From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2315AC433B4 for ; Wed, 19 May 2021 00:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03A0E613AC for ; Wed, 19 May 2021 00:51:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352899AbhESAw1 (ORCPT ); Tue, 18 May 2021 20:52:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352873AbhESAu6 (ORCPT ); Tue, 18 May 2021 20:50:58 -0400 Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [IPv6:2607:5300:60:148a::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D89EAC061760; Tue, 18 May 2021 17:49:39 -0700 (PDT) Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94 #2 (Red Hat Linux)) id 1ljAOU-00G4GG-Mm; Wed, 19 May 2021 00:49:02 +0000 From: Al Viro To: Linus Torvalds Cc: Jia He , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Jonathan Corbet , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , "Eric W . Biederman" , "Darrick J. Wong" , "Peter Zijlstra (Intel)" , Ira Weiny , Eric Biggers , "Ahmed S. Darwish" , "open list:DOCUMENTATION" , Linux Kernel Mailing List , linux-s390 , linux-fsdevel Subject: [PATCH 14/14] getcwd(2): clean up error handling Date: Wed, 19 May 2021 00:49:01 +0000 Message-Id: <20210519004901.3829541-14-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210519004901.3829541-1-viro@zeniv.linux.org.uk> References: <20210519004901.3829541-1-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Signed-off-by: Al Viro --- fs/d_path.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) diff --git a/fs/d_path.c b/fs/d_path.c index 8a9cd44f6689..23a53f7b5c71 100644 --- a/fs/d_path.c +++ b/fs/d_path.c @@ -390,9 +390,11 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) rcu_read_lock(); get_fs_root_and_pwd_rcu(current->fs, &root, &pwd); - error = -ENOENT; - if (!d_unlinked(pwd.dentry)) { - unsigned long len; + if (unlikely(d_unlinked(pwd.dentry))) { + rcu_read_unlock(); + error = -ENOENT; + } else { + unsigned len; DECLARE_BUFFER(b, page, PATH_MAX); prepend(&b, "", 1); @@ -400,23 +402,16 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) prepend(&b, "(unreachable)", 13); rcu_read_unlock(); - if (b.len < 0) { - error = -ENAMETOOLONG; - goto out; - } - - error = -ERANGE; len = PATH_MAX - b.len; - if (len <= size) { + if (unlikely(len > PATH_MAX)) + error = -ENAMETOOLONG; + else if (unlikely(len > size)) + error = -ERANGE; + else if (copy_to_user(buf, b.buf, len)) + error = -EFAULT; + else error = len; - if (copy_to_user(buf, b.buf, len)) - error = -EFAULT; - } - } else { - rcu_read_unlock(); } - -out: __putname(page); return error; } -- 2.11.0