Port over the last of the tinylogin applets

 -Erik

11 files changed, 791 insertions, 3 deletions

diff --git a/libbb/Makefile.in b/libbb/Makefile.in
index c6493bfa6..2af70f8c7 100644
--- a/libbb/Makefile.in
+++ b/libbb/Makefile.in
@@ -34,17 +34,21 @@ LIBBB_SRC:= \
         my_getpwuid.c parse_mode.c parse_number.c perror_msg.c perror_msg_and_die.c \
         print_file.c process_escape_sequence.c read_package_field.c recursive_action.c \
         safe_read.c safe_strncpy.c syscalls.c syslog_msg_with_name.c time_string.c \
-        trim.c unzip.c uncompress.c vdprintf.c verror_msg.c vperror_msg.c wfopen.c xfuncs.c \
+        trim.c unzip.c uncompress.c vdprintf.c verror_msg.c vperror_msg.c wfopen.c \
         xgetcwd.c xreadlink.c xregcomp.c interface.c remove_file.c last_char_is.c \
         copyfd.c vherror_msg.c herror_msg.c herror_msg_and_die.c xgethostbyname.c \
         dirname.c make_directory.c create_icmp_socket.c u_signal_names.c arith.c \
-        simplify_path.c inet_common.c inode_hash.c
+        simplify_path.c inet_common.c inode_hash.c obscure.c pwd2spwd.c xfuncs.c \
+        correct_password.c change_identity.c setup_environment.c run_shell.c \
+        pw_encrypt.c restricted_shell.c
 LIBBB_OBJS=$(patsubst %.c,$(LIBBB_DIR)%.o, $(LIBBB_SRC))
 
 LIBBB_MSRC:=$(LIBBB_DIR)messages.c
 LIBBB_MOBJ:=full_version.o name_too_long.o omitting_directory.o not_a_directory.o \
         memory_exhausted.o invalid_date.o invalid_option.o io_error.o dash_dash_help.o \
-        write_error.o too_few_args.o name_longer_than_foo.o unknown.o can_not_create_raw_socket.o
+        write_error.o too_few_args.o name_longer_than_foo.o unknown.o can_not_create_raw_socket.o \
+        shadow_file.o passwd_file.o group_file.o gshadow_file.o nologin_file.o securetty_file.o \
+        motd_file.o
 LIBBB_MOBJS=$(patsubst %,$(LIBBB_DIR)%, $(LIBBB_MOBJ))
 
 libraries-y+=$(LIBBB_DIR)$(LIBBB_AR)
diff --git a/libbb/change_identity.c b/libbb/change_identity.c
new file mode 100644
index 000000000..819b216e0
--- /dev/null
+++ b/libbb/change_identity.c
@@ -0,0 +1,54 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <ctype.h>
+
+#include "libbb.h"
+
+
+/* Become the user and group(s) specified by PW.  */
+void change_identity ( const struct passwd *pw )
+{
+        if ( initgroups ( pw-> pw_name, pw-> pw_gid ) == -1 )
+                perror_msg_and_die ( "cannot set groups" );
+        endgrent ( );
+
+        if ( setgid ( pw-> pw_gid ))
+                perror_msg_and_die ( "cannot set group id" );
+        if ( setuid ( pw->pw_uid ))
+                perror_msg_and_die ( "cannot set user id" );
+}
+
diff --git a/libbb/correct_password.c b/libbb/correct_password.c
new file mode 100644
index 000000000..758b89eed
--- /dev/null
+++ b/libbb/correct_password.c
@@ -0,0 +1,78 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <ctype.h>
+#include <crypt.h>
+
+#include "libbb.h"
+
+
+
+/* Ask the user for a password.
+   Return 1 if the user gives the correct password for entry PW,
+   0 if not.  Return 1 without asking for a password if run by UID 0
+   or if PW has an empty password.  */
+
+int correct_password ( const struct passwd *pw )
+{
+        char *unencrypted, *encrypted, *correct;
+        
+#ifdef CONFIG_FEATURE_SHADOWPASSWDS
+        if (( strcmp ( pw-> pw_passwd, "x" ) == 0 ) || ( strcmp ( pw-> pw_passwd, "*" ) == 0 )) {
+                struct spwd *sp = getspnam ( pw-> pw_name );
+                
+                if ( !sp )
+                        error_msg_and_die ( "no valid shadow password" );
+                
+                correct = sp-> sp_pwdp;
+        }
+        else
+#endif
+        correct = pw-> pw_passwd;
+
+        if ( correct == 0 || correct[0] == '\0' )
+                return 1;
+
+        unencrypted = getpass ( "Password: " );
+        if ( !unencrypted )
+        {
+                fputs ( "getpass: cannot open /dev/tty\n", stderr );
+                return 0;
+        }
+        encrypted = crypt ( unencrypted, correct );
+        memset ( unencrypted, 0, xstrlen ( unencrypted ));
+        return ( strcmp ( encrypted, correct ) == 0 ) ? 1 : 0;
+}
diff --git a/libbb/libc5.c b/libbb/libc5.c
index df622f65b..af15d1ac7 100644
--- a/libbb/libc5.c
+++ b/libbb/libc5.c
@@ -11,6 +11,24 @@
 
 #if __GNU_LIBRARY__ < 5
 
+/*
+ * Some systems already have updwtmp().  Some don't...  This is
+ * the updwtmp() implementation from uClibc, Copyright 2002 by
+ * Erik Andersen <andersee@debian.org> 
+ */
+extern void updwtmp(const char *wtmp_file, const struct utmp *lutmp)
+{
+        int fd;
+
+        fd = open(wtmp_file, O_APPEND | O_WRONLY, 0);
+        if (fd >= 0) {
+                if (lockf(fd, F_LOCK, 0)==0) {
+                        write(fd, (const char *) lutmp, sizeof(struct utmp));
+                        lockf(fd, F_ULOCK, 0);
+                        close(fd);
+                }
+        }
+}
 
 /* Copyright (C) 1991 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
diff --git a/libbb/messages.c b/libbb/messages.c
index 895cfdc2b..185c1ee91 100644
--- a/libbb/messages.c
+++ b/libbb/messages.c
@@ -66,3 +66,39 @@
 #ifdef L_can_not_create_raw_socket
         const char * const can_not_create_raw_socket = "can`t create raw socket";
 #endif
+
+#ifdef L_passwd_file
+#define PASSWD_FILE        "/etc/passwd"
+const char * const passwd_file = PASSWD_FILE;
+#endif
+
+#ifdef L_shadow_file
+#define SHADOW_FILE        "/etc/shadow"
+const char * const shadow_file = SHADOW_FILE;
+#endif
+
+#ifdef L_group_file
+#define GROUP_FILE         "/etc/group"
+const char * const group_file = GROUP_FILE;
+#endif
+
+#ifdef L_gshadow_file
+#define GSHADOW_FILE       "/etc/gshadow"
+const char * const gshadow_file = GSHADOW_FILE;
+#endif
+
+#ifdef L_nologin_file
+#define NOLOGIN_FILE       "/etc/nologin"
+const char * const nologin_file = NOLOGIN_FILE;
+#endif
+
+#ifdef L_securetty_file
+#define SECURETTY_FILE     "/etc/securetty"
+const char * const securetty_file = SECURETTY_FILE;
+#endif
+
+#ifdef L_motd_file
+#define MOTD_FILE          "/etc/motd"
+const char * const motd_file = MOTD_FILE;
+#endif
+
diff --git a/libbb/obscure.c b/libbb/obscure.c
new file mode 100644
index 000000000..dc7de751d
--- /dev/null
+++ b/libbb/obscure.c
@@ -0,0 +1,246 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1994, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+/*
+ * This version of obscure.c contains modifications to support "cracklib"
+ * by Alec Muffet (alec.muffett@uk.sun.com).  You must obtain the Cracklib
+ * library source code for this function to operate.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
+#include "libbb.h"
+
+/*
+ * can't be a palindrome - like `R A D A R' or `M A D A M'
+ */
+
+static int palindrome(const char *old, const char *newval)
+{
+        int i, j;
+
+        i = strlen(newval);
+
+        for (j = 0; j < i; j++)
+                if (newval[i - j - 1] != newval[j])
+                        return 0;
+
+        return 1;
+}
+
+/*
+ * more than half of the characters are different ones.
+ */
+
+static int similiar(const char *old, const char *newval)
+{
+        int i, j;
+
+        for (i = j = 0; newval[i] && old[i]; i++)
+                if (strchr(newval, old[i]))
+                        j++;
+
+        if (i >= j * 2)
+                return 0;
+
+        return 1;
+}
+
+/*
+ * a nice mix of characters.
+ */
+
+static int simple(const char *old, const char *newval)
+{
+        int digits = 0;
+        int uppers = 0;
+        int lowers = 0;
+        int others = 0;
+        int size;
+        int i;
+
+        for (i = 0; newval[i]; i++) {
+                if (isdigit(newval[i]))
+                        digits++;
+                else if (isupper(newval[i]))
+                        uppers++;
+                else if (islower(newval[i]))
+                        lowers++;
+                else
+                        others++;
+        }
+
+        /*
+         * The scam is this - a password of only one character type
+         * must be 8 letters long.  Two types, 7, and so on.
+         */
+
+        size = 9;
+        if (digits)
+                size--;
+        if (uppers)
+                size--;
+        if (lowers)
+                size--;
+        if (others)
+                size--;
+
+        if (size <= i)
+                return 0;
+
+        return 1;
+}
+
+static char *str_lower(char *string)
+{
+        char *cp;
+
+        for (cp = string; *cp; cp++)
+                *cp = tolower(*cp);
+        return string;
+}
+
+static char *password_check(const char *old, const char *newval, const struct passwd *pwdp)
+{
+        char *msg = NULL;
+        char *oldmono, *newmono, *wrapped;
+
+        if (strcmp(newval, old) == 0)
+                return "no change";
+
+        newmono = str_lower(xstrdup(newval));
+        oldmono = str_lower(xstrdup(old));
+        wrapped = (char *) xmalloc(strlen(oldmono) * 2 + 1);
+        strcpy(wrapped, oldmono);
+        strcat(wrapped, oldmono);
+
+        if (palindrome(oldmono, newmono))
+                msg = "a palindrome";
+
+        if (!msg && strcmp(oldmono, newmono) == 0)
+                msg = "case changes only";
+
+        if (!msg && similiar(oldmono, newmono))
+                msg = "too similiar";
+
+        if (!msg && simple(old, newval))
+                msg = "too simple";
+
+        if (!msg && strstr(wrapped, newmono))
+                msg = "rotated";
+
+        bzero(newmono, strlen(newmono));
+        bzero(oldmono, strlen(oldmono));
+        bzero(wrapped, strlen(wrapped));
+        free(newmono);
+        free(oldmono);
+        free(wrapped);
+
+        return msg;
+}
+
+static char *obscure_msg(const char *old, const char *newval, const struct passwd *pwdp)
+{
+        int maxlen, oldlen, newlen;
+        char *new1, *old1, *msg;
+
+        oldlen = strlen(old);
+        newlen = strlen(newval);
+
+#if 0                                                   /* why not check the password when set for the first time?  --marekm */
+        if (old[0] == '\0')
+                /* return (1); */
+                return NULL;
+#endif
+
+        if (newlen < 5)
+                return "too short";
+
+        /*
+         * Remaining checks are optional.
+         */
+        /* Not for us -- Sean
+         *if (!getdef_bool("OBSCURE_CHECKS_ENAB"))
+         *      return NULL;
+         */
+        msg = password_check(old, newval, pwdp);
+        if (msg)
+                return msg;
+
+        /* The traditional crypt() truncates passwords to 8 chars.  It is
+           possible to circumvent the above checks by choosing an easy
+           8-char password and adding some random characters to it...
+           Example: "password$%^&*123".  So check it again, this time
+           truncated to the maximum length.  Idea from npasswd.  --marekm */
+
+        maxlen = 8;
+        if (oldlen <= maxlen && newlen <= maxlen)
+                return NULL;
+
+        new1 = (char *) xstrdup(newval);
+        old1 = (char *) xstrdup(old);
+        if (newlen > maxlen)
+                new1[maxlen] = '\0';
+        if (oldlen > maxlen)
+                old1[maxlen] = '\0';
+
+        msg = password_check(old1, new1, pwdp);
+
+        bzero(new1, newlen);
+        bzero(old1, oldlen);
+        free(new1);
+        free(old1);
+
+        return msg;
+}
+
+/*
+ * Obscure - see if password is obscure enough.
+ *
+ *      The programmer is encouraged to add as much complexity to this
+ *      routine as desired.  Included are some of my favorite ways to
+ *      check passwords.
+ */
+
+extern int obscure(const char *old, const char *newval, const struct passwd *pwdp)
+{
+        char *msg = obscure_msg(old, newval, pwdp);
+
+        /*  if (msg) { */
+        if (msg != NULL) {
+                printf("Bad password: %s.\n", msg);
+                /* return 0; */
+                return 1;
+        }
+        /* return 1; */
+        return 0;
+}
diff --git a/libbb/pw_encrypt.c b/libbb/pw_encrypt.c
new file mode 100644
index 000000000..0e4eb9f8a
--- /dev/null
+++ b/libbb/pw_encrypt.c
@@ -0,0 +1,48 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routine.
+ *
+ * Copyright (C) 1999-2002 by Erik Andersen <andersee@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <string.h>
+#include <crypt.h>
+#include "libbb.h"
+
+
+extern char *pw_encrypt(const char *clear, const char *salt)
+{
+        static char cipher[128];
+        char *cp;
+
+#ifdef CONFIG_FEATURE_SHA1_PASSWORDS
+        if (strncmp(salt, "$2$", 3) == 0) {
+                return sha1_crypt(clear);
+        }
+#endif
+        cp = (char *) crypt(clear, salt);
+        /* if crypt (a nonstandard crypt) returns a string too large,
+           truncate it so we don't overrun buffers and hope there is
+           enough security in what's left */
+        if (strlen(cp) > sizeof(cipher)-1) {
+                cp[sizeof(cipher)-1] = 0;
+        }
+        strcpy(cipher, cp);
+        return cipher;
+}
+
diff --git a/libbb/pwd2spwd.c b/libbb/pwd2spwd.c
new file mode 100644
index 000000000..95a2e4684
--- /dev/null
+++ b/libbb/pwd2spwd.c
@@ -0,0 +1,73 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1994, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <time.h>
+#include <sys/types.h>
+#include "libbb.h"
+
+/*
+ * pwd_to_spwd - create entries for new spwd structure
+ *
+ *      pwd_to_spwd() creates a new (struct spwd) containing the
+ *      information in the pointed-to (struct passwd).
+ */
+#define DAY (24L*3600L)
+#define WEEK (7*DAY)
+#define SCALE DAY
+struct spwd *pwd_to_spwd(const struct passwd *pw)
+{
+        static struct spwd sp;
+
+        /*
+         * Nice, easy parts first.  The name and passwd map directly
+         * from the old password structure to the new one.
+         */
+        sp.sp_namp = pw->pw_name;
+        sp.sp_pwdp = pw->pw_passwd;
+
+        /*
+         * Defaults used if there is no pw_age information.
+         */
+        sp.sp_min = 0;
+        sp.sp_max = (10000L * DAY) / SCALE;
+        sp.sp_lstchg = time((time_t *) 0) / SCALE;
+
+        /*
+         * These fields have no corresponding information in the password
+         * file.  They are set to uninitialized values.
+         */
+        sp.sp_warn = -1;
+        sp.sp_expire = -1;
+        sp.sp_inact = -1;
+        sp.sp_flag = -1;
+
+        return &sp;
+}
+
diff --git a/libbb/restricted_shell.c b/libbb/restricted_shell.c
new file mode 100644
index 000000000..74a64140f
--- /dev/null
+++ b/libbb/restricted_shell.c
@@ -0,0 +1,57 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <ctype.h>
+#include "libbb.h"
+
+
+
+/* Return 1 if SHELL is a restricted shell (one not returned by
+   getusershell), else 0, meaning it is a standard shell.  */
+
+int restricted_shell ( const char *shell )
+{
+        char *line;
+
+        setusershell ( );
+        while (( line = getusershell ( ))) {
+                if (( *line != '#' ) && ( strcmp ( line, shell ) == 0 ))
+                        break;
+        }
+        endusershell ( );
+        return line ? 0 : 1;
+}
+
diff --git a/libbb/run_shell.c b/libbb/run_shell.c
new file mode 100644
index 000000000..30050fecb
--- /dev/null
+++ b/libbb/run_shell.c
@@ -0,0 +1,81 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <ctype.h>
+#include "libbb.h"
+
+
+/* Run SHELL, or DEFAULT_SHELL if SHELL is empty.
+   If COMMAND is nonzero, pass it to the shell with the -c option.
+   If ADDITIONAL_ARGS is nonzero, pass it to the shell as more
+   arguments.  */
+
+void run_shell ( const char *shell, int loginshell, const char *command, const char **additional_args )
+{
+        const char **args;
+        int argno = 1;
+        int additional_args_cnt = 0;
+        
+        for ( args = additional_args; args && *args; args++ )
+                additional_args_cnt++;
+
+        if ( additional_args )
+                args = (const char **) xmalloc (sizeof (char *) * ( 4  + additional_args_cnt ));
+        else
+                args = (const char **) xmalloc (sizeof (char *) * 4 );
+                
+        args [0] = get_last_path_component ( xstrdup ( shell ));
+        
+        if ( loginshell ) {
+                char *args0 = xmalloc ( xstrlen ( args [0] ) + 2 );
+                args0 [0] = '-';
+                strcpy ( args0 + 1, args [0] );
+                args [0] = args0;
+        }
+    
+        if ( command ) {
+                args [argno++] = "-c";
+                args [argno++] = command;
+        }
+        if ( additional_args ) {
+                for ( ; *additional_args; ++additional_args )
+                        args [argno++] = *additional_args;
+        }
+        args [argno] = 0;
+        execv ( shell, (char **) args );
+        perror_msg_and_die ( "cannot run %s", shell );
+}
+
diff --git a/libbb/setup_environment.c b/libbb/setup_environment.c
new file mode 100644
index 000000000..dc171fa1f
--- /dev/null
+++ b/libbb/setup_environment.c
@@ -0,0 +1,93 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
+ * All rights reserved.
+ *
+ * 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. Neither the name of Julianne F. Haugh 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 JULIE HAUGH 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 JULIE HAUGH 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.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <ctype.h>
+#include "libbb.h"
+
+
+
+#define DEFAULT_LOGIN_PATH      "/bin:/usr/bin"
+#define DEFAULT_ROOT_LOGIN_PATH "/usr/sbin:/bin:/usr/bin:/sbin"
+
+static void xsetenv ( const char *key, const char *value )
+{
+            if ( setenv ( key, value, 1 ))
+                                error_msg_and_die ( "out of memory" );
+}
+
+void setup_environment ( const char *shell, int loginshell, int changeenv, const struct passwd *pw )
+{
+        if ( loginshell ) {
+                char *term;
+        
+                /* Change the current working directory to be the home directory
+                 * of the user.  It is a fatal error for this process to be unable
+                 * to change to that directory.  There is no "default" home
+                 * directory.
+                 * Some systems default to HOME=/
+                 */              
+                if ( chdir ( pw-> pw_dir )) {
+                        if ( chdir ( "/" )) {
+                                syslog ( LOG_WARNING, "unable to cd to %s' for user %s'\n", pw-> pw_dir, pw-> pw_name );
+                                error_msg_and_die ( "cannot cd to home directory or /" );
+                        }
+                        fputs ( "warning: cannot change to home directory\n", stderr );
+                }
+
+                /* Leave TERM unchanged.  Set HOME, SHELL, USER, LOGNAME, PATH.
+                   Unset all other environment variables.  */
+                term = getenv ("TERM");
+                clearenv ( );
+                if ( term )
+                        xsetenv ( "TERM", term );
+                xsetenv ( "HOME",    pw-> pw_dir );
+                xsetenv ( "SHELL",   shell );
+                xsetenv ( "USER",    pw-> pw_name );
+                xsetenv ( "LOGNAME", pw-> pw_name );
+                xsetenv ( "PATH",    ( pw-> pw_uid ? DEFAULT_LOGIN_PATH : DEFAULT_ROOT_LOGIN_PATH ));
+        }
+        else if ( changeenv ) {
+                /* Set HOME, SHELL, and if not becoming a super-user,
+                   USER and LOGNAME.  */
+                xsetenv ( "HOME",  pw-> pw_dir );
+                xsetenv ( "SHELL", shell );
+                if  ( pw-> pw_uid ) {
+                        xsetenv ( "USER",    pw-> pw_name );
+                        xsetenv ( "LOGNAME", pw-> pw_name );
+                }
+        }
+}
+