From 0c7f2cad142fcc87eebe60cc08bfb2ed1b44f719 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 4 Jul 2018 12:42:50 +0300 Subject: [PATCH] drm/virtio: fix bounds check in virtio_gpu_cmd_get_capset() [ Upstream commit 09c4b49457434fa74749ad6194ef28464d9f5df9 ] This doesn't affect runtime because in the current code "idx" is always valid. First, we read from "vgdev->capsets[idx].max_size" before checking whether "idx" is within bounds. And secondly the bounds check is off by one so we could end up reading one element beyond the end of the vgdev->capsets[] array. Fixes: 62fb7a5e1096 ("virtio-gpu: add 3d/virgl support") Signed-off-by: Dan Carpenter Link: http://patchwork.freedesktop.org/patch/msgid/20180704094250.m7sgvvzg3dhcvv3h@kili.mountain Signed-off-by: Gerd Hoffmann Signed-off-by: Sasha Levin --- drivers/gpu/drm/virtio/virtgpu_vq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index a1b3ea1ccb65..772a5a3b0ce1 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -681,11 +681,11 @@ int virtio_gpu_cmd_get_capset(struct virtio_gpu_device *vgdev, { struct virtio_gpu_get_capset *cmd_p; struct virtio_gpu_vbuffer *vbuf; - int max_size = vgdev->capsets[idx].max_size; + int max_size; struct virtio_gpu_drv_cap_cache *cache_ent; void *resp_buf; - if (idx > vgdev->num_capsets) + if (idx >= vgdev->num_capsets) return -EINVAL; if (version > vgdev->capsets[idx].max_version) @@ -695,6 +695,7 @@ int virtio_gpu_cmd_get_capset(struct virtio_gpu_device *vgdev, if (!cache_ent) return -ENOMEM; + max_size = vgdev->capsets[idx].max_size; cache_ent->caps_cache = kmalloc(max_size, GFP_KERNEL); if (!cache_ent->caps_cache) { kfree(cache_ent); -- 2.20.1