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From:   Kees Cook <keescook@chromium.org>
To:     Damien Le Moal <dlemoal@kernel.org>
Cc:     Kees Cook <keescook@chromium.org>, linux-ide@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
Subject: [PATCH] libata: Annotate struct ata_cpr_log with __counted_by
Date:   Fri, 22 Sep 2023 10:52:11 -0700
Message-Id: <20230922175210.work.239-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 ata_cpr_log.

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

Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: linux-ide@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/libata.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 3c17a5053f00..f91e8e7f1c00 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -656,7 +656,7 @@ struct ata_cpr {
 
 struct ata_cpr_log {
 	u8			nr_cpr;
-	struct ata_cpr		cpr[];
+	struct ata_cpr		cpr[] __counted_by(nr_cpr);
 };
 
 struct ata_device {
-- 
2.34.1