[PATCH 4/7] RDMA/siw: Annotate struct siw_pbl with __counted_by

[Kees Cook]

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 siw_pbl.

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

Cc: Bernard Metzler <bmt@xxxxxxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Leon Romanovsky <leon@xxxxxxxxxx>
Cc: linux-rdma@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/infiniband/sw/siw/siw.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
index 1c78c1ca7d7a..cec5cccd2e75 100644
--- a/drivers/infiniband/sw/siw/siw.h
+++ b/drivers/infiniband/sw/siw/siw.h
@@ -137,7 +137,7 @@ struct siw_pble {
 struct siw_pbl {
 	unsigned int num_buf;
 	unsigned int max_buf;
-	struct siw_pble pbe[];
+	struct siw_pble pbe[] __counted_by(max_buf);
 };
 
 /*
-- 
2.34.1