xref: /openssh-portable/audit-linux.c (revision 9b655dc9)
1 /*
2  * Copyright 2010 Red Hat, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  *
25  * Red Hat author: Jan F. Chadima <jchadima@redhat.com>
26  */
27 
28 #include "includes.h"
29 #if defined(USE_LINUX_AUDIT)
30 #include <libaudit.h>
31 #include <unistd.h>
32 #include <string.h>
33 
34 #include "log.h"
35 #include "audit.h"
36 #include "canohost.h"
37 #include "packet.h"
38 
39 const char *audit_username(void);
40 
41 int
linux_audit_record_event(int uid,const char * username,const char * hostname,const char * ip,const char * ttyn,int success)42 linux_audit_record_event(int uid, const char *username, const char *hostname,
43     const char *ip, const char *ttyn, int success)
44 {
45 	int audit_fd, rc, saved_errno;
46 
47 	if ((audit_fd = audit_open()) < 0) {
48 		if (errno == EINVAL || errno == EPROTONOSUPPORT ||
49 		    errno == EAFNOSUPPORT)
50 			return 1; /* No audit support in kernel */
51 		else
52 			return 0; /* Must prevent login */
53 	}
54 	rc = audit_log_acct_message(audit_fd, AUDIT_USER_LOGIN,
55 	    NULL, "login", username ? username : "(unknown)",
56 	    username == NULL ? uid : -1, hostname, ip, ttyn, success);
57 	saved_errno = errno;
58 	close(audit_fd);
59 
60 	/*
61 	 * Do not report error if the error is EPERM and sshd is run as non
62 	 * root user.
63 	 */
64 	if ((rc == -EPERM) && (geteuid() != 0))
65 		rc = 0;
66 	errno = saved_errno;
67 
68 	return rc >= 0;
69 }
70 
71 /* Below is the sshd audit API code */
72 
73 void
audit_connection_from(const char * host,int port)74 audit_connection_from(const char *host, int port)
75 {
76 	/* not implemented */
77 }
78 
79 void
audit_run_command(const char * command)80 audit_run_command(const char *command)
81 {
82 	/* not implemented */
83 }
84 
85 void
audit_session_open(struct logininfo * li)86 audit_session_open(struct logininfo *li)
87 {
88 	if (linux_audit_record_event(li->uid, NULL, li->hostname, NULL,
89 	    li->line, 1) == 0)
90 		fatal("linux_audit_write_entry failed: %s", strerror(errno));
91 }
92 
93 void
audit_session_close(struct logininfo * li)94 audit_session_close(struct logininfo *li)
95 {
96 	/* not implemented */
97 }
98 
99 void
audit_event(struct ssh * ssh,ssh_audit_event_t event)100 audit_event(struct ssh *ssh, ssh_audit_event_t event)
101 {
102 	switch(event) {
103 	case SSH_AUTH_SUCCESS:
104 	case SSH_CONNECTION_CLOSE:
105 	case SSH_NOLOGIN:
106 	case SSH_LOGIN_EXCEED_MAXTRIES:
107 	case SSH_LOGIN_ROOT_DENIED:
108 		break;
109 	case SSH_AUTH_FAIL_NONE:
110 	case SSH_AUTH_FAIL_PASSWD:
111 	case SSH_AUTH_FAIL_KBDINT:
112 	case SSH_AUTH_FAIL_PUBKEY:
113 	case SSH_AUTH_FAIL_HOSTBASED:
114 	case SSH_AUTH_FAIL_GSSAPI:
115 	case SSH_INVALID_USER:
116 		linux_audit_record_event(-1, audit_username(), NULL,
117 		    ssh_remote_ipaddr(ssh), "sshd", 0);
118 		break;
119 	default:
120 		debug("%s: unhandled event %d", __func__, event);
121 		break;
122 	}
123 }
124 #endif /* USE_LINUX_AUDIT */
125