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 mediatable.

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

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Shaokun Zhang <redacted>
Cc: netdev@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Signed-off-by: Kees Cook <redacted>
---
 drivers/net/ethernet/dec/tulip/tulip.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/dec/tulip/tulip.h b/drivers/net/ethernet/dec/tulip/tulip.h
index 0ed598dc7569..bd786dfbc066 100644
--- a/drivers/net/ethernet/dec/tulip/tulip.h
+++ b/drivers/net/ethernet/dec/tulip/tulip.h

@@ -381,7 +381,7 @@ struct mediatable {
 	unsigned has_reset:6;
 	u32 csr15dir;
 	u32 csr15val;		/* 21143 NWay setting. */
-	struct medialeaf mleaf[];
+	struct medialeaf mleaf[] __counted_by(leafcount);
 };
 
 

-- 
2.34.1