From: Arseniy Krasnov <avkrasnov@salutedevices.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
Stefano Garzarella <sgarzare@redhat.com>,
Jeongjun Park <aha310510@gmail.com>,
Jason Wang <jasowang@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
<virtualization@lists.linux.dev>,
<syzbot+6c21aeb59d0e82eb2782@syzkaller.appspotmail.com>,
<syzkaller-bugs@googlegroups.com>,
Krasnov Arseniy <oxffffaa@gmail.com>
Subject: Re: [PATCH virt] virt: fix uninit-value in vhost_vsock_dev_open
Date: Sun, 5 May 2024 22:53:39 +0300 [thread overview]
Message-ID: <d0550fea-58b6-3aa5-a8ac-27308183d6f8@salutedevices.com> (raw)
In-Reply-To: <20240422100010-mutt-send-email-mst@kernel.org>
> But now that it's explained, the bugfix as proposed is incomplete:
> userspace can set features twice and the second time will leak
> old VIRTIO_VSOCK_F_SEQPACKET bit value.
>
> And I am pretty sure the Fixes tag is wrong.
>
> So I wrote this, but I actually don't have a set for
> seqpacket to test this. Arseny could you help test maybe?
> Thanks!
Hi! Sorry for late reply! Just run vsock test suite with this patch -
seems everything is ok!
>
>
> commit bcc17a060d93b198d8a17a9b87b593f41337ee28
> Author: Michael S. Tsirkin <mst@redhat.com>
> Date: Mon Apr 22 10:03:13 2024 -0400
>
> vhost/vsock: always initialize seqpacket_allow
>
> There are two issues around seqpacket_allow:
> 1. seqpacket_allow is not initialized when socket is
> created. Thus if features are never set, it will be
> read uninitialized.
> 2. if VIRTIO_VSOCK_F_SEQPACKET is set and then cleared,
> then seqpacket_allow will not be cleared appropriately
> (existing apps I know about don't usually do this but
> it's legal and there's no way to be sure no one relies
> on this).
>
> To fix:
> - initialize seqpacket_allow after allocation
> - set it unconditionally in set_features
>
> Reported-by: syzbot+6c21aeb59d0e82eb2782@syzkaller.appspotmail.com
> Reported-by: Jeongjun Park <aha310510@gmail.com>
> Fixes: ced7b713711f ("vhost/vsock: support SEQPACKET for transport").
> Cc: Arseny Krasnov <arseny.krasnov@kaspersky.com>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index ec20ecff85c7..bf664ec9341b 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -667,6 +667,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
> }
>
> vsock->guest_cid = 0; /* no CID assigned yet */
> + vsock->seqpacket_allow = false;
>
> atomic_set(&vsock->queued_replies, 0);
>
> @@ -810,8 +811,7 @@ static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features)
> goto err;
> }
>
> - if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
> - vsock->seqpacket_allow = true;
> + vsock->seqpacket_allow = features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET);
>
> for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
> vq = &vsock->vqs[i];
prev parent reply other threads:[~2024-05-05 20:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000be4e1c06166fdc85@google.com>
2024-04-20 8:57 ` [PATCH virt] virt: fix uninit-value in vhost_vsock_dev_open Jeongjun Park
2024-04-20 10:05 ` Michael S. Tsirkin
2024-04-21 3:06 ` Jeongjun Park
2024-04-22 13:00 ` Stefan Hajnoczi
2024-04-22 14:20 ` Michael S. Tsirkin
2024-05-05 19:53 ` Arseniy Krasnov [this message]
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