[PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by

From: Kees Cook <keescook@chromium.org>
To: Mark Fasheh <mark@fasheh.com>
Cc: Kees Cook <keescook@chromium.org>,
	Joel Becker <jlbec@evilplan.org>,
	Joseph Qi <joseph.qi@linux.alibaba.com>,
	ocfs2-devel@lists.linux.dev,
	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] ocfs2: Annotate struct ocfs2_slot_info with __counted_by
Date: Fri, 15 Sep 2023 13:15:23 -0700	[thread overview]
Message-ID: <20230915201522.never.979-kees@kernel.org> (raw)

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 ocfs2_slot_info.

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

Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 fs/ocfs2/slot_map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index da7718cef735..e544c704b583 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -37,7 +37,7 @@ struct ocfs2_slot_info {
 	unsigned int si_blocks;
 	struct buffer_head **si_bh;
 	unsigned int si_num_slots;
-	struct ocfs2_slot si_slots[];
+	struct ocfs2_slot si_slots[] __counted_by(si_num_slots);
 };
 
 
-- 
2.34.1

