In commits like 969e50b61a ("net: Pad short frames to minimum size
before sending from SLiRP/TAP") we switched away from requiring
network devices to handle short frames to instead having the net core
code do the padding of short frames out to the ETH_ZLEN minimum size.
We then dropped the code for handling short frames from the network
devices in a series of commits like 140eae9c8f ("hw/net: e1000:
Remove the logic of padding short frames in the receive path").
This missed one route where the device's receive code can still see a
short frame: if the device is in loopback mode and it transmits a
short frame via the qemu_receive_packet() function, this will be fed
back into its own receive code without being padded.
Add the padding logic to qemu_receive_packet().
This fixes a buffer overrun which can be triggered in the
e1000_receive_iov() logic via the loopback code path.
Other devices that use qemu_receive_packet() to implement loopback
are cadence_gem, dp8393x, lan9118, msf2-emac, pcnet, rtl8139
and sungem.
Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3043
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
a01344d9d7