From f6364313725f147eb692beaff432376ad879db3f Mon Sep 17 00:00:00 2001
From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Date: Sat, 24 Jul 2021 19:18:24 +0800
Subject: drm/vmwgfx: fix potential UAF in vmwgfx_surface.c
Git-commit: 2bc5da528dd570c5ecabc107e6fbdbc55974276f
Patch-mainline: v5.15-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
drm_file.master should be protected by either drm_device.master_mutex
or drm_file.master_lookup_lock when being dereferenced. However,
drm_master_get is called on unprotected file_priv->master pointers in
vmw_surface_define_ioctl and vmw_gb_surface_define_internal.
This is fixed by replacing drm_master_get with drm_file_get_master.
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Zack Rusin <zackr@vmware.com>
Signed-off-by: Zack Rusin <zackr@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210724111824.59266-4-desmondcheongzx@gmail.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 0eba47762bed..5d53a5f9d123 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -865,7 +865,7 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
user_srf->prime.base.shareable = false;
user_srf->prime.base.tfile = NULL;
if (drm_is_primary_client(file_priv))
- user_srf->master = drm_master_get(file_priv->master);
+ user_srf->master = drm_file_get_master(file_priv);
/**
* From this point, the generic resource management functions
@@ -1534,7 +1534,7 @@ vmw_gb_surface_define_internal(struct drm_device *dev,
user_srf = container_of(srf, struct vmw_user_surface, srf);
if (drm_is_primary_client(file_priv))
- user_srf->master = drm_master_get(file_priv->master);
+ user_srf->master = drm_file_get_master(file_priv);
res = &user_srf->srf.res;
--
2.38.1