From 22da19f900be6b90b6984522708b203ac9bce1e6 Mon Sep 17 00:00:00 2001 From: Luo Jiaxing Date: Mon, 8 Mar 2021 16:32:52 +0800 Subject: [PATCH] drm/nouveau/device: use snprintf() to replace strncpy() to avoid NUL-terminated string loss MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- drivers/gpu/drm/nouveau/nvkm/engine/device/user.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/user.c index f28894fdede9..113ddc103ac2 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; } -- 2.11.0