[PATCH] vhost/vsock: always initialize seqpacket_allow

[PATCH] vhost/vsock: always initialize seqpacket_allow

[Michael S. Tsirkin]

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>
Tested-by: Arseniy Krasnov <avkrasnov@salutedevices.com>

---


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

Re: [PATCH] vhost/vsock: always initialize seqpacket_allow

[Jason Wang]

On Wed, May 15, 2024 at 11:05 PM Michael S. Tsirkin <mst@redhat.com> 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 <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>
> Tested-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

Re: [PATCH] vhost/vsock: always initialize seqpacket_allow

[Stefano Garzarella]

On Wed, May 15, 2024 at 11:05:43AM GMT, Michael S. Tsirkin 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 <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>
>Tested-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>
>---
>
>
>Reposting now it's been tested.
>
> drivers/vhost/vsock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Thanks for fixing this issue!

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Re: [PATCH] vhost/vsock: always initialize seqpacket_allow

[Eugenio Perez Martin]

On Wed, May 15, 2024 at 5:05 PM Michael S. Tsirkin <mst@redhat.com> 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 <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>
> Tested-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
>

Reviewed-by: Eugenio Pérez <eperezma@redhat.com>

Thanks!

> ---
>
>
> 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
>

Re: [PATCH] vhost/vsock: always initialize seqpacket_allow

[Jakub Kicinski]

On Wed, 15 May 2024 11:05:43 -0400 Michael S. Tsirkin 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).

Acked-by: Jakub Kicinski <kuba@kernel.org>
-- 
pw-bot: nap

Re: [PATCH] vhost/vsock: always initialize seqpacket_allow

[박정준]

nice patch

> 2024. 5. 16. 오전 12:05, Michael S. Tsirkin <mst@redhat.com> 작성:
> 
> 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>
> Tested-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
> 
> ---
> 
> 
> 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
>