From 3cd1f90972bd3ec39bdcde537e591ae4334eddb3 Mon Sep 17 00:00:00 2001
From: Conrad Meyer <cem@FreeBSD.org>
Date: Wed, 4 Oct 2017 01:12:26 +0000
Subject: [PATCH] chpass(1): Check crypt(3) return and handle error
 appropriately

This change is spiritually similar to the earlier r231994.

PR:		222756
Submitted by:	Lubos Boucek <bouceklubos AT gmail.com>
Obtained from:	DragonflyBSD 2020c8fec4168a5020f984a093224fade3074b25
---
 usr.bin/chpass/chpass.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/usr.bin/chpass/chpass.c b/usr.bin/chpass/chpass.c
index 9f9be5335a68..74c96beb92e7 100644
--- a/usr.bin/chpass/chpass.c
+++ b/usr.bin/chpass/chpass.c
@@ -82,7 +82,7 @@ main(int argc, char *argv[])
 	struct passwd lpw, *old_pw, *pw;
 	int ch, pfd, tfd;
 	const char *password;
-	char *arg = NULL;
+	char *arg = NULL, *cryptpw;
 	uid_t uid;
 #ifdef YP
 	struct ypclnt *ypclnt;
@@ -228,8 +228,8 @@ main(int argc, char *argv[])
 
 	if (old_pw && !master_mode) {
 		password = getpass("Password: ");
-		if (strcmp(crypt(password, old_pw->pw_passwd),
-		    old_pw->pw_passwd) != 0)
+		cryptpw = crypt(password, old_pw->pw_passwd);
+		if (cryptpw == NULL || strcmp(cryptpw, old_pw->pw_passwd) != 0)
 			baduser();
 	} else {
 		password = "";