From 705df5466c98f3efdd2b68d3b31dad86858acad7 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 24 Feb 2021 11:44:36 +0800 Subject: [PATCH] net: introduce qemu_receive_packet() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Philippe Mathieu-Daudé Cc: qemu-stable@nongnu.org Signed-off-by: Jason Wang --- 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,