aio: Annotate struct kioctx_table with __counted_by
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 kioctx_table.
[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: linux-aio@kvack.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Message-Id: <20230915201413.never.881-kees@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff --git a/fs/aio.c b/fs/aio.c
index a4c2a6b..f8589ca 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -80,7 +80,7 @@ struct aio_ring {
struct kioctx_table {
struct rcu_head rcu;
unsigned nr;
- struct kioctx __rcu *table[];
+ struct kioctx __rcu *table[] __counted_by(nr);
};
struct kioctx_cpu {
