- (dtucker) [Makefile.in auth.c auth.h auth1.c auth2.c loginrec.c monitor.c

   monitor.h monitor_wrap.c monitor_wrap.h session.c sshd.c] Bug #125:
   (first stage) Add audit instrumentation to sshd, currently disabled by
   default.  with suggestions from and djm@

13 files changed, 211 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 07ae663d7..e2dc30e5a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,10 @@
    attempts (currently only for password, kbdint and C/R, only on Linux and
    HP-UX), based on code from login.c from util-linux. With ashok_kovai at
    hotmail.com, ok djm@
+ - (dtucker) [Makefile.in auth.c auth.h auth1.c auth2.c loginrec.c monitor.c
+   monitor.h monitor_wrap.c monitor_wrap.h session.c sshd.c] Bug #125:
+   (first stage) Add audit instrumentation to sshd, currently disabled by
+   default.  with suggestions from and djm@
 
 20050201
  - (dtucker) [log.c] Bug #973: force log_init() to open syslog, since on some
@@ -2068,4 +2072,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.3632 2005/02/02 12:30:24 dtucker Exp $
+$Id: ChangeLog,v 1.3633 2005/02/02 13:20:53 dtucker Exp $
diff --git a/Makefile.in b/Makefile.in
index 8a1c9f7c0..c6cfef11a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,4 +1,4 @@
-# $Id: Makefile.in,v 1.267 2005/01/18 01:05:18 dtucker Exp $
+# $Id: Makefile.in,v 1.268 2005/02/02 13:20:53 dtucker Exp $
 
 # uncomment if you run a non bourne compatable shell. Ie. csh
 #SHELL = @SH@
@@ -85,7 +85,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \
         monitor_mm.o monitor.o monitor_wrap.o kexdhs.o kexgexs.o \
         auth-krb5.o \
         auth2-gss.o gss-serv.o gss-serv-krb5.o \
-        loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o
+        loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o audit.o
 
 MANPAGES        = scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-rand-helper.8.out ssh-keysign.8.out sshd_config.5.out ssh_config.5.out
 MANPAGES_IN     = scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-rand-helper.8 ssh-keysign.8 sshd_config.5 ssh_config.5
diff --git a/auth.c b/auth.c
index b6c00c12b..bbf3a54a4 100644
--- a/auth.c
+++ b/auth.c
@@ -51,6 +51,7 @@ RCSID("$OpenBSD: auth.c,v 1.57 2005/01/22 08:17:59 dtucker Exp $");
 #include "bufaux.h"
 #include "packet.h"
 #include "loginrec.h"
+#include "monitor_wrap.h"
 
 /* import */
 extern ServerOptions options;
@@ -251,6 +252,44 @@ auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
                 record_failed_login(authctxt->user,
                     get_canonical_hostname(options.use_dns), "ssh");
 #endif
+#ifdef AUDIT_EVENTS
+        if (authenticated == 0 && !authctxt->postponed) {
+                ssh_audit_event_t event;
+
+                debug3("audit failed auth attempt, method %s euid %d",
+                    method, (int)geteuid());
+                /*
+                 * Because the auth loop is used in both monitor and slave,
+                 * we must be careful to send each event only once and with
+                 * enough privs to write the event.
+                 */
+                event = audit_classify_auth(method);
+                switch(event) {
+                case AUTH_FAIL_NONE:
+                case AUTH_FAIL_PASSWD:
+                case AUTH_FAIL_KBDINT:
+                        if (geteuid() == 0)
+                                audit_event(event);
+                        break;
+                case AUTH_FAIL_PUBKEY:
+                case AUTH_FAIL_HOSTBASED:
+                case AUTH_FAIL_GSSAPI:
+                        /*
+                         * This is required to handle the case where privsep
+                         * is enabled but it's root logging in, since
+                         * use_privsep won't be cleared until after a
+                         * successful login.
+                         */
+                        if (geteuid() == 0)
+                                audit_event(event);
+                        else
+                                PRIVSEP(audit_event(event));
+                        break;
+                default:
+                        error("unknown authentication audit event %d", event);
+                }
+        }
+#endif
 }
 
 /*
@@ -476,6 +515,9 @@ getpwnamallow(const char *user)
                 record_failed_login(user,
                     get_canonical_hostname(options.use_dns), "ssh");
 #endif
+#ifdef AUDIT_EVENTS
+                audit_event(INVALID_USER);
+#endif /* AUDIT_EVENTS */
                 return (NULL);
         }
         if (!allowed_user(pw))
diff --git a/auth.h b/auth.h
index 6c0089dc7..8d1f93403 100644
--- a/auth.h
+++ b/auth.h
@@ -130,6 +130,7 @@ int auth_shadow_pwexpired(Authctxt *);
 #endif
 
 #include "auth-pam.h"
+#include "audit.h"
 void remove_kbdint_device(const char *);
 
 void disable_forwarding(void);
diff --git a/auth1.c b/auth1.c
index 2a9d18b9a..aeb5d8cb9 100644
--- a/auth1.c
+++ b/auth1.c
@@ -247,8 +247,12 @@ do_authloop(Authctxt *authctxt)
 #else
                 /* Special handling for root */
                 if (authenticated && authctxt->pw->pw_uid == 0 &&
-                    !auth_root_allowed(get_authname(type)))
+                    !auth_root_allowed(get_authname(type))) {
                         authenticated = 0;
+# ifdef AUDIT_EVENTS
+                        PRIVSEP(audit_event(LOGIN_ROOT_DENIED));
+# endif
+                }
 #endif
 
 #ifdef USE_PAM
@@ -283,8 +287,12 @@ do_authloop(Authctxt *authctxt)
                 if (authenticated)
                         return;
 
-                if (authctxt->failures++ > options.max_authtries)
+                if (authctxt->failures++ > options.max_authtries) {
+#ifdef AUDIT_EVENTS
+                        PRIVSEP(audit_event(LOGIN_EXCEED_MAXTRIES));
+#endif
                         packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
+                }
 
                 packet_start(SSH_SMSG_FAILURE);
                 packet_send();
diff --git a/auth2.c b/auth2.c
index 60e261f7f..2727e0ff5 100644
--- a/auth2.c
+++ b/auth2.c
@@ -167,6 +167,9 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
                         if (options.use_pam)
                                 PRIVSEP(start_pam(authctxt));
 #endif
+#ifdef AUDIT_EVENTS
+                        PRIVSEP(audit_event(INVALID_USER));
+#endif
                 }
                 setproctitle("%s%s", authctxt->valid ? user : "unknown",
                     use_privsep ? " [net]" : "");
@@ -214,8 +217,12 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 
         /* Special handling for root */
         if (authenticated && authctxt->pw->pw_uid == 0 &&
-            !auth_root_allowed(method))
+            !auth_root_allowed(method)) {
                 authenticated = 0;
+#ifdef AUDIT_EVENTS
+                PRIVSEP(audit_event(LOGIN_ROOT_DENIED));
+#endif
+        }
 
 #ifdef USE_PAM
         if (options.use_pam && authenticated) {
@@ -255,8 +262,12 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
                 /* now we can break out */
                 authctxt->success = 1;
         } else {
-                if (authctxt->failures++ > options.max_authtries)
+                if (authctxt->failures++ > options.max_authtries) {
+#ifdef AUDIT_EVENTS
+                        PRIVSEP(audit_event(LOGIN_EXCEED_MAXTRIES));
+#endif
                         packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
+                }
                 methods = authmethods_get();
                 packet_start(SSH2_MSG_USERAUTH_FAILURE);
                 packet_put_cstring(methods);
diff --git a/loginrec.c b/loginrec.c
index e77318ba3..0fa9bdea7 100644
--- a/loginrec.c
+++ b/loginrec.c
@@ -154,6 +154,7 @@
 #include "atomicio.h"
 #include "packet.h"
 #include "canohost.h"
+#include "auth.h"
 
 #ifdef HAVE_UTIL_H
 # include <util.h>
@@ -163,7 +164,7 @@
 # include <libutil.h>
 #endif
 
-RCSID("$Id: loginrec.c,v 1.63 2005/02/02 12:30:25 dtucker Exp $");
+RCSID("$Id: loginrec.c,v 1.64 2005/02/02 13:20:53 dtucker Exp $");
 
 /**
  ** prototypes for helper functions in this file
@@ -443,6 +444,12 @@ login_write(struct logininfo *li)
            !sys_auth_record_login(li->username,li->hostname,li->line))
                 logit("Writing login record failed for %s", li->username);
 #endif
+#ifdef AUDIT_EVENTS
+        if (li->type == LTYPE_LOGIN)
+                audit_session_open(li->line);
+        else if (li->type == LTYPE_LOGOUT)
+                audit_session_close(li->line);
+#endif
         return (0);
 }
 
diff --git a/monitor.c b/monitor.c
index 00d4a785f..ce7784aa1 100644
--- a/monitor.c
+++ b/monitor.c
@@ -143,6 +143,11 @@ int mm_answer_gss_userok(int, Buffer *);
 int mm_answer_gss_checkmic(int, Buffer *);
 #endif
 
+#ifdef AUDIT_EVENTS
+int mm_answer_audit_event(int, Buffer *);
+int mm_answer_audit_command(int, Buffer *);
+#endif
+
 static Authctxt *authctxt;
 static BIGNUM *ssh1_challenge = NULL;   /* used for ssh1 rsa auth */
 
@@ -186,6 +191,9 @@ struct mon_table mon_dispatch_proto20[] = {
     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 #endif
+#ifdef AUDIT_EVENTS
+    {MONITOR_REQ_AUDIT_EVENT, 0, mm_answer_audit_event},
+#endif
 #ifdef BSD_AUTH
     {MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
     {MONITOR_REQ_BSDAUTHRESPOND, MON_AUTH,mm_answer_bsdauthrespond},
@@ -211,6 +219,10 @@ struct mon_table mon_dispatch_postauth20[] = {
     {MONITOR_REQ_PTY, 0, mm_answer_pty},
     {MONITOR_REQ_PTYCLEANUP, 0, mm_answer_pty_cleanup},
     {MONITOR_REQ_TERM, 0, mm_answer_term},
+#ifdef AUDIT_EVENTS
+    {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
+    {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT, mm_answer_audit_command},
+#endif
     {0, 0, NULL}
 };
 
@@ -239,6 +251,9 @@ struct mon_table mon_dispatch_proto15[] = {
     {MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
     {MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
 #endif
+#ifdef AUDIT_EVENTS
+    {MONITOR_REQ_AUDIT_EVENT, 0, mm_answer_audit_event},
+#endif
     {0, 0, NULL}
 };
 
@@ -246,6 +261,10 @@ struct mon_table mon_dispatch_postauth15[] = {
     {MONITOR_REQ_PTY, MON_ONCE, mm_answer_pty},
     {MONITOR_REQ_PTYCLEANUP, MON_ONCE, mm_answer_pty_cleanup},
     {MONITOR_REQ_TERM, 0, mm_answer_term},
+#ifdef AUDIT_EVENTS
+    {MONITOR_REQ_AUDIT_EVENT, MON_PERMIT, mm_answer_audit_event},
+    {MONITOR_REQ_AUDIT_COMMAND, MON_PERMIT|MON_ONCE, mm_answer_audit_command},
+#endif
     {0, 0, NULL}
 };
 
@@ -609,6 +628,9 @@ mm_answer_pwnamallow(int sock, Buffer *m)
         if (options.use_pam)
                 monitor_permit(mon_dispatch, MONITOR_REQ_PAM_START, 1);
 #endif
+#ifdef AUDIT_EVENTS
+        monitor_permit(mon_dispatch, MONITOR_REQ_AUDIT_EVENT, 1);
+#endif
 
         return (0);
 }
@@ -1491,6 +1513,49 @@ mm_answer_term(int sock, Buffer *req)
         exit(res);
 }
 
+#ifdef AUDIT_EVENTS
+/* Report that an audit event occurred */
+int
+mm_answer_audit_event(int socket, Buffer *m)
+{
+        ssh_audit_event_t event;
+
+        debug3("%s entering", __func__);
+
+        event = buffer_get_int(m);
+        buffer_free(m);
+        switch(event) {
+        case AUTH_FAIL_PUBKEY:
+        case AUTH_FAIL_HOSTBASED:
+        case AUTH_FAIL_GSSAPI:
+        case LOGIN_EXCEED_MAXTRIES:
+        case LOGIN_ROOT_DENIED:
+        case CONNECTION_CLOSE:
+                audit_event(event);
+                break;
+        default:
+                fatal("Audit event type %d not permitted", event);
+        }
+
+        return (0);
+}
+
+int
+mm_answer_audit_command(int socket, Buffer *m)
+{
+        u_int len;
+        char *cmd;
+
+        debug3("%s entering", __func__);
+        cmd = buffer_get_string(m, &len);
+        /* sanity check command, if so how? */
+        audit_run_command(cmd);
+        xfree(cmd);
+        buffer_free(m);
+        return (0);
+}
+#endif /* AUDIT_EVENTS */
+
 void
 monitor_apply_keystate(struct monitor *pmonitor)
 {
diff --git a/monitor.h b/monitor.h
index 621a4ad18..13ce3e1ca 100644
--- a/monitor.h
+++ b/monitor.h
@@ -59,6 +59,7 @@ enum monitor_reqtype {
         MONITOR_REQ_PAM_QUERY, MONITOR_ANS_PAM_QUERY,
         MONITOR_REQ_PAM_RESPOND, MONITOR_ANS_PAM_RESPOND,
         MONITOR_REQ_PAM_FREE_CTX, MONITOR_ANS_PAM_FREE_CTX,
+        MONITOR_REQ_AUDIT_EVENT, MONITOR_REQ_AUDIT_COMMAND,
         MONITOR_REQ_TERM
 };
 
diff --git a/monitor_wrap.c b/monitor_wrap.c
index 23857639b..983b24072 100644
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1103,6 +1103,36 @@ mm_auth_rsa_verify_response(Key *key, BIGNUM *p, u_char response[16])
         return (success);
 }
 
+#ifdef AUDIT_EVENTS
+void
+mm_audit_event(ssh_audit_event_t event)
+{
+        Buffer m;
+
+        debug3("%s entering", __func__);
+
+        buffer_init(&m);
+        buffer_put_int(&m, event);
+
+        mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_EVENT, &m);
+        buffer_free(&m);
+}
+
+void
+mm_audit_run_command(const char *command)
+{
+        Buffer m;
+
+        debug3("%s entering command %s", __func__, command);
+
+        buffer_init(&m);
+        buffer_put_cstring(&m, command);
+
+        mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_COMMAND, &m);
+        buffer_free(&m);
+}
+#endif /* AUDIT_EVENTS */
+
 #ifdef GSSAPI
 OM_uint32
 mm_ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID goid)
diff --git a/monitor_wrap.h b/monitor_wrap.h
index e5cf5718c..7ed241aa8 100644
--- a/monitor_wrap.h
+++ b/monitor_wrap.h
@@ -74,6 +74,12 @@ int mm_sshpam_respond(void *, u_int, char **);
 void mm_sshpam_free_ctx(void *);
 #endif
 
+#ifdef AUDIT_EVENTS
+#include "audit.h"
+void mm_audit_event(ssh_audit_event_t);
+void mm_audit_run_command(const char *);
+#endif
+
 struct Session;
 void mm_terminate(void);
 int mm_pty_allocate(int *, int *, char *, int);
diff --git a/session.c b/session.c
index 4d7ac9de7..b645144c5 100644
--- a/session.c
+++ b/session.c
@@ -665,6 +665,18 @@ do_exec(Session *s, const char *command)
                 debug("Forced command '%.900s'", command);
         }
 
+#ifdef AUDIT_EVENTS
+        if (command != NULL)
+                PRIVSEP(audit_run_command(command));
+        else if (s->ttyfd == -1) {
+                char *shell = s->pw->pw_shell;
+
+                if (shell[0] == '\0')   /* empty shell means /bin/sh */
+                        shell =_PATH_BSHELL;
+                PRIVSEP(audit_run_command(shell));
+        }
+#endif
+
 #ifdef GSSAPI
         if (options.gss_authentication) {
                 temporarily_use_uid(s->pw);
@@ -2321,6 +2333,10 @@ do_cleanup(Authctxt *authctxt)
         }
 #endif
 
+#ifdef AUDIT_EVENTS
+        PRIVSEP(audit_event(CONNECTION_CLOSE));
+#endif
+
         /* remove agent socket */
         auth_sock_cleanup_proc(authctxt->pw);
 
diff --git a/sshd.c b/sshd.c
index 23d6962c0..e61870ea5 100644
--- a/sshd.c
+++ b/sshd.c
@@ -1628,6 +1628,9 @@ main(int ac, char **av)
         remote_port = get_remote_port();
         remote_ip = get_remote_ipaddr();
 
+#ifdef AUDIT_EVENTS
+        audit_connection_from(remote_ip, remote_port);
+#endif
 #ifdef LIBWRAP
         /* Check whether logins are denied from this host. */
         if (packet_connection_is_on_socket()) {
@@ -1697,6 +1700,10 @@ main(int ac, char **av)
         }
 
  authenticated:
+#ifdef AUDIT_EVENTS
+        audit_event(AUTH_SUCCESS);
+#endif
+
         /*
          * In privilege separation, we fork another child and prepare
          * file descriptor passing.
@@ -2010,5 +2017,10 @@ cleanup_exit(int i)
 {
         if (the_authctxt)
                 do_cleanup(the_authctxt);
+#ifdef AUDIT_EVENTS
+        /* done after do_cleanup so it can cancel the PAM auth 'thread' */
+        if (!use_privsep || mm_is_monitor())
+                audit_event(CONNECTION_ABANDON);
+#endif
         _exit(i);
 }