diff options
Diffstat (limited to 'meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch')
-rw-r--r-- | meta/recipes-devtools/qemu/qemu/CVE-2021-20196.patch | 62 |
1 files changed, 62 insertions, 0 deletions
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 @@ | |||
1 | From 94608c59045791dfd35102bc59b792e96f2cfa30 Mon Sep 17 00:00:00 2001 | ||
2 | From: Vivek Kumbhar <vkumbhar@mvista.com> | ||
3 | Date: Tue, 29 Nov 2022 15:57:13 +0530 | ||
4 | Subject: [PATCH] CVE-2021-20196 | ||
5 | |||
6 | Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/1ab95af033a419e7a64e2d58e67dd96b20af5233] | ||
7 | CVE: CVE-2021-20196 | ||
8 | Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com> | ||
9 | |||
10 | hw/block/fdc: Kludge missing floppy drive to fix CVE-2021-20196 | ||
11 | |||
12 | Guest might select another drive on the bus by setting the | ||
13 | DRIVE_SEL bit of the DIGITAL OUTPUT REGISTER (DOR). | ||
14 | The current controller model doesn't expect a BlockBackend | ||
15 | to be NULL. A simple way to fix CVE-2021-20196 is to create | ||
16 | an empty BlockBackend when it is missing. All further | ||
17 | accesses will be safely handled, and the controller state | ||
18 | machines keep behaving correctly. | ||
19 | --- | ||
20 | hw/block/fdc.c | 19 ++++++++++++++++++- | ||
21 | 1 file changed, 18 insertions(+), 1 deletion(-) | ||
22 | |||
23 | diff --git a/hw/block/fdc.c b/hw/block/fdc.c | ||
24 | index ac5d31e8..e128e975 100644 | ||
25 | --- a/hw/block/fdc.c | ||
26 | +++ b/hw/block/fdc.c | ||
27 | @@ -58,6 +58,11 @@ | ||
28 | } \ | ||
29 | } while (0) | ||
30 | |||
31 | +/* Anonymous BlockBackend for empty drive */ | ||
32 | +static BlockBackend *blk_create_empty_drive(void) | ||
33 | +{ | ||
34 | + return blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL); | ||
35 | +} | ||
36 | |||
37 | /********************************************************/ | ||
38 | /* qdev floppy bus */ | ||
39 | @@ -1356,7 +1361,19 @@ static FDrive *get_drv(FDCtrl *fdctrl, int unit) | ||
40 | |||
41 | static FDrive *get_cur_drv(FDCtrl *fdctrl) | ||
42 | { | ||
43 | - return get_drv(fdctrl, fdctrl->cur_drv); | ||
44 | + FDrive *cur_drv = get_drv(fdctrl, fdctrl->cur_drv); | ||
45 | + | ||
46 | + if (!cur_drv->blk) { | ||
47 | + /* | ||
48 | + * Kludge: empty drive line selected. Create an anonymous | ||
49 | + * BlockBackend to avoid NULL deref with various BlockBackend | ||
50 | + * API calls within this model (CVE-2021-20196). | ||
51 | + * Due to the controller QOM model limitations, we don't | ||
52 | + * attach the created to the controller device. | ||
53 | + */ | ||
54 | + cur_drv->blk = blk_create_empty_drive(); | ||
55 | + } | ||
56 | + return cur_drv; | ||
57 | } | ||
58 | |||
59 | /* Status A register : 0x00 (read-only) */ | ||
60 | -- | ||
61 | 2.25.1 | ||
62 | |||