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 "lib/util/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, 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_library();
  84
  85         ctrl = set_ctrl(pamh, flags, argc, argv);
  86
  87         /* Get a few bytes so we can pass our return value to
  88                 pam_sm_setcred(). */
  89         ret_data = SMB_MALLOC_P(int);
  90
  91         /* we need to do this before we call AUTH_RETURN */
  92         /* Getting into places that might use LDAP -- protect the app
  93         from a SIGPIPE it's not expecting */
  94         oldsig_handler = CatchSignal(SIGPIPE, SIG_IGN);
  95
  96         /* get the username */
  97         retval = pam_get_user( pamh, &name, "Username: " );
  98         if ( retval != PAM_SUCCESS ) {
  99                 if (on( SMB_DEBUG, ctrl )) {
 100                         _log_err(pamh, LOG_DEBUG, "auth: could not identify user");
 101                 }
 102                 AUTH_RETURN;
 103         }
 104         if (on( SMB_DEBUG, ctrl )) {
 105                 _log_err(pamh, LOG_DEBUG, "username [%s] obtained", name );
 106         }
 107
 108         if (geteuid() != 0) {
 109                 _log_err(pamh, LOG_DEBUG, "Cannot access samba password database, not running as root.");
 110                 retval = PAM_AUTHINFO_UNAVAIL;
 111                 AUTH_RETURN;
 112         }
 113
 114         if (!initialize_password_db(True, NULL)) {
 115                 _log_err(pamh, LOG_ALERT, "Cannot access samba password database" );
 116                 retval = PAM_AUTHINFO_UNAVAIL;
 117                 AUTH_RETURN;
 118         }
 119
 120         sampass = samu_new( NULL );
 121         if (!sampass) {
 122                 _log_err(pamh, LOG_ALERT, "Cannot talloc a samu struct" );
 123                 retval = nt_status_to_pam(NT_STATUS_NO_MEMORY);
 124                 AUTH_RETURN;
 125         }
 126
 127         found = pdb_getsampwnam( sampass, name );
 128
 129         if (on( SMB_MIGRATE, ctrl )) {
 130                 retval = _smb_add_user(pamh, ctrl, name, sampass, found);
 131                 TALLOC_FREE(sampass);
 132                 AUTH_RETURN;
 133         }
 134
 135         if (!found) {
 136                 _log_err(pamh, LOG_ALERT, "Failed to find entry for user %s.", name);
 137                 retval = PAM_USER_UNKNOWN;
 138                 TALLOC_FREE(sampass);
 139                 sampass = NULL;
 140                 AUTH_RETURN;
 141         }
 142
 143         /* if this user does not have a password... */
 144
 145         if (_smb_blankpasswd( ctrl, sampass )) {
 146                 TALLOC_FREE(sampass);
 147                 retval = PAM_SUCCESS;
 148                 AUTH_RETURN;
 149         }
 150
 151         /* get this user's authentication token */
 152
 153         retval = _smb_read_password(pamh, ctrl, NULL, "Password: ", NULL, _SMB_AUTHTOK, &p);
 154         if (retval != PAM_SUCCESS ) {
 155                 _log_err(pamh,LOG_CRIT, "auth: no password provided for [%s]", name);
 156                 TALLOC_FREE(sampass);
 157                 AUTH_RETURN;
 158         }
 159
 160         /* verify the password of this user */
 161
 162         retval = _smb_verify_password( pamh, sampass, p, ctrl );
 163         TALLOC_FREE(sampass);
 164         p = NULL;
 165         AUTH_RETURN;
 166 }
 167
 168 /*
 169  * This function is for setting samba credentials.  If anyone comes up
 170  * with any credentials they think should be set, let me know.
 171  */
 172
 173 int pam_sm_setcred(pam_handle_t *pamh, int flags,
 174                    int argc, const char **argv)
 175 {
 176         int retval, *pretval = NULL;
 177
 178         retval = PAM_SUCCESS;
 179
 180         _pam_get_data(pamh, "smb_setcred_return", &pretval);
 181         if(pretval) {
 182                 retval = *pretval;
 183                 SAFE_FREE(pretval);
 184         }
 185         pam_set_data(pamh, "smb_setcred_return", NULL, NULL);
 186
 187         return retval;
 188 }
 189
 190 /* Helper function for adding a user to the db. */
 191 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
 192                          const char *name, struct samu *sampass, bool exist)
 193 {
 194         char *err_str = NULL;
 195         char *msg_str = NULL;
 196         const char *pass = NULL;
 197         int retval;
 198
 199         /* Get the authtok; if we don't have one, silently fail. */
 200         retval = _pam_get_item( pamh, PAM_AUTHTOK, &pass );
 201
 202         if (retval != PAM_SUCCESS) {
 203                 _log_err(pamh, LOG_ALERT
 204                         , "pam_get_item returned error to pam_sm_authenticate" );
 205                 return PAM_AUTHTOK_RECOVER_ERR;
 206         } else if (pass == NULL) {
 207                 return PAM_AUTHTOK_RECOVER_ERR;
 208         }
 209
 210         /* Add the user to the db if they aren't already there. */
 211         if (!exist) {
 212                 retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_ADD_USER|LOCAL_SET_PASSWORD,
 213                                         pass, &err_str, &msg_str));
 214                 if (!retval && err_str) {
 215                         make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 216                 } else if (msg_str) {
 217                         make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 218                 }
 219                 pass = NULL;
 220
 221                 SAFE_FREE(err_str);
 222                 SAFE_FREE(msg_str);
 223                 return PAM_IGNORE;
 224         } else {
 225                 /* mimick 'update encrypted' as long as the 'no pw req' flag is not set */
 226                 if ( pdb_get_acct_ctrl(sampass) & ~ACB_PWNOTREQ ) {
 227                         retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_SET_PASSWORD,
 228                                         pass, &err_str, &msg_str));
 229                         if (!retval && err_str) {
 230                                 make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 231                         } else if (msg_str) {
 232                                 make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 233                         }
 234                 }
 235         }
 236
 237         SAFE_FREE(err_str);
 238         SAFE_FREE(msg_str);
 239         pass = NULL;
 240         return PAM_IGNORE;
 241 }
 242
 243 /* static module data */
 244 #ifdef PAM_STATIC
 245 struct pam_module _pam_smbpass_auth_modstruct = {
 246         "pam_smbpass",
 247         pam_sm_authenticate,
 248         pam_sm_setcred,
 249         NULL,
 250         NULL,
 251         NULL,
 252         NULL
 253 };
 254 #endif