lkml.org 
[lkml]   [2012]   [Apr]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH for 3.4] virtio-scsi: fix TMF use-after-free
    Date
    Fix a race in TMF path, where cmd may have been already freed
    by virtscsi_complete_free after waking up from the completion.

    Cc: James Bottomley <JBottomley@parallels.com>
    Cc: linux-scsi@vger.kernel.org
    Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    ---
    drivers/scsi/virtio_scsi.c | 24 +++++++++++++-----------
    1 file changed, 13 insertions(+), 11 deletions(-)

    diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
    index efccd72..1b38431 100644
    --- a/drivers/scsi/virtio_scsi.c
    +++ b/drivers/scsi/virtio_scsi.c
    @@ -175,7 +175,8 @@ static void virtscsi_complete_free(void *buf)

    if (cmd->comp)
    complete_all(cmd->comp);
    - mempool_free(cmd, virtscsi_cmd_pool);
    + else
    + mempool_free(cmd, virtscsi_cmd_pool);
    }

    static void virtscsi_ctrl_done(struct virtqueue *vq)
    @@ -311,21 +312,22 @@ out:
    static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd)
    {
    DECLARE_COMPLETION_ONSTACK(comp);
    - int ret;
    + int ret = FAILED;

    cmd->comp = &comp;
    - ret = virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
    - sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
    - GFP_NOIO);
    - if (ret < 0)
    - return FAILED;
    + if (virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd,
    + sizeof cmd->req.tmf, sizeof cmd->resp.tmf,
    + GFP_NOIO) < 0)
    + goto out;

    wait_for_completion(&comp);
    - if (cmd->resp.tmf.response != VIRTIO_SCSI_S_OK &&
    - cmd->resp.tmf.response != VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
    - return FAILED;
    + if (cmd->resp.tmf.response == VIRTIO_SCSI_S_OK ||
    + cmd->resp.tmf.response == VIRTIO_SCSI_S_FUNCTION_SUCCEEDED)
    + ret = SUCCESS;

    - return SUCCESS;
    +out:
    + mempool_free(cmd, virtscsi_cmd_pool);
    + return ret;
    }

    static int virtscsi_device_reset(struct scsi_cmnd *sc)
    --
    1.7.9.3


    \
     
     \ /
      Last update: 2012-04-18 22:37    [W:0.030 / U:395.308 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site