1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  * Copyright (c) 2016 by Delphix. All rights reserved.
26  */
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <sys/stat.h>
31 #include <sys/systeminfo.h>
32 #include <bsm/audit.h>
33 #include <bsm/libbsm.h>
34 #include <bsm/audit_uevents.h>
35 #include <bsm/audit_private.h>
36 #include <unistd.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <pwd.h>
40 
41 #include <locale.h>
42 #include "generic.h"
43 
44 #define	AUDIT_GET_DIFFS_NO_CRONTAB	1
45 #define	AUDIT_GET_DIFFS_CRONTAB		0
46 #define	AUDIT_GET_DIFFS_ERR		-1
47 #define	AUDIT_GET_DIFFS_NO_DIFFS	-2
48 
49 static int	audit_crontab_get_diffs(char *cf, char *tmp_name,
50 		    char **bufptr);
51 
52 int
audit_crontab_modify(char * path,char * tmp_path,int sorf)53 audit_crontab_modify(char *path, char *tmp_path, int sorf)
54 {
55 	int r, create = 0;
56 	char *diffs = NULL;
57 
58 	if (cannot_audit(0)) {
59 		return (0);
60 	} else {
61 		au_event_t event;
62 		char *anc_name;
63 		auditinfo_addr_t ai;
64 
65 		if (getaudit_addr(&ai, sizeof (ai))) {
66 			return (-1);
67 		}
68 
69 		r = audit_crontab_get_diffs(path, tmp_path, &diffs);
70 
71 		if (r == AUDIT_GET_DIFFS_NO_DIFFS) {
72 			return (0);
73 		}
74 		if (diffs != NULL && r != AUDIT_GET_DIFFS_ERR) {
75 			aug_save_text(diffs);
76 			free(diffs);
77 		}
78 
79 		if (r == AUDIT_GET_DIFFS_NO_CRONTAB) {
80 			create = 1;
81 			if (diffs == NULL)
82 				aug_save_text("");
83 		}
84 
85 		/*
86 		 * create an ancilary file if audit characteristics exist
87 		 * else delete an ancilary if if one exists
88 		 */
89 
90 		anc_name = audit_cron_make_anc_name(path);
91 		if (anc_name == NULL)
92 			r = -1;
93 		else if (audit_crontab_process_not_audited()) {
94 			(void) unlink(anc_name);
95 			free(anc_name);
96 		} else {
97 			r = audit_cron_setinfo(anc_name, &ai);
98 			free(anc_name);
99 		}
100 		aug_init();
101 		aug_save_auid(ai.ai_auid);
102 		aug_save_euid(geteuid());
103 		aug_save_egid(getegid());
104 		aug_save_uid(getuid());
105 		aug_save_gid(getgid());
106 		aug_save_pid(getpid());
107 		aug_save_asid(ai.ai_asid);
108 		aug_save_tid_ex(ai.ai_termid.at_port, ai.ai_termid.at_addr,
109 			ai.ai_termid.at_type);
110 
111 
112 		aug_save_path(path);
113 		event = (create) ? AUE_crontab_create : AUE_crontab_mod;
114 		aug_save_event(event);
115 		aug_save_sorf(sorf);
116 
117 		if (aug_audit() != 0)
118 			return (-1);
119 		return (r);
120 	}
121 }
122 
123 int
audit_crontab_delete(char * path,int sorf)124 audit_crontab_delete(char *path, int sorf)
125 {
126 	int r = 0;
127 
128 	if (cannot_audit(0)) {
129 		return (0);
130 	} else {
131 		char *anc_name;
132 		anc_name = audit_cron_make_anc_name(path);
133 		if (anc_name != NULL) {
134 			r = unlink(anc_name);
135 			free(anc_name);
136 		} else
137 			r = -1;
138 
139 		aug_init();
140 		(void) aug_save_me();
141 
142 		aug_save_path(path);
143 		aug_save_event(AUE_crontab_delete);
144 		aug_save_sorf(sorf);
145 		if (aug_audit() != 0)
146 			return (-1);
147 		return (r);
148 	}
149 }
150 
151 /*
152  * gets differences between old and new crontab files.
153  * arguments:
154  * cf        - name of crontab file
155  * tmp_name  - name of new crontab file
156  * bufptr    - pointer to an array of characters with
157  *             either an error message or an output of "diff" command.
158  *
159  * results:
160  * AUDIT_GET_DIFFS_ERR       - errors;
161  *			file not exists (do not free *bufptr in this case)
162  * AUDIT_GET_DIFFS_NO_DIFFS  - errors;
163  *			file exists (do not free *bufptr in this case)
164  * AUDIT_GET_DIFFS_CRONTAB      - OK, old crontab file exists.
165  * AUDIT_GET_DIFFS_NO_CRONTAB   - OK. there is no crontab file.
166  */
167 static int
audit_crontab_get_diffs(char * cf,char * tmp_name,char ** bufptr)168 audit_crontab_get_diffs(char *cf, char *tmp_name, char **bufptr)
169 {
170 	struct stat st, st_tmp;
171 	uid_t	euid;
172 	int	len, r = AUDIT_GET_DIFFS_CRONTAB;
173 	char	*buf = NULL, err_buf[128];
174 
175 	(void) memset(err_buf, 0, 128);
176 	euid = geteuid();
177 	if (seteuid(0) == -1) {
178 		r = AUDIT_GET_DIFFS_ERR;
179 		(void) snprintf(err_buf, sizeof (err_buf),
180 		    "crontab: seteuid: %s\n", strerror(errno));
181 		goto exit_diff;
182 	}
183 	if (stat(cf, &st) == -1) {
184 		if (errno == ENOENT) {
185 			r = AUDIT_GET_DIFFS_NO_CRONTAB;
186 		} else {
187 			r = AUDIT_GET_DIFFS_ERR;
188 			(void) snprintf(err_buf, sizeof (err_buf),
189 				"crontab: %s: stat: %s\n",
190 				cf, strerror(errno));
191 			goto exit_diff;
192 		}
193 		len = 0;
194 	} else
195 		len = st.st_size;
196 
197 	if (stat(tmp_name, &st_tmp) == -1) {
198 		r = AUDIT_GET_DIFFS_ERR;
199 		(void) snprintf(err_buf, sizeof (err_buf),
200 			"crontab: %s: stat: %s\n",
201 			tmp_name, strerror(errno));
202 		goto exit_diff;
203 	}
204 
205 	if (st_tmp.st_size == 0 && len == 0) {
206 	/* there is no difference */
207 		r = AUDIT_GET_DIFFS_NO_DIFFS;
208 		*bufptr = NULL;
209 		goto exit_diff;
210 	}
211 
212 exit_diff:
213 	/* return information on create or update crontab */
214 	(void) seteuid(euid);
215 	switch (r) {
216 	case AUDIT_GET_DIFFS_ERR:
217 		if (buf != NULL)
218 			free(buf);
219 		*bufptr = err_buf;
220 		break;
221 	case AUDIT_GET_DIFFS_NO_DIFFS:
222 		if (buf != NULL)
223 			free(buf);
224 		*bufptr = NULL;
225 		break;
226 	case AUDIT_GET_DIFFS_CRONTAB:
227 		if (buf != NULL) {
228 			if (strlen(buf) != 0) {
229 				*bufptr = buf;
230 			} else {
231 				r = AUDIT_GET_DIFFS_NO_DIFFS;
232 				*bufptr = NULL;
233 			}
234 		}
235 		break;
236 	case AUDIT_GET_DIFFS_NO_CRONTAB:
237 		if (buf != NULL) {
238 			if (strlen(buf) != 0) {
239 				*bufptr = buf;
240 			} else {
241 				*bufptr = NULL;
242 				free(buf);
243 			}
244 		}
245 		break;
246 	}
247 
248 	return (r);
249 }
250 
251 /*
252  * audit_crontab_not_allowed determines if we have a case that should be audited
253  * but we can't.  If auditing is enabled but the current process is not
254  * audited, then the ruid of the user doing the editing must be the owner
255  * id of the file to be edited.
256  *
257  * When audit_crontab_not_allowed is called, ruid is for the crontab file
258  * to be modified or created.
259  */
260 
261 #define	PWD_BUFFER_SIZE	512
262 
263 int
audit_crontab_not_allowed(uid_t ruid,char * user)264 audit_crontab_not_allowed(uid_t ruid, char *user) {
265 	struct passwd		pwd;
266 	char			buffer[PWD_BUFFER_SIZE];
267 	int			rc = 0;		/* 0 == allow */
268 
269 	if (!cannot_audit(0)) {			/* allow access if audit off */
270 		if (getpwnam_r(user, &pwd, buffer, PWD_BUFFER_SIZE) == NULL) {
271 			rc = 1;			/* deny access if invalid */
272 		} else if (ruid == pwd.pw_uid)
273 			rc = 0;			/* editing their own crontab */
274 		else
275 			rc = audit_crontab_process_not_audited();
276 	}
277 	return (rc);
278 }
279 
280 int
audit_crontab_process_not_audited()281 audit_crontab_process_not_audited() {
282 	struct auditpinfo_addr	info;
283 	int	rc;
284 
285 	info.ap_pid = getpid();
286 	if (auditon(A_GETPINFO_ADDR, (caddr_t)&info, sizeof (info)) != 0)
287 		rc = 0;			/* audit failure: not enabled */
288 	else
289 		rc = (info.ap_auid == AU_NOAUDITID);
290 
291 	return (rc);
292 }
293