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Diffstat (limited to 'loginutils/tinylogin.c')
| -rw-r--r-- | loginutils/tinylogin.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/loginutils/tinylogin.c b/loginutils/tinylogin.c new file mode 100644 index 0000000..bd611fd --- /dev/null +++ b/loginutils/tinylogin.c @@ -0,0 +1,209 @@ +/* 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; +} |