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net: introduce qemu_receive_packet()

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Fix CVE-2021-3416

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 use qemu_net_queue_send() here since for loop
back 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.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jiajie Li <lijiajie11@huawei.com>
This commit is contained in:
Chen Qun 2021-05-14 10:14:02 +08:00
parent 39931380cb
commit 775c850c1f
1 changed files with 167 additions and 0 deletions
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167
net-introduce-qemu_receive_packet.patch Normal file
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@ -0,0 +1,167 @@
From f34f6b6e78b8b3f401cc31a0d7c06a1c9ea9ad08 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Fri, 14 May 2021 10:14:02 +0800
Subject: [PATCH] net: introduce qemu_receive_packet()
Fix CVE-2021-3416
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 use qemu_net_queue_send() here since for loop
back 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.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jiajie Li <lijiajie11@huawei.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 acf0451fc4..5609b2ecba 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -143,12 +143,17 @@ 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 7d4098254f..3b5631879c 100644
--- a/net/net.c
+++ b/net/net.c
@@ -514,6 +514,17 @@ 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();
@@ -526,13 +537,7 @@ 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,
@@ -665,6 +670,25 @@ 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 61276ca4be..7c0b72c8ef 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,
--
2.27.0