| Message ID | 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-engine-pm-base-c-v1-1-4b09ed453f84@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/nouveau/pm: refactor deprecated strncpy | expand |
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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> The "- 1" use in the original code is strong evidence for this being a sane conversion. :) Reviewed-by: Kees Cook <keescook@chromium.org>
Nice catch! Reviewed-by: Lyude Paul <lyude@redhat.com> 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: linux-hardening@vger.kernel.org > > Signed-off-by: Justin Stitt <justinstitt@google.com> > > The "- 1" use in the original code is strong evidence for this being a > sane conversion. :) > > Reviewed-by: Kees Cook <keescook@chromium.org> >
...oops, responded to the wrong email :P Reviewed-by: Lyude Paul <lyude@redhat.com> 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: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com> > --- > 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 <justinstitt@google.com> >
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) {
`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: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinstitt@google.com> --- drivers/gpu/drm/nouveau/nvkm/engine/pm/base.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230914-strncpy-drivers-gpu-drm-nouveau-nvkm-engine-pm-base-c-38bf9c78bc0f Best regards, -- Justin Stitt <justinstitt@google.com>