Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752050AbdITUq5 (ORCPT ); Wed, 20 Sep 2017 16:46:57 -0400 Received: from mail-pg0-f42.google.com ([74.125.83.42]:50516 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751944AbdITUqQ (ORCPT ); Wed, 20 Sep 2017 16:46:16 -0400 X-Google-Smtp-Source: AOwi7QCeaV39ApqN5/uDadByIfJoBIZO0h6zwAzrkO/+0n3gzWBaSZaviVqrhFHp4NCVNd2vhdy7hQ== From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Vlad Yasevich , Neil Horman , "David S. Miller" , linux-sctp@vger.kernel.org, netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Subject: [PATCH v3 22/31] sctp: Copy struct sctp_sock.autoclose to userspace using put_user() Date: Wed, 20 Sep 2017 13:45:28 -0700 Message-Id: <1505940337-79069-23-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1505940337-79069-1-git-send-email-keescook@chromium.org> References: <1505940337-79069-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1392 Lines: 38 From: David Windsor The autoclose field can be copied with put_user(), so there is no need to use copy_to_user(). In both cases, hardened usercopy is being bypassed since the size is constant, and not open to runtime manipulation. This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor [kees: adjust commit log] Cc: Vlad Yasevich Cc: Neil Horman Cc: "David S. Miller" Cc: linux-sctp@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/sctp/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index aa4f86d64545..e070c0934638 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -4893,7 +4893,7 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv len = sizeof(int); if (put_user(len, optlen)) return -EFAULT; - if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int))) + if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval)) return -EFAULT; return 0; } -- 2.7.4