From: Dongli Zhang dongli.zhang@oracle.com
[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ]
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.
CVE-2025-38074 Cc: stable@vger.kernel.org#5.10.x Cc: gregkh@linuxfoundation.org Signed-off-by: Dongli Zhang dongli.zhang@oracle.com Acked-by: Jason Wang jasowang@redhat.com Reviewed-by: Mike Christie michael.christie@oracle.com Message-Id: 20250403063028.16045-2-dongli.zhang@oracle.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org [ Conflicts in drivers/vhost/scsi.c bacause vhost_scsi_complete_cmd_work() has been refactored. ] Signed-off-by: Xinyu Zheng zhengxinyu6@huawei.com --- drivers/vhost/scsi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index a23a65e7d828..fcde3752b4f1 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -579,8 +579,10 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work) ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter); if (likely(ret == sizeof(v_rsp))) { struct vhost_scsi_virtqueue *q; - vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0); q = container_of(cmd->tvc_vq, struct vhost_scsi_virtqueue, vq); + mutex_lock(&q->vq.mutex); + vhost_add_used(cmd->tvc_vq, cmd->tvc_vq_desc, 0); + mutex_unlock(&q->vq.mutex); vq = q - vs->vqs; __set_bit(vq, signal); } else @@ -1193,8 +1195,11 @@ 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); }
[ Sasha's backport helper bot ]
Hi,
✅ All tests passed successfully. No issues detected. No action required from the submitter.
The upstream commit SHA1 provided is correct: f591cf9fce724e5075cc67488c43c6e39e8cbe27
WARNING: Author mismatch between patch and upstream commit: Backport author: Xinyu Zhengzhengxinyu6@huawei.com Commit author: Dongli Zhangdongli.zhang@oracle.com
Status in newer kernel trees: 6.15.y | Present (exact SHA1) 6.12.y | Present (different SHA1: bd8c9404e44a) 6.6.y | Present (different SHA1: ca85c2d0db5f) 6.1.y | Not found 5.15.y | Not found
Note: The patch differs from the upstream commit: --- 1: f591cf9fce724 < -: ------------- vhost-scsi: protect vq->log_used with vq->mutex -: ------------- > 1: 4cd7a98212613 vhost-scsi: protect vq->log_used with vq->mutex ---
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-5.10.y | Success | Success |
On Wed, Jul 02, 2025 at 08:29:45AM +0000, Xinyu Zheng wrote:
From: Dongli Zhang dongli.zhang@oracle.com
[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ]
The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false.
vhost-thread QEMU-threadvhost_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.
CVE-2025-38074
This is not needed.
Cc: stable@vger.kernel.org#5.10.x
What about 5.15.y and 6.1.y? We can't take a patch just for 5.10 as that would cause regressions, right?
Please provide all relevant backports and I will be glad to queue them up then. I'll drop this from my queue for now, thanks.
greg k-h
On 7/10/2025 9:41 PM, Greg KH wrote:
On Wed, Jul 02, 2025 at 08:29:45AM +0000, Xinyu Zheng wrote:
From: Dongli Zhang dongli.zhang@oracle.com
[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ]
The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false.
vhost-thread QEMU-threadvhost_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.
CVE-2025-38074
This is not needed.
Cc: stable@vger.kernel.org#5.10.x
What about 5.15.y and 6.1.y? We can't take a patch just for 5.10 as that would cause regressions, right?
Please provide all relevant backports and I will be glad to queue them up then. I'll drop this from my queue for now, thanks.
greg k-h
Sorry for forgetting the 5.15.y and 6.1.y patches. I will resend it as soon as possible. Thanks for pointing out my patch format error.
Xinyu Zheng
linux-stable-mirror@lists.linaro.org
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Greg KH -
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zhengxinyu (E)