From: Kees Cook <keescook@chromium.org>
Date: Wed, 16 Jun 2021 20:26:15 +0000 (-0700)
Subject: RDMA/core: Use flexible array for mad data
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6d33cabf2baf304730d01a942095416b3a8329ab;p=linux.git

RDMA/core: Use flexible array for mad data

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally reading across neighboring array fields.

Without a flexible array, this looks like an attempt to perform a memcpy()
read beyond the end of the packet->mad.data array:

drivers/infiniband/core/user_mad.c:
	memcpy(packet->msg->mad, packet->mad.data, IB_MGMT_MAD_HDR);

Switch from [0] to [] to use the appropriately handled type for trailing
bytes.

Link: https://lore.kernel.org/r/20210616202615.1247242-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---

diff --git a/include/uapi/rdma/ib_user_mad.h b/include/uapi/rdma/ib_user_mad.h
index 90c0cf228020d..10b5f6a4c6773 100644
--- a/include/uapi/rdma/ib_user_mad.h
+++ b/include/uapi/rdma/ib_user_mad.h
@@ -143,7 +143,7 @@ struct ib_user_mad_hdr {
  */
 struct ib_user_mad {
 	struct ib_user_mad_hdr hdr;
-	__aligned_u64	data[0];
+	__aligned_u64	data[];
 };
 
 /*