Commit e219688f authored by Doug Horn's avatar Doug Horn Committed by Gerd Hoffmann

Fix use after free in get_capset_info callback.

If a response to virtio_gpu_cmd_get_capset_info takes longer than
five seconds to return, the callback will access freed kernel memory
in vg->capsets.
Signed-off-by: default avatarDoug Horn <doughorn@google.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200902210847.2689-2-gurchetansingh@chromium.orgSigned-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent 707d561f
......@@ -80,8 +80,10 @@ static void virtio_gpu_get_capsets(struct virtio_gpu_device *vgdev,
vgdev->capsets[i].id > 0, 5 * HZ);
if (ret == 0) {
DRM_ERROR("timed out waiting for cap set %d\n", i);
spin_lock(&vgdev->display_info_lock);
kfree(vgdev->capsets);
vgdev->capsets = NULL;
spin_unlock(&vgdev->display_info_lock);
return;
}
DRM_INFO("cap set %d: id %d, max-version %d, max-size %d\n",
......
......@@ -684,9 +684,13 @@ static void virtio_gpu_cmd_get_capset_info_cb(struct virtio_gpu_device *vgdev,
int i = le32_to_cpu(cmd->capset_index);
spin_lock(&vgdev->display_info_lock);
if (vgdev->capsets) {
vgdev->capsets[i].id = le32_to_cpu(resp->capset_id);
vgdev->capsets[i].max_version = le32_to_cpu(resp->capset_max_version);
vgdev->capsets[i].max_size = le32_to_cpu(resp->capset_max_size);
} else {
DRM_ERROR("invalid capset memory.");
}
spin_unlock(&vgdev->display_info_lock);
wake_up(&vgdev->resp_wq);
}
......
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