source3/pam_smbpass/pam_smb_auth.c

   1 /* Unix NT password database implementation, version 0.7.5.
   2  *
   3  * This program is free software; you can redistribute it and/or modify it under
   4  * the terms of the GNU General Public License as published by the Free
   5  * Software Foundation; either version 3 of the License, or (at your option)
   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 /* indicate the following groups are defined */
  18 #define PAM_SM_AUTH
  19
  20 #include "includes.h"
  21 #include "debug.h"
  22
  23 #ifndef LINUX
  24
  25 /* This is only used in the Sun implementation. */
  26 #if defined(HAVE_SECURITY_PAM_APPL_H)
  27 #include <security/pam_appl.h>
  28 #elif defined(HAVE_PAM_PAM_APPL_H)
  29 #include <pam/pam_appl.h>
  30 #endif
  31
  32 #endif  /* LINUX */
  33
  34 #if defined(HAVE_SECURITY_PAM_MODULES_H)
  35 #include <security/pam_modules.h>
  36 #elif defined(HAVE_PAM_PAM_MODULES_H)
  37 #include <pam/pam_modules.h>
  38 #endif
  39
  40 #include "general.h"
  41
  42 #include "support.h"
  43
  44 #define AUTH_RETURN                                             \
  45 do {                                                            \
  46         /* Restore application signal handler */                \
  47         CatchSignal(SIGPIPE, SIGNAL_CAST oldsig_handler);       \
  48         if(ret_data) {                                          \
  49                 *ret_data = retval;                             \
  50                 pam_set_data( pamh, "smb_setcred_return"        \
  51                               , (void *) ret_data, NULL );      \
  52         }                                                       \
  53         return retval;                                          \
  54 } while (0)
  55
  56 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
  57                          const char *name, struct samu *sampass, bool exist);
  58
  59
  60 /*
  61  * pam_sm_authenticate() authenticates users against the samba password file.
  62  *
  63  *      First, obtain the password from the user. Then use a
  64  *      routine in 'support.c' to authenticate the user.
  65  */
  66
  67 #define _SMB_AUTHTOK  "-SMB-PASS"
  68
  69 int pam_sm_authenticate(pam_handle_t *pamh, int flags,
  70                         int argc, const char **argv)
  71 {
  72         unsigned int ctrl;
  73         int retval, *ret_data = NULL;
  74         struct samu *sampass = NULL;
  75         const char *name;
  76         void (*oldsig_handler)(int) = NULL;
  77         bool found;
  78
  79         /* Points to memory managed by the PAM library. Do not free. */
  80         char *p = NULL;
  81
  82         /* Samba initialization. */
  83         load_case_tables();
  84         lp_set_in_client(True);
  85
  86         ctrl = set_ctrl(pamh, flags, argc, argv);
  87
  88         /* Get a few bytes so we can pass our return value to
  89                 pam_sm_setcred(). */
  90         ret_data = SMB_MALLOC_P(int);
  91
  92         /* we need to do this before we call AUTH_RETURN */
  93         /* Getting into places that might use LDAP -- protect the app
  94         from a SIGPIPE it's not expecting */
  95         oldsig_handler = CatchSignal(SIGPIPE, SIGNAL_CAST SIG_IGN);
  96
  97         /* get the username */
  98         retval = pam_get_user( pamh, &name, "Username: " );
  99         if ( retval != PAM_SUCCESS ) {
 100                 if (on( SMB_DEBUG, ctrl )) {
 101                         _log_err(pamh, LOG_DEBUG, "auth: could not identify user");
 102                 }
 103                 AUTH_RETURN;
 104         }
 105         if (on( SMB_DEBUG, ctrl )) {
 106                 _log_err(pamh, LOG_DEBUG, "username [%s] obtained", name );
 107         }
 108
 109         if (geteuid() != 0) {
 110                 _log_err(pamh, LOG_DEBUG, "Cannot access samba password database, not running as root.");
 111                 retval = PAM_AUTHINFO_UNAVAIL;
 112                 AUTH_RETURN;
 113         }
 114
 115         if (!initialize_password_db(True, NULL)) {
 116                 _log_err(pamh, LOG_ALERT, "Cannot access samba password database" );
 117                 retval = PAM_AUTHINFO_UNAVAIL;
 118                 AUTH_RETURN;
 119         }
 120
 121         sampass = samu_new( NULL );
 122         if (!sampass) {
 123                 _log_err(pamh, LOG_ALERT, "Cannot talloc a samu struct" );
 124                 retval = nt_status_to_pam(NT_STATUS_NO_MEMORY);
 125                 AUTH_RETURN;
 126         }
 127
 128         found = pdb_getsampwnam( sampass, name );
 129
 130         if (on( SMB_MIGRATE, ctrl )) {
 131                 retval = _smb_add_user(pamh, ctrl, name, sampass, found);
 132                 TALLOC_FREE(sampass);
 133                 AUTH_RETURN;
 134         }
 135
 136         if (!found) {
 137                 _log_err(pamh, LOG_ALERT, "Failed to find entry for user %s.", name);
 138                 retval = PAM_USER_UNKNOWN;
 139                 TALLOC_FREE(sampass);
 140                 sampass = NULL;
 141                 AUTH_RETURN;
 142         }
 143
 144         /* if this user does not have a password... */
 145
 146         if (_smb_blankpasswd( ctrl, sampass )) {
 147                 TALLOC_FREE(sampass);
 148                 retval = PAM_SUCCESS;
 149                 AUTH_RETURN;
 150         }
 151
 152         /* get this user's authentication token */
 153
 154         retval = _smb_read_password(pamh, ctrl, NULL, "Password: ", NULL, _SMB_AUTHTOK, &p);
 155         if (retval != PAM_SUCCESS ) {
 156                 _log_err(pamh,LOG_CRIT, "auth: no password provided for [%s]", name);
 157                 TALLOC_FREE(sampass);
 158                 AUTH_RETURN;
 159         }
 160
 161         /* verify the password of this user */
 162
 163         retval = _smb_verify_password( pamh, sampass, p, ctrl );
 164         TALLOC_FREE(sampass);
 165         p = NULL;
 166         AUTH_RETURN;
 167 }
 168
 169 /*
 170  * This function is for setting samba credentials.  If anyone comes up
 171  * with any credentials they think should be set, let me know.
 172  */
 173
 174 int pam_sm_setcred(pam_handle_t *pamh, int flags,
 175                    int argc, const char **argv)
 176 {
 177         int retval, *pretval = NULL;
 178
 179         retval = PAM_SUCCESS;
 180
 181         _pam_get_data(pamh, "smb_setcred_return", &pretval);
 182         if(pretval) {
 183                 retval = *pretval;
 184                 SAFE_FREE(pretval);
 185         }
 186         pam_set_data(pamh, "smb_setcred_return", NULL, NULL);
 187
 188         return retval;
 189 }
 190
 191 /* Helper function for adding a user to the db. */
 192 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
 193                          const char *name, struct samu *sampass, bool exist)
 194 {
 195         char *err_str = NULL;
 196         char *msg_str = NULL;
 197         const char *pass = NULL;
 198         int retval;
 199
 200         /* Get the authtok; if we don't have one, silently fail. */
 201         retval = _pam_get_item( pamh, PAM_AUTHTOK, &pass );
 202
 203         if (retval != PAM_SUCCESS) {
 204                 _log_err(pamh, LOG_ALERT
 205                         , "pam_get_item returned error to pam_sm_authenticate" );
 206                 return PAM_AUTHTOK_RECOVER_ERR;
 207         } else if (pass == NULL) {
 208                 return PAM_AUTHTOK_RECOVER_ERR;
 209         }
 210
 211         /* Add the user to the db if they aren't already there. */
 212         if (!exist) {
 213                 retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_ADD_USER|LOCAL_SET_PASSWORD,
 214                                         pass, &err_str, &msg_str));
 215                 if (!retval && err_str) {
 216                         make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 217                 } else if (msg_str) {
 218                         make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 219                 }
 220                 pass = NULL;
 221
 222                 SAFE_FREE(err_str);
 223                 SAFE_FREE(msg_str);
 224                 return PAM_IGNORE;
 225         } else {
 226                 /* mimick 'update encrypted' as long as the 'no pw req' flag is not set */
 227                 if ( pdb_get_acct_ctrl(sampass) & ~ACB_PWNOTREQ ) {
 228                         retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_SET_PASSWORD,
 229                                         pass, &err_str, &msg_str));
 230                         if (!retval && err_str) {
 231                                 make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 232                         } else if (msg_str) {
 233                                 make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 234                         }
 235                 }
 236         }
 237
 238         SAFE_FREE(err_str);
 239         SAFE_FREE(msg_str);
 240         pass = NULL;
 241         return PAM_IGNORE;
 242 }
 243
 244 /* static module data */
 245 #ifdef PAM_STATIC
 246 struct pam_module _pam_smbpass_auth_modstruct = {
 247         "pam_smbpass",
 248         pam_sm_authenticate,
 249         pam_sm_setcred,
 250         NULL,
 251         NULL,
 252         NULL,
 253         NULL
 254 };
 255 #endif