audit-bsm.c

   1 /* $Id: audit-bsm.c,v 1.6 2008/02/25 10:05:04 dtucker Exp $ */
   2
   3 /*
   4  * TODO
   5  *
   6  * - deal with overlap between this and sys_auth_allowed_user
   7  *   sys_auth_record_login and record_failed_login.
   8  */
   9
  10 /*
  11  * Copyright 1988-2002 Sun Microsystems, Inc.  All rights reserved.
  12  * Use is subject to license terms.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  *
  34  */
  35 /* #pragma ident        "@(#)bsmaudit.c 1.1     01/09/17 SMI" */
  36
  37 #include "includes.h"
  38 #if defined(USE_BSM_AUDIT)
  39
  40 #include <sys/types.h>
  41
  42 #include <errno.h>
  43 #include <netdb.h>
  44 #include <stdarg.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47
  48 #include "ssh.h"
  49 #include "log.h"
  50 #include "key.h"
  51 #include "hostfile.h"
  52 #include "auth.h"
  53 #include "xmalloc.h"
  54
  55 #ifndef AUE_openssh
  56 # define AUE_openssh     32800
  57 #endif
  58 #include <bsm/audit.h>
  59 #include <bsm/libbsm.h>
  60 #include <bsm/audit_uevents.h>
  61 #include <bsm/audit_record.h>
  62 #include <locale.h>
  63
  64 #if defined(HAVE_GETAUDIT_ADDR)
  65 #define AuditInfoStruct         auditinfo_addr
  66 #define AuditInfoTermID         au_tid_addr_t
  67 #define SetAuditFunc(a,b)       setaudit_addr((a),(b))
  68 #define SetAuditFuncText        "setaudit_addr"
  69 #define AUToSubjectFunc         au_to_subject_ex
  70 #define AUToReturnFunc(a,b)     au_to_return32((a), (int32_t)(b))
  71 #else
  72 #define AuditInfoStruct         auditinfo
  73 #define AuditInfoTermID         au_tid_t
  74 #define SetAuditFunc(a,b)       setaudit(a)
  75 #define SetAuditFuncText        "setaudit"
  76 #define AUToSubjectFunc         au_to_subject
  77 #define AUToReturnFunc(a,b)     au_to_return((a), (u_int)(b))
  78 #endif
  79
  80 #ifndef cannot_audit
  81 extern int      cannot_audit(int);
  82 #endif
  83 extern void     aug_init(void);
  84 extern void     aug_save_auid(au_id_t);
  85 extern void     aug_save_uid(uid_t);
  86 extern void     aug_save_euid(uid_t);
  87 extern void     aug_save_gid(gid_t);
  88 extern void     aug_save_egid(gid_t);
  89 extern void     aug_save_pid(pid_t);
  90 extern void     aug_save_asid(au_asid_t);
  91 extern void     aug_save_tid(dev_t, unsigned int);
  92 extern void     aug_save_tid_ex(dev_t, u_int32_t *, u_int32_t);
  93 extern int      aug_save_me(void);
  94 extern int      aug_save_namask(void);
  95 extern void     aug_save_event(au_event_t);
  96 extern void     aug_save_sorf(int);
  97 extern void     aug_save_text(char *);
  98 extern void     aug_save_text1(char *);
  99 extern void     aug_save_text2(char *);
 100 extern void     aug_save_na(int);
 101 extern void     aug_save_user(char *);
 102 extern void     aug_save_path(char *);
 103 extern int      aug_save_policy(void);
 104 extern void     aug_save_afunc(int (*)(int));
 105 extern int      aug_audit(void);
 106 extern int      aug_na_selected(void);
 107 extern int      aug_selected(void);
 108 extern int      aug_daemon_session(void);
 109
 110 #ifndef HAVE_GETTEXT
 111 # define gettext(a)     (a)
 112 #endif
 113
 114 extern Authctxt *the_authctxt;
 115 static AuditInfoTermID ssh_bsm_tid;
 116
 117 /* Below is the low-level BSM interface code */
 118
 119 /*
 120  * aug_get_machine is only required on IPv6 capable machines, we use a
 121  * different mechanism in audit_connection_from() for IPv4-only machines.
 122  * getaudit_addr() is only present on IPv6 capable machines.
 123  */
 124 #if defined(HAVE_AUG_GET_MACHINE) || !defined(HAVE_GETAUDIT_ADDR)
 125 extern int      aug_get_machine(char *, u_int32_t *, u_int32_t *);
 126 #else
 127 static int
 128 aug_get_machine(char *host, u_int32_t *addr, u_int32_t *type)
 129 {
 130         struct addrinfo *ai;
 131         struct sockaddr_in *in4;
 132         struct sockaddr_in6 *in6;
 133         int ret = 0, r;
 134
 135         if ((r = getaddrinfo(host, NULL, NULL, &ai)) != 0) {
 136                 error("BSM audit: getaddrinfo failed for %.100s: %.100s", host,
 137                     r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
 138                 return -1;
 139         }
 140
 141         switch (ai->ai_family) {
 142         case AF_INET:
 143                 in4 = (struct sockaddr_in *)ai->ai_addr;
 144                 *type = AU_IPv4;
 145                 memcpy(addr, &in4->sin_addr, sizeof(struct in_addr));
 146                 break;
 147 #ifdef AU_IPv6
 148         case AF_INET6:
 149                 in6 = (struct sockaddr_in6 *)ai->ai_addr;
 150                 *type = AU_IPv6;
 151                 memcpy(addr, &in6->sin6_addr, sizeof(struct in6_addr));
 152                 break;
 153 #endif
 154         default:
 155                 error("BSM audit: unknown address family for %.100s: %d",
 156                     host, ai->ai_family);
 157                 ret = -1;
 158         }
 159         freeaddrinfo(ai);
 160         return ret;
 161 }
 162 #endif
 163
 164 /*
 165  * Check if the specified event is selected (enabled) for auditing.
 166  * Returns 1 if the event is selected, 0 if not and -1 on failure.
 167  */
 168 static int
 169 selected(char *username, uid_t uid, au_event_t event, int sf)
 170 {
 171         int rc, sorf;
 172         char naflags[512];
 173         struct au_mask mask;
 174
 175         mask.am_success = mask.am_failure = 0;
 176         if (uid < 0) {
 177                 /* get flags for non-attributable (to a real user) events */
 178                 rc = getacna(naflags, sizeof(naflags));
 179                 if (rc == 0)
 180                         (void) getauditflagsbin(naflags, &mask);
 181         } else
 182                 rc = au_user_mask(username, &mask);
 183
 184         sorf = (sf == 0) ? AU_PRS_SUCCESS : AU_PRS_FAILURE;
 185         return(au_preselect(event, &mask, sorf, AU_PRS_REREAD));
 186 }
 187
 188 static void
 189 bsm_audit_record(int typ, char *string, au_event_t event_no)
 190 {
 191         int             ad, rc, sel;
 192         uid_t           uid = -1;
 193         gid_t           gid = -1;
 194         pid_t           pid = getpid();
 195         AuditInfoTermID tid = ssh_bsm_tid;
 196
 197         if (the_authctxt != NULL && the_authctxt->valid) {
 198                 uid = the_authctxt->pw->pw_uid;
 199                 gid = the_authctxt->pw->pw_gid;
 200         }
 201
 202         rc = (typ == 0) ? 0 : -1;
 203         sel = selected(the_authctxt->user, uid, event_no, rc);
 204         debug3("BSM audit: typ %d rc %d \"%s\"", typ, rc, string);
 205         if (!sel)
 206                 return; /* audit event does not match mask, do not write */
 207
 208         debug3("BSM audit: writing audit new record");
 209         ad = au_open();
 210
 211         (void) au_write(ad, AUToSubjectFunc(uid, uid, gid, uid, gid,
 212             pid, pid, &tid));
 213         (void) au_write(ad, au_to_text(string));
 214         (void) au_write(ad, AUToReturnFunc(typ, rc));
 215
 216         rc = au_close(ad, AU_TO_WRITE, event_no);
 217         if (rc < 0)
 218                 error("BSM audit: %s failed to write \"%s\" record: %s",
 219                     __func__, string, strerror(errno));
 220 }
 221
 222 static void
 223 bsm_audit_session_setup(void)
 224 {
 225         int rc;
 226         struct AuditInfoStruct info;
 227         au_mask_t mask;
 228
 229         if (the_authctxt == NULL) {
 230                 error("BSM audit: session setup internal error (NULL ctxt)");
 231                 return;
 232         }
 233
 234         if (the_authctxt->valid)
 235                 info.ai_auid = the_authctxt->pw->pw_uid;
 236         else
 237                 info.ai_auid = -1;
 238         info.ai_asid = getpid();
 239         mask.am_success = 0;
 240         mask.am_failure = 0;
 241
 242         (void) au_user_mask(the_authctxt->user, &mask);
 243
 244         info.ai_mask.am_success  = mask.am_success;
 245         info.ai_mask.am_failure  = mask.am_failure;
 246
 247         info.ai_termid = ssh_bsm_tid;
 248
 249         rc = SetAuditFunc(&info, sizeof(info));
 250         if (rc < 0)
 251                 error("BSM audit: %s: %s failed: %s", __func__,
 252                     SetAuditFuncText, strerror(errno));
 253 }
 254
 255 static void
 256 bsm_audit_bad_login(const char *what)
 257 {
 258         char textbuf[BSM_TEXTBUFSZ];
 259
 260         if (the_authctxt->valid) {
 261                 (void) snprintf(textbuf, sizeof (textbuf),
 262                         gettext("invalid %s for user %s"),
 263                             what, the_authctxt->user);
 264                 bsm_audit_record(4, textbuf, AUE_openssh);
 265         } else {
 266                 (void) snprintf(textbuf, sizeof (textbuf),
 267                         gettext("invalid user name \"%s\""),
 268                             the_authctxt->user);
 269                 bsm_audit_record(3, textbuf, AUE_openssh);
 270         }
 271 }
 272
 273 /* Below is the sshd audit API code */
 274
 275 void
 276 audit_connection_from(const char *host, int port)
 277 {
 278         AuditInfoTermID *tid = &ssh_bsm_tid;
 279         char buf[1024];
 280
 281         if (cannot_audit(0))
 282                 return;
 283         debug3("BSM audit: connection from %.100s port %d", host, port);
 284
 285         /* populate our terminal id structure */
 286 #if defined(HAVE_GETAUDIT_ADDR)
 287         tid->at_port = (dev_t)port;
 288         aug_get_machine((char *)host, &(tid->at_addr[0]), &(tid->at_type));
 289         snprintf(buf, sizeof(buf), "%08x %08x %08x %08x", tid->at_addr[0],
 290             tid->at_addr[1], tid->at_addr[2], tid->at_addr[3]);
 291         debug3("BSM audit: iptype %d machine ID %s", (int)tid->at_type, buf);
 292 #else
 293         /* this is used on IPv4-only machines */
 294         tid->port = (dev_t)port;
 295         tid->machine = inet_addr(host);
 296         snprintf(buf, sizeof(buf), "%08x", tid->machine);
 297         debug3("BSM audit: machine ID %s", buf);
 298 #endif
 299 }
 300
 301 void
 302 audit_run_command(const char *command)
 303 {
 304         /* not implemented */
 305 }
 306
 307 void
 308 audit_session_open(const char *ttyn)
 309 {
 310         /* not implemented */
 311 }
 312
 313 void
 314 audit_session_close(const char *ttyn)
 315 {
 316         /* not implemented */
 317 }
 318
 319 void
 320 audit_event(ssh_audit_event_t event)
 321 {
 322         char    textbuf[BSM_TEXTBUFSZ];
 323         static int logged_in = 0;
 324         const char *user = the_authctxt ? the_authctxt->user : "(unknown user)";
 325
 326         if (cannot_audit(0))
 327                 return;
 328
 329         switch(event) {
 330         case SSH_AUTH_SUCCESS:
 331                 logged_in = 1;
 332                 bsm_audit_session_setup();
 333                 snprintf(textbuf, sizeof(textbuf),
 334                     gettext("successful login %s"), user);
 335                 bsm_audit_record(0, textbuf, AUE_openssh);
 336                 break;
 337
 338         case SSH_CONNECTION_CLOSE:
 339                 /*
 340                  * We can also get a close event if the user attempted auth
 341                  * but never succeeded.
 342                  */
 343                 if (logged_in) {
 344                         snprintf(textbuf, sizeof(textbuf),
 345                             gettext("sshd logout %s"), the_authctxt->user);
 346                         bsm_audit_record(0, textbuf, AUE_logout);
 347                 } else {
 348                         debug("%s: connection closed without authentication",
 349                             __func__);
 350                 }
 351                 break;
 352
 353         case SSH_NOLOGIN:
 354                 bsm_audit_record(1,
 355                     gettext("logins disabled by /etc/nologin"), AUE_openssh);
 356                 break;
 357
 358         case SSH_LOGIN_EXCEED_MAXTRIES:
 359                 snprintf(textbuf, sizeof(textbuf),
 360                     gettext("too many tries for user %s"), the_authctxt->user);
 361                 bsm_audit_record(1, textbuf, AUE_openssh);
 362                 break;
 363
 364         case SSH_LOGIN_ROOT_DENIED:
 365                 bsm_audit_record(2, gettext("not_console"), AUE_openssh);
 366                 break;
 367
 368         case SSH_AUTH_FAIL_PASSWD:
 369                 bsm_audit_bad_login("password");
 370                 break;
 371
 372         case SSH_AUTH_FAIL_KBDINT:
 373                 bsm_audit_bad_login("interactive password entry");
 374                 break;
 375
 376         default:
 377                 debug("%s: unhandled event %d", __func__, event);
 378         }
 379 }
 380 #endif /* BSM */