From owner-svn-src-stable@freebsd.org Sat Mar 18 23:55:51 2017 Return-Path: Delivered-To: svn-src-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 7D519D12578; Sat, 18 Mar 2017 23:55:51 +0000 (UTC) (envelope-from trasz@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 mx1.freebsd.org (Postfix) with ESMTPS id 27BC71F43; Sat, 18 Mar 2017 23:55:51 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id v2INtoS1005803; Sat, 18 Mar 2017 23:55:50 GMT (envelope-from trasz@FreeBSD.org) Received: (from trasz@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id v2INtoD5005802; Sat, 18 Mar 2017 23:55:50 GMT (envelope-from trasz@FreeBSD.org) Message-Id: <201703182355.v2INtoD5005802@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: trasz set sender to trasz@FreeBSD.org using -f From: Edward Tomasz Napierala Date: Sat, 18 Mar 2017 23:55:50 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r315519 - stable/11/sys/kern X-SVN-Group: stable-11 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 18 Mar 2017 23:55:51 -0000 Author: trasz Date: Sat Mar 18 23:55:50 2017 New Revision: 315519 URL: https://svnweb.freebsd.org/changeset/base/315519 Log: MFC r311284: Fix bug that would result in a kernel crash in some cases involving a symlink and an autofs mount request. The crash was caused by namei() calling bcopy() with a negative length, caused by numeric underflow: in lookup(), in the relookup path, the ni_pathlen was decremented too many times. The bug was introduced in r296715. Big thanks to Alex Deiter for his help with debugging this. Modified: stable/11/sys/kern/vfs_lookup.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/kern/vfs_lookup.c ============================================================================== --- stable/11/sys/kern/vfs_lookup.c Sat Mar 18 23:37:00 2017 (r315518) +++ stable/11/sys/kern/vfs_lookup.c Sat Mar 18 23:55:50 2017 (r315519) @@ -622,11 +622,13 @@ needs_exclusive_leaf(struct mount *mp, i int lookup(struct nameidata *ndp) { - char *cp; /* pointer into pathname argument */ + char *cp; /* pointer into pathname argument */ + char *prev_ni_next; /* saved ndp->ni_next */ struct vnode *dp = NULL; /* the directory we are searching */ struct vnode *tdp; /* saved dp */ struct mount *mp; /* mount table entry */ struct prison *pr; + size_t prev_ni_pathlen; /* saved ndp->ni_pathlen */ int docache; /* == 0 do not cache last component */ int wantparent; /* 1 => wantparent or lockparent flag */ int rdonly; /* lookup read-only flag bit */ @@ -688,7 +690,11 @@ dirloop: printf("{%s}: ", cnp->cn_nameptr); *cp = c; } #endif + prev_ni_pathlen = ndp->ni_pathlen; ndp->ni_pathlen -= cnp->cn_namelen; + KASSERT(ndp->ni_pathlen <= PATH_MAX, + ("%s: ni_pathlen underflow to %zd\n", __func__, ndp->ni_pathlen)); + prev_ni_next = ndp->ni_next; ndp->ni_next = cp; /* @@ -1009,6 +1015,8 @@ nextname: ("lookup: invalid path state.")); if (relookup) { relookup = 0; + ndp->ni_pathlen = prev_ni_pathlen; + ndp->ni_next = prev_ni_next; if (ndp->ni_dvp != dp) vput(ndp->ni_dvp); else