Re: [PATCH] vhost/vsock: always initialize seqpacket_allow
From: Eugenio Perez Martin <eperezma@redhat.com>
Date: 2024-05-16 13:38:26
Also in:
kvm, lkml, virtualization
On Wed, May 15, 2024 at 5:05 PM Michael S. Tsirkin [off-list ref] wrote:
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 <redacted>
Fixes: ced7b713711f ("vhost/vsock: support SEQPACKET for transport").
Cc: Arseny Krasnov <redacted>
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 <redacted>
Tested-by: Arseniy Krasnov <redacted>Reviewed-by: Eugenio Pérez <eperezma@redhat.com> Thanks!
quoted hunk ↗ jump to hunk
--- Reposting now it's been tested. drivers/vhost/vsock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)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]; --MST