helpers/basic_auth/PAM/basic_pam_auth.cc

   1 /*
   2  * $Id$
   3  *
   4  * PAM authenticator module for Squid.
   5  * Copyright (C) 1999,2002,2003 Henrik Nordstrom <hno@squid-cache.org>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  20  *
  21  * Install instructions:
  22  *
  23  * This program authenticates users against a PAM configured authentication
  24  * service "squid". This allows you to authenticate Squid users to any
  25  * authentication source for which you have a PAM module. Commonly available
  26  * PAM modules includes "UNIX", RADIUS, Kerberos and SMB, but a lot of other
  27  * PAM modules are available from various sources.
  28  *
  29  * Example PAM configuration for standard UNIX passwd authentication:
  30  * /etc/pam.conf:
  31  *  squid auth     required /lib/security/pam_unix.so.1
  32  *  squid account  required /lib/security/pam_unix.so.1
  33  *
  34  * Note that some PAM modules (for example shadow password authentication)
  35  * requires the program to be installed suid root to gain access to the
  36  * user password database
  37  *
  38  * Change Log:
  39  *
  40  *   Version 2.3, 2009-11-06
  41  *      Converted to C++. Brought into line with Squid-3 code styles.
  42  *
  43  *   Version 2.2, 2003-11-05
  44  *      One shot mode is now the default mode of operation
  45  *      with persistent PAM connections enabled by -t option.
  46  *      Support for clearing the PAM_AUTHTOK attribute on
  47  *      persistent PAM connections.
  48  *
  49  *   Version 2.1, 2002-08-12
  50  *      Squid-2.5 support (URL encoded login, password strings)
  51  *
  52  *   Version 2.0, 2002-01-07
  53  *      One shot mode, command line options
  54  *      man page
  55  *
  56  *   Version 1.3, 1999-12-10
  57  *      Bugfix release 1.3 to work around Solaris 2.6
  58  *      brokenness (not sending arguments to conversation
  59  *      functions)
  60  *
  61  *   Version 1.2, internal release
  62  *
  63  *   Version 1.1, 1999-05-11
  64  *      Initial version
  65  *
  66  * Compile this program with: gcc -o basic_pam_auth basic_pam_auth.cc -lpam -ldl
  67  */
  68 #include "squid.h"
  69 #include "helpers/defines.h"
  70 #include "rfc1738.h"
  71 #include "util.h"
  72
  73 #if HAVE_STDIO_H
  74 #include <stdio.h>
  75 #endif
  76 #if HAVE_ASSERT_H
  77 #include <assert.h>
  78 #endif
  79 #if HAVE_STRING_H
  80 #include <string.h>
  81 #endif
  82 #if HAVE_SIGNAL_H
  83 #include <signal.h>
  84 #endif
  85 #if HAVE_TIME_H
  86 #include <time.h>
  87 #endif
  88 #if HAVE_UNISTD_H
  89 #include <unistd.h>
  90 #endif
  91 #if HAVE_SECURITY_PAM_APPL_H
  92 #include <security/pam_appl.h>
  93 #endif
  94
  95 /* The default PAM service name */
  96 #if !defined(DEFAULT_SQUID_PAM_SERVICE)
  97 #define DEFAULT_SQUID_PAM_SERVICE "squid"
  98 #endif
  99
 100 /* The default TTL */
 101 #if !defined(DEFAULT_SQUID_PAM_TTL)
 102 #define DEFAULT_SQUID_PAM_TTL 0
 103 #endif
 104
 105 #if _SQUID_SOLARIS_
 106 static char *password = NULL;   /* Workaround for Solaris 2.6 brokenness */
 107 #endif
 108
 109 extern "C" int password_conversation(int num_msg, PAM_CONV_FUNC_CONST_PARM struct pam_message **msg,
 110                                      struct pam_response **resp, void *appdata_ptr);
 111
 112 /**
 113  * A simple "conversation" function returning the supplied password.
 114  * Has a bit to much error control, but this is my first PAM application
 115  * so I'd rather check everything than make any mistakes. The function
 116  * expects a single converstation message of type PAM_PROMPT_ECHO_OFF.
 117  */
 118 int
 119 password_conversation(int num_msg, PAM_CONV_FUNC_CONST_PARM struct pam_message **msg, struct pam_response **resp, void *appdata_ptr)
 120 {
 121     if (num_msg != 1 || msg[0]->msg_style != PAM_PROMPT_ECHO_OFF) {
 122         debug("ERROR: Unexpected PAM converstaion '%d/%s'\n", msg[0]->msg_style, msg[0]->msg);
 123         return PAM_CONV_ERR;
 124     }
 125 #if _SQUID_SOLARIS_
 126     if (!appdata_ptr) {
 127         /* Workaround for Solaris 2.6 where the PAM library is broken
 128          * and does not pass appdata_ptr to the conversation routine
 129          */
 130         appdata_ptr = password;
 131     }
 132 #endif
 133     if (!appdata_ptr) {
 134         debug("ERROR: No password available to password_converstation!\n");
 135         return PAM_CONV_ERR;
 136     }
 137     *resp = static_cast<struct pam_response *>(calloc(num_msg, sizeof(struct pam_response)));
 138     if (!*resp) {
 139         debug("ERROR: Out of memory!\n");
 140         return PAM_CONV_ERR;
 141     }
 142     (*resp)[0].resp = xstrdup((char *) appdata_ptr);
 143     (*resp)[0].resp_retcode = 0;
 144
 145     return ((*resp)[0].resp ? PAM_SUCCESS : PAM_CONV_ERR);
 146 }
 147
 148 static struct pam_conv conv = {
 149     &password_conversation,
 150     NULL
 151 };
 152
 153 static void usage(char *program)
 154 {
 155     fprintf(stderr, "Usage: %s [options..]\n", program);
 156     fprintf(stderr, " -n service_name\n");
 157     fprintf(stderr, "           The PAM service name (default \"%s\")\n", DEFAULT_SQUID_PAM_SERVICE);
 158     fprintf(stderr, " -t ttl    PAM connection ttl in seconds (default %d)\n", DEFAULT_SQUID_PAM_TTL);
 159     fprintf(stderr, "           during this time the same connection will be reused\n");
 160     fprintf(stderr, "           to authenticate all users\n");
 161     fprintf(stderr, " -o        Do not perform account mgmt (account expiration etc)\n");
 162     fprintf(stderr, " -1        Only one user authentication per PAM connection\n");
 163 }
 164
 165 int
 166 main(int argc, char *argv[])
 167 {
 168     pam_handle_t *pamh = NULL;
 169     int retval = PAM_SUCCESS;
 170     char *user;
 171     char *password_buf;
 172     char buf[HELPER_INPUT_BUFFER];
 173     time_t pamh_created = 0;
 174     int ttl = DEFAULT_SQUID_PAM_TTL;
 175     const char *service = DEFAULT_SQUID_PAM_SERVICE;
 176     int no_acct_mgmt = 0;
 177
 178     /* make standard output line buffered */
 179     setvbuf(stdout, NULL, _IOLBF, 0);
 180
 181     while (1) {
 182         int ch = getopt(argc, argv, "1n:t:o");
 183         switch (ch) {
 184         case -1:
 185             goto start;
 186         case 'n':
 187             service = optarg;
 188             break;
 189         case 't':
 190             ttl = atoi(optarg);
 191             break;
 192         case '1':
 193             ttl = 0;
 194             break;
 195         case 'o':
 196             no_acct_mgmt = 1;
 197             break;
 198         default:
 199             fprintf(stderr, "FATAL: Unknown getopt value '%c'\n", ch);
 200             usage(argv[0]);
 201             exit(1);
 202         }
 203     }
 204 start:
 205     if (optind < argc) {
 206         fprintf(stderr, "FATAL: Unknown option '%s'\n", argv[optind]);
 207         usage(argv[0]);
 208         exit(1);
 209     }
 210
 211     while (fgets(buf, HELPER_INPUT_BUFFER, stdin)) {
 212         user = buf;
 213         password_buf = strchr(buf, '\n');
 214         if (!password_buf) {
 215             debug("ERROR: %s: Unexpected input '%s'\n", argv[0], buf);
 216             goto error;
 217         }
 218         *password_buf = '\0';
 219         password_buf = strchr(buf, ' ');
 220         if (!password_buf) {
 221             debug("ERROR: %s: Unexpected input '%s'\n", argv[0], buf);
 222             goto error;
 223         }
 224         *password_buf++ = '\0';
 225         rfc1738_unescape(user);
 226         rfc1738_unescape(password_buf);
 227         conv.appdata_ptr = (char *) password_buf;       /* from buf above. not allocated */
 228
 229 #if _SQUID_SOLARIS_
 230         /* Workaround for Solaris 2.6 where the PAM library is broken
 231          * and does not pass appdata_ptr to the conversation routine
 232          */
 233         password = password_buf;
 234 #endif
 235         if (ttl == 0) {
 236             /* Create PAM connection */
 237             retval = pam_start(service, user, &conv, &pamh);
 238             if (retval != PAM_SUCCESS) {
 239                 debug("ERROR: failed to create PAM authenticator\n");
 240                 goto error;
 241             }
 242         } else if (!pamh || (time(NULL) - pamh_created) >= ttl || pamh_created > time(NULL)) {
 243             /* Close previous PAM connection */
 244             if (pamh) {
 245                 retval = pam_end(pamh, retval);
 246                 if (retval != PAM_SUCCESS) {
 247                     debug("WARNING: failed to release PAM authenticator\n");
 248                 }
 249                 pamh = NULL;
 250             }
 251             /* Initialize persistent PAM connection */
 252             retval = pam_start(service, "squid@", &conv, &pamh);
 253             if (retval != PAM_SUCCESS) {
 254                 debug("ERROR: failed to create PAM authenticator\n");
 255                 goto error;
 256             }
 257             pamh_created = time(NULL);
 258         }
 259         /* Authentication */
 260         retval = PAM_SUCCESS;
 261         if (ttl != 0) {
 262             if (retval == PAM_SUCCESS)
 263                 retval = pam_set_item(pamh, PAM_USER, user);
 264             if (retval == PAM_SUCCESS)
 265                 retval = pam_set_item(pamh, PAM_CONV, &conv);
 266         }
 267         if (retval == PAM_SUCCESS)
 268             retval = pam_authenticate(pamh, 0);
 269         if (retval == PAM_SUCCESS && !no_acct_mgmt)
 270             retval = pam_acct_mgmt(pamh, 0);
 271         if (retval == PAM_SUCCESS) {
 272             SEND_OK("");
 273         } else {
 274 error:
 275             SEND_ERR("");
 276         }
 277         /* cleanup */
 278         retval = PAM_SUCCESS;
 279 #if defined(PAM_AUTHTOK)
 280         if (ttl != 0) {
 281             if (retval == PAM_SUCCESS)
 282                 retval = pam_set_item(pamh, PAM_AUTHTOK, NULL);
 283         }
 284 #endif
 285         if (ttl == 0 || retval != PAM_SUCCESS) {
 286             retval = pam_end(pamh, retval);
 287             if (retval != PAM_SUCCESS) {
 288                 debug("WARNING: failed to release PAM authenticator\n");
 289             }
 290             pamh = NULL;
 291         }
 292     }
 293
 294     if (pamh) {
 295         retval = pam_end(pamh, retval);
 296         if (retval != PAM_SUCCESS) {
 297             pamh = NULL;
 298             debug("ERROR: failed to release PAM authenticator\n");
 299         }
 300     }
 301     return 0;
 302 }