qemu: backport patch fix for CVE-2020-13791

Upstream patch:
https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00979.html

CVE: CVE-2020-13791

(From OE-Core rev: 6d4e6302fa21b1c663b94b05088ecf9b9d544c0a)

Signed-off-by: Davide Gardenal <davide.gardenal@huawei.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 45 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index 0bdc917783..25c2cdef3a 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -97,6 +97,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://CVE-2020-13253_3.patch \
            file://CVE-2020-13253_4.patch \
            file://CVE-2020-13253_5.patch \
+           file://CVE-2020-13791.patch \
            "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch b/meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch
new file mode 100644
index 0000000000..1e8278f7b7
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch
@@ -0,0 +1,44 @@
+Date:   Thu, 4 Jun 2020 16:25:24 +0530
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Subject:        [PATCH v3] ati-vga: check address before reading configuration bytes (CVE-2020-13791)
+
+While reading PCI configuration bytes, a guest may send an
+address towards the end of the configuration space. It may lead
+to an OOB access issue. Add check to ensure 'address + size' is
+within PCI configuration space.
+
+CVE: CVE-2020-13791
+
+Upstream-Status: Submitted
+https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00979.html
+
+Reported-by: Ren Ding <rding@gatech.edu>
+Reported-by: Hanqing Zhao <hanqing@gatech.edu>
+Reported-by: Yi Ren <c4tren@gmail.com>
+Suggested-by: BALATON Zoltan <balaton@eik.bme.hu>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Signed-off-by: Davide Gardenal <davide.gardenal@huawei.com>
+---
+ hw/display/ati.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+Update v3: avoid modifying 'addr' variable
+  -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00834.html
+
+diff --git a/hw/display/ati.c b/hw/display/ati.c
+index 67604e68de..b4d0fd88b7 100644
+--- a/hw/display/ati.c
++++ b/hw/display/ati.c
+@@ -387,7 +387,9 @@ static uint64_t ati_mm_read(void *opaque, hwaddr addr, unsigned int size)
+         val = s->regs.crtc_pitch;
+         break;
+     case 0xf00 ... 0xfff:
+-        val = pci_default_read_config(&s->dev, addr - 0xf00, size);
++        if ((addr - 0xf00) + size <= pci_config_size(&s->dev)) {
++            val = pci_default_read_config(&s->dev, addr - 0xf00, size);
++        }
+         break;
+     case CUR_OFFSET:
+         val = s->regs.cur_offset;
+-- 
+2.26.2