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 static void ret_data_cleanup(pam_handle_t *pamh, void *data, int error_status)
  45 {
  46         free(data);
  47 }
  48
  49 #define AUTH_RETURN                                             \
  50 do {                                                            \
  51         /* Restore application signal handler */                \
  52         CatchSignal(SIGPIPE, oldsig_handler);                   \
  53         if(ret_data) {                                          \
  54                 *ret_data = retval;                             \
  55                 pam_set_data(pamh,                              \
  56                         "smb_setcred_return",                   \
  57                         (void *)ret_data,                       \
  58                         ret_data_cleanup);                      \
  59         }                                                       \
  60         TALLOC_FREE(frame);                                     \
  61         return retval;                                          \
  62 } while (0)
  63
  64 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
  65                          const char *name, struct samu *sampass, bool exist);
  66
  67
  68 /*
  69  * pam_sm_authenticate() authenticates users against the samba password file.
  70  *
  71  *      First, obtain the password from the user. Then use a
  72  *      routine in 'support.c' to authenticate the user.
  73  */
  74
  75 #define _SMB_AUTHTOK  "-SMB-PASS"
  76
  77 int pam_sm_authenticate(pam_handle_t *pamh, int flags,
  78                         int argc, const char **argv)
  79 {
  80         unsigned int ctrl;
  81         int retval, *ret_data = NULL;
  82         struct samu *sampass = NULL;
  83         const char *name;
  84         void (*oldsig_handler)(int) = NULL;
  85         bool found;
  86         TALLOC_CTX *frame = talloc_stackframe();
  87
  88         /* Points to memory managed by the PAM library. Do not free. */
  89         char *p = NULL;
  90
  91         /* Samba initialization. */
  92         load_case_tables_library();
  93
  94         ctrl = set_ctrl(pamh, flags, argc, argv);
  95
  96         /* Get a few bytes so we can pass our return value to
  97                 pam_sm_setcred(). */
  98         ret_data = SMB_MALLOC_P(int);
  99
 100         /* we need to do this before we call AUTH_RETURN */
 101         /* Getting into places that might use LDAP -- protect the app
 102         from a SIGPIPE it's not expecting */
 103         oldsig_handler = CatchSignal(SIGPIPE, SIG_IGN);
 104
 105         /* get the username */
 106         retval = pam_get_user( pamh, &name, "Username: " );
 107         if ( retval != PAM_SUCCESS ) {
 108                 if (on( SMB_DEBUG, ctrl )) {
 109                         _log_err(pamh, LOG_DEBUG, "auth: could not identify user");
 110                 }
 111                 AUTH_RETURN;
 112         }
 113         if (on( SMB_DEBUG, ctrl )) {
 114                 _log_err(pamh, LOG_DEBUG, "username [%s] obtained", name );
 115         }
 116
 117         if (geteuid() != 0) {
 118                 _log_err(pamh, LOG_DEBUG, "Cannot access samba password database, not running as root.");
 119                 retval = PAM_AUTHINFO_UNAVAIL;
 120                 AUTH_RETURN;
 121         }
 122
 123         if (!initialize_password_db(True, NULL)) {
 124                 _log_err(pamh, LOG_ALERT, "Cannot access samba password database" );
 125                 retval = PAM_AUTHINFO_UNAVAIL;
 126                 AUTH_RETURN;
 127         }
 128
 129         sampass = samu_new( NULL );
 130         if (!sampass) {
 131                 _log_err(pamh, LOG_ALERT, "Cannot talloc a samu struct" );
 132                 retval = nt_status_to_pam(NT_STATUS_NO_MEMORY);
 133                 AUTH_RETURN;
 134         }
 135
 136         found = pdb_getsampwnam( sampass, name );
 137
 138         if (on( SMB_MIGRATE, ctrl )) {
 139                 retval = _smb_add_user(pamh, ctrl, name, sampass, found);
 140                 TALLOC_FREE(sampass);
 141                 AUTH_RETURN;
 142         }
 143
 144         if (!found) {
 145                 _log_err(pamh, LOG_ALERT, "Failed to find entry for user %s.", name);
 146                 retval = PAM_USER_UNKNOWN;
 147                 TALLOC_FREE(sampass);
 148                 sampass = NULL;
 149                 AUTH_RETURN;
 150         }
 151
 152         /* if this user does not have a password... */
 153
 154         if (_smb_blankpasswd( ctrl, sampass )) {
 155                 TALLOC_FREE(sampass);
 156                 retval = PAM_SUCCESS;
 157                 AUTH_RETURN;
 158         }
 159
 160         /* get this user's authentication token */
 161
 162         retval = _smb_read_password(pamh, ctrl, NULL, "Password: ", NULL, _SMB_AUTHTOK, &p);
 163         if (retval != PAM_SUCCESS ) {
 164                 _log_err(pamh,LOG_CRIT, "auth: no password provided for [%s]", name);
 165                 TALLOC_FREE(sampass);
 166                 AUTH_RETURN;
 167         }
 168
 169         /* verify the password of this user */
 170
 171         retval = _smb_verify_password( pamh, sampass, p, ctrl );
 172         TALLOC_FREE(sampass);
 173         p = NULL;
 174         AUTH_RETURN;
 175 }
 176
 177 /*
 178  * This function is for setting samba credentials.  If anyone comes up
 179  * with any credentials they think should be set, let me know.
 180  */
 181
 182 int pam_sm_setcred(pam_handle_t *pamh, int flags,
 183                    int argc, const char **argv)
 184 {
 185         int retval, *pretval = NULL;
 186
 187         retval = PAM_SUCCESS;
 188
 189         _pam_get_data(pamh, "smb_setcred_return", &pretval);
 190         if(pretval) {
 191                 retval = *pretval;
 192                 SAFE_FREE(pretval);
 193         }
 194         pam_set_data(pamh, "smb_setcred_return", NULL, NULL);
 195
 196         return retval;
 197 }
 198
 199 /* Helper function for adding a user to the db. */
 200 static int _smb_add_user(pam_handle_t *pamh, unsigned int ctrl,
 201                          const char *name, struct samu *sampass, bool exist)
 202 {
 203         char *err_str = NULL;
 204         char *msg_str = NULL;
 205         const char *pass = NULL;
 206         int retval;
 207         TALLOC_CTX *frame = talloc_stackframe();
 208
 209         /* Get the authtok; if we don't have one, silently fail. */
 210         retval = _pam_get_item( pamh, PAM_AUTHTOK, &pass );
 211
 212         if (retval != PAM_SUCCESS) {
 213                 _log_err(pamh, LOG_ALERT
 214                         , "pam_get_item returned error to pam_sm_authenticate" );
 215                 TALLOC_FREE(frame);
 216                 return PAM_AUTHTOK_RECOVER_ERR;
 217         }
 218
 219         /* Add the user to the db if they aren't already there. */
 220         if (!exist) {
 221                 retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_ADD_USER|LOCAL_SET_PASSWORD,
 222                                         pass, &err_str, &msg_str));
 223                 if (!retval && err_str) {
 224                         make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 225                 } else if (msg_str) {
 226                         make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 227                 }
 228                 pass = NULL;
 229
 230                 SAFE_FREE(err_str);
 231                 SAFE_FREE(msg_str);
 232                 TALLOC_FREE(frame);
 233                 return PAM_IGNORE;
 234         } else {
 235                 /* mimick 'update encrypted' as long as the 'no pw req' flag is not set */
 236                 if ( pdb_get_acct_ctrl(sampass) & ~ACB_PWNOTREQ ) {
 237                         retval = NT_STATUS_IS_OK(local_password_change(name, LOCAL_SET_PASSWORD,
 238                                         pass, &err_str, &msg_str));
 239                         if (!retval && err_str) {
 240                                 make_remark(pamh, ctrl, PAM_ERROR_MSG, err_str );
 241                         } else if (msg_str) {
 242                                 make_remark(pamh, ctrl, PAM_TEXT_INFO, msg_str );
 243                         }
 244                 }
 245         }
 246
 247         SAFE_FREE(err_str);
 248         SAFE_FREE(msg_str);
 249         pass = NULL;
 250         TALLOC_FREE(frame);
 251         return PAM_IGNORE;
 252 }
 253
 254 /* static module data */
 255 #ifdef PAM_STATIC
 256 struct pam_module _pam_smbpass_auth_modstruct = {
 257         "pam_smbpass",
 258         pam_sm_authenticate,
 259         pam_sm_setcred,
 260         NULL,
 261         NULL,
 262         NULL,
 263         NULL
 264 };
 265 #endif