From: Vivek Kumbhar <vkumb...@mvista.com> Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/1ab95af033a419e7a64e2d58e67dd96b20af5233]
Signed-off-by: Vivek Kumbhar <vkumb...@mvista.com> Signed-off-by: Steve Sakoman <st...@sakoman.com> --- meta/recipes-devtools/qemu/qemu.inc | 1 + .../qemu/qemu/CVE-2021-20196.patch | 62 +++++++++++++++++++ 2 files changed, 63 insertions(+) create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc index 764f948a28..a915b54c1a 100644 --- a/meta/recipes-devtools/qemu/qemu.inc +++ b/meta/recipes-devtools/qemu/qemu.inc @@ -113,6 +113,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \ file://CVE-2022-0216-2.patch \ file://CVE-2021-3750.patch \ file://CVE-2021-3638.patch \ + file://CVE-2021-20196.patch \ " UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar" diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch b/meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch new file mode 100644 index 0000000000..e9b815740f --- /dev/null +++ b/meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch @@ -0,0 +1,62 @@ +From 94608c59045791dfd35102bc59b792e96f2cfa30 Mon Sep 17 00:00:00 2001 +From: Vivek Kumbhar <vkumb...@mvista.com> +Date: Tue, 29 Nov 2022 15:57:13 +0530 +Subject: [PATCH] CVE-2021-20196 + +Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/1ab95af033a419e7a64e2d58e67dd96b20af5233] +CVE: CVE-2021-20196 +Signed-off-by: Vivek Kumbhar <vkumb...@mvista.com> + +hw/block/fdc: Kludge missing floppy drive to fix CVE-2021-20196 + +Guest might select another drive on the bus by setting the +DRIVE_SEL bit of the DIGITAL OUTPUT REGISTER (DOR). +The current controller model doesn't expect a BlockBackend +to be NULL. A simple way to fix CVE-2021-20196 is to create +an empty BlockBackend when it is missing. All further +accesses will be safely handled, and the controller state +machines keep behaving correctly. +--- + hw/block/fdc.c | 19 ++++++++++++++++++- + 1 file changed, 18 insertions(+), 1 deletion(-) + +diff --git a/hw/block/fdc.c b/hw/block/fdc.c +index ac5d31e8..e128e975 100644 +--- a/hw/block/fdc.c ++++ b/hw/block/fdc.c +@@ -58,6 +58,11 @@ + } \ + } while (0) + ++/* Anonymous BlockBackend for empty drive */ ++static BlockBackend *blk_create_empty_drive(void) ++{ ++ return blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL); ++} + + /********************************************************/ + /* qdev floppy bus */ +@@ -1356,7 +1361,19 @@ static FDrive *get_drv(FDCtrl *fdctrl, int unit) + + static FDrive *get_cur_drv(FDCtrl *fdctrl) + { +- return get_drv(fdctrl, fdctrl->cur_drv); ++ FDrive *cur_drv = get_drv(fdctrl, fdctrl->cur_drv); ++ ++ if (!cur_drv->blk) { ++ /* ++ * Kludge: empty drive line selected. Create an anonymous ++ * BlockBackend to avoid NULL deref with various BlockBackend ++ * API calls within this model (CVE-2021-20196). ++ * Due to the controller QOM model limitations, we don't ++ * attach the created to the controller device. ++ */ ++ cur_drv->blk = blk_create_empty_drive(); ++ } ++ return cur_drv; + } + + /* Status A register : 0x00 (read-only) */ +-- +2.25.1 + -- 2.25.1
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