[PATCH 3.16 173/178] drm/vmwgfx: Make sure backup_handle is always valid
From: Ben Hutchings
Date: Sun Jul 16 2017 - 10:05:36 EST
3.16.46-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Sinclair Yeh <syeh@xxxxxxxxxx>
commit 07678eca2cf9c9a18584e546c2b2a0d0c9a3150c upstream.
When vmw_gb_surface_define_ioctl() is called with an existing buffer,
we end up returning an uninitialized variable in the backup_handle.
The fix is to first initialize backup_handle to 0 just to be sure, and
second, when a user-provided buffer is found, we will use the
req->buffer_handle as the backup_handle.
Reported-by: Murray McAllister <murray.mcallister@xxxxxxxxxxxxxxx>
Signed-off-by: Sinclair Yeh <syeh@xxxxxxxxxx>
Reviewed-by: Deepak Rawat <drawat@xxxxxxxxxx>
[bwh: Backported to 3.16: There's no size check after vmw_user_dmabuf_lookup(),
so only check ret == 0.]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -1245,7 +1245,7 @@ int vmw_gb_surface_define_ioctl(struct d
int ret;
uint32_t size;
const struct svga3d_surface_desc *desc;
- uint32_t backup_handle;
+ uint32_t backup_handle = 0;
if (req->mip_levels > DRM_VMW_MAX_MIP_LEVELS)
return -EINVAL;
@@ -1317,6 +1317,8 @@ int vmw_gb_surface_define_ioctl(struct d
ret = vmw_user_dmabuf_lookup(tfile, req->buffer_handle,
&res->backup,
&user_srf->backup_base);
+ if (ret == 0)
+ backup_handle = req->buffer_handle;
} else if (req->drm_surface_flags &
drm_vmw_surface_flag_create_buffer)
ret = vmw_user_dmabuf_alloc(dev_priv, tfile,