usr/src/lib/pam_modules/unix_auth/unix_auth.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26
  27 #include <stdlib.h>
  28 #include <pwd.h>
  29 #include <shadow.h>
  30 #include <syslog.h>
  31 #include <errno.h>
  32 #include <string.h>
  33 #include <crypt.h>
  34 #include <unistd.h>
  35 #include <user_attr.h>
  36 #include <auth_attr.h>
  37 #include <userdefs.h>
  38 #include <deflt.h>
  39 #include <sys/stat.h>
  40 #include <sys/param.h>
  41 #include <stdarg.h>
  42
  43 #include <security/pam_appl.h>
  44 #include <security/pam_modules.h>
  45 #include <security/pam_impl.h>
  46
  47 #include <libintl.h>
  48
  49 #include <passwdutil.h>
  50
  51 #define LOGINADMIN      "/etc/default/login"
  52 #define MAXTRYS         5
  53
  54 /*PRINTFLIKE2*/
  55 void
  56 error(pam_handle_t *pamh, char *fmt, ...)
  57 {
  58         va_list ap;
  59         char messages[1][PAM_MAX_MSG_SIZE];
  60
  61         va_start(ap, fmt);
  62         (void) vsnprintf(messages[0], sizeof (messages[0]), fmt, ap);
  63         (void) __pam_display_msg(pamh, PAM_ERROR_MSG, 1, messages, NULL);
  64         va_end(ap);
  65 }
  66
  67 static int
  68 get_max_failed(char *user)
  69 {
  70         char *val = NULL;
  71         userattr_t *uattr;
  72         int do_lock = 0;
  73         int retval = 0;
  74         char *p;
  75         void    *defp;
  76
  77         if ((uattr = getusernam(user)) != NULL)
  78                 val = kva_match(uattr->attr, USERATTR_LOCK_AFTER_RETRIES_KW);
  79
  80         if (val != NULL) {
  81                 do_lock = (strcasecmp(val, "yes") == 0);
  82         } else if ((defp = defopen_r(AUTH_POLICY)) != NULL) {
  83                 int flags;
  84                 flags = defcntl_r(DC_GETFLAGS, 0, defp);
  85                 TURNOFF(flags, DC_CASE);
  86                 (void) defcntl_r(DC_SETFLAGS, flags, defp);
  87                 if ((p = defread_r("LOCK_AFTER_RETRIES=", defp)) != NULL)
  88                         do_lock = (strcasecmp(p, "yes") == 0);
  89                 defclose_r(defp);
  90         }
  91
  92         if (uattr != NULL)
  93                 free_userattr(uattr);
  94
  95         if (do_lock) {
  96                 retval = MAXTRYS;
  97                 if ((defp = defopen_r(LOGINADMIN)) != NULL) {
  98                         if ((p = defread_r("RETRIES=", defp)) != NULL)
  99                                 retval = atoi(p);
 100                         defclose_r(defp);
 101                 }
 102         }
 103
 104         return (retval);
 105 }
 106
 107 static void
 108 display_warning(pam_handle_t *pamh, int failures, char *homedir)
 109 {
 110         char hushpath[MAXPATHLEN];
 111         struct stat buf;
 112
 113         (void) snprintf(hushpath, sizeof (hushpath), "%s/.hushlogin", homedir);
 114         if (stat(hushpath, &buf) == 0)
 115                 return;
 116
 117         if (failures == 1)
 118                 error(pamh, "Warning: 1 failed login attempt since last "
 119                     "successful login.");
 120         else if (failures < FAILCOUNT_MASK)
 121                 error(pamh, "Warning: %d failed login attempts since last "
 122                     "successful login.", failures);
 123         else
 124                 error(pamh, "Warning: at least %d failed login attempts since "
 125                     "last successful login.", failures);
 126 }
 127
 128 /*
 129  * int pam_sm_authenticate(pamh, flags, arc, argv)
 130  *
 131  * This routine verifies that the password as stored in the
 132  * PAM_AUTHTOK item is indeed the password that belongs to the user
 133  * as stored in PAM_USER.
 134  *
 135  * This routine will not establish Secure RPC Credentials, the pam_dhkeys
 136  * module should be stacked before us if Secure RPC Credentials are needed
 137  * to obtain passwords.
 138  */
 139 int
 140 pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
 141 {
 142         int     i;
 143         int     debug = 0;
 144         int     nowarn = (flags & PAM_SILENT) != 0;
 145         char    *user;
 146         char    *passwd;
 147         char    *rep_passwd;
 148         char    *crypt_passwd;
 149         char    *repository_name;
 150         struct pam_repository *auth_rep;
 151         pwu_repository_t *pwu_rep;
 152         attrlist attr_pw[4];
 153         int     result;
 154         int     server_policy = 0;
 155         int     old_failed_count;
 156         char    *homedir = NULL;
 157         int     dolock = 1;
 158
 159         for (i = 0; i < argc; i++) {
 160                 if (strcmp(argv[i], "debug") == 0)
 161                         debug = 1;
 162                 else if (strcmp(argv[i], "nowarn") == 0)
 163                         nowarn = 1;
 164                 else if (strcmp(argv[i], "server_policy") == 0)
 165                         server_policy = 1;
 166                 else if (strcmp(argv[i], "nolock") == 0)
 167                         dolock = 0;
 168         }
 169
 170         if (debug)
 171                 __pam_log(LOG_AUTH | LOG_DEBUG,
 172                     "pam_unix_auth: entering pam_sm_authenticate()");
 173
 174         if (pam_get_item(pamh, PAM_USER, (void **)&user) != PAM_SUCCESS) {
 175                 __pam_log(LOG_AUTH | LOG_DEBUG, "pam_unix_auth: USER not set");
 176                 return (PAM_SYSTEM_ERR);
 177         }
 178
 179         if (user == NULL || *user == '\0') {
 180                 __pam_log(LOG_AUTH | LOG_DEBUG,
 181                     "pam_unix_auth: USER NULL or empty!\n");
 182                 return (PAM_USER_UNKNOWN);
 183         }
 184
 185         if (pam_get_item(pamh, PAM_AUTHTOK, (void **)&passwd) != PAM_SUCCESS) {
 186                 __pam_log(LOG_AUTH | LOG_DEBUG,
 187                     "pam_unix_auth: AUTHTOK not set!\n");
 188                 return (PAM_SYSTEM_ERR);
 189         }
 190
 191         result = pam_get_item(pamh, PAM_REPOSITORY, (void **)&auth_rep);
 192         if (result == PAM_SUCCESS && auth_rep != NULL) {
 193                 if ((pwu_rep = calloc(1, sizeof (*pwu_rep))) == NULL)
 194                         return (PAM_BUF_ERR);
 195                 pwu_rep->type = auth_rep->type;
 196                 pwu_rep->scope = auth_rep->scope;
 197                 pwu_rep->scope_len = auth_rep->scope_len;
 198         } else {
 199                 pwu_rep = PWU_DEFAULT_REP;
 200         }
 201
 202         /*
 203          * Get password and the name of the repository where the
 204          * password resides.
 205          */
 206         attr_pw[0].type = ATTR_PASSWD;          attr_pw[0].next = &attr_pw[1];
 207         attr_pw[1].type = ATTR_REP_NAME;        attr_pw[1].next = &attr_pw[2];
 208         /*
 209          * Also get the current number of failed logins; we use
 210          * this later to determine whether we need to reset the count
 211          * on a succesful authentication. We use the home-directory
 212          * to look for .hushlogin in order to optionaly surpress the
 213          * "failed attempts" message.
 214          */
 215         attr_pw[2].type = ATTR_FAILED_LOGINS;   attr_pw[2].next = &attr_pw[3];
 216         attr_pw[3].type = ATTR_HOMEDIR;         attr_pw[3].next = NULL;
 217
 218         result = __get_authtoken_attr(user, pwu_rep, attr_pw);
 219
 220         if (pwu_rep != PWU_DEFAULT_REP)
 221                 free(pwu_rep);
 222
 223         if (result == PWU_NOT_FOUND) {
 224                 __pam_log(LOG_AUTH | LOG_DEBUG,
 225                     "pam_unix_auth: user %s not found\n", user);
 226                 return (PAM_USER_UNKNOWN);
 227         }
 228
 229         if (result == PWU_DENIED) {
 230                 __pam_log(LOG_AUTH | LOG_DEBUG,
 231                     "pam_unix_auth: failed to obtain attributes");
 232                 return (PAM_PERM_DENIED);
 233         }
 234
 235         if (result != PWU_SUCCESS)
 236                 return (PAM_SYSTEM_ERR);
 237
 238         rep_passwd = attr_pw[0].data.val_s;
 239         repository_name = attr_pw[1].data.val_s;
 240         old_failed_count = attr_pw[2].data.val_i;
 241         homedir = attr_pw[3].data.val_s;
 242
 243         /*
 244          * Chop off old SunOS-style password aging information.
 245          *
 246          * Note: old style password aging is only defined for UNIX-style
 247          *       crypt strings, hence the comma will always be at position 14.
 248          * Note: This code is here because some other vendors might still
 249          *       support this style of password aging. If we don't remove
 250          *       the age field, no one will be able to login.
 251          * XXX   yank this code when we're certain this "compatibility"
 252          *       isn't needed anymore.
 253          */
 254         if (rep_passwd != NULL && rep_passwd[0] != '$' &&
 255             strlen(rep_passwd) > 13 && rep_passwd[13] == ',')
 256                 rep_passwd[13] = '\0';
 257
 258         /* Is a password check required? */
 259         if (rep_passwd == NULL || *rep_passwd == '\0') {
 260                 if (flags & PAM_DISALLOW_NULL_AUTHTOK) {
 261                         result = PAM_AUTH_ERR;
 262                         __pam_log(LOG_AUTH | LOG_NOTICE,
 263                             "pam_unix_auth: empty password for %s not allowed.",
 264                             user);
 265                         goto out;
 266                 } else {
 267                         result = PAM_SUCCESS;
 268                         goto out;
 269                 }
 270         }
 271
 272         /*
 273          * Password check *is* required. Make sure we have a valid
 274          * pointer in PAM_AUTHTOK
 275          */
 276         if (passwd == NULL) {
 277                 result = PAM_AUTH_ERR;
 278                 goto out;
 279         }
 280
 281         if (server_policy &&
 282             strcmp(repository_name, "files") != 0 &&
 283             strcmp(repository_name, "nis") != 0) {
 284                 result = PAM_IGNORE;
 285                 goto out;
 286         }
 287
 288         /* Now check the entered password */
 289         if ((crypt_passwd = crypt(passwd, rep_passwd)) == NULL) {
 290                 switch (errno) {
 291                 case ENOMEM:
 292                         result = PAM_BUF_ERR;
 293                         break;
 294                 case ELIBACC:
 295                         result = PAM_OPEN_ERR;
 296                         break;
 297                 default:
 298                         result = PAM_SYSTEM_ERR;
 299                 }
 300                 goto out;
 301         }
 302
 303         if (strcmp(crypt_passwd, rep_passwd) == 0)
 304                 result = PAM_SUCCESS;
 305         else
 306                 result = PAM_AUTH_ERR;
 307
 308         /* Clear or increment failed failed count */
 309         if (dolock && (result == PAM_SUCCESS && old_failed_count > 0)) {
 310                 old_failed_count = __rst_failed_count(user, repository_name);
 311                 if (nowarn == 0 && old_failed_count > 0)
 312                         display_warning(pamh, old_failed_count, homedir);
 313         } else if (dolock && result == PAM_AUTH_ERR) {
 314                 int max_failed = get_max_failed(user);
 315                 if (max_failed != 0) {
 316                         if (__incr_failed_count(user, repository_name,
 317                             max_failed) == PWU_ACCOUNT_LOCKED)
 318                                 result = PAM_MAXTRIES;
 319                 }
 320         }
 321 out:
 322         if (rep_passwd)
 323                 free(rep_passwd);
 324         if (repository_name)
 325                 free(repository_name);
 326         if (homedir)
 327                 free(homedir);
 328         return (result);
 329 }
 330
 331 /*ARGSUSED*/
 332 int
 333 pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
 334 {
 335         return (PAM_IGNORE);
 336 }