audit-bsm.c

   1 /* $Id: audit-bsm.c,v 1.1 2005/02/20 10:08:00 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 "ssh.h"
  41 #include "log.h"
  42 #include "auth.h"
  43 #include "xmalloc.h"
  44
  45 #ifndef AUE_openssh
  46 # define AUE_openssh     32800
  47 #endif
  48 #include <bsm/audit.h>
  49 #include <bsm/libbsm.h>
  50 #include <bsm/audit_uevents.h>
  51 #include <bsm/audit_record.h>
  52 #include <locale.h>
  53
  54 #if defined(HAVE_GETAUDIT_ADDR)
  55 #define AuditInfoStruct         auditinfo_addr
  56 #define AuditInfoTermID         au_tid_addr_t
  57 #define GetAuditFunc(a,b)       getaudit_addr((a),(b))
  58 #define GetAuditFuncText        "getaudit_addr"
  59 #define SetAuditFunc(a,b)       setaudit_addr((a),(b))
  60 #define SetAuditFuncText        "setaudit_addr"
  61 #define AUToSubjectFunc         au_to_subject_ex
  62 #define AUToReturnFunc(a,b)     au_to_return32((a), (int32_t)(b))
  63 #else
  64 #define AuditInfoStruct         auditinfo
  65 #define AuditInfoTermID         au_tid_t
  66 #define GetAuditFunc(a,b)       getaudit(a)
  67 #define GetAuditFuncText        "getaudit"
  68 #define SetAuditFunc(a,b)       setaudit(a)
  69 #define SetAuditFuncText        "setaudit"
  70 #define AUToSubjectFunc         au_to_subject
  71 #define AUToReturnFunc(a,b)     au_to_return((a), (u_int)(b))
  72 #endif
  73
  74 extern int      cannot_audit(int);
  75 extern void     aug_init(void);
  76 extern dev_t    aug_get_port(void);
  77 extern int      aug_get_machine(char *, u_int32_t *, u_int32_t *);
  78 extern void     aug_save_auid(au_id_t);
  79 extern void     aug_save_uid(uid_t);
  80 extern void     aug_save_euid(uid_t);
  81 extern void     aug_save_gid(gid_t);
  82 extern void     aug_save_egid(gid_t);
  83 extern void     aug_save_pid(pid_t);
  84 extern void     aug_save_asid(au_asid_t);
  85 extern void     aug_save_tid(dev_t, unsigned int);
  86 extern void     aug_save_tid_ex(dev_t, u_int32_t *, u_int32_t);
  87 extern int      aug_save_me(void);
  88 extern int      aug_save_namask(void);
  89 extern void     aug_save_event(au_event_t);
  90 extern void     aug_save_sorf(int);
  91 extern void     aug_save_text(char *);
  92 extern void     aug_save_text1(char *);
  93 extern void     aug_save_text2(char *);
  94 extern void     aug_save_na(int);
  95 extern void     aug_save_user(char *);
  96 extern void     aug_save_path(char *);
  97 extern int      aug_save_policy(void);
  98 extern void     aug_save_afunc(int (*)(int));
  99 extern int      aug_audit(void);
 100 extern int      aug_na_selected(void);
 101 extern int      aug_selected(void);
 102 extern int      aug_daemon_session(void);
 103
 104 #ifndef HAVE_GETTEXT
 105 # define gettext(a)     (a)
 106 #endif
 107
 108 extern Authctxt *the_authctxt;
 109 static AuditInfoTermID ssh_bsm_tid;
 110
 111 /* Below is the low-level BSM interface code */
 112
 113 /*
 114  * Check if the specified event is selected (enabled) for auditing.
 115  * Returns 1 if the event is selected, 0 if not and -1 on failure.
 116  */
 117 static int
 118 selected(char *username, uid_t uid, au_event_t event, int sf)
 119 {
 120         int rc, sorf;
 121         char naflags[512];
 122         struct au_mask mask;
 123
 124         mask.am_success = mask.am_failure = 0;
 125         if (uid < 0) {
 126                 /* get flags for non-attributable (to a real user) events */
 127                 rc = getacna(naflags, sizeof(naflags));
 128                 if (rc == 0)
 129                         (void) getauditflagsbin(naflags, &mask);
 130         } else
 131                 rc = au_user_mask(username, &mask);
 132
 133         sorf = (sf == 0) ? AU_PRS_SUCCESS : AU_PRS_FAILURE;
 134         return(au_preselect(event, &mask, sorf, AU_PRS_REREAD));
 135 }
 136
 137 static void
 138 bsm_audit_record(int typ, char *string, au_event_t event_no)
 139 {
 140         int             ad, rc, sel;
 141         uid_t           uid = -1;
 142         gid_t           gid = -1;
 143         pid_t           pid = getpid();
 144         AuditInfoTermID tid = ssh_bsm_tid;
 145
 146         if (the_authctxt != NULL && the_authctxt->valid) {
 147                 uid = the_authctxt->pw->pw_uid;
 148                 gid = the_authctxt->pw->pw_gid;
 149         }
 150
 151         rc = (typ == 0) ? 0 : -1;
 152         sel = selected(the_authctxt->user, uid, event_no, rc);
 153         debug3("BSM audit: typ %d rc %d \"%s\"", typ, rc, string);
 154         if (!sel)
 155                 return; /* audit event does not match mask, do not write */
 156
 157         debug3("BSM audit: writing audit new record");
 158         ad = au_open();
 159
 160         (void) au_write(ad, AUToSubjectFunc(uid, uid, gid, uid, gid,
 161             pid, pid, &tid));
 162         (void) au_write(ad, au_to_text(string));
 163         (void) au_write(ad, AUToReturnFunc(typ, rc));
 164
 165         rc = au_close(ad, AU_TO_WRITE, event_no);
 166         if (rc < 0)
 167                 error("BSM audit: %s failed to write \"%s\" record: %s",
 168                     __func__, string, strerror(errno));
 169 }
 170
 171 static void
 172 bsm_audit_session_setup(void)
 173 {
 174         int rc;
 175         struct AuditInfoStruct info;
 176         au_mask_t mask;
 177
 178         if (the_authctxt == NULL) {
 179                 error("BSM audit: session setup internal error (NULL ctxt)");
 180                 return;
 181         }
 182
 183         if (the_authctxt->valid)
 184                 info.ai_auid = the_authctxt->pw->pw_uid;
 185         else
 186                 info.ai_auid = -1;
 187         info.ai_asid = getpid();
 188         mask.am_success = 0;
 189         mask.am_failure = 0;
 190
 191         (void) au_user_mask(the_authctxt->user, &mask);
 192
 193         info.ai_mask.am_success  = mask.am_success;
 194         info.ai_mask.am_failure  = mask.am_failure;
 195
 196         info.ai_termid = ssh_bsm_tid;
 197
 198         rc = SetAuditFunc(&info, sizeof(info));
 199         if (rc < 0)
 200                 error("BSM audit: %s: %s failed: %s", __func__,
 201                     SetAuditFuncText, strerror(errno));
 202 }
 203
 204 static void
 205 bsm_audit_bad_login(const char *what)
 206 {
 207         char textbuf[BSM_TEXTBUFSZ];
 208
 209         if (the_authctxt->valid) {
 210                 (void) snprintf(textbuf, sizeof (textbuf),
 211                         gettext("invalid %s for user %s"),
 212                             what, the_authctxt->user);
 213                 bsm_audit_record(4, textbuf, AUE_openssh);
 214         } else {
 215                 (void) snprintf(textbuf, sizeof (textbuf),
 216                         gettext("invalid user name \"%s\""),
 217                             the_authctxt->user);
 218                 bsm_audit_record(3, textbuf, AUE_openssh);
 219         }
 220 }
 221
 222 /* Below is the sshd audit API code */
 223
 224 void
 225 audit_connection_from(const char *host, int port)
 226 {
 227         AuditInfoTermID *tid = &ssh_bsm_tid;
 228         char buf[1024];
 229
 230         if (cannot_audit(0))
 231                 return;
 232         debug3("BSM audit: connection from %.100s port %d", host, port);
 233
 234         /* populate our terminal id structure */
 235 #if defined(HAVE_GETAUDIT_ADDR)
 236         tid->at_port = (dev_t)port;
 237         aug_get_machine((char *)host, &(tid->at_addr[0]), &(tid->at_type));
 238         snprintf(buf, sizeof(buf), "%08x %08x %08x %08x", tid->at_addr[0],
 239             tid->at_addr[1], tid->at_addr[2], tid->at_addr[3]);
 240         debug3("BSM audit: iptype %d machine ID %s", (int)tid->at_type, buf);
 241 #else
 242         /* this is used on IPv4-only machines */
 243         tid->port = (dev_t)port;
 244         tid->machine = inet_addr(host);
 245         snprintf(buf, sizeof(buf), "%08x", tid->machine);
 246         debug3("BSM audit: machine ID %s", buf);
 247 #endif
 248 }
 249
 250 void
 251 audit_run_command(const char *command)
 252 {
 253         /* not implemented */
 254 }
 255
 256 void
 257 audit_session_open(const char *ttyn)
 258 {
 259         /* not implemented */
 260 }
 261
 262 void
 263 audit_session_close(const char *ttyn)
 264 {
 265         /* not implemented */
 266 }
 267
 268 void
 269 audit_event(ssh_audit_event_t event)
 270 {
 271         char    textbuf[BSM_TEXTBUFSZ];
 272         static int logged_in = 0;
 273         const char *user = the_authctxt ? the_authctxt->user : "(unknown user)";
 274
 275         if (cannot_audit(0))
 276                 return;
 277
 278         switch(event) {
 279         case SSH_AUTH_SUCCESS:
 280                 logged_in = 1;
 281                 bsm_audit_session_setup();
 282                 snprintf(textbuf, sizeof(textbuf),
 283                     gettext("successful login %s"), user);
 284                 bsm_audit_record(0, textbuf, AUE_openssh);
 285                 break;
 286
 287         case SSH_CONNECTION_CLOSE:
 288                 /*
 289                  * We can also get a close event if the user attempted auth
 290                  * but never succeeded.
 291                  */
 292                 if (logged_in) {
 293                         snprintf(textbuf, sizeof(textbuf),
 294                             gettext("sshd logout %s"), the_authctxt->user);
 295                         bsm_audit_record(0, textbuf, AUE_logout);
 296                 } else {
 297                         debug("%s: connection closed without authentication",
 298                             __func__);
 299                 }
 300                 break;
 301
 302         case SSH_NOLOGIN:
 303                 bsm_audit_record(1,
 304                     gettext("logins disabled by /etc/nologin"), AUE_openssh);
 305                 break;
 306
 307         case SSH_LOGIN_EXCEED_MAXTRIES:
 308                 snprintf(textbuf, sizeof(textbuf),
 309                     gettext("too many tries for user %s"), the_authctxt->user);
 310                 bsm_audit_record(1, textbuf, AUE_openssh);
 311                 break;
 312
 313         case SSH_LOGIN_ROOT_DENIED:
 314                 bsm_audit_record(2, gettext("not_console"), AUE_openssh);
 315                 break;
 316
 317         case SSH_AUTH_FAIL_PASSWD:
 318                 bsm_audit_bad_login("password");
 319                 break;
 320
 321         case SSH_AUTH_FAIL_KBDINT:
 322                 bsm_audit_bad_login("interactive password entry");
 323                 break;
 324
 325         default:
 326                 debug("%s: unhandled event %d", __func__, event);
 327         }
 328 }
 329 #endif /* BSM */