From owner-svn-src-all@freebsd.org  Wed Sep  4 04:44:03 2019
Return-Path: <owner-svn-src-all@freebsd.org>
Delivered-To: svn-src-all@mailman.nyi.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.nyi.freebsd.org (Postfix) with ESMTP id BFA2DE4724;
 Wed,  4 Sep 2019 04:44:03 +0000 (UTC)
 (envelope-from delphij@FreeBSD.org)
Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org
 [IPv6:2610:1c1:1:606c::19:3])
 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
 server-signature RSA-PSS (4096 bits)
 client-signature RSA-PSS (4096 bits) client-digest SHA256)
 (Client CN "mxrelay.nyi.freebsd.org",
 Issuer "Let's Encrypt Authority X3" (verified OK))
 by mx1.freebsd.org (Postfix) with ESMTPS id 46NWS34hZ1z3JyX;
 Wed,  4 Sep 2019 04:44:03 +0000 (UTC)
 (envelope-from delphij@FreeBSD.org)
Received: from repo.freebsd.org (repo.freebsd.org
 [IPv6:2610:1c1:1:6068::e6a:0])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 85A5BE4A4;
 Wed,  4 Sep 2019 04:44:03 +0000 (UTC)
 (envelope-from delphij@FreeBSD.org)
Received: from repo.freebsd.org ([127.0.1.37])
 by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x844i3An093001;
 Wed, 4 Sep 2019 04:44:03 GMT (envelope-from delphij@FreeBSD.org)
Received: (from delphij@localhost)
 by repo.freebsd.org (8.15.2/8.15.2/Submit) id x844i369093000;
 Wed, 4 Sep 2019 04:44:03 GMT (envelope-from delphij@FreeBSD.org)
Message-Id: <201909040444.x844i369093000@repo.freebsd.org>
X-Authentication-Warning: repo.freebsd.org: delphij set sender to
 delphij@FreeBSD.org using -f
From: Xin LI <delphij@FreeBSD.org>
Date: Wed, 4 Sep 2019 04:44:03 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r351802 - head/sbin/fsck_msdosfs
X-SVN-Group: head
X-SVN-Commit-Author: delphij
X-SVN-Commit-Paths: head/sbin/fsck_msdosfs
X-SVN-Commit-Revision: 351802
X-SVN-Commit-Repository: base
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-all@freebsd.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "SVN commit messages for the entire src tree \(except for &quot;
 user&quot; and &quot; projects&quot; \)" <svn-src-all.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-all/>
List-Post: <mailto:svn-src-all@freebsd.org>
List-Help: <mailto:svn-src-all-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-all>,
 <mailto:svn-src-all-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 04 Sep 2019 04:44:03 -0000

Author: delphij
Date: Wed Sep  4 04:44:03 2019
New Revision: 351802
URL: https://svnweb.freebsd.org/changeset/base/351802

Log:
  Correct overflow logic in fullpath().
  
  Obtained from:	OpenBSD
  MFC after:	3 days

Modified:
  head/sbin/fsck_msdosfs/dir.c

Modified: head/sbin/fsck_msdosfs/dir.c
==============================================================================
--- head/sbin/fsck_msdosfs/dir.c	Wed Sep  4 04:38:31 2019	(r351801)
+++ head/sbin/fsck_msdosfs/dir.c	Wed Sep  4 04:44:03 2019	(r351802)
@@ -169,20 +169,24 @@ fullpath(struct dosDirEntry *dir)
 	char *cp, *np;
 	int nl;
 
-	cp = namebuf + sizeof namebuf - 1;
-	*cp = '\0';
-	do {
+	cp = namebuf + sizeof namebuf;
+	*--cp = '\0';
+
+	for(;;) {
 		np = dir->lname[0] ? dir->lname : dir->name;
 		nl = strlen(np);
-		if ((cp -= nl) <= namebuf + 1)
+		if (cp <= namebuf + 1 + nl) {
+			*--cp = '?';
 			break;
+		}
+		cp -= nl;
 		memcpy(cp, np, nl);
+		dir = dir->parent;
+		if (!dir)
+			break;
 		*--cp = '/';
-	} while ((dir = dir->parent) != NULL);
-	if (dir)
-		*--cp = '?';
-	else
-		cp++;
+	}
+
 	return cp;
 }