firewire: Annotate struct fw_node 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 fw_node.

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

Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: linux1394-devel@lists.sourceforge.net
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230922175334.work.335-kees@kernel.org
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 2a05f411328fd45c81bd2a9e55c10370d504d40e..95c10f3d2282f59c814b27c3440de2b69b34484d 100644 (file)
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -191,7 +191,7 @@ struct fw_node {
        /* Upper layer specific data. */
        void *data;
 
-       struct fw_node *ports[];
+       struct fw_node *ports[] __counted_by(port_count);
 };
 
 static inline struct fw_node *fw_node_get(struct fw_node *node)