Re: [Nouveau] [PATCH] drm/nouveau/core: refactor deprecated strncpy
Eek, I didn't realize how many instances of this we had. Thanks for doing this :) Reviewed-by: Lyude Paul On Thu, 2023-09-14 at 21:40 +, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > A suitable replacement is `strscpy` [2] due to the fact that it guarantees > NUL-termination on the destination buffer without unnecessarily NUL-padding. > > There is likely no bug in the current implementation due to the safeguard: > > cname[sizeof(cname) - 1] = '\0'; > ... however we can provide simpler and easier to understand code using > the newer (and recommended) `strscpy` api. > > Link: > https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings > [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html > [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-harden...@vger.kernel.org > Signed-off-by: Justin Stitt > --- > drivers/gpu/drm/nouveau/nvkm/core/firmware.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > index 91fb494d4009..374212da9e95 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > +++ b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > @@ -79,8 +79,7 @@ nvkm_firmware_get(const struct nvkm_subdev *subdev, const > char *fwname, int ver, > int i; > > /* Convert device name to lowercase */ > - strncpy(cname, device->chip->name, sizeof(cname)); > - cname[sizeof(cname) - 1] = '\0'; > + strscpy(cname, device->chip->name, sizeof(cname)); > i = strlen(cname); > while (i) { > --i; > > --- > base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec > change-id: > 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-core-firmware-c-791223838b72 > > Best regards, > -- > Justin Stitt > -- Cheers, Lyude Paul (she/her) Software Engineer at Red Hat
Re: [PATCH] drm/nouveau/core: refactor deprecated strncpy
On Thu, Sep 14, 2023 at 09:40:49PM +, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We should prefer more robust and less ambiguous string interfaces. > > A suitable replacement is `strscpy` [2] due to the fact that it guarantees > NUL-termination on the destination buffer without unnecessarily NUL-padding. > > There is likely no bug in the current implementation due to the safeguard: > | cname[sizeof(cname) - 1] = '\0'; > ... however we can provide simpler and easier to understand code using > the newer (and recommended) `strscpy` api. > > Link: > https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings > [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html > [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-harden...@vger.kernel.org > Signed-off-by: Justin Stitt > --- > drivers/gpu/drm/nouveau/nvkm/core/firmware.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > index 91fb494d4009..374212da9e95 100644 > --- a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > +++ b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c > @@ -79,8 +79,7 @@ nvkm_firmware_get(const struct nvkm_subdev *subdev, const > char *fwname, int ver, > int i; > > /* Convert device name to lowercase */ > - strncpy(cname, device->chip->name, sizeof(cname)); > - cname[sizeof(cname) - 1] = '\0'; > + strscpy(cname, device->chip->name, sizeof(cname)); > i = strlen(cname); > while (i) { > --i; Yup, consumed by strlen() and snprintf(). Looks like a standard conversion. :) Reviewed-by: Kees Cook -Kees > > --- > base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec > change-id: > 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-core-firmware-c-791223838b72 > > Best regards, > -- > Justin Stitt > -- Kees Cook
[PATCH] drm/nouveau/core: refactor deprecated strncpy
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should prefer more robust and less ambiguous string interfaces. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. There is likely no bug in the current implementation due to the safeguard: | cname[sizeof(cname) - 1] = '\0'; ... however we can provide simpler and easier to understand code using the newer (and recommended) `strscpy` api. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-harden...@vger.kernel.org Signed-off-by: Justin Stitt --- drivers/gpu/drm/nouveau/nvkm/core/firmware.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c index 91fb494d4009..374212da9e95 100644 --- a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c +++ b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c @@ -79,8 +79,7 @@ nvkm_firmware_get(const struct nvkm_subdev *subdev, const char *fwname, int ver, int i; /* Convert device name to lowercase */ - strncpy(cname, device->chip->name, sizeof(cname)); - cname[sizeof(cname) - 1] = '\0'; + strscpy(cname, device->chip->name, sizeof(cname)); i = strlen(cname); while (i) { --i; --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-core-firmware-c-791223838b72 Best regards, -- Justin Stitt