From: Dongli Zhang Date: Thu, 3 Apr 2025 06:29:46 +0000 (-0700) Subject: vhost-scsi: protect vq->log_used with vq->mutex X-Git-Tag: v6.15-rc4~34^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f591cf9fce724e5075cc67488c43c6e39e8cbe27;p=thirdparty%2Flinux.git vhost-scsi: protect vq->log_used with vq->mutex The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false. vhost-thread QEMU-thread vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); vq->log_used = false now! mutex_unlock(&vq->mutex); QEMU gfree(vq->log_base) log_used() -> log_write(vq->log_base) Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be reclaimed via gfree(). As a result, this causes invalid memory writes to QEMU userspace. The control queue path has the same issue. Signed-off-by: Dongli Zhang Acked-by: Jason Wang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-2-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin --- diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index f6f5a7ac78945..f846f2aa7c870 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -627,6 +627,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) int ret; llnode = llist_del_all(&svq->completion_list); + + mutex_lock(&svq->vq.mutex); + llist_for_each_entry_safe(cmd, t, llnode, tvc_completion_list) { se_cmd = &cmd->tvc_se_cmd; @@ -660,6 +663,8 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) vhost_scsi_release_cmd_res(se_cmd); } + mutex_unlock(&svq->vq.mutex); + if (signal) vhost_signal(&svq->vs->dev, &svq->vq); } @@ -1432,8 +1437,11 @@ static void vhost_scsi_tmf_resp_work(struct vhost_work *work) else resp_code = VIRTIO_SCSI_S_FUNCTION_REJECTED; + mutex_lock(&tmf->svq->vq.mutex); vhost_scsi_send_tmf_resp(tmf->vhost, &tmf->svq->vq, tmf->in_iovs, tmf->vq_desc, &tmf->resp_iov, resp_code); + mutex_unlock(&tmf->svq->vq.mutex); + vhost_scsi_release_tmf_res(tmf); }