From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Neil Armstrong <neil.armstrong@linaro.org>,
dri-devel@lists.freedesktop.org,
linux-amlogic@lists.infradead.org,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>,
Sami Tolvanen <samitolvanen@google.com>,
llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
patches@lists.linux.dev
Subject: Re: [PATCH] drm/meson: Fix return type of meson_encoder_cvbs_mode_valid()
Date: Wed, 2 Nov 2022 12:06:34 -0700 [thread overview]
Message-ID: <202211021206.F5C5954F66@keescook> (raw)
In-Reply-To: <20221102155242.1927166-1-nathan@kernel.org>
On Wed, Nov 02, 2022 at 08:52:42AM -0700, Nathan Chancellor wrote:
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> drivers/gpu/drm/meson/meson_encoder_cvbs.c:211:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .mode_valid = meson_encoder_cvbs_mode_valid,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> ->mode_valid() in 'struct drm_bridge_funcs' expects a return type of
> 'enum drm_mode_status', not 'int'. Adjust the return type of
> meson_encoder_cvbs_mode_valid() to match the prototype's to resolve the
> warning and CFI failure.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Reported-by: Sami Tolvanen <samitolvanen@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Neil Armstrong <neil.armstrong@linaro.org>,
Tom Rix <trix@redhat.com>,
llvm@lists.linux.dev, Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
patches@lists.linux.dev, Sami Tolvanen <samitolvanen@google.com>,
linux-amlogic@lists.infradead.org
Subject: Re: [PATCH] drm/meson: Fix return type of meson_encoder_cvbs_mode_valid()
Date: Wed, 2 Nov 2022 12:06:34 -0700 [thread overview]
Message-ID: <202211021206.F5C5954F66@keescook> (raw)
In-Reply-To: <20221102155242.1927166-1-nathan@kernel.org>
On Wed, Nov 02, 2022 at 08:52:42AM -0700, Nathan Chancellor wrote:
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> drivers/gpu/drm/meson/meson_encoder_cvbs.c:211:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .mode_valid = meson_encoder_cvbs_mode_valid,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> ->mode_valid() in 'struct drm_bridge_funcs' expects a return type of
> 'enum drm_mode_status', not 'int'. Adjust the return type of
> meson_encoder_cvbs_mode_valid() to match the prototype's to resolve the
> warning and CFI failure.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Reported-by: Sami Tolvanen <samitolvanen@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Neil Armstrong <neil.armstrong@linaro.org>,
dri-devel@lists.freedesktop.org,
linux-amlogic@lists.infradead.org,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>,
Sami Tolvanen <samitolvanen@google.com>,
llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
patches@lists.linux.dev
Subject: Re: [PATCH] drm/meson: Fix return type of meson_encoder_cvbs_mode_valid()
Date: Wed, 2 Nov 2022 12:06:34 -0700 [thread overview]
Message-ID: <202211021206.F5C5954F66@keescook> (raw)
In-Reply-To: <20221102155242.1927166-1-nathan@kernel.org>
On Wed, Nov 02, 2022 at 08:52:42AM -0700, Nathan Chancellor wrote:
> With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> indirect call targets are validated against the expected function
> pointer prototype to make sure the call target is valid to help mitigate
> ROP attacks. If they are not identical, there is a failure at run time,
> which manifests as either a kernel panic or thread getting killed. A
> proposed warning in clang aims to catch these at compile time, which
> reveals:
>
> drivers/gpu/drm/meson/meson_encoder_cvbs.c:211:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict]
> .mode_valid = meson_encoder_cvbs_mode_valid,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 error generated.
>
> ->mode_valid() in 'struct drm_bridge_funcs' expects a return type of
> 'enum drm_mode_status', not 'int'. Adjust the return type of
> meson_encoder_cvbs_mode_valid() to match the prototype's to resolve the
> warning and CFI failure.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> Reported-by: Sami Tolvanen <samitolvanen@google.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
next prev parent reply other threads:[~2022-11-02 19:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-02 15:52 [PATCH] drm/meson: Fix return type of meson_encoder_cvbs_mode_valid() Nathan Chancellor
2022-11-02 15:52 ` Nathan Chancellor
2022-11-02 15:52 ` Nathan Chancellor
2022-11-02 19:06 ` Kees Cook [this message]
2022-11-02 19:06 ` Kees Cook
2022-11-02 19:06 ` Kees Cook
2022-11-03 8:41 ` Neil Armstrong
2022-11-03 8:41 ` Neil Armstrong
2022-11-03 8:41 ` Neil Armstrong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202211021206.F5C5954F66@keescook \
--to=keescook@chromium.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=neil.armstrong@linaro.org \
--cc=patches@lists.linux.dev \
--cc=samitolvanen@google.com \
--cc=trix@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.