On 9/22/23 11:54, Kees Cook wrote:
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 watch_filter.

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

Cc: David Howells <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Siddh Raman Pant <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Qian Cai <[email protected]>
Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

---
  include/linux/watch_queue.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h
index 45cd42f55d49..429c7b6afead 100644
--- a/include/linux/watch_queue.h
+++ b/include/linux/watch_queue.h
@@ -32,7 +32,7 @@ struct watch_filter {
                DECLARE_BITMAP(type_filter, WATCH_TYPE__NR);
        };
        u32                     nr_filters;     /* Number of filters */
-       struct watch_type_filter filters[];
+       struct watch_type_filter filters[] __counted_by(nr_filters);
  };
struct watch_queue {

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