Imported Upstream version 93u+upstream

1 files changed, 71 insertions, 0 deletions

diff --git a/src/lib/libast/preroot/ispreroot.c b/src/lib/libast/preroot/ispreroot.c
new file mode 100644
index 0000000..36bf62c
--- /dev/null
+++ b/src/lib/libast/preroot/ispreroot.c
@@ -0,0 +1,71 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
+*                      and is licensed under the                       *
+*                 Eclipse Public License, Version 1.0                  *
+*                    by AT&T Intellectual Property                     *
+*                                                                      *
+*                A copy of the License is available at                 *
+*          http://www.eclipse.org/org/documents/epl-v10.html           *
+*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
+*                                                                      *
+*              Information and Software Systems Research               *
+*                            AT&T Research                             *
+*                           Florham Park NJ                            *
+*                                                                      *
+*                 Glenn Fowler <gsf@research.att.com>                  *
+*                  David Korn <dgk@research.att.com>                   *
+*                   Phong Vo <kpv@research.att.com>                    *
+*                                                                      *
+***********************************************************************/
+#pragma prototyped
+/*
+ * AT&T Bell Laboratories
+ * return 1 if dir [any dir] is the preroot
+ */
+
+#include <ast.h>
+#include <preroot.h>
+
+#if FS_PREROOT
+
+#include <ls.h>
+
+/*
+ * return 1 if files a and b are the same under preroot
+ *
+ * NOTE: the kernel disables preroot for set-uid processes
+ */
+
+static int
+same(const char* a, const char* b)
+{
+	int		i;
+	int		euid;
+	int		ruid;
+
+	struct stat	ast;
+	struct stat	bst;
+
+	if ((ruid = getuid()) != (euid = geteuid())) setuid(ruid);
+	i = !stat(a, &ast) && !stat(b, &bst) && ast.st_dev == bst.st_dev && ast.st_ino == bst.st_ino;
+	if (ruid != euid) setuid(euid);
+	return(i);
+}
+
+int
+ispreroot(const char* dir)
+{
+	static int	prerooted = -1;
+
+	if (dir) return(same("/", dir));
+	if (prerooted < 0) prerooted = !same("/", PR_REAL);
+	return(prerooted);
+}
+
+#else
+
+NoN(ispreroot)
+
+#endif