source/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         setup_logging("pam_smbpass",False);
  85         lp_set_in_client(True);
  86
  87         ctrl = set_ctrl(flags, argc, argv);
  88
  89         /* Get a few bytes so we can pass our return value to
  90                 pam_sm_setcred(). */
  91         ret_data = SMB_MALLOC_P(int);
  92
  93         /* we need to do this before we call AUTH_RETURN */
  94         /* Getting into places that might use LDAP -- protect the app
  95         from a SIGPIPE it's not expecting */
  96         oldsig_handler = CatchSignal(SIGPIPE, SIGNAL_CAST SIG_IGN);
  97
  98         /* get the username */
  99         retval = pam_get_user( pamh, &name, "Username: " );
 100         if ( retval != PAM_SUCCESS ) {
 101                 if (on( SMB_DEBUG, ctrl )) {
 102                         _log_err(LOG_DEBUG, "auth: could not identify user");
 103                 }
 104                 AUTH_RETURN;
 105         }
 106         if (on( SMB_DEBUG, ctrl )) {
 107                 _log_err( LOG_DEBUG, "username [%s] obtained", name );
 108         }
 109
 110         if (geteuid() != 0) {
 111                 _log_err( LOG_DEBUG, "Cannot access samba password database, not running as root.");
 112                 retval = PAM_AUTHINFO_UNAVAIL;
 113                 AUTH_RETURN;
 114         }
 115
 116         if (!initialize_password_db(True, NULL)) {
 117                 _log_err( LOG_ALERT, "Cannot access samba password database" );
 118                 retval = PAM_AUTHINFO_UNAVAIL;
 119                 AUTH_RETURN;
 120         }
 121
 122         sampass = samu_new( NULL );
 123         if (!sampass) {
 124                 _log_err( LOG_ALERT, "Cannot talloc a samu struct" );
 125                 retval = nt_status_to_pam(NT_STATUS_NO_MEMORY);
 126                 AUTH_RETURN;
 127         }
 128
 129         found = pdb_getsampwnam( sampass, name );
 130
 131         if (on( SMB_MIGRATE, ctrl )) {
 132                 retval = _smb_add_user(pamh, ctrl, name, sampass, found);
 133                 TALLOC_FREE(sampass);
 134                 AUTH_RETURN;
 135         }
 136
 137         if (!found) {
 138                 _log_err(LOG_ALERT, "Failed to find entry for user %s.", name);
 139                 retval = PAM_USER_UNKNOWN;
 140                 TALLOC_FREE(sampass);
 141                 sampass = NULL;
 142                 AUTH_RETURN;
 143         }
 144
 145         /* if this user does not have a password... */
 146
 147         if (_smb_blankpasswd( ctrl, sampass )) {
 148                 TALLOC_FREE(sampass);
 149                 retval = PAM_SUCCESS;
 150                 AUTH_RETURN;
 151         }
 152
 153         /* get this user's authentication token */
 154
 155         retval = _smb_read_password(pamh, ctrl, NULL, "Password: ", NULL, _SMB_AUTHTOK, &p);
 156         if (retval != PAM_SUCCESS ) {
 157                 _log_err(LOG_CRIT, "auth: no password provided for [%s]", name);
 158                 TALLOC_FREE(sampass);
 159                 AUTH_RETURN;
 160         }
 161
 162         /* verify the password of this user */
 163
 164         retval = _smb_verify_password( pamh, sampass, p, ctrl );
 165         TALLOC_FREE(sampass);
 166         p = NULL;
 167         AUTH_RETURN;
 168 }
 169
 170 /*
 171  * This function is for setting samba credentials.  If anyone comes up
 172  * with any credentials they think should be set, let me know.
 173  */
 174
 175 int pam_sm_setcred(pam_handle_t *pamh, int flags,
 176                    int argc, const char **argv)
 177 {
 178         int retval, *pretval = NULL;
 179
 180         retval = PAM_SUCCESS;
 181
 182         pam_get_data(pamh, "smb_setcred_return", (const void **) &pretval);
 183         if(pretval) {
 184                 retval = *pretval;
 185                 SAFE_FREE(pretval);
 186         }
 187         pam_set_data(pamh, "smb_setcred_return", NULL, NULL);
 188
 189         return retval;
 190 }
 191
 192 /* Helper function for adding a user to the db. */
 193 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
 194                          const char *name, struct samu *sampass, bool exist)
 195 {
 196         char *err_str = NULL;
 197         char *msg_str = NULL;
 198         const char *pass = NULL;
 199         int retval;
 200
 201         /* Get the authtok; if we don't have one, silently fail. */
 202         retval = pam_get_item( pamh, PAM_AUTHTOK, (const void **) &pass );
 203
 204         if (retval != PAM_SUCCESS) {
 205                 _log_err( LOG_ALERT
 206                         , "pam_get_item returned error to pam_sm_authenticate" );
 207                 return PAM_AUTHTOK_RECOVER_ERR;
 208         } else if (pass == NULL) {
 209                 return PAM_AUTHTOK_RECOVER_ERR;
 210         }
 211
 212         /* Add the user to the db if they aren't already there. */
 213         if (!exist) {
 214                 retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_ADD_USER|LOCAL_SET_PASSWORD,
 215                                         pass, &err_str, &msg_str));
 216                 if (!retval && err_str) {
 217                         make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 218                 } else if (msg_str) {
 219                         make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 220                 }
 221                 pass = NULL;
 222
 223                 SAFE_FREE(err_str);
 224                 SAFE_FREE(msg_str);
 225                 return PAM_IGNORE;
 226         } else {
 227                 /* mimick 'update encrypted' as long as the 'no pw req' flag is not set */
 228                 if ( pdb_get_acct_ctrl(sampass) & ~ACB_PWNOTREQ ) {
 229                         retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_SET_PASSWORD,
 230                                         pass, &err_str, &msg_str));
 231                         if (!retval && err_str) {
 232                                 make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 233                         } else if (msg_str) {
 234                                 make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 235                         }
 236                 }
 237         }
 238
 239         SAFE_FREE(err_str);
 240         SAFE_FREE(msg_str);
 241         pass = NULL;
 242         return PAM_IGNORE;
 243 }
 244
 245 /* static module data */
 246 #ifdef PAM_STATIC
 247 struct pam_module _pam_smbpass_auth_modstruct = {
 248         "pam_smbpass",
 249         pam_sm_authenticate,
 250         pam_sm_setcred,
 251         NULL,
 252         NULL,
 253         NULL,
 254         NULL
 255 };
 256 #endif