From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <nathan@kernel.org>,
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>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Tom Rix <trix@redhat.com>,
intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
patches@lists.linux.dev
Subject: Re: [PATCH] drm/i915: Fix CFI violation with show_dynamic_id()
Date: Thu, 12 May 2022 14:30:17 -0700 [thread overview]
Message-ID: <DEB6A9AC-845E-4656-A596-E6341D3C287F@chromium.org> (raw)
In-Reply-To: <20220512211704.3158759-1-nathan@kernel.org>
On May 12, 2022 2:17:04 PM PDT, Nathan Chancellor <nathan@kernel.org> wrote:
>When an attribute group is created with sysfs_create_group(), the
>->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show()
>callback to kobj_attr_show(). kobj_attr_show() uses container_of() to
>get the ->show() callback from the attribute it was passed, meaning the
>->show() callback needs to be the same type as the ->show() callback in
>'struct kobj_attribute'.
>
>However, show_dynamic_id() has the type of the ->show() callback in
>'struct device_attribute', which causes a CFI violation when opening the
>'id' sysfs node under drm/card0/metrics. This happens to work because
>the layout of 'struct kobj_attribute' and 'struct device_attribute' are
>the same, so the container_of() cast happens to allow the ->show()
>callback to still work.
>
>Change the type of show_dynamic_id() to match the ->show() callback in
>'struct kobj_attributes' and update the type of sysfs_metric_id to
>match, which resolves the CFI violation.
>
>Fixes: f89823c21224 ("drm/i915/perf: Implement I915_PERF_ADD/REMOVE_CONFIG interface")
>Signed-off-by: Nathan Chancellor <nathan@kernel.org>
This matches my own investigation into the error. Thanks for putting the patch together! :)
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2022-05-12 21:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-12 21:17 [PATCH] drm/i915: Fix CFI violation with show_dynamic_id() Nathan Chancellor
2022-05-12 21:30 ` Kees Cook [this message]
2022-05-12 21:30 ` Sami Tolvanen
2022-05-13 10:08 ` Tvrtko Ursulin
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=DEB6A9AC-845E-4656-A596-E6341D3C287F@chromium.org \
--to=keescook@chromium.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=patches@lists.linux.dev \
--cc=rodrigo.vivi@intel.com \
--cc=samitolvanen@google.com \
--cc=trix@redhat.com \
--cc=tvrtko.ursulin@linux.intel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).