From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932654AbdKONSB (ORCPT ); Wed, 15 Nov 2017 08:18:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:55370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbdKONRx (ORCPT ); Wed, 15 Nov 2017 08:17:53 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EBADD218DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jlayton@kernel.org From: Jeff Layton To: linux-fsdevel@vger.kernel.org Cc: Vitaly Lipatov , hch@lst.de, bfields@fieldses.org, Alexander Viro , linux-kernel@vger.kernel.org Subject: [PATCH] fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscall Date: Wed, 15 Nov 2017 08:17:50 -0500 Message-Id: <20171115131750.27717-1-jlayton@kernel.org> X-Mailer: git-send-email 2.14.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeff Layton Currently, we're capping the values too low in the F_GETLK64 case. The fields in that structure are 64-bit values, so we shouldn't need to any sort of fixup there. Make sure we check that assumption at build time in the future however by ensuring that the sizes we're copying will fit. Fixes: 94073ad77fff2 (fs/locks: don't mess with the address limit in compat_fcntl64) Reported-by: Vitaly Lipatov Signed-off-by: Jeff Layton --- fs/fcntl.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index e15bcc4265d0..0522e283a4f4 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -563,6 +563,9 @@ static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __u { struct compat_flock64 fl; + BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start)); + BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len)); + memset(&fl, 0, sizeof(struct compat_flock64)); copy_flock_fields(&fl, kfl); if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64))) @@ -641,12 +644,8 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, if (err) break; err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock); - if (err) - break; - err = fixup_compat_flock(&flock); - if (err) - return err; - err = put_compat_flock64(&flock, compat_ptr(arg)); + if (!err) + err = put_compat_flock64(&flock, compat_ptr(arg)); break; case F_SETLK: case F_SETLKW: -- 2.14.3