From 64739516a74afb6963d80152262725c6f63b6ed5 Mon Sep 17 00:00:00 2001
From: millert <millert@openbsd.org>
Date: Mon, 23 Dec 1996 04:58:34 +0000
Subject: [PATCH] Avoid spoofing when cd'ing to subdirs.  First cut.

---
 lib/libc/gen/fts.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/lib/libc/gen/fts.c b/lib/libc/gen/fts.c
index 9aa05381a21..99902818f32 100644
--- a/lib/libc/gen/fts.c
+++ b/lib/libc/gen/fts.c
@@ -32,7 +32,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: fts.c,v 1.2 1996/08/19 08:22:59 tholo Exp $";
+static char rcsid[] = "$OpenBSD: fts.c,v 1.3 1996/12/23 04:58:34 millert Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
@@ -336,12 +336,30 @@ fts_read(sp)
 		 * FTS_STOP or the fts_info field of the node.
 		 */
 		if (sp->fts_child) {
-			if (CHDIR(sp, p->fts_accpath)) {
-				p->fts_errno = errno;
-				p->fts_flags |= FTS_DONTCHDIR;
-				for (p = sp->fts_child; p; p = p->fts_link)
-					p->fts_accpath =
-					    p->fts_parent->fts_accpath;
+			if (!ISSET(FTS_NOCHDIR)) {
+				struct stat *parent1, *fts_statp2, *parent2;
+				int ret;
+
+				/* XXX - make readable somehow */
+				if (!ISSET(FTS_NOSTAT) && !ISSET(FTS_LOGICAL))
+					ret = ((lstat(".", parent1) != 0) ||
+					(chdir(p->fts_accpath) != 0) ||
+					(lstat(".", fts_statp2) != 0) ||
+					(lstat("..", parent2) != 0) ||
+					(p->fts_dev != fts_statp2->st_dev) ||
+					(p->fts_ino != fts_statp2->st_ino) ||
+					(parent1->st_dev != parent2->st_dev) ||
+					(parent1->st_ino != parent2->st_ino));
+				else
+					ret = chdir(p->fts_accpath);
+
+				if (ret) {
+					p->fts_errno = errno;
+					p->fts_flags |= FTS_DONTCHDIR;
+					for (p = sp->fts_child; p; p = p->fts_link)
+						p->fts_accpath =
+						    p->fts_parent->fts_accpath;
+				}
 			}
 		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
 			if (ISSET(FTS_STOP))
-- 
2.20.1