diff options
Diffstat (limited to 'Linux-PAM/modules/pam_userdb/pam_userdb.c')
| -rw-r--r-- | Linux-PAM/modules/pam_userdb/pam_userdb.c | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/Linux-PAM/modules/pam_userdb/pam_userdb.c b/Linux-PAM/modules/pam_userdb/pam_userdb.c new file mode 100644 index 00000000..86c7238b --- /dev/null +++ b/Linux-PAM/modules/pam_userdb/pam_userdb.c @@ -0,0 +1,490 @@ +/* pam_userdb module */ + +/* + * $Id: pam_userdb.c,v 1.7 2004/09/28 13:48:47 kukuk Exp $ + * Written by Cristian Gafton <gafton@redhat.com> 1996/09/10 + * See the end of the file for Copyright Information + */ + +#include <security/_pam_aconf.h> + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <syslog.h> +#include <stdarg.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> + +#include "pam_userdb.h" + +#ifdef HAVE_NDBM_H +# include <ndbm.h> +#else +# ifdef HAVE_DB_H +# define DB_DBM_HSEARCH 1 /* use the dbm interface */ +# include <db.h> +# else +# error "failed to find a libdb or equivalent" +# endif +#endif + +/* + * here, we make a definition for the externally accessible function + * in this file (this definition is required for static a module + * but strongly encouraged generally) it is used to instruct the + * modules include file to define the function prototypes. + */ + +#define PAM_SM_AUTH +#define PAM_SM_ACCOUNT + +#include <security/pam_modules.h> + +/* some syslogging */ + +static void _pam_log(int err, const char *format, ...) +{ + va_list args; + + va_start(args, format); + openlog(MODULE_NAME, LOG_CONS|LOG_PID, LOG_AUTH); + vsyslog(err, format, args); + va_end(args); + closelog(); +} + +static int +_pam_parse (int argc, const char **argv, + char **database, char **cryptmode) +{ + int ctrl; + + *database = NULL; + *cryptmode = NULL; + + /* step through arguments */ + for (ctrl = 0; argc-- > 0; ++argv) + { + /* generic options */ + + if (!strcmp(*argv,"debug")) + ctrl |= PAM_DEBUG_ARG; + else if (!strcasecmp(*argv, "icase")) + ctrl |= PAM_ICASE_ARG; + else if (!strcasecmp(*argv, "dump")) + ctrl |= PAM_DUMP_ARG; + else if (!strcasecmp(*argv, "unknown_ok")) + ctrl |= PAM_UNKNOWN_OK_ARG; + else if (!strcasecmp(*argv, "key_only")) + ctrl |= PAM_KEY_ONLY_ARG; + else if (!strncasecmp(*argv,"db=", 3)) + { + *database = strdup((*argv) + 3); + if ((*database == NULL) || (strlen (*database) == 0)) + _pam_log(LOG_ERR, + "pam_parse: could not parse argument \"%s\"", + *argv); + } + else if (!strncasecmp(*argv,"crypt=", 6)) + { + *cryptmode = strdup((*argv) + 6); + if ((*cryptmode == NULL) || (strlen (*cryptmode) == 0)) + _pam_log(LOG_ERR, + "pam_parse: could not parse argument \"%s\"", + *argv); + } + else + { + _pam_log(LOG_ERR, "pam_parse: unknown option; %s", *argv); + } + } + + return ctrl; +} + + +/* + * Looks up an user name in a database and checks the password + * + * return values: + * 1 = User not found + * 0 = OK + * -1 = Password incorrect + * -2 = System error + */ +static int +user_lookup (const char *database, const char *cryptmode, + const char *user, const char *pass, int ctrl) +{ + DBM *dbm; + datum key, data; + + /* Open the DB file. */ + dbm = dbm_open(database, O_RDONLY, 0644); + if (dbm == NULL) { + _pam_log(LOG_ERR, "user_lookup: could not open database `%s'", + database); + return -2; + } + + /* dump out the database contents for debugging */ + if (ctrl & PAM_DUMP_ARG) { + _pam_log(LOG_INFO, "Database dump:"); + for (key = dbm_firstkey(dbm); key.dptr != NULL; + key = dbm_nextkey(dbm)) { + data = dbm_fetch(dbm, key); + _pam_log(LOG_INFO, "key[len=%d] = `%s', data[len=%d] = `%s'", + key.dsize, key.dptr, data.dsize, data.dptr); + } + } + + /* do some more init work */ + memset(&key, 0, sizeof(key)); + memset(&data, 0, sizeof(data)); + if (ctrl & PAM_KEY_ONLY_ARG) { + key.dptr = malloc(strlen(user) + 1 + strlen(pass) + 1); + sprintf(key.dptr, "%s-%s", user, pass); + key.dsize = strlen(key.dptr); + } else { + key.dptr = x_strdup(user); + key.dsize = strlen(user); + } + + if (key.dptr) { + data = dbm_fetch(dbm, key); + memset(key.dptr, 0, key.dsize); + free(key.dptr); + } + + if (ctrl & PAM_DEBUG_ARG) { + _pam_log(LOG_INFO, "password in database is [%p]`%s', len is %d", + data.dptr, (char *) data.dptr, data.dsize); + } + + if (data.dptr != NULL) { + int compare = 0; + + if (ctrl & PAM_KEY_ONLY_ARG) + { + dbm_close (dbm); + return 0; /* found it, data contents don't matter */ + } + + if (strncasecmp(cryptmode, "crypt", 5) == 0) { + + /* crypt(3) password storage */ + + char *cryptpw; + char salt[2]; + + if (data.dsize != 13) { + compare = -2; + } else if (ctrl & PAM_ICASE_ARG) { + compare = -2; + } else { + salt[0] = *data.dptr; + salt[1] = *(data.dptr + 1); + + cryptpw = crypt (pass, salt); + + if (cryptpw) { + compare = strncasecmp (data.dptr, cryptpw, data.dsize); + } else { + compare = -2; + if (ctrl & PAM_DEBUG_ARG) { + _pam_log(LOG_INFO, "crypt() returned NULL"); + } + }; + + }; + + } else { + + /* Unknown password encryption method - + * default to plaintext password storage + */ + + if (strlen(pass) != data.dsize) { + compare = 1; /* wrong password len -> wrong password */ + } else if (ctrl & PAM_ICASE_ARG) { + compare = strncasecmp(data.dptr, pass, data.dsize); + } else { + compare = strncmp(data.dptr, pass, data.dsize); + } + + if (strncasecmp(cryptmode, "none", 4) && ctrl & PAM_DEBUG_ARG) { + _pam_log(LOG_INFO, "invalid value for crypt parameter: %s", + cryptmode); + _pam_log(LOG_INFO, "defaulting to plaintext password mode"); + } + + } + + dbm_close(dbm); + if (compare == 0) + return 0; /* match */ + else + return -1; /* wrong */ + } else { + int saw_user = 0; + + if (ctrl & PAM_DEBUG_ARG) { + _pam_log(LOG_INFO, "error returned by dbm_fetch: %s", + strerror(errno)); + } + + /* probably we should check dbm_error() here */ + + if ((ctrl & PAM_KEY_ONLY_ARG) == 0) { + dbm_close(dbm); + return 1; /* not key_only, so no entry => no entry for the user */ + } + + /* now handle the key_only case */ + for (key = dbm_firstkey(dbm); + key.dptr != NULL; + key = dbm_nextkey(dbm)) { + int compare; + /* first compare the user portion (case sensitive) */ + compare = strncmp(key.dptr, user, strlen(user)); + if (compare == 0) { + /* assume failure */ + compare = -1; + /* if we have the divider where we expect it to be... */ + if (key.dptr[strlen(user)] == '-') { + saw_user = 1; + if (key.dsize == strlen(user) + 1 + strlen(pass)) { + if (ctrl & PAM_ICASE_ARG) { + /* compare the password portion (case insensitive)*/ + compare = strncasecmp(key.dptr + strlen(user) + 1, + pass, + strlen(pass)); + } else { + /* compare the password portion (case sensitive) */ + compare = strncmp(key.dptr + strlen(user) + 1, + pass, + strlen(pass)); + } + } + } + if (compare == 0) { + dbm_close(dbm); + return 0; /* match */ + } + } + } + dbm_close(dbm); + if (saw_user) + return -1; /* saw the user, but password mismatch */ + else + return 1; /* not found */ + } + + /* NOT REACHED */ + return -2; +} + +/* --- authentication management functions (only) --- */ + +PAM_EXTERN +int pam_sm_authenticate(pam_handle_t *pamh, int flags, + int argc, const char **argv) +{ + const char *username; + const char *password; + char *database = NULL; + char *cryptmode = NULL; + int retval = PAM_AUTH_ERR, ctrl; + + /* parse arguments */ + ctrl = _pam_parse(argc, argv, &database, &cryptmode); + if ((database == NULL) || (strlen(database) == 0)) { + if (ctrl & PAM_DEBUG_ARG) + _pam_log(LOG_DEBUG,"can not get the database name"); + return PAM_SERVICE_ERR; + } + + /* Get the username */ + retval = pam_get_user(pamh, &username, NULL); + if ((retval != PAM_SUCCESS) || (!username)) { + if (ctrl & PAM_DEBUG_ARG) + _pam_log(LOG_DEBUG,"can not get the username"); + return PAM_SERVICE_ERR; + } + + /* Converse just to be sure we have a password */ + retval = conversation(pamh); + if (retval != PAM_SUCCESS) { + _pam_log(LOG_ERR, "could not obtain password for `%s'", + username); + return PAM_CONV_ERR; + } + + /* Check if we got a password. The docs say that if we didn't have one, + * and use_authtok was specified as an argument, that we converse with the + * user anyway, so check for one and handle a failure for that case. If + * use_authtok wasn't specified, then we've already asked once and needn't + * do so again. */ + retval = pam_get_item(pamh, PAM_AUTHTOK, (const void **) &password); + if ((retval != PAM_SUCCESS) && ((ctrl & PAM_USE_AUTHTOK_ARG) != 0)) { + retval = conversation(pamh); + if (retval != PAM_SUCCESS) { + _pam_log(LOG_ERR, "could not obtain password for `%s'", + username); + return PAM_CONV_ERR; + } + } + + /* Get the password */ + retval = pam_get_item(pamh, PAM_AUTHTOK, (const void **)&password); + if (retval != PAM_SUCCESS) { + _pam_log(LOG_ERR, "Could not retrieve user's password"); + return -2; + } + + if (ctrl & PAM_DEBUG_ARG) + _pam_log(LOG_INFO, "Verify user `%s' with password `%s'", + username, password); + + /* Now use the username to look up password in the database file */ + retval = user_lookup(database, cryptmode, username, password, ctrl); + switch (retval) { + case -2: + /* some sort of system error. The log was already printed */ + return PAM_SERVICE_ERR; + case -1: + /* incorrect password */ + _pam_log(LOG_WARNING, + "user `%s' denied access (incorrect password)", + username); + return PAM_AUTH_ERR; + case 1: + /* the user does not exist in the database */ + if (ctrl & PAM_DEBUG_ARG) + _pam_log(LOG_NOTICE, "user `%s' not found in the database", + username); + return PAM_USER_UNKNOWN; + case 0: + /* Otherwise, the authentication looked good */ + _pam_log(LOG_NOTICE, "user '%s' granted acces", username); + return PAM_SUCCESS; + default: + /* we don't know anything about this return value */ + _pam_log(LOG_ERR, + "internal module error (retval = %d, user = `%s'", + retval, username); + return PAM_SERVICE_ERR; + } + + /* should not be reached */ + return PAM_IGNORE; +} + +PAM_EXTERN +int pam_sm_setcred(pam_handle_t *pamh, int flags, + int argc, const char **argv) +{ + return PAM_SUCCESS; +} + +PAM_EXTERN +int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags, int argc, const char **argv) +{ + const char *username; + char *database = NULL; + char *cryptmode = NULL; + int retval = PAM_AUTH_ERR, ctrl; + + /* parse arguments */ + ctrl = _pam_parse(argc, argv, &database, &cryptmode); + + /* Get the username */ + retval = pam_get_user(pamh, &username, NULL); + if ((retval != PAM_SUCCESS) || (!username)) { + if (ctrl & PAM_DEBUG_ARG) + _pam_log(LOG_DEBUG,"can not get the username"); + return PAM_SERVICE_ERR; + } + + /* Now use the username to look up password in the database file */ + retval = user_lookup(database, cryptmode, username, "", ctrl); + switch (retval) { + case -2: + /* some sort of system error. The log was already printed */ + return PAM_SERVICE_ERR; + case -1: + /* incorrect password, but we don't care */ + /* FALL THROUGH */ + case 0: + /* authentication succeeded. dumbest password ever. */ + return PAM_SUCCESS; + case 1: + /* the user does not exist in the database */ + return PAM_USER_UNKNOWN; + default: + /* we don't know anything about this return value */ + _pam_log(LOG_ERR, + "internal module error (retval = %d, user = `%s'", + retval, username); + return PAM_SERVICE_ERR; + } + + return PAM_SUCCESS; +} + + +#ifdef PAM_STATIC + +/* static module data */ + +struct pam_module _pam_userdb_modstruct = { + "pam_userdb", + pam_sm_authenticate, + pam_sm_setcred, + pam_sm_acct_mgmt, + NULL, + NULL, + NULL, +}; + +#endif + +/* + * Copyright (c) Cristian Gafton <gafton@redhat.com>, 1999 + * 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, and the entire permission notice in its entirety, + * including the disclaimer of warranties. + * 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. The name of the author may not be used to endorse or promote + * products derived from this software without specific prior + * written permission. + * + * ALTERNATIVELY, this product may be distributed under the terms of + * the GNU Public License, in which case the provisions of the GPL are + * required INSTEAD OF the above restrictions. (This clause is + * necessary due to a potential bad interaction between the GPL and + * the restrictions contained in a BSD-style copyright.) + * + * THIS SOFTWARE IS PROVIDED `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 AUTHOR 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. + */ |