qemu: Security fix for CVE-2020-28916

Source: qemu.org
MR: 107262
Type: Security Fix
Disposition: Backport from https://git.qemu.org/?p=qemu.git;a=commit;h=c2cb511634012344e3d0fe49a037a33b12d8a98a
ChangeID: 3024b894ab045c1a74ab2276359d5e599ec9e822
Description:

Affects qemu < 5.0.0

(From OE-Core rev: 55aa94e9185ecd93612c64cdd982a89d633284e2)

Signed-off-by: Armin Kuster <akuster@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 49 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index 3113d638d7..211c03e57b 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -90,6 +90,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://CVE-2020-12829_4.patch \
            file://CVE-2020-12829_5.patch \
            file://CVE-2020-27617.patch \
+           file://CVE-2020-28916.patch \
            "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2020-28916.patch b/meta/recipes-devtools/qemu/qemu/CVE-2020-28916.patch
new file mode 100644
index 0000000000..756b1c1495
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/CVE-2020-28916.patch
@@ -0,0 +1,48 @@
+From c2cb511634012344e3d0fe49a037a33b12d8a98a Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+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 <pjp@fedoraproject.org>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+
+Upstream-Status: Backport
+CVE: CVE-2020-28916
+Signed-off-by: Armin Kuster <akuster@mvista.com>
+
+---
+ 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
+