[dunfell] 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

Signed-off-by: Davide Gardenal <davide.gardenal@huawei.com>
---
 meta/recipes-devtools/qemu/qemu.inc           |  1 +
 .../qemu/qemu/CVE-2020-13791.patch            | 40 +++++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch

On Wed, Mar 23, 2022 at 7:02 AM Davide Gardenal
<davidegarde2000@gmail.com> wrote:
>
> Upstream patch:
> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00979.html
>
> CVE: CVE-2020-13791
>
> Signed-off-by: Davide Gardenal <davide.gardenal@huawei.com>
> ---
>  meta/recipes-devtools/qemu/qemu.inc           |  1 +
>  .../qemu/qemu/CVE-2020-13791.patch            | 40 +++++++++++++++++++
>  2 files changed, 41 insertions(+)
>  create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch
>
> diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
> index ef9bc3f64a..01cda49eee 100644
> --- a/meta/recipes-devtools/qemu/qemu.inc
> +++ b/meta/recipes-devtools/qemu/qemu.inc
> @@ -92,6 +92,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
>             file://CVE-2020-27617.patch \
>             file://CVE-2020-28916.patch \
>             file://CVE-2021-3682.patch \
> +           file://CVE-2020-13791.patch \
>             "

Note that there is another CVE fix currently on the list for review
(CVE-2020-13253) so you'll need to rebase with that patch included and
send a v2 since that patch will be merged before yours.

>  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..6026f02e54
> --- /dev/null
> +++ b/meta/recipes-devtools/qemu/qemu/CVE-2020-13791.patch
> @@ -0,0 +1,40 @@
> +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

Also needs the Upstream-status tag and your Signed-off-by

Thanks for helping with CVE's!

Steve

> +
> +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>
> +---
> + 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
> --
> 2.32.0
>
>
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