* [PATCH] gpu/xen: Fix a use after free in xen_drm_drv_init
@ 2021-03-23 1:46 ` Lv Yunlong
0 siblings, 0 replies; 4+ messages in thread
From: Lv Yunlong @ 2021-03-23 1:46 UTC (permalink / raw)
To: oleksandr_andrushchenko, airlied, daniel
Cc: dri-devel, xen-devel, linux-kernel, Lv Yunlong
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>
---
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;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] gpu/xen: Fix a use after free in xen_drm_drv_init
@ 2021-03-23 1:46 ` Lv Yunlong
0 siblings, 0 replies; 4+ messages in thread
From: Lv Yunlong @ 2021-03-23 1:46 UTC (permalink / raw)
To: oleksandr_andrushchenko, airlied, daniel
Cc: xen-devel, Lv Yunlong, linux-kernel, dri-devel
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>
---
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;
}
--
2.25.1
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] gpu/xen: Fix a use after free in xen_drm_drv_init
2021-03-23 1:46 ` Lv Yunlong
@ 2021-03-25 6:53 ` Oleksandr Andrushchenko
-1 siblings, 0 replies; 4+ messages in thread
From: Oleksandr Andrushchenko @ 2021-03-25 6:53 UTC (permalink / raw)
To: Lv Yunlong, airlied, daniel; +Cc: dri-devel, xen-devel, linux-kernel
Hi,
good catch
On 3/23/21 3:46 AM, Lv Yunlong wrote:
> 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>
Thank you for the patch,
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Will apply to drm-misc-next-fixes
Thank you,
Oleksandr
> ---
> 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;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] gpu/xen: Fix a use after free in xen_drm_drv_init
@ 2021-03-25 6:53 ` Oleksandr Andrushchenko
0 siblings, 0 replies; 4+ messages in thread
From: Oleksandr Andrushchenko @ 2021-03-25 6:53 UTC (permalink / raw)
To: Lv Yunlong, airlied, daniel; +Cc: xen-devel, linux-kernel, dri-devel
Hi,
good catch
On 3/23/21 3:46 AM, Lv Yunlong wrote:
> 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>
Thank you for the patch,
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Will apply to drm-misc-next-fixes
Thank you,
Oleksandr
> ---
> 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;
> }
>
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-03-25 8:15 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-23 1:46 [PATCH] gpu/xen: Fix a use after free in xen_drm_drv_init Lv Yunlong
2021-03-23 1:46 ` Lv Yunlong
2021-03-25 6:53 ` Oleksandr Andrushchenko
2021-03-25 6:53 ` Oleksandr Andrushchenko
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.