| Message ID | 20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-v1-1-c3f92df942e0@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915: refactor deprecated strncpy | expand |
On Thu, Sep 14, 2023 at 09:14:07PM +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. > > `ctx` is zero allocated and as such strncpy's NUL-padding behavior was > strictly a performance hit which should now be resolved. It should be > noted, however, that performance is not critical in these selftests, > especially by these margins. > > 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/i915/gem/selftests/mock_context.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c > index 8ac6726ec16b..025b9c773b93 100644 > --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c > +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c > @@ -36,7 +36,7 @@ mock_context(struct drm_i915_private *i915, > if (name) { > struct i915_ppgtt *ppgtt; > > - strncpy(ctx->name, name, sizeof(ctx->name) - 1); > + strscpy(ctx->name, name, sizeof(ctx->name) - 1); I'd expect the "- 1" to go away... -Kees > > ppgtt = mock_ppgtt(i915, name); > if (!ppgtt) > > --- > base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec > change-id: 20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-980c8ecc9142 > > Best regards, > -- > Justin Stitt <justinstitt@google.com> >
diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c index 8ac6726ec16b..025b9c773b93 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c @@ -36,7 +36,7 @@ mock_context(struct drm_i915_private *i915, if (name) { struct i915_ppgtt *ppgtt; - strncpy(ctx->name, name, sizeof(ctx->name) - 1); + strscpy(ctx->name, name, sizeof(ctx->name) - 1); ppgtt = mock_ppgtt(i915, name); if (!ppgtt)
`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. `ctx` is zero allocated and as such strncpy's NUL-padding behavior was strictly a performance hit which should now be resolved. It should be noted, however, that performance is not critical in these selftests, especially by these margins. 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/i915/gem/selftests/mock_context.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-980c8ecc9142 Best regards, -- Justin Stitt <justinstitt@google.com>