* [PATCH AUTOSEL 5.11 16/51] gpu/xen: Fix a use after free in xen_drm_drv_init
[not found] <20210412162256.313524-1-sashal@kernel.org>
@ 2021-04-12 16:22 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2021-04-12 16:22 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Lv Yunlong, Oleksandr Andrushchenko, Sasha Levin, dri-devel, xen-devel
From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
[ Upstream commit 52762efa2b256ed1c5274e5177cbd52ee11a2f6a ]
In function displback_changed, has the call chain
displback_connect(front_info)->xen_drm_drv_init(front_info).
We can see that drm_info is assigned to front_info->drm_info
and drm_info is freed in fail branch in xen_drm_drv_init().
Later displback_disconnect(front_info) is called and it calls
xen_drm_drv_fini(front_info) cause a use after free by
drm_info = front_info->drm_info statement.
My patch has done two things. First fixes the fail label which
drm_info = kzalloc() failed and still free the drm_info.
Second sets front_info->drm_info to NULL to avoid uaf.
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323014656.10068-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/xen/xen_drm_front.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
index 30d9adf31c84..9f14d99c763c 100644
--- a/drivers/gpu/drm/xen/xen_drm_front.c
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -521,7 +521,7 @@ static int xen_drm_drv_init(struct xen_drm_front_info *front_info)
drm_dev = drm_dev_alloc(&xen_drm_driver, dev);
if (IS_ERR(drm_dev)) {
ret = PTR_ERR(drm_dev);
- goto fail;
+ goto fail_dev;
}
drm_info->drm_dev = drm_dev;
@@ -551,8 +551,10 @@ static int xen_drm_drv_init(struct xen_drm_front_info *front_info)
drm_kms_helper_poll_fini(drm_dev);
drm_mode_config_cleanup(drm_dev);
drm_dev_put(drm_dev);
-fail:
+fail_dev:
kfree(drm_info);
+ front_info->drm_info = NULL;
+fail:
return ret;
}
--
2.30.2
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2021-04-12 16:23 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <20210412162256.313524-1-sashal@kernel.org>
2021-04-12 16:22 ` [PATCH AUTOSEL 5.11 16/51] gpu/xen: Fix a use after free in xen_drm_drv_init Sasha Levin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).