Jason Wang 25c01bd19d net: drop too large packet early ... We try to detect and drop too large packet (>INT_MAX) in 1592a99470 ("net: ignore packet size greater than INT_MAX") during packet delivering. Unfortunately, this is not sufficient as we may hit another integer overflow when trying to queue such large packet in qemu_net_queue_append_iov(): - size of the allocation may overflow on 32bit - packet->size is integer which may overflow even on 64bit Fixing this by moving the check to qemu_sendv_packet_async() which is the entrance of all networking codes and reduce the limit to NET_BUFSIZE to be more conservative. This works since: - For the callers that call qemu_sendv_packet_async() directly, they only care about if zero is returned to determine whether to prevent the source from producing more packets. A callback will be triggered if peer can accept more then source could be enabled. This is usually used by high speed networking implementation like virtio-net or netmap. - For the callers that call qemu_sendv_packet() that calls qemu_sendv_packet_async() indirectly, they often ignore the return value. In this case qemu will just the drop packets if peer can't receive. Qemu will copy the packet if it was queued. So it was safe for both kinds of the callers to assume the packet was sent. Since we move the check from qemu_deliver_packet_iov() to qemu_sendv_packet_async(), it would be safer to make qemu_deliver_packet_iov() static to prevent any external user in the future. This is a revised patch of CVE-2018-17963. Cc: qemu-stable@nongnu.org Cc: Li Qiang <liq3ea@163.com> Fixes: 1592a99470 ("net: ignore packet size greater than INT_MAX") Reported-by: Li Qiang <liq3ea@gmail.com> Reviewed-by: Li Qiang <liq3ea@gmail.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Message-id: 20181204035347.6148-2-jasowang@redhat.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>		2018-12-04 11:06:15 +00:00
..
can_emu.h	net/can: simple messages transport implementation for QEMU	2018-02-13 11:44:13 +01:00
can_host.h	net/can: simple messages transport implementation for QEMU	2018-02-13 11:44:13 +01:00
checksum.h	net: Transmit zero UDP checksum as 0xFFFF	2017-11-20 11:08:00 +08:00
eth.h	net: fix misaligned member access	2018-03-02 18:44:00 +00:00
filter.h	filter: Add handle_event method for NetFilterClass	2018-10-19 11:15:03 +08:00
net.h	net: drop too large packet early	2018-12-04 11:06:15 +00:00
queue.h	net/queue: export qemu_net_queue_append_iov	2015-10-12 13:31:18 +08:00
slirp.h	net: Remove the deprecated -tftp, -bootp, -redir and -smb options	2018-08-31 09:53:03 +02:00
tap.h	Drop superfluous includes of qapi-types.h and test-qapi-types.h	2018-02-09 05:05:11 +01:00
vhost_net.h	tap: setting error appropriately when calling net_init_tap_one()	2018-03-05 10:30:16 +08:00
vhost-user.h	Clean up ill-advised or unusual header guards	2016-07-12 16:20:46 +02:00