netdev - [PATCH] vsock/virtio: add support for MSG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1569522214-28223-1-git-send-email-matiasevara@gmail.com>
Date:   Thu, 26 Sep 2019 18:23:34 +0000
From:   Matias Ezequiel Vara Larsen <matiasevara@...il.com>
To:     stefanha@...hat.com
Cc:     davem@...emloft.net, kvm@...r.kernel.org,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, matiasevara@...il.com,
        sgarzare@...hat.com
Subject: [PATCH] vsock/virtio: add support for MSG_PEEK

This patch adds support for MSG_PEEK. In such a case, packets are not
removed from the rx_queue and credit updates are not sent.

Signed-off-by: Matias Ezequiel Vara Larsen <matiasevara@...il.com>
---
 net/vmw_vsock/virtio_transport_common.c | 50 +++++++++++++++++++++++++++++++--
 1 file changed, 47 insertions(+), 3 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
index 94cc0fa..938f2ed 100644
--- a/net/vmw_vsock/virtio_transport_common.c
+++ b/net/vmw_vsock/virtio_transport_common.c
@@ -264,6 +264,50 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk,
 }
 
 static ssize_t
+virtio_transport_stream_do_peek(struct vsock_sock *vsk,
+				struct msghdr *msg,
+				size_t len)
+{
+	struct virtio_vsock_sock *vvs = vsk->trans;
+	struct virtio_vsock_pkt *pkt;
+	size_t bytes, total = 0;
+	int err = -EFAULT;
+
+	spin_lock_bh(&vvs->rx_lock);
+
+	list_for_each_entry(pkt, &vvs->rx_queue, list) {
+		if (total == len)
+			break;
+
+		bytes = len - total;
+		if (bytes > pkt->len - pkt->off)
+			bytes = pkt->len - pkt->off;
+
+		/* sk_lock is held by caller so no one else can dequeue.
+		 * Unlock rx_lock since memcpy_to_msg() may sleep.
+		 */
+		spin_unlock_bh(&vvs->rx_lock);
+
+		err = memcpy_to_msg(msg, pkt->buf + pkt->off, bytes);
+		if (err)
+			goto out;
+
+		spin_lock_bh(&vvs->rx_lock);
+
+		total += bytes;
+	}
+
+	spin_unlock_bh(&vvs->rx_lock);
+
+	return total;
+
+out:
+	if (total)
+		err = total;
+	return err;
+}
+
+static ssize_t
 virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,
 				   struct msghdr *msg,
 				   size_t len)
@@ -330,9 +374,9 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk,
 				size_t len, int flags)
 {
 	if (flags & MSG_PEEK)
-		return -EOPNOTSUPP;
-
-	return virtio_transport_stream_do_dequeue(vsk, msg, len);
+		return virtio_transport_stream_do_peek(vsk, msg, len);
+	else
+		return virtio_transport_stream_do_dequeue(vsk, msg, len);
 }
 EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);
 
-- 
2.7.4