drm/radeon: Read buffer overflow

Check whether index is within bounds before grabbing the element.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 05a44896dffb..f1ba8ff41130 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -722,13 +722,14 @@ int r100_cs_packet_parse(struct radeon_cs_parser *p,
                          unsigned idx)
 {
         struct radeon_cs_chunk *ib_chunk = &p->chunks[p->chunk_ib_idx];
-        uint32_t header = ib_chunk->kdata[idx];
+        uint32_t header;
 
         if (idx >= ib_chunk->length_dw) {
                 DRM_ERROR("Can not parse packet at %d after CS end %d !\n",
                           idx, ib_chunk->length_dw);
                 return -EINVAL;
         }
+        header = ib_chunk->kdata[idx];
         pkt->idx = idx;
         pkt->type = CP_PACKET_GET_TYPE(header);
         pkt->count = CP_PACKET_GET_COUNT(header);