| /* 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 "busybox.h" |
| |
| #include <stdio.h> |
| #include <errno.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <syslog.h> |
| #include <ctype.h> |
| |
| #include "pwd.h" |
| #include "grp.h" |
| |
| #ifdef CONFIG_FEATURE_SHADOWPASSWDS |
| #include "shadow.h" |
| #endif |
| |
| #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" ); |
| } |
| |
| /* 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" ); |
| } |
| |
| /* 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 ); |
| } |
| |
| /* 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; |
| } |
| |
| /* Update `environ' for the new shell based on PW, with SHELL being |
| the value for the SHELL environment variable. */ |
| |
| 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 ); |
| } |
| } |
| } |
| |
| /* 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; |
| } |