openbsd-compat/port-aix.c

   1 /*
   2  *
   3  * Copyright (c) 2001 Gert Doering.  All rights reserved.
   4  * Copyright (c) 2003,2004,2005,2006 Darren Tucker.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  */
  27 #include "includes.h"
  28
  29 #include "xmalloc.h"
  30 #include "buffer.h"
  31 #include "key.h"
  32 #include "hostfile.h"
  33 #include "auth.h"
  34 #include "ssh.h"
  35 #include "log.h"
  36
  37 #ifdef _AIX
  38
  39 #include <errno.h>
  40 #if defined(HAVE_NETDB_H)
  41 # include <netdb.h>
  42 #endif
  43 #include <uinfo.h>
  44 #include <stdarg.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47 #include <sys/socket.h>
  48
  49 #ifdef WITH_AIXAUTHENTICATE
  50 # include <login.h>
  51 # include <userpw.h>
  52 # if defined(HAVE_SYS_AUDIT_H) && defined(AIX_LOGINFAILED_4ARG)
  53 #  include <sys/audit.h>
  54 # endif
  55 # include <usersec.h>
  56 #endif
  57
  58 #include "port-aix.h"
  59
  60 static char *lastlogin_msg = NULL;
  61
  62 # ifdef HAVE_SETAUTHDB
  63 static char old_registry[REGISTRY_SIZE] = "";
  64 # endif
  65
  66 /*
  67  * AIX has a "usrinfo" area where logname and other stuff is stored -
  68  * a few applications actually use this and die if it's not set
  69  *
  70  * NOTE: TTY= should be set, but since no one uses it and it's hard to
  71  * acquire due to privsep code.  We will just drop support.
  72  */
  73 void
  74 aix_usrinfo(struct passwd *pw)
  75 {
  76         u_int i;
  77         size_t len;
  78         char *cp;
  79
  80         len = sizeof("LOGNAME= NAME= ") + (2 * strlen(pw->pw_name));
  81         cp = xmalloc(len);
  82
  83         i = snprintf(cp, len, "LOGNAME=%s%cNAME=%s%c", pw->pw_name, '\0',
  84             pw->pw_name, '\0');
  85         if (usrinfo(SETUINFO, cp, i) == -1)
  86                 fatal("Couldn't set usrinfo: %s", strerror(errno));
  87         debug3("AIX/UsrInfo: set len %d", i);
  88
  89         xfree(cp);
  90 }
  91
  92 # ifdef WITH_AIXAUTHENTICATE
  93 /*
  94  * Remove embedded newlines in string (if any).
  95  * Used before logging messages returned by AIX authentication functions
  96  * so the message is logged on one line.
  97  */
  98 void
  99 aix_remove_embedded_newlines(char *p)
 100 {
 101         if (p == NULL)
 102                 return;
 103
 104         for (; *p; p++) {
 105                 if (*p == '\n')
 106                         *p = ' ';
 107         }
 108         /* Remove trailing whitespace */
 109         if (*--p == ' ')
 110                 *p = '\0';
 111 }
 112
 113 /*
 114  * Test specifically for the case where SYSTEM == NONE and AUTH1 contains
 115  * anything other than NONE or SYSTEM, which indicates that the admin has
 116  * configured the account for purely AUTH1-type authentication.
 117  *
 118  * Since authenticate() doesn't check AUTH1, and sshd can't sanely support
 119  * AUTH1 itself, in such a case authenticate() will allow access without
 120  * authentation, which is almost certainly not what the admin intends.
 121  *
 122  * (The native tools, eg login, will process the AUTH1 list in addition to
 123  * the SYSTEM list by using ckuserID(), however ckuserID() and AUTH1 methods
 124  * have been deprecated since AIX 4.2.x and would be very difficult for sshd
 125  * to support.
 126  *
 127  * Returns 0 if an unsupportable combination is found, 1 otherwise.
 128  */
 129 static int
 130 aix_valid_authentications(const char *user)
 131 {
 132         char *auth1, *sys, *p;
 133         int valid = 1;
 134
 135         if (getuserattr((char *)user, S_AUTHSYSTEM, &sys, SEC_CHAR) != 0) {
 136                 logit("Can't retrieve attribute SYSTEM for %s: %.100s",
 137                     user, strerror(errno));
 138                 return 0;
 139         }
 140
 141         debug3("AIX SYSTEM attribute %s", sys);
 142         if (strcmp(sys, "NONE") != 0)
 143                 return 1;       /* not "NONE", so is OK */
 144
 145         if (getuserattr((char *)user, S_AUTH1, &auth1, SEC_LIST) != 0) {
 146                 logit("Can't retrieve attribute auth1 for %s: %.100s",
 147                     user, strerror(errno));
 148                 return 0;
 149         }
 150
 151         p = auth1;
 152         /* A SEC_LIST is concatenated strings, ending with two NULs. */
 153         while (p[0] != '\0' && p[1] != '\0') {
 154                 debug3("AIX auth1 attribute list member %s", p);
 155                 if (strcmp(p, "NONE") != 0 && strcmp(p, "SYSTEM")) {
 156                         logit("Account %s has unsupported auth1 value '%s'",
 157                             user, p);
 158                         valid = 0;
 159                 }
 160                 p += strlen(p) + 1;
 161         }
 162
 163         return (valid);
 164 }
 165
 166 /*
 167  * Do authentication via AIX's authenticate routine.  We loop until the
 168  * reenter parameter is 0, but normally authenticate is called only once.
 169  *
 170  * Note: this function returns 1 on success, whereas AIX's authenticate()
 171  * returns 0.
 172  */
 173 int
 174 sys_auth_passwd(Authctxt *ctxt, const char *password)
 175 {
 176         char *authmsg = NULL, *msg = NULL, *name = ctxt->pw->pw_name;
 177         int authsuccess = 0, expired, reenter, result;
 178
 179         do {
 180                 result = authenticate((char *)name, (char *)password, &reenter,
 181                     &authmsg);
 182                 aix_remove_embedded_newlines(authmsg);
 183                 debug3("AIX/authenticate result %d, authmsg %.100s", result,
 184                     authmsg);
 185         } while (reenter);
 186
 187         if (!aix_valid_authentications(name))
 188                 result = -1;
 189
 190         if (result == 0) {
 191                 authsuccess = 1;
 192
 193                 /*
 194                  * Record successful login.  We don't have a pty yet, so just
 195                  * label the line as "ssh"
 196                  */
 197                 aix_setauthdb(name);
 198
 199                 /*
 200                  * Check if the user's password is expired.
 201                  */
 202                 expired = passwdexpired(name, &msg);
 203                 if (msg && *msg) {
 204                         buffer_append(ctxt->loginmsg, msg, strlen(msg));
 205                         aix_remove_embedded_newlines(msg);
 206                 }
 207                 debug3("AIX/passwdexpired returned %d msg %.100s", expired, msg);
 208
 209                 switch (expired) {
 210                 case 0: /* password not expired */
 211                         break;
 212                 case 1: /* expired, password change required */
 213                         ctxt->force_pwchange = 1;
 214                         break;
 215                 default: /* user can't change(2) or other error (-1) */
 216                         logit("Password can't be changed for user %s: %.100s",
 217                             name, msg);
 218                         if (msg)
 219                                 xfree(msg);
 220                         authsuccess = 0;
 221                 }
 222
 223                 aix_restoreauthdb();
 224         }
 225
 226         if (authmsg != NULL)
 227                 xfree(authmsg);
 228
 229         return authsuccess;
 230 }
 231
 232 /*
 233  * Check if specified account is permitted to log in.
 234  * Returns 1 if login is allowed, 0 if not allowed.
 235  */
 236 int
 237 sys_auth_allowed_user(struct passwd *pw, Buffer *loginmsg)
 238 {
 239         char *msg = NULL;
 240         int result, permitted = 0;
 241         struct stat st;
 242
 243         /*
 244          * Don't perform checks for root account (PermitRootLogin controls
 245          * logins via ssh) or if running as non-root user (since
 246          * loginrestrictions will always fail due to insufficient privilege).
 247          */
 248         if (pw->pw_uid == 0 || geteuid() != 0) {
 249                 debug3("%s: not checking", __func__);
 250                 return 1;
 251         }
 252
 253         result = loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &msg);
 254         if (result == 0)
 255                 permitted = 1;
 256         /*
 257          * If restricted because /etc/nologin exists, the login will be denied
 258          * in session.c after the nologin message is sent, so allow for now
 259          * and do not append the returned message.
 260          */
 261         if (result == -1 && errno == EPERM && stat(_PATH_NOLOGIN, &st) == 0)
 262                 permitted = 1;
 263         else if (msg != NULL)
 264                 buffer_append(loginmsg, msg, strlen(msg));
 265         if (msg == NULL)
 266                 msg = xstrdup("(none)");
 267         aix_remove_embedded_newlines(msg);
 268         debug3("AIX/loginrestrictions returned %d msg %.100s", result, msg);
 269
 270         if (!permitted)
 271                 logit("Login restricted for %s: %.100s", pw->pw_name, msg);
 272         xfree(msg);
 273         return permitted;
 274 }
 275
 276 int
 277 sys_auth_record_login(const char *user, const char *host, const char *ttynm,
 278     Buffer *loginmsg)
 279 {
 280         char *msg = NULL;
 281         int success = 0;
 282
 283         aix_setauthdb(user);
 284         if (loginsuccess((char *)user, (char *)host, (char *)ttynm, &msg) == 0) {
 285                 success = 1;
 286                 if (msg != NULL) {
 287                         debug("AIX/loginsuccess: msg %s", msg);
 288                         if (lastlogin_msg == NULL)
 289                                 lastlogin_msg = msg;
 290                 }
 291         }
 292         aix_restoreauthdb();
 293         return (success);
 294 }
 295
 296 char *
 297 sys_auth_get_lastlogin_msg(const char *user, uid_t uid)
 298 {
 299         char *msg = lastlogin_msg;
 300
 301         lastlogin_msg = NULL;
 302         return msg;
 303 }
 304
 305 #  ifdef CUSTOM_FAILED_LOGIN
 306 /*
 307  * record_failed_login: generic "login failed" interface function
 308  */
 309 void
 310 record_failed_login(const char *user, const char *hostname, const char *ttyname)
 311 {
 312         if (geteuid() != 0)
 313                 return;
 314
 315         aix_setauthdb(user);
 316 #   ifdef AIX_LOGINFAILED_4ARG
 317         loginfailed((char *)user, (char *)hostname, (char *)ttyname,
 318             AUDIT_FAIL_AUTH);
 319 #   else
 320         loginfailed((char *)user, (char *)hostname, (char *)ttyname);
 321 #   endif
 322         aix_restoreauthdb();
 323 }
 324 #  endif /* CUSTOM_FAILED_LOGIN */
 325
 326 /*
 327  * If we have setauthdb, retrieve the password registry for the user's
 328  * account then feed it to setauthdb.  This will mean that subsequent AIX auth
 329  * functions will only use the specified loadable module.  If we don't have
 330  * setauthdb this is a no-op.
 331  */
 332 void
 333 aix_setauthdb(const char *user)
 334 {
 335 #  ifdef HAVE_SETAUTHDB
 336         char *registry;
 337
 338         if (setuserdb(S_READ) == -1) {
 339                 debug3("%s: Could not open userdb to read", __func__);
 340                 return;
 341         }
 342
 343         if (getuserattr((char *)user, S_REGISTRY, &registry, SEC_CHAR) == 0) {
 344                 if (setauthdb(registry, old_registry) == 0)
 345                         debug3("AIX/setauthdb set registry '%s'", registry);
 346                 else
 347                         debug3("AIX/setauthdb set registry '%s' failed: %s",
 348                             registry, strerror(errno));
 349         } else
 350                 debug3("%s: Could not read S_REGISTRY for user: %s", __func__,
 351                     strerror(errno));
 352         enduserdb();
 353 #  endif /* HAVE_SETAUTHDB */
 354 }
 355
 356 /*
 357  * Restore the user's registry settings from old_registry.
 358  * Note that if the first aix_setauthdb fails, setauthdb("") is still safe
 359  * (it restores the system default behaviour).  If we don't have setauthdb,
 360  * this is a no-op.
 361  */
 362 void
 363 aix_restoreauthdb(void)
 364 {
 365 #  ifdef HAVE_SETAUTHDB
 366         if (setauthdb(old_registry, NULL) == 0)
 367                 debug3("%s: restoring old registry '%s'", __func__,
 368                     old_registry);
 369         else
 370                 debug3("%s: failed to restore old registry %s", __func__,
 371                     old_registry);
 372 #  endif /* HAVE_SETAUTHDB */
 373 }
 374
 375 # endif /* WITH_AIXAUTHENTICATE */
 376
 377 # if defined(AIX_GETNAMEINFO_HACK) && !defined(BROKEN_ADDRINFO)
 378 # undef getnameinfo
 379 /*
 380  * For some reason, AIX's getnameinfo will refuse to resolve the all-zeros
 381  * IPv6 address into its textual representation ("::"), so we wrap it
 382  * with a function that will.
 383  */
 384 int
 385 sshaix_getnameinfo(const struct sockaddr *sa, size_t salen, char *host,
 386     size_t hostlen, char *serv, size_t servlen, int flags)
 387 {
 388         struct sockaddr_in6 *sa6;
 389         u_int32_t *a6;
 390
 391         if (flags & (NI_NUMERICHOST|NI_NUMERICSERV) &&
 392             sa->sa_family == AF_INET6) {
 393                 sa6 = (struct sockaddr_in6 *)sa;
 394                 a6 = sa6->sin6_addr.u6_addr.u6_addr32;
 395
 396                 if (a6[0] == 0 && a6[1] == 0 && a6[2] == 0 && a6[3] == 0) {
 397                         strlcpy(host, "::", hostlen);
 398                         snprintf(serv, servlen, "%d", sa6->sin6_port);
 399                         return 0;
 400                 }
 401         }
 402         return getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
 403 }
 404 # endif /* AIX_GETNAMEINFO_HACK */
 405
 406 # if defined(USE_GETGRSET)
 407 #  include <stdlib.h>
 408 int
 409 getgrouplist(const char *user, gid_t pgid, gid_t *groups, int *grpcnt)
 410 {
 411         char *cp, *grplist, *grp;
 412         gid_t gid;
 413         int ret = 0, ngroups = 0, maxgroups;
 414         long l;
 415
 416         maxgroups = *grpcnt;
 417
 418         if ((cp = grplist = getgrset(user)) == NULL)
 419                 return -1;
 420
 421         /* handle zero-length case */
 422         if (maxgroups <= 0) {
 423                 *grpcnt = 0;
 424                 return -1;
 425         }
 426
 427         /* copy primary group */
 428         groups[ngroups++] = pgid;
 429
 430         /* copy each entry from getgrset into group list */
 431         while ((grp = strsep(&grplist, ",")) != NULL) {
 432                 l = strtol(grp, NULL, 10);
 433                 if (ngroups >= maxgroups || l == LONG_MIN || l == LONG_MAX) {
 434                         ret = -1;
 435                         goto out;
 436                 }
 437                 gid = (gid_t)l;
 438                 if (gid == pgid)
 439                         continue;       /* we have already added primary gid */
 440                 groups[ngroups++] = gid;
 441         }
 442 out:
 443         free(cp);
 444         *grpcnt = ngroups;
 445         return ret;
 446 }
 447 # endif /* USE_GETGRSET */
 448
 449 #endif /* _AIX */