qemu: fix CVE-2020-13800

(From OE-Core rev: 2c5f827b285c465fb6eb1d2aff9ec1f4e56cb202)

Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 64 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index a9ef3b78bf..618cc50180 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -34,6 +34,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://CVE-2020-10761.patch \
            file://CVE-2020-13362.patch \
            file://CVE-2020-13659.patch \
+           file://CVE-2020-13800.patch \
            "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2020-13800.patch b/meta/recipes-devtools/qemu/qemu/CVE-2020-13800.patch
new file mode 100644
index 0000000000..52bfafbbae
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/CVE-2020-13800.patch
@@ -0,0 +1,63 @@
+From a98610c429d52db0937c1e48659428929835c455 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Thu, 4 Jun 2020 14:38:30 +0530
+Subject: [PATCH] ati-vga: check mm_index before recursive call
+ (CVE-2020-13800)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+While accessing VGA registers via ati_mm_read/write routines,
+a guest may set 's->regs.mm_index' such that it leads to infinite
+recursion. Check mm_index value to avoid such recursion. Log an
+error message for wrong values.
+
+Reported-by: Ren Ding <rding@gatech.edu>
+Reported-by: Hanqing Zhao <hanqing@gatech.edu>
+Reported-by: Yi Ren <c4tren@gmail.com>
+Message-id: 20200604090830.33885-1-ppandit@redhat.com
+Suggested-by: BALATON Zoltan <balaton@eik.bme.hu>
+Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
+
+Upstream-Status: Backport [a98610c429d52db0937c1e48659428929835c455]
+CVE: CVE-2020-13800
+Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
+---
+ hw/display/ati.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/hw/display/ati.c b/hw/display/ati.c
+index 065f197678..67604e68de 100644
+--- a/hw/display/ati.c
++++ b/hw/display/ati.c
+@@ -285,8 +285,11 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size)
+             if (idx <= s->vga.vram_size - size) {
+                 val = ldn_le_p(s->vga.vram_ptr + idx, size);
+             }
+-        } else {
++        } else if (s->regs.mm_index > MM_DATA + 3) {
+             val = ati_mm_read(s, s->regs.mm_index + addr - MM_DATA, size);
++        } else {
++            qemu_log_mask(LOG_GUEST_ERROR,
++                "ati_mm_read: mm_index too small: %u\n", s->regs.mm_index);
+         }
+         break;
+     case BIOS_0_SCRATCH ... BUS_CNTL - 1:
+@@ -520,8 +523,11 @@ static void ati_mm_write(void *opaque, hwaddr addr,
+             if (idx <= s->vga.vram_size - size) {
+                 stn_le_p(s->vga.vram_ptr + idx, size, data);
+             }
+-        } else {
++        } else if (s->regs.mm_index > MM_DATA + 3) {
+             ati_mm_write(s, s->regs.mm_index + addr - MM_DATA, data, size);
++        } else {
++            qemu_log_mask(LOG_GUEST_ERROR,
++                "ati_mm_write: mm_index too small: %u\n", s->regs.mm_index);
+         }
+         break;
+     case BIOS_0_SCRATCH ... BUS_CNTL - 1:
+-- 
+2.20.1
+