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    [from the cache]
©2003-2011 Jasper Spaans