diff options
Diffstat (limited to 'modules/pam_userdb/pam_userdb.c')
| -rw-r--r-- | modules/pam_userdb/pam_userdb.c | 512 |
1 files changed, 512 insertions, 0 deletions
diff --git a/modules/pam_userdb/pam_userdb.c b/modules/pam_userdb/pam_userdb.c new file mode 100644 index 0000000..cab37b3 --- /dev/null +++ b/modules/pam_userdb/pam_userdb.c @@ -0,0 +1,512 @@ +/* pam_userdb module */ + +/* + * Written by Cristian Gafton <gafton@redhat.com> 1996/09/10 + * See the end of the file for Copyright Information + */ + +#include "config.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> +#ifdef HAVE_LIBXCRYPT +#include <xcrypt.h> +#elif defined(HAVE_CRYPT_H) +#include <crypt.h> +#endif + +#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 */ +# define HAVE_DBM /* for BerkDB 5.0 and later */ +# 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> +#include <security/pam_ext.h> +#include <security/_pam_macros.h> + +/* + * Conversation function to obtain the user's password + */ +static int +obtain_authtok(pam_handle_t *pamh) +{ + char *resp; + const void *item; + int retval; + + retval = pam_prompt(pamh, PAM_PROMPT_ECHO_OFF, &resp, _("Password: ")); + + if (retval != PAM_SUCCESS) + return retval; + + if (resp == NULL) + return PAM_CONV_ERR; + + /* set the auth token */ + retval = pam_set_item(pamh, PAM_AUTHTOK, resp); + + /* clean it up */ + _pam_overwrite(resp); + _pam_drop(resp); + + if ( (retval != PAM_SUCCESS) || + (retval = pam_get_item(pamh, PAM_AUTHTOK, &item)) + != PAM_SUCCESS ) { + return retval; + } + + return retval; +} + +static int +_pam_parse (pam_handle_t *pamh, int argc, const char **argv, + const char **database, const 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 (!strcasecmp(*argv, "use_first_pass")) + ctrl |= PAM_USE_FPASS_ARG; + else if (!strcasecmp(*argv, "try_first_pass")) + ctrl |= PAM_TRY_FPASS_ARG; + else if (!strncasecmp(*argv,"db=", 3)) + { + *database = (*argv) + 3; + if (**database == '\0') { + *database = NULL; + pam_syslog(pamh, LOG_ERR, + "db= specification missing argument - ignored"); + } + } + else if (!strncasecmp(*argv,"crypt=", 6)) + { + *cryptmode = (*argv) + 6; + if (**cryptmode == '\0') + pam_syslog(pamh, LOG_ERR, + "crypt= specification missing argument - ignored"); + } + else + { + pam_syslog(pamh, LOG_ERR, "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 (pam_handle_t *pamh, 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_syslog(pamh, LOG_ERR, + "user_lookup: could not open database `%s': %m", database); + return -2; + } + + /* dump out the database contents for debugging */ + if (ctrl & PAM_DUMP_ARG) { + pam_syslog(pamh, LOG_INFO, "Database dump:"); + for (key = dbm_firstkey(dbm); key.dptr != NULL; + key = dbm_nextkey(dbm)) { + data = dbm_fetch(dbm, key); + pam_syslog(pamh, 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) { + if (asprintf(&key.dptr, "%s-%s", user, pass) < 0) + key.dptr = NULL; + else + key.dsize = strlen(key.dptr); + } else { + key.dptr = 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_syslog(pamh, LOG_INFO, + "password in database is [%p]`%.*s', len is %d", + data.dptr, data.dsize, (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 (cryptmode && strncasecmp(cryptmode, "crypt", 5) == 0) { + + /* crypt(3) password storage */ + + char *cryptpw = NULL; + + if (data.dsize < 13) { + compare = -2; + } else if (ctrl & PAM_ICASE_ARG) { + compare = -2; + } else { +#ifdef HAVE_CRYPT_R + struct crypt_data *cdata = NULL; + cdata = malloc(sizeof(*cdata)); + if (cdata != NULL) { + cdata->initialized = 0; + cryptpw = crypt_r(pass, data.dptr, cdata); + } +#else + cryptpw = crypt (pass, data.dptr); +#endif + if (cryptpw && strlen(cryptpw) == (size_t)data.dsize) { + compare = memcmp(data.dptr, cryptpw, data.dsize); + } else { + compare = -2; + if (ctrl & PAM_DEBUG_ARG) { + if (cryptpw) + pam_syslog(pamh, LOG_INFO, "lengths of computed and stored hashes differ"); + else + pam_syslog(pamh, LOG_INFO, "crypt() returned NULL"); + } + } +#ifdef HAVE_CRYPT_R + free(cdata); +#endif + } + + } else { + + /* Unknown password encryption method - + * default to plaintext password storage + */ + + if (strlen(pass) != (size_t)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 (cryptmode && strncasecmp(cryptmode, "none", 4) + && (ctrl & PAM_DEBUG_ARG)) { + pam_syslog(pamh, LOG_INFO, "invalid value for crypt parameter: %s", + cryptmode); + pam_syslog(pamh, 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_syslog(pamh, LOG_INFO, "error returned by dbm_fetch: %m"); + } + + /* 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 ((size_t)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) --- */ + +int +pam_sm_authenticate(pam_handle_t *pamh, int flags UNUSED, + int argc, const char **argv) +{ + const char *username; + const void *password; + const char *database = NULL; + const char *cryptmode = NULL; + int retval = PAM_AUTH_ERR, ctrl; + + /* parse arguments */ + ctrl = _pam_parse(pamh, argc, argv, &database, &cryptmode); + if (database == NULL) { + pam_syslog(pamh, LOG_ERR, "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)) { + pam_syslog(pamh, LOG_ERR, "can not get the username"); + return PAM_SERVICE_ERR; + } + + if ((ctrl & PAM_USE_FPASS_ARG) == 0 && (ctrl & PAM_TRY_FPASS_ARG) == 0) { + /* Converse to obtain a password */ + retval = obtain_authtok(pamh); + if (retval != PAM_SUCCESS) { + pam_syslog(pamh, LOG_ERR, "can not obtain password from user"); + return retval; + } + } + + /* Check if we got a password */ + retval = pam_get_item(pamh, PAM_AUTHTOK, &password); + if (retval != PAM_SUCCESS || password == NULL) { + if ((ctrl & PAM_TRY_FPASS_ARG) != 0) { + /* Converse to obtain a password */ + retval = obtain_authtok(pamh); + if (retval != PAM_SUCCESS) { + pam_syslog(pamh, LOG_ERR, "can not obtain password from user"); + return retval; + } + retval = pam_get_item(pamh, PAM_AUTHTOK, &password); + } + if (retval != PAM_SUCCESS || password == NULL) { + pam_syslog(pamh, LOG_ERR, "can not recover user password"); + return PAM_AUTHTOK_RECOVERY_ERR; + } + } + + if (ctrl & PAM_DEBUG_ARG) + pam_syslog(pamh, LOG_INFO, "Verify user `%s' with a password", + username); + + /* Now use the username to look up password in the database file */ + retval = user_lookup(pamh, 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_syslog(pamh, LOG_NOTICE, + "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_syslog(pamh, LOG_NOTICE, + "user `%s' not found in the database", username); + return PAM_USER_UNKNOWN; + case 0: + /* Otherwise, the authentication looked good */ + pam_syslog(pamh, LOG_NOTICE, "user '%s' granted access", username); + return PAM_SUCCESS; + default: + /* we don't know anything about this return value */ + pam_syslog(pamh, LOG_ERR, + "internal module error (retval = %d, user = `%s'", + retval, username); + return PAM_SERVICE_ERR; + } + + /* should not be reached */ + return PAM_IGNORE; +} + +int +pam_sm_setcred(pam_handle_t *pamh UNUSED, int flags UNUSED, + int argc UNUSED, const char **argv UNUSED) +{ + return PAM_SUCCESS; +} + +int +pam_sm_acct_mgmt(pam_handle_t *pamh, int flags UNUSED, + int argc, const char **argv) +{ + const char *username; + const char *database = NULL; + const char *cryptmode = NULL; + int retval = PAM_AUTH_ERR, ctrl; + + /* parse arguments */ + ctrl = _pam_parse(pamh, argc, argv, &database, &cryptmode); + + /* Get the username */ + retval = pam_get_user(pamh, &username, NULL); + if ((retval != PAM_SUCCESS) || (!username)) { + pam_syslog(pamh, LOG_ERR,"can not get the username"); + return PAM_SERVICE_ERR; + } + + /* Now use the username to look up password in the database file */ + retval = user_lookup(pamh, 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_syslog(pamh, LOG_ERR, + "internal module error (retval = %d, user = `%s'", + retval, username); + return PAM_SERVICE_ERR; + } + + return PAM_SUCCESS; +} + +/* + * 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. + */ |