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From: Justin Stitt <justinstitt@google.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	Justin Stitt <justinstitt@google.com>
Subject: [PATCH] drm/i915: refactor deprecated strncpy
Date: Thu, 14 Sep 2023 21:14:07 +0000	[thread overview]
Message-ID: <20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-v1-1-c3f92df942e0@google.com> (raw)

`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);
 
 		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>


WARNING: multiple messages have this Message-ID (diff)
From: Justin Stitt <justinstitt@google.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	 Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	 Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org,
	Justin Stitt <justinstitt@google.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-hardening@vger.kernel.org
Subject: [PATCH] drm/i915: refactor deprecated strncpy
Date: Thu, 14 Sep 2023 21:14:07 +0000	[thread overview]
Message-ID: <20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-v1-1-c3f92df942e0@google.com> (raw)

`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);
 
 		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>


WARNING: multiple messages have this Message-ID (diff)
From: Justin Stitt <justinstitt@google.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	 Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	 Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org,
	Justin Stitt <justinstitt@google.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-hardening@vger.kernel.org
Subject: [Intel-gfx] [PATCH] drm/i915: refactor deprecated strncpy
Date: Thu, 14 Sep 2023 21:14:07 +0000	[thread overview]
Message-ID: <20230914-strncpy-drivers-gpu-drm-i915-gem-selftests-mock_context-c-v1-1-c3f92df942e0@google.com> (raw)

`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);
 
 		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>


             reply	other threads:[~2023-09-14 21:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-14 21:14 Justin Stitt [this message]
2023-09-14 21:14 ` [Intel-gfx] [PATCH] drm/i915: refactor deprecated strncpy Justin Stitt
2023-09-14 21:14 ` Justin Stitt
2023-09-15  4:38 ` Kees Cook
2023-09-15  4:38   ` [Intel-gfx] " Kees Cook
2023-09-15  4:38   ` Kees Cook
2023-09-18 23:18 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2023-09-18 23:32 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork

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