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