diff options
Diffstat (limited to 'meta/recipes-devtools/qemu/qemu/CVE-2021-20196_2.patch')
| -rw-r--r-- | meta/recipes-devtools/qemu/qemu/CVE-2021-20196_2.patch | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2021-20196_2.patch b/meta/recipes-devtools/qemu/qemu/CVE-2021-20196_2.patch new file mode 100644 index 0000000000..dd442ccb8f --- /dev/null +++ b/meta/recipes-devtools/qemu/qemu/CVE-2021-20196_2.patch @@ -0,0 +1,67 @@ +From 1d48445a951fd5504190a38abeda70ea9372cf77 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com> +Date: Wed, 24 Nov 2021 17:15:35 +0100 +Subject: [PATCH 12/12] hw/block/fdc: Kludge missing floppy drive to fix + CVE-2021-20196 +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +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. + +Cc: qemu-stable@nongnu.org +Fixes: CVE-2021-20196 +Reported-by: Gaoning Pan (Ant Security Light-Year Lab) <pgn@zju.edu.cn> +Reviewed-by: Darren Kenny <darren.kenny@oracle.com> +Reviewed-by: Hanna Reitz <hreitz@redhat.com> +Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> +Message-id: 20211124161536.631563-3-philmd@redhat.com +BugLink: https://bugs.launchpad.net/qemu/+bug/1912780 +Resolves: https://gitlab.com/qemu-project/qemu/-/issues/338 +Reviewed-by: Darren Kenny <darren.kenny@oracle.com> +Reviewed-by: Hanna Reitz <hreitz@redhat.com> +Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> +Signed-off-by: John Snow <jsnow@redhat.com> + +Upstream-Status: Backport [1ab95af033a419e7a64e2d58e67dd96b20af5233] +CVE: CVE-2021-20196 + +Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com> +--- + hw/block/fdc.c | 14 +++++++++++++- + 1 file changed, 13 insertions(+), 1 deletion(-) + +diff --git a/hw/block/fdc.c b/hw/block/fdc.c +index 854b4f172..a736c4d14 100644 +--- a/hw/block/fdc.c ++++ b/hw/block/fdc.c +@@ -1365,7 +1365,19 @@ 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) */ +-- +2.31.1 + |