From c2cb511634012344e3d0fe49a037a33b12d8a98a Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Wed, 11 Nov 2020 18:36:36 +0530 Subject: [PATCH] hw/net/e1000e: advance desc_offset in case of null descriptor While receiving packets via e1000e_write_packet_to_guest() routine, 'desc_offset' is advanced only when RX descriptor is processed. And RX descriptor is not processed if it has NULL buffer address. This may lead to an infinite loop condition. Increament 'desc_offset' to process next descriptor in the ring to avoid infinite loop. Reported-by: Cheol-woo Myung <330cjfdn@gmail.com> Signed-off-by: Prasad J Pandit Signed-off-by: Jason Wang Upstream-Status: Backport CVE: CVE-2020-28916 Signed-off-by: Armin Kuster --- hw/net/e1000e_core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c index d8b9e4b2f4..095c01ebc6 100644 --- a/hw/net/e1000e_core.c +++ b/hw/net/e1000e_core.c @@ -1596,13 +1596,13 @@ e1000e_write_packet_to_guest(E1000ECore *core, struct NetRxPkt *pkt, (const char *) &fcs_pad, e1000x_fcs_len(core->mac)); } } - desc_offset += desc_size; - if (desc_offset >= total_size) { - is_last = true; - } } else { /* as per intel docs; skip descriptors with null buf addr */ trace_e1000e_rx_null_descriptor(); } + desc_offset += desc_size; + if (desc_offset >= total_size) { + is_last = true; + } e1000e_write_rx_descr(core, desc, is_last ? core->rx_pkt : NULL, rss_info, do_ps ? ps_hdr_len : 0, &bastate.written); -- 2.25.1