Avoid possible null deref if ypclnt_new returns null

PR:		bin/172979
Submitted by:	Erik Cederstrand <erik@cederstrand.dk>
Approved by:	cperciva
MFC after:	3 days

1 files changed, 305 insertions, 0 deletions

diff --git a/chpass/chpass.c b/chpass/chpass.c
new file mode 100644
index 0000000..9f9be53
--- /dev/null
+++ b/chpass/chpass.c
@@ -0,0 +1,305 @@
+/*-
+ * Copyright (c) 1988, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 2002 Networks Associates Technology, Inc.
+ * All rights reserved.
+ *
+ * Portions of this software were developed for the FreeBSD Project by
+ * ThinkSec AS and NAI Labs, the Security Research Division of Network
+ * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
+ * ("CBOSS"), as part of the DARPA CHATS research program.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if 0
+#ifndef lint
+static const char copyright[] =
+"@(#) Copyright (c) 1988, 1993, 1994\n\
+	The Regents of the University of California.  All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)chpass.c	8.4 (Berkeley) 4/2/94";
+#endif /* not lint */
+#endif
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+
+#include <err.h>
+#include <errno.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef YP
+#include <ypclnt.h>
+#endif
+
+#include <pw_scan.h>
+#include <libutil.h>
+
+#include "chpass.h"
+
+int master_mode;
+
+static void	baduser(void);
+static void	usage(void);
+
+int
+main(int argc, char *argv[])
+{
+	enum { NEWSH, LOADENTRY, EDITENTRY, NEWPW, NEWEXP } op;
+	struct passwd lpw, *old_pw, *pw;
+	int ch, pfd, tfd;
+	const char *password;
+	char *arg = NULL;
+	uid_t uid;
+#ifdef YP
+	struct ypclnt *ypclnt;
+	const char *yp_domain = NULL, *yp_host = NULL;
+#endif
+
+	pw = old_pw = NULL;
+	op = EDITENTRY;
+#ifdef YP
+	while ((ch = getopt(argc, argv, "a:p:s:e:d:h:loy")) != -1)
+#else
+	while ((ch = getopt(argc, argv, "a:p:s:e:")) != -1)
+#endif
+		switch (ch) {
+		case 'a':
+			op = LOADENTRY;
+			arg = optarg;
+			break;
+		case 's':
+			op = NEWSH;
+			arg = optarg;
+			break;
+		case 'p':
+			op = NEWPW;
+			arg = optarg;
+			break;
+		case 'e':
+			op = NEWEXP;
+			arg = optarg;
+			break;
+#ifdef YP
+		case 'd':
+			yp_domain = optarg;
+			break;
+		case 'h':
+			yp_host = optarg;
+			break;
+		case 'l':
+		case 'o':
+		case 'y':
+			/* compatibility */
+			break;
+#endif
+		case '?':
+		default:
+			usage();
+		}
+
+	argc -= optind;
+	argv += optind;
+
+	if (argc > 1)
+		usage();
+
+	uid = getuid();
+
+	if (op == EDITENTRY || op == NEWSH || op == NEWPW || op == NEWEXP) {
+		if (argc == 0) {
+			if ((pw = getpwuid(uid)) == NULL)
+				errx(1, "unknown user: uid %lu",
+				    (unsigned long)uid);
+		} else {
+			if ((pw = getpwnam(*argv)) == NULL)
+				errx(1, "unknown user: %s", *argv);
+			if (uid != 0 && uid != pw->pw_uid)
+				baduser();
+		}
+
+		/* Make a copy for later verification */
+		if ((pw = pw_dup(pw)) == NULL ||
+		    (old_pw = pw_dup(pw)) == NULL)
+			err(1, "pw_dup");
+	}
+
+#ifdef YP
+	if (pw != NULL && (pw->pw_fields & _PWF_SOURCE) == _PWF_NIS) {
+		ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_host);
+		master_mode = (ypclnt != NULL &&
+		    ypclnt_connect(ypclnt) != -1 &&
+		    ypclnt_havepasswdd(ypclnt) == 1);
+		ypclnt_free(ypclnt);
+	} else
+#endif
+	master_mode = (uid == 0);
+
+	if (op == NEWSH) {
+		/* protect p_shell -- it thinks NULL is /bin/sh */
+		if (!arg[0])
+			usage();
+		if (p_shell(arg, pw, (ENTRY *)NULL) == -1)
+			exit(1);
+	}
+
+	if (op == NEWEXP) {
+		if (uid)	/* only root can change expire */
+			baduser();
+		if (p_expire(arg, pw, (ENTRY *)NULL) == -1)
+			exit(1);
+	}
+
+	if (op == LOADENTRY) {
+		if (uid)
+			baduser();
+		pw = &lpw;
+		old_pw = NULL;
+		if (!__pw_scan(arg, pw, _PWSCAN_WARN|_PWSCAN_MASTER))
+			exit(1);
+	}
+
+	if (op == NEWPW) {
+		if (uid)
+			baduser();
+
+		if (strchr(arg, ':'))
+			errx(1, "invalid format for password");
+		pw->pw_passwd = arg;
+	}
+
+	if (op == EDITENTRY) {
+		/*
+		 * We don't really need pw_*() here, but pw_edit() (used
+		 * by edit()) is just too useful...
+		 */
+		if (pw_init(NULL, NULL))
+			err(1, "pw_init()");
+		if ((tfd = pw_tmp(-1)) == -1) {
+			pw_fini();
+			err(1, "pw_tmp()");
+		}
+		free(pw);
+		pw = edit(pw_tempname(), old_pw);
+		pw_fini();
+		if (pw == NULL)
+			err(1, "edit()");
+		/* 
+		 * pw_equal does not check for crypted passwords, so we
+		 * should do it explicitly
+		 */
+		if (pw_equal(old_pw, pw) && 
+		    strcmp(old_pw->pw_passwd, pw->pw_passwd) == 0)
+			errx(0, "user information unchanged");
+	}
+
+	if (old_pw && !master_mode) {
+		password = getpass("Password: ");
+		if (strcmp(crypt(password, old_pw->pw_passwd),
+		    old_pw->pw_passwd) != 0)
+			baduser();
+	} else {
+		password = "";
+	}
+
+	if (old_pw != NULL)
+		pw->pw_fields |= (old_pw->pw_fields & _PWF_SOURCE);
+	switch (pw->pw_fields & _PWF_SOURCE) {
+#ifdef YP
+	case _PWF_NIS:
+		ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_host);
+		if (ypclnt == NULL) {
+			warnx("ypclnt_new failed");
+			exit(1);
+		}
+		if (ypclnt_connect(ypclnt) == -1 ||
+		    ypclnt_passwd(ypclnt, pw, password) == -1) {
+			warnx("%s", ypclnt->error);
+			ypclnt_free(ypclnt);
+			exit(1);
+		}
+		ypclnt_free(ypclnt);
+		errx(0, "NIS user information updated");
+#endif /* YP */
+	case 0:
+	case _PWF_FILES:
+		if (pw_init(NULL, NULL))
+			err(1, "pw_init()");
+		if ((pfd = pw_lock()) == -1) {
+			pw_fini();
+			err(1, "pw_lock()");
+		}
+		if ((tfd = pw_tmp(-1)) == -1) {
+			pw_fini();
+			err(1, "pw_tmp()");
+		}
+		if (pw_copy(pfd, tfd, pw, old_pw) == -1) {
+			pw_fini();
+			err(1, "pw_copy");
+		}
+		if (pw_mkdb(pw->pw_name) == -1) {
+			pw_fini();
+			err(1, "pw_mkdb()");
+		}
+		pw_fini();
+		errx(0, "user information updated");
+		break;
+	default:
+		errx(1, "unsupported passwd source");
+	}
+}
+
+static void
+baduser(void)
+{
+
+	errx(1, "%s", strerror(EACCES));
+}
+
+static void
+usage(void)
+{
+
+	(void)fprintf(stderr,
+	    "usage: chpass%s %s [user]\n",
+#ifdef YP
+	    " [-d domain] [-h host]",
+#else
+	    "",
+#endif
+	    "[-a list] [-p encpass] [-s shell] [-e mmm dd yy]");
+	exit(1);
+}