From 33a28349a7f394d364003c68aa806ee87562187d Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Mon, 21 Jan 2019 03:47:20 +0000
Subject: [PATCH] Revert r343117.

It breaks the special mode specified by passing "-" as one of the
input files.  Revert for now while we discuss a fix.

PR:		234885
Reported by:	delphij
MFC after:	now
---
 usr.bin/cmp/cmp.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/usr.bin/cmp/cmp.c b/usr.bin/cmp/cmp.c
index dcf32a98dcc7..b8d5dba14ec4 100644
--- a/usr.bin/cmp/cmp.c
+++ b/usr.bin/cmp/cmp.c
@@ -116,16 +116,14 @@ main(int argc, char *argv[])
 	if (argc < 2 || argc > 4)
 		usage();
 
-	if (caph_limit_stdio() == -1)
-		err(ERR_EXIT, "failed to limit stdio");
-
 	/* Backward compatibility -- handle "-" meaning stdin. */
 	special = 0;
 	if (strcmp(file1 = argv[0], "-") == 0) {
 		special = 1;
-		fd1 = STDIN_FILENO;
+		fd1 = 0;
 		file1 = "stdin";
-	} else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
+	}
+	else if ((fd1 = open(file1, oflag, 0)) < 0 && errno != EMLINK) {
 		if (!sflag)
 			err(ERR_EXIT, "%s", file1);
 		else
@@ -136,9 +134,10 @@ main(int argc, char *argv[])
 			errx(ERR_EXIT,
 				"standard input may only be specified once");
 		special = 1;
-		fd2 = STDIN_FILENO;
+		fd2 = 0;
 		file2 = "stdin";
-	} else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
+	}
+	else if ((fd2 = open(file2, oflag, 0)) < 0 && errno != EMLINK) {
 		if (!sflag)
 			err(ERR_EXIT, "%s", file2);
 		else
@@ -176,6 +175,16 @@ main(int argc, char *argv[])
 	if (caph_fcntls_limit(fd2, fcntls) < 0)
 		err(ERR_EXIT, "unable to limit fcntls for %s", file2);
 
+	if (!special) {
+		cap_rights_init(&rights);
+		if (caph_rights_limit(STDIN_FILENO, &rights) < 0) {
+			err(ERR_EXIT, "unable to limit stdio");
+		}
+	}
+
+	if (caph_limit_stdout() == -1 || caph_limit_stderr() == -1)
+		err(ERR_EXIT, "unable to limit stdio");
+
 	caph_cache_catpages();
 
 	if (caph_enter() < 0)