From: Paolo Abeni pabeni@redhat.com
stable inclusion from stable-5.10.68 commit cad96d0e50e4149758d43bcc3bd13f6381312362 bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 3c4cea8fa7f71f00c5279547043a84bc2a4d8b8c upstream.
If the sendmsg() call in vhost_tx_batch() fails, both the 'batched_xdp' and 'done_idx' indexes are left unchanged. If such failure happens when batched_xdp == VHOST_NET_BATCH, the next call to vhost_net_build_xdp() will access and write memory outside the xdp buffers area.
Since sendmsg() can only error with EBADFD, this change addresses the issue explicitly freeing the XDP buffers batch on error.
Fixes: 0a0be13b8fe2 ("vhost_net: batch submitting XDP buffers to underlayer sockets") Suggested-by: Jason Wang jasowang@redhat.com Signed-off-by: Paolo Abeni pabeni@redhat.com Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/vhost/net.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index c8784dfafdd7..da02c3e96e7b 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -466,7 +466,7 @@ static void vhost_tx_batch(struct vhost_net *net, .num = nvq->batched_xdp, .ptr = nvq->xdp, }; - int err; + int i, err;
if (nvq->batched_xdp == 0) goto signal_used; @@ -475,6 +475,15 @@ static void vhost_tx_batch(struct vhost_net *net, err = sock->ops->sendmsg(sock, msghdr, 0); if (unlikely(err < 0)) { vq_err(&nvq->vq, "Fail to batch sending packets\n"); + + /* free pages owned by XDP; since this is an unlikely error path, + * keep it simple and avoid more complex bulk update for the + * used pages + */ + for (i = 0; i < nvq->batched_xdp; ++i) + put_page(virt_to_head_page(nvq->xdp[i].data)); + nvq->batched_xdp = 0; + nvq->done_idx = 0; return; }