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From:   Kees Cook <keescook@chromium.org>
To:     Jaroslav Kysela <perex@perex.cz>
Cc:     Kees Cook <keescook@chromium.org>, Takashi Iwai <tiwai@suse.com>,
        Cezary Rojewski <cezary.rojewski@intel.com>,
        alsa-devel@alsa-project.org, Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Kai Vehmanen <kai.vehmanen@linux.intel.com>,
        Jason Montleon <jmontleo@redhat.com>,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        linux-hardening@vger.kernel.org
Subject: [PATCH] ALSA: hda: Annotate struct hda_conn_list with __counted_by
Date:   Fri, 22 Sep 2023 10:50:42 -0700
Message-Id: <20230922175042.work.547-kees@kernel.org>
MIME-Version: 1.0
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Precedence: bulk

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct hda_conn_list.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Cezary Rojewski <cezary.rojewski@intel.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 sound/pci/hda/hda_codec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 33af707a65ab..01718b1fc9a7 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -88,7 +88,7 @@ struct hda_conn_list {
 	struct list_head list;
 	int len;
 	hda_nid_t nid;
-	hda_nid_t conns[];
+	hda_nid_t conns[] __counted_by(len);
 };
 
 /* look up the cached results */
-- 
2.34.1