CVE-2021-20257 QEMU: net: e1000: infinite loop while processing transmit descriptors

[P J P <ppandit () redhat com>]

  Hello,

An infinite loop issue was found in the e1000 NIC emulator of the QEMU. It 
occurs while processing transmit (tx) descriptors in process_tx_desc, if 
various descriptor fields are initialised with invalid values. A guest may use 
this flaw to consume cpu cycles on the host resulting in DoS scenario.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg07428.html

'CVE-2021-20257' assigned by Red Hat Inc.

This issue was independently reported by Sergej Schumilo, Cornelius 
Aschermann, Simon Werner of Ruhr-University Bochum; Cheolwoo Myung of Seoul 
National University; And Alexander Bulekov (CC'd).


Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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