lkml.org 
[lkml]   [2020]   [Oct]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH AUTOSEL 5.4 60/80] Fix use after free in get_capset_info callback.
    Date
    From: Doug Horn <doughorn@google.com>

    [ Upstream commit e219688fc5c3d0d9136f8d29d7e0498388f01440 ]

    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: Doug Horn <doughorn@google.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/20200902210847.2689-2-gurchetansingh@chromium.org
    Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/gpu/drm/virtio/virtgpu_kms.c | 2 ++
    drivers/gpu/drm/virtio/virtgpu_vq.c | 10 +++++++---
    2 files changed, 9 insertions(+), 3 deletions(-)

    diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
    index c190702fab726..6dcc05ab31eba 100644
    --- a/drivers/gpu/drm/virtio/virtgpu_kms.c
    +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
    @@ -96,8 +96,10 @@ 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",
    diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
    index 7ac20490e1b4c..92022a83bbd5e 100644
    --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
    +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
    @@ -572,9 +572,13 @@ 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);
    - 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);
    + 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);
    }
    --
    2.25.1
    \
     
     \ /
      Last update: 2020-10-18 21:43    [W:4.213 / U:0.276 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site