/* vi: set sw=4 ts=4: */ /* * Copyright 1989 - 1991, Julianne Frances Haugh * 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 #include #include #include #include #include #include #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; }