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 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 packet_fanout. Cc: "David S. Miller" <[email protected]> Cc: Eric Dumazet <[email protected]> Cc: Jakub Kicinski <[email protected]> Cc: Paolo Abeni <[email protected]> Cc: Willem de Bruijn <[email protected]> Cc: Anqi Shen <[email protected]> Cc: [email protected] Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1] Signed-off-by: Kees Cook <[email protected]> --- net/packet/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/packet/internal.h b/net/packet/internal.h index 63f4865202c1..d29c94c45159 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -94,7 +94,7 @@ struct packet_fanout { spinlock_t lock; refcount_t sk_ref; struct packet_type prot_hook ____cacheline_aligned_in_smp; - struct sock __rcu *arr[]; + struct sock __rcu *arr[] __counted_by(max_num_members); }; struct packet_rollover { -- 2.34.1
