`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.
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: [email protected]
Signed-off-by: Justin Stitt <[email protected]>
---
drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
index 8fe0444f761e..131db2645f84 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
@@ -462,7 +462,7 @@ nvkm_perfmon_mthd_query_domain(struct nvkm_perfmon *perfmon,
args->v0.id = di;
args->v0.signal_nr = nvkm_perfdom_count_perfsig(dom);
- strncpy(args->v0.name, dom->name, sizeof(args->v0.name) - 1);
+ strscpy(args->v0.name, dom->name, sizeof(args->v0.name));
/* Currently only global counters (PCOUNTER) are implemented
* but this will be different for local counters (MP). */
@@ -513,8 +513,7 @@ nvkm_perfmon_mthd_query_signal(struct nvkm_perfmon *perfmon,
snprintf(args->v0.name, sizeof(args->v0.name),
"/%s/%02x", dom->name, si);
} else {
- strncpy(args->v0.name, sig->name,
- sizeof(args->v0.name) - 1);
+ strscpy(args->v0.name, sig->name, sizeof(args->v0.name));
}
args->v0.signal = si;
@@ -572,7 +571,7 @@ nvkm_perfmon_mthd_query_source(struct nvkm_perfmon *perfmon,
args->v0.source = sig->source[si];
args->v0.mask = src->mask;
- strncpy(args->v0.name, src->name, sizeof(args->v0.name) - 1);
+ strscpy(args->v0.name, src->name, sizeof(args->v0.name));
}
if (++si < source_nr) {
---
base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
change-id: 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-engine-pm-base-c-38bf9c78bc0f
Best regards,
--
Justin Stitt <[email protected]>
On Thu, Sep 14, 2023 at 10:17:08PM +0000, 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.
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
The "- 1" use in the original code is strong evidence for this being a
sane conversion. :)
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
...oops, responded to the wrong email :P
Reviewed-by: Lyude Paul <[email protected]>
On Thu, 2023-09-14 at 22:17 +0000, 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.
>
> 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: [email protected]
> Signed-off-by: Justin Stitt <[email protected]>
> ---
> drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
> index 8fe0444f761e..131db2645f84 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c
> @@ -462,7 +462,7 @@ nvkm_perfmon_mthd_query_domain(struct nvkm_perfmon *perfmon,
>
> args->v0.id = di;
> args->v0.signal_nr = nvkm_perfdom_count_perfsig(dom);
> - strncpy(args->v0.name, dom->name, sizeof(args->v0.name) - 1);
> + strscpy(args->v0.name, dom->name, sizeof(args->v0.name));
>
> /* Currently only global counters (PCOUNTER) are implemented
> * but this will be different for local counters (MP). */
> @@ -513,8 +513,7 @@ nvkm_perfmon_mthd_query_signal(struct nvkm_perfmon *perfmon,
> snprintf(args->v0.name, sizeof(args->v0.name),
> "/%s/%02x", dom->name, si);
> } else {
> - strncpy(args->v0.name, sig->name,
> - sizeof(args->v0.name) - 1);
> + strscpy(args->v0.name, sig->name, sizeof(args->v0.name));
> }
>
> args->v0.signal = si;
> @@ -572,7 +571,7 @@ nvkm_perfmon_mthd_query_source(struct nvkm_perfmon *perfmon,
>
> args->v0.source = sig->source[si];
> args->v0.mask = src->mask;
> - strncpy(args->v0.name, src->name, sizeof(args->v0.name) - 1);
> + strscpy(args->v0.name, src->name, sizeof(args->v0.name));
> }
>
> if (++si < source_nr) {
>
> ---
> base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec
> change-id: 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-engine-pm-base-c-38bf9c78bc0f
>
> Best regards,
> --
> Justin Stitt <[email protected]>
>
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
Nice catch!
Reviewed-by: Lyude Paul <[email protected]>
Will push in just a moment
On Thu, 2023-09-14 at 21:59 -0700, Kees Cook wrote:
> On Thu, Sep 14, 2023 at 10:17:08PM +0000, 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.
> >
> > 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: [email protected]
> > Signed-off-by: Justin Stitt <[email protected]>
>
> The "- 1" use in the original code is strong evidence for this being a
> sane conversion. :)
>
> Reviewed-by: Kees Cook <[email protected]>
>
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat