[ 14/22] drm/radeon: fix handling of variable sized arrays for router objects

Greg Kroah-Hartman
2013-09-29T19:59:34Z

From: Alex Deucher <alexander.deucher@amd.com>

commit fb93df1c2d8b3b1fb16d6ee9e32554e0c038815d upstream.

The table has the following format:

typedef struct _ATOM_SRC_DST_TABLE_FOR_ONE_OBJECT //usSrcDstTableOffset pointing to this structure
{
UCHAR ucNumberOfSrc;
USHORT usSrcObjectID[1];
UCHAR ucNumberOfDst;
USHORT usDstObjectID[1];
}ATOM_SRC_DST_TABLE_FOR_ONE_OBJECT;

usSrcObjectID[] and usDstObjectID[] are variably sized, so we
can't access them directly. Use pointers and update the offset
appropriately when accessing the Dst members.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/radeon/radeon_atombios.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -715,13 +715,16 @@ bool radeon_get_atom_connector_info_from
(ATOM_SRC_DST_TABLE_FOR_ONE_OBJECT *)
(ctx->bios + data_offset +
le16_to_cpu(router_obj->asObjects[k].usSrcDstTableOffset));
+ u8 *num_dst_objs = (u8 *)
+ ((u8 *)router_src_dst_table + 1 +
+ (router_src_dst_table->ucNumberOfSrc * 2));
+ u16 *dst_objs = (u16 *)(num_dst_objs + 1);
int enum_id;

router.router_id = router_obj_id;
- for (enum_id = 0; enum_id < router_src_dst_table->ucNumberOfDst;
- enum_id++) {
+ for (enum_id = 0; enum_id < (*num_dst_objs); enum_id++) {
if (le16_to_cpu(path->usConnObjectId) ==
- le16_to_cpu(router_src_dst_table->usDstObjectID[enum_id]))
+ le16_to_cpu(dst_objs[enum_id]))
break;
}