This patch sets the skb owner in the recv and send path for virtio.
For the send path, this solves the leak caused when
virtio_transport_purge_skbs() finds skb->sk is always NULL and therefore
never matches it with the current socket. Setting the owner upon
allocation fixes this.
For the recv path, this ensures correctness of accounting and also
correct transfer of ownership in vsock_loopback (when skbs are sent from
one socket and received by another).
Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
Signed-off-by: Bobby Eshleman <[email protected]>
Reported-by: Cong Wang <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/
---
Changes in v3:
- virtio/vsock: use skb_set_owner_sk_safe() instead of
skb_set_owner_{r,w}
- virtio/vsock: reject allocating/receiving skb if sk_refcnt==0 and WARN_ONCE
- Link to v2: https://lore.kernel.org/r/[email protected]
Changes in v2:
- virtio/vsock: add skb_set_owner_r to recv_pkt()
- Link to v1: https://lore.kernel.org/r/[email protected]
---
net/vmw_vsock/virtio_transport_common.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 957cdc01c8e8..c927dc302faa 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -94,6 +94,11 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
info->op,
info->flags);
+ if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
+ WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
+ goto out;
+ }
+
return skb;
out:
@@ -1294,6 +1299,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
goto free_pkt;
}
+ if (!skb_set_owner_sk_safe(skb, sk)) {
+ WARN_ONCE(1, "receiving vsock socket has sk_refcnt == 0\n");
+ goto free_pkt;
+ }
+
vsk = vsock_sk(sk);
lock_sock(sk);
---
base-commit: e5b42483ccce50d5b957f474fd332afd4ef0c27b
change-id: 20230327-vsock-fix-leak-b1cef1582aa8
Best regards,
--
Bobby Eshleman <[email protected]>
On Wed, Mar 29, 2023 at 04:51:58PM +0000, Bobby Eshleman wrote:
>This patch sets the skb owner in the recv and send path for virtio.
>
>For the send path, this solves the leak caused when
>virtio_transport_purge_skbs() finds skb->sk is always NULL and therefore
>never matches it with the current socket. Setting the owner upon
>allocation fixes this.
>
>For the recv path, this ensures correctness of accounting and also
>correct transfer of ownership in vsock_loopback (when skbs are sent from
>one socket and received by another).
>
>Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
>Signed-off-by: Bobby Eshleman <[email protected]>
>Reported-by: Cong Wang <[email protected]>
>Link: https://lore.kernel.org/all/[email protected]/
>---
>Changes in v3:
>- virtio/vsock: use skb_set_owner_sk_safe() instead of
> skb_set_owner_{r,w}
>- virtio/vsock: reject allocating/receiving skb if sk_refcnt==0 and WARN_ONCE
>- Link to v2: https://lore.kernel.org/r/[email protected]
>
>Changes in v2:
>- virtio/vsock: add skb_set_owner_r to recv_pkt()
>- Link to v1: https://lore.kernel.org/r/[email protected]
>---
> net/vmw_vsock/virtio_transport_common.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index 957cdc01c8e8..c927dc302faa 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -94,6 +94,11 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info,
> info->op,
> info->flags);
>
>+ if (info->vsk && !skb_set_owner_sk_safe(skb, sk_vsock(info->vsk))) {
>+ WARN_ONCE(1, "failed to allocate skb on vsock socket with sk_refcnt == 0\n");
>+ goto out;
>+ }
>+
> return skb;
>
> out:
>@@ -1294,6 +1299,11 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> goto free_pkt;
> }
>
>+ if (!skb_set_owner_sk_safe(skb, sk)) {
>+ WARN_ONCE(1, "receiving vsock socket has sk_refcnt == 0\n");
>+ goto free_pkt;
>+ }
>+
LGTM!
I would have put the condition inside WARN_ONCE() because I find it
more readable (e.g. WARN_ONCE(!skb_set_owner_sk_safe(skb, sk), ...),
but I don't have a strong opinion on that, so that's fine too:
Reviewed-by: Stefano Garzarella <[email protected]>
Thanks,
Stefano
Hello:
This patch was applied to netdev/net.git (main)
by David S. Miller <[email protected]>:
On Wed, 29 Mar 2023 16:51:58 +0000 you wrote:
> This patch sets the skb owner in the recv and send path for virtio.
>
> For the send path, this solves the leak caused when
> virtio_transport_purge_skbs() finds skb->sk is always NULL and therefore
> never matches it with the current socket. Setting the owner upon
> allocation fixes this.
>
> [...]
Here is the summary with links:
- [net,v3] virtio/vsock: fix leaks due to missing skb owner
https://git.kernel.org/netdev/net/c/f9d2b1e146e0
You are awesome, thank you!
--
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