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openssh/audit-bsm.c

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/*
* TODO
*
* - deal with overlap between this and sys_auth_allowed_user
* sys_auth_record_login and record_failed_login.
*/
/*
* Copyright 1988-2002 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/* #pragma ident "@(#)bsmaudit.c 1.1 01/09/17 SMI" */
#include "includes.h"
#if defined(USE_BSM_AUDIT)
#include <sys/types.h>
#include <errno.h>
#include <netdb.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#ifdef BROKEN_BSM_API
#include <libscf.h>
#endif
#include "ssh.h"
#include "log.h"
#include "hostfile.h"
#include "auth.h"
#include "xmalloc.h"
#ifndef AUE_openssh
# define AUE_openssh 32800
#endif
#include <bsm/audit.h>
#include <bsm/libbsm.h>
#include <bsm/audit_uevents.h>
#include <bsm/audit_record.h>
#include <locale.h>
#if defined(HAVE_GETAUDIT_ADDR)
#define AuditInfoStruct auditinfo_addr
#define AuditInfoTermID au_tid_addr_t
#define SetAuditFunc(a,b) setaudit_addr((a),(b))
#define SetAuditFuncText "setaudit_addr"
#define AUToSubjectFunc au_to_subject_ex
#define AUToReturnFunc(a,b) au_to_return32((a), (int32_t)(b))
#else
#define AuditInfoStruct auditinfo
#define AuditInfoTermID au_tid_t
#define SetAuditFunc(a,b) setaudit(a)
#define SetAuditFuncText "setaudit"
#define AUToSubjectFunc au_to_subject
#define AUToReturnFunc(a,b) au_to_return((a), (u_int)(b))
#endif
#ifndef cannot_audit
extern int cannot_audit(int);
#endif
extern void aug_init(void);
extern void aug_save_auid(au_id_t);
extern void aug_save_uid(uid_t);
extern void aug_save_euid(uid_t);
extern void aug_save_gid(gid_t);
extern void aug_save_egid(gid_t);
extern void aug_save_pid(pid_t);
extern void aug_save_asid(au_asid_t);
extern void aug_save_tid(dev_t, unsigned int);
extern void aug_save_tid_ex(dev_t, u_int32_t *, u_int32_t);
extern int aug_save_me(void);
extern int aug_save_namask(void);
extern void aug_save_event(au_event_t);
extern void aug_save_sorf(int);
extern void aug_save_text(char *);
extern void aug_save_text1(char *);
extern void aug_save_text2(char *);
extern void aug_save_na(int);
extern void aug_save_user(char *);
extern void aug_save_path(char *);
extern int aug_save_policy(void);
extern void aug_save_afunc(int (*)(int));
extern int aug_audit(void);
extern int aug_na_selected(void);
extern int aug_selected(void);
extern int aug_daemon_session(void);
#ifndef HAVE_GETTEXT
# define gettext(a) (a)
#endif
extern Authctxt *the_authctxt;
static AuditInfoTermID ssh_bsm_tid;
#ifdef BROKEN_BSM_API
/* For some reason this constant is no longer defined
in Solaris 11. */
#define BSM_TEXTBUFSZ 256
#endif
/* Below is the low-level BSM interface code */
/*
* aug_get_machine is only required on IPv6 capable machines, we use a
* different mechanism in audit_connection_from() for IPv4-only machines.
* getaudit_addr() is only present on IPv6 capable machines.
*/
#if defined(HAVE_AUG_GET_MACHINE) || !defined(HAVE_GETAUDIT_ADDR)
extern int aug_get_machine(char *, u_int32_t *, u_int32_t *);
#else
static int
aug_get_machine(char *host, u_int32_t *addr, u_int32_t *type)
{
struct addrinfo *ai;
struct sockaddr_in *in4;
struct sockaddr_in6 *in6;
int ret = 0, r;
if ((r = getaddrinfo(host, NULL, NULL, &ai)) != 0) {
error("BSM audit: getaddrinfo failed for %.100s: %.100s", host,
r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
return -1;
}
switch (ai->ai_family) {
case AF_INET:
in4 = (struct sockaddr_in *)ai->ai_addr;
*type = AU_IPv4;
memcpy(addr, &in4->sin_addr, sizeof(struct in_addr));
break;
#ifdef AU_IPv6
case AF_INET6:
in6 = (struct sockaddr_in6 *)ai->ai_addr;
*type = AU_IPv6;
memcpy(addr, &in6->sin6_addr, sizeof(struct in6_addr));
break;
#endif
default:
error("BSM audit: unknown address family for %.100s: %d",
host, ai->ai_family);
ret = -1;
}
freeaddrinfo(ai);
return ret;
}
#endif
#ifdef BROKEN_BSM_API
/*
In Solaris 11 the audit daemon has been moved to SMF. In the process
they simply dropped getacna() from the API, since it read from a now
non-existent config file. This function re-implements getacna() to
read from the SMF repository instead.
*/
int
getacna(char *auditstring, int len)
{
scf_handle_t *handle = NULL;
scf_property_t *property = NULL;
scf_value_t *value = NULL;
int ret = 0;
/*
* The man page for getacna on Solaris 10 states we should return -2
* in case of error and set errno to indicate the error. We don't
* bother with errno here, though, since the only use of this function
* below doesn't check for errors anyway.
*/
handle = scf_handle_create(SCF_VERSION);
if (handle == NULL)
return -2;
ret = scf_handle_bind(handle);
if (ret == -1)
return -2;
property = scf_property_create(handle);
if (property == NULL)
return -2;
ret = scf_handle_decode_fmri(handle,
"svc:/system/auditd:default/:properties/preselection/naflags",
NULL, NULL, NULL, NULL, property, 0);
if (ret == -1)
return -2;
value = scf_value_create(handle);
if (value == NULL)
return -2;
ret = scf_property_get_value(property, value);
if (ret == -1)
return -2;
ret = scf_value_get_astring(value, auditstring, len);
if (ret == -1)
return -2;
scf_value_destroy(value);
scf_property_destroy(property);
scf_handle_destroy(handle);
return 0;
}
#endif
/*
* Check if the specified event is selected (enabled) for auditing.
* Returns 1 if the event is selected, 0 if not and -1 on failure.
*/
static int
selected(char *username, uid_t uid, au_event_t event, int sf)
{
int rc, sorf;
char naflags[512];
struct au_mask mask;
mask.am_success = mask.am_failure = 0;
if (uid < 0) {
/* get flags for non-attributable (to a real user) events */
rc = getacna(naflags, sizeof(naflags));
if (rc == 0)
(void) getauditflagsbin(naflags, &mask);
} else
rc = au_user_mask(username, &mask);
sorf = (sf == 0) ? AU_PRS_SUCCESS : AU_PRS_FAILURE;
return(au_preselect(event, &mask, sorf, AU_PRS_REREAD));
}
static void
bsm_audit_record(int typ, char *string, au_event_t event_no)
{
int ad, rc, sel;
uid_t uid = -1;
gid_t gid = -1;
pid_t pid = getpid();
AuditInfoTermID tid = ssh_bsm_tid;
if (the_authctxt != NULL && the_authctxt->valid) {
uid = the_authctxt->pw->pw_uid;
gid = the_authctxt->pw->pw_gid;
}
rc = (typ == 0) ? 0 : -1;
sel = selected(the_authctxt->user, uid, event_no, rc);
debug3("BSM audit: typ %d rc %d \"%s\"", typ, rc, string);
if (!sel)
return; /* audit event does not match mask, do not write */
debug3("BSM audit: writing audit new record");
ad = au_open();
(void) au_write(ad, AUToSubjectFunc(uid, uid, gid, uid, gid,
pid, pid, &tid));
(void) au_write(ad, au_to_text(string));
(void) au_write(ad, AUToReturnFunc(typ, rc));
#ifdef BROKEN_BSM_API
/*
* The last argument is the event modifier flags. For some seemingly
* undocumented reason it was added in Solaris 11.
*/
rc = au_close(ad, AU_TO_WRITE, event_no, 0);
#else
rc = au_close(ad, AU_TO_WRITE, event_no);
#endif
if (rc < 0)
error("BSM audit: %s failed to write \"%s\" record: %s",
__func__, string, strerror(errno));
}
static void
bsm_audit_session_setup(void)
{
int rc;
struct AuditInfoStruct info;
au_mask_t mask;
if (the_authctxt == NULL) {
error("BSM audit: session setup internal error (NULL ctxt)");
return;
}
if (the_authctxt->valid)
info.ai_auid = the_authctxt->pw->pw_uid;
else
info.ai_auid = -1;
info.ai_asid = getpid();
mask.am_success = 0;
mask.am_failure = 0;
(void) au_user_mask(the_authctxt->user, &mask);
info.ai_mask.am_success = mask.am_success;
info.ai_mask.am_failure = mask.am_failure;
info.ai_termid = ssh_bsm_tid;
rc = SetAuditFunc(&info, sizeof(info));
if (rc < 0)
error("BSM audit: %s: %s failed: %s", __func__,
SetAuditFuncText, strerror(errno));
}
static void
bsm_audit_bad_login(const char *what)
{
char textbuf[BSM_TEXTBUFSZ];
if (the_authctxt->valid) {
(void) snprintf(textbuf, sizeof (textbuf),
gettext("invalid %s for user %s"),
what, the_authctxt->user);
bsm_audit_record(4, textbuf, AUE_openssh);
} else {
(void) snprintf(textbuf, sizeof (textbuf),
gettext("invalid user name \"%s\""),
the_authctxt->user);
bsm_audit_record(3, textbuf, AUE_openssh);
}
}
/* Below is the sshd audit API code */
void
audit_connection_from(const char *host, int port)
{
AuditInfoTermID *tid = &ssh_bsm_tid;
char buf[1024];
if (cannot_audit(0))
return;
debug3("BSM audit: connection from %.100s port %d", host, port);
/* populate our terminal id structure */
#if defined(HAVE_GETAUDIT_ADDR)
tid->at_port = (dev_t)port;
aug_get_machine((char *)host, &(tid->at_addr[0]), &(tid->at_type));
snprintf(buf, sizeof(buf), "%08x %08x %08x %08x", tid->at_addr[0],
tid->at_addr[1], tid->at_addr[2], tid->at_addr[3]);
debug3("BSM audit: iptype %d machine ID %s", (int)tid->at_type, buf);
#else
/* this is used on IPv4-only machines */
tid->port = (dev_t)port;
tid->machine = inet_addr(host);
snprintf(buf, sizeof(buf), "%08x", tid->machine);
debug3("BSM audit: machine ID %s", buf);
#endif
}
void
audit_run_command(const char *command)
{
/* not implemented */
}
void
audit_session_open(struct logininfo *li)
{
/* not implemented */
}
void
audit_session_close(struct logininfo *li)
{
/* not implemented */
}
void
audit_event(struct ssh *ssh, ssh_audit_event_t event)
{
char textbuf[BSM_TEXTBUFSZ];
static int logged_in = 0;
const char *user = the_authctxt ? the_authctxt->user : "(unknown user)";
if (cannot_audit(0))
return;
switch(event) {
case SSH_AUTH_SUCCESS:
logged_in = 1;
bsm_audit_session_setup();
snprintf(textbuf, sizeof(textbuf),
gettext("successful login %s"), user);
bsm_audit_record(0, textbuf, AUE_openssh);
break;
case SSH_CONNECTION_CLOSE:
/*
* We can also get a close event if the user attempted auth
* but never succeeded.
*/
if (logged_in) {
snprintf(textbuf, sizeof(textbuf),
gettext("sshd logout %s"), the_authctxt->user);
bsm_audit_record(0, textbuf, AUE_logout);
} else {
debug("%s: connection closed without authentication",
__func__);
}
break;
case SSH_NOLOGIN:
bsm_audit_record(1,
gettext("logins disabled by /etc/nologin"), AUE_openssh);
break;
case SSH_LOGIN_EXCEED_MAXTRIES:
snprintf(textbuf, sizeof(textbuf),
gettext("too many tries for user %s"), the_authctxt->user);
bsm_audit_record(1, textbuf, AUE_openssh);
break;
case SSH_LOGIN_ROOT_DENIED:
bsm_audit_record(2, gettext("not_console"), AUE_openssh);
break;
case SSH_AUTH_FAIL_PASSWD:
bsm_audit_bad_login("password");
break;
case SSH_AUTH_FAIL_KBDINT:
bsm_audit_bad_login("interactive password entry");
break;
default:
debug("%s: unhandled event %d", __func__, event);
}
}
#endif /* BSM */
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