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From: Jason Wang <jasowang@redhat.com>
Date: Wed, 24 Feb 2021 11:44:36 +0800
Subject: [PATCH 01/10] net: introduce qemu_receive_packet()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Commit-Id: 705df5466c98f3efdd2b68d3b31dad86858acad7
Some NIC supports loopback mode and this is done by calling
nc->info->receive() directly which in fact suppresses the effort of
reentrancy check that is done in qemu_net_queue_send().
Unfortunately we can't use qemu_net_queue_send() here since for
loopback there's no sender as peer, so this patch introduce a
qemu_receive_packet() which is used for implementing loopback mode
for a NIC with this check.
NIC that supports loopback mode will be converted to this helper.
This is intended to address CVE-2021-3416.
Cc: Prasad J Pandit <ppandit@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
include/net/net.h | 5 +++++
include/net/queue.h | 8 ++++++++
net/net.c | 38 +++++++++++++++++++++++++++++++-------
net/queue.c | 22 ++++++++++++++++++++++
4 files changed, 66 insertions(+), 7 deletions(-)
diff --git a/include/net/net.h b/include/net/net.h
index 919facaad2..4f56cae0fa 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -144,12 +144,17 @@ void *qemu_get_nic_opaque(NetClientState *nc);
void qemu_del_net_client(NetClientState *nc);
typedef void (*qemu_nic_foreach)(NICState *nic, void *opaque);
void qemu_foreach_nic(qemu_nic_foreach func, void *opaque);
+int qemu_can_receive_packet(NetClientState *nc);
int qemu_can_send_packet(NetClientState *nc);
ssize_t qemu_sendv_packet(NetClientState *nc, const struct iovec *iov,
int iovcnt);
ssize_t qemu_sendv_packet_async(NetClientState *nc, const struct iovec *iov,
int iovcnt, NetPacketSent *sent_cb);
ssize_t qemu_send_packet(NetClientState *nc, const uint8_t *buf, int size);
+ssize_t qemu_receive_packet(NetClientState *nc, const uint8_t *buf, int size);
+ssize_t qemu_receive_packet_iov(NetClientState *nc,
+ const struct iovec *iov,
+ int iovcnt);
ssize_t qemu_send_packet_raw(NetClientState *nc, const uint8_t *buf, int size);
ssize_t qemu_send_packet_async(NetClientState *nc, const uint8_t *buf,
int size, NetPacketSent *sent_cb);
diff --git a/include/net/queue.h b/include/net/queue.h
index c0269bb1dc..9f2f289d77 100644
--- a/include/net/queue.h
+++ b/include/net/queue.h
@@ -55,6 +55,14 @@ void qemu_net_queue_append_iov(NetQueue *queue,
void qemu_del_net_queue(NetQueue *queue);
+ssize_t qemu_net_queue_receive(NetQueue *queue,
+ const uint8_t *data,
+ size_t size);
+
+ssize_t qemu_net_queue_receive_iov(NetQueue *queue,
+ const struct iovec *iov,
+ int iovcnt);
+
ssize_t qemu_net_queue_send(NetQueue *queue,
NetClientState *sender,
unsigned flags,
diff --git a/net/net.c b/net/net.c
index 77b35eafc5..edf9b95418 100644
--- a/net/net.c
+++ b/net/net.c
@@ -529,6 +529,17 @@ int qemu_set_vnet_be(NetClientState *nc, bool is_be)
#endif
}
+int qemu_can_receive_packet(NetClientState *nc)
+{
+ if (nc->receive_disabled) {
+ return 0;
+ } else if (nc->info->can_receive &&
+ !nc->info->can_receive(nc)) {
+ return 0;
+ }
+ return 1;
+}
+
int qemu_can_send_packet(NetClientState *sender)
{
int vm_running = runstate_is_running();
@@ -541,13 +552,7 @@ int qemu_can_send_packet(NetClientState *sender)
return 1;
}
- if (sender->peer->receive_disabled) {
- return 0;
- } else if (sender->peer->info->can_receive &&
- !sender->peer->info->can_receive(sender->peer)) {
- return 0;
- }
- return 1;
+ return qemu_can_receive_packet(sender->peer);
}
static ssize_t filter_receive_iov(NetClientState *nc,
@@ -680,6 +685,25 @@ ssize_t qemu_send_packet(NetClientState *nc, const uint8_t *buf, int size)
return qemu_send_packet_async(nc, buf, size, NULL);
}
+ssize_t qemu_receive_packet(NetClientState *nc, const uint8_t *buf, int size)
+{
+ if (!qemu_can_receive_packet(nc)) {
+ return 0;
+ }
+
+ return qemu_net_queue_receive(nc->incoming_queue, buf, size);
+}
+
+ssize_t qemu_receive_packet_iov(NetClientState *nc, const struct iovec *iov,
+ int iovcnt)
+{
+ if (!qemu_can_receive_packet(nc)) {
+ return 0;
+ }
+
+ return qemu_net_queue_receive_iov(nc->incoming_queue, iov, iovcnt);
+}
+
ssize_t qemu_send_packet_raw(NetClientState *nc, const uint8_t *buf, int size)
{
return qemu_send_packet_async_with_flags(nc, QEMU_NET_PACKET_FLAG_RAW,
diff --git a/net/queue.c b/net/queue.c
index 19e32c80fd..c872d51df8 100644
--- a/net/queue.c
+++ b/net/queue.c
@@ -182,6 +182,28 @@ static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
return ret;
}
+ssize_t qemu_net_queue_receive(NetQueue *queue,
+ const uint8_t *data,
+ size_t size)
+{
+ if (queue->delivering) {
+ return 0;
+ }
+
+ return qemu_net_queue_deliver(queue, NULL, 0, data, size);
+}
+
+ssize_t qemu_net_queue_receive_iov(NetQueue *queue,
+ const struct iovec *iov,
+ int iovcnt)
+{
+ if (queue->delivering) {
+ return 0;
+ }
+
+ return qemu_net_queue_deliver_iov(queue, NULL, 0, iov, iovcnt);
+}
+
ssize_t qemu_net_queue_send(NetQueue *queue,
NetClientState *sender,
unsigned flags,
--
2.30.2
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