In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Add flexible array to represent start of buf_info, improving readability
and avoid future warning where memcpy() thinks it is writing past the
end of the structure.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/net/hyperv/hyperv_net.h | 1 +
drivers/net/hyperv/rndis_filter.c | 6 ++----
2 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index b11aa68b44ec..bc48855dff10 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -1170,6 +1170,7 @@ struct rndis_set_request {
u32 info_buflen;
u32 info_buf_offset;
u32 dev_vc_handle;
+ u8 info_buf[];
};
/* Response to NdisSetRequest */
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 983bf362466a..f6c9c2a670f9 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1051,10 +1051,8 @@ static int rndis_filter_set_packet_filter(struct rndis_device *dev,
set = &request->request_msg.msg.set_req;
set->oid = RNDIS_OID_GEN_CURRENT_PACKET_FILTER;
set->info_buflen = sizeof(u32);
- set->info_buf_offset = sizeof(struct rndis_set_request);
-
- memcpy((void *)(unsigned long)set + sizeof(struct rndis_set_request),
- &new_filter, sizeof(u32));
+ set->info_buf_offset = offsetof(typeof(*set), info_buf);
+ memcpy(set->info_buf, &new_filter, sizeof(u32));
ret = rndis_filter_send_request(dev, request);
if (ret == 0) {
--
2.30.2
