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| author | Lv Yunlong <lyl2019@mail.ustc.edu.cn> | 2021-03-23 02:46:56 +0100 |
|---|---|---|
| committer | Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> | 2021-03-26 06:40:03 +0100 |
| commit | 52762efa2b256ed1c5274e5177cbd52ee11a2f6a (patch) | |
| tree | 3487d388c1c06ab4ccc8c61ee04b727520c9f335 /drivers/gpu/drm/xen | |
| parent | drm/etnaviv: User FOLL_LONGTERM in userptr (diff) | |
| download | linux-52762efa2b256ed1c5274e5177cbd52ee11a2f6a.tar.xz linux-52762efa2b256ed1c5274e5177cbd52ee11a2f6a.zip | |
gpu/xen: Fix a use after free in xen_drm_drv_init
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
Diffstat (limited to 'drivers/gpu/drm/xen')
| -rw-r--r-- | drivers/gpu/drm/xen/xen_drm_front.c | 6 |
1 files 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 @@ fail_modeset: 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; } |