From a0f90c8815706981c483a652a6aefca51a5e191c Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Thu, 27 Jan 2022 18:34:19 +1000 Subject: drm/vmwgfx: Fix stale file descriptors on failed usercopy A failing usercopy of the fence_rep object will lead to a stale entry in the file descriptor table as put_unused_fd() won't release it. This enables userland to refer to a dangling 'file' object through that still valid file descriptor, leading to all kinds of use-after-free exploitation scenarios. Fix this by deferring the call to fd_install() until after the usercopy has succeeded. Fixes: c906965dee22 ("drm/vmwgfx: Add export fence to file descriptor support") Signed-off-by: Mathias Krause Signed-off-by: Zack Rusin Signed-off-by: Dave Airlie Signed-off-by: Linus Torvalds --- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm/vmwgfx/vmwgfx_kms.c') diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c index 4e693e8de2c3..bbd2f4ec08ec 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c @@ -2501,7 +2501,7 @@ void vmw_kms_helper_validation_finish(struct vmw_private *dev_priv, if (file_priv) vmw_execbuf_copy_fence_user(dev_priv, vmw_fpriv(file_priv), ret, user_fence_rep, fence, - handle, -1, NULL); + handle, -1); if (out_fence) *out_fence = fence; else -- cgit v1.2.3