL-terminated strin... X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=22da19f900be6b90b6984522708b203ac9bce1e6;p=linux.git 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 Signed-off-by: Ben Skeggs Reviewed-by: Karol Herbst Signed-off-by: Karol Herbst 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 f28894fdede94..113ddc103ac26 100644 --- 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; }