1 | /*- |
2 | * Copyright (c) 1999-2020 Apple Inc. |
3 | * All rights reserved. |
4 | * |
5 | * @APPLE_BSD_LICENSE_HEADER_START@ |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * 3. Neither the name of Apple Inc. ("Apple") nor the names of |
16 | * its contributors may be used to endorse or promote products derived |
17 | * from this software without specific prior written permission. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND |
20 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
21 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
22 | * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR |
23 | * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
24 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
25 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
26 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
27 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
28 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | * |
31 | * @APPLE_BSD_LICENSE_HEADER_END@ |
32 | */ |
33 | /* |
34 | * NOTICE: This file was modified by McAfee Research in 2004 to introduce |
35 | * support for mandatory and extensible security protections. This notice |
36 | * is included in support of clause 2.2 (b) of the Apple Public License, |
37 | * Version 2.0. |
38 | */ |
39 | |
40 | #include <sys/kernel.h> |
41 | #include <sys/proc.h> |
42 | #include <sys/kauth.h> |
43 | #include <sys/queue.h> |
44 | #include <sys/systm.h> |
45 | |
46 | #include <bsm/audit.h> |
47 | #include <bsm/audit_internal.h> |
48 | #include <bsm/audit_kevents.h> |
49 | |
50 | #include <security/audit/audit.h> |
51 | #include <security/audit/audit_private.h> |
52 | |
53 | #include <mach/host_priv.h> |
54 | #include <mach/host_special_ports.h> |
55 | #include <mach/audit_triggers_server.h> |
56 | |
57 | #include <kern/host.h> |
58 | #include <kern/zalloc.h> |
59 | #include <kern/sched_prim.h> |
60 | |
61 | #if CONFIG_AUDIT |
62 | |
63 | #if CONFIG_MACF |
64 | #include <bsm/audit_record.h> |
65 | #include <security/mac.h> |
66 | #include <security/mac_framework.h> |
67 | #include <security/mac_policy.h> |
68 | #define MAC_ARG_PREFIX "arg: " |
69 | #define MAC_ARG_PREFIX_LEN 5 |
70 | |
71 | ZONE_DEFINE(audit_mac_label_zone, "audit_mac_label_zone" , |
72 | MAC_AUDIT_LABEL_LEN, ZC_NONE); |
73 | |
74 | int |
75 | audit_mac_new(proc_t p, struct kaudit_record *ar) |
76 | { |
77 | struct mac mac; |
78 | |
79 | /* |
80 | * Retrieve the MAC labels for the process. |
81 | */ |
82 | ar->k_ar.ar_cred_mac_labels = zalloc_flags(audit_mac_label_zone, |
83 | Z_WAITOK | Z_NOFAIL); |
84 | mac.m_buflen = MAC_AUDIT_LABEL_LEN; |
85 | mac.m_string = ar->k_ar.ar_cred_mac_labels; |
86 | if (mac_cred_label_externalize_audit(p, mac: &mac)) { |
87 | zfree(audit_mac_label_zone, ar->k_ar.ar_cred_mac_labels); |
88 | return 1; |
89 | } |
90 | |
91 | /* |
92 | * grab space for the reconds. |
93 | */ |
94 | ar->k_ar.ar_mac_records = (struct mac_audit_record_list_t *) |
95 | kalloc_type(struct mac_audit_record_list_t, Z_WAITOK); |
96 | if (ar->k_ar.ar_mac_records == NULL) { |
97 | zfree(audit_mac_label_zone, ar->k_ar.ar_cred_mac_labels); |
98 | return 1; |
99 | } |
100 | LIST_INIT(ar->k_ar.ar_mac_records); |
101 | ar->k_ar.ar_forced_by_mac = 0; |
102 | |
103 | return 0; |
104 | } |
105 | |
106 | void |
107 | audit_mac_free(struct kaudit_record *ar) |
108 | { |
109 | struct mac_audit_record *head, *next; |
110 | |
111 | if (ar->k_ar.ar_vnode1_mac_labels != NULL) { |
112 | zfree(audit_mac_label_zone, ar->k_ar.ar_vnode1_mac_labels); |
113 | } |
114 | if (ar->k_ar.ar_vnode2_mac_labels != NULL) { |
115 | zfree(audit_mac_label_zone, ar->k_ar.ar_vnode2_mac_labels); |
116 | } |
117 | if (ar->k_ar.ar_cred_mac_labels != NULL) { |
118 | zfree(audit_mac_label_zone, ar->k_ar.ar_cred_mac_labels); |
119 | } |
120 | if (ar->k_ar.ar_arg_mac_string != NULL) { |
121 | kfree_data(ar->k_ar.ar_arg_mac_string, |
122 | MAC_MAX_LABEL_BUF_LEN + MAC_ARG_PREFIX_LEN); |
123 | } |
124 | |
125 | /* |
126 | * Free the audit data from the MAC policies. |
127 | */ |
128 | head = LIST_FIRST(ar->k_ar.ar_mac_records); |
129 | while (head != NULL) { |
130 | next = LIST_NEXT(head, records); |
131 | zfree(mac_audit_data_zone, head->data); |
132 | kfree_type(struct mac_audit_record, head); |
133 | head = next; |
134 | } |
135 | kfree_type(struct mac_audit_record_list_t, ar->k_ar.ar_mac_records); |
136 | } |
137 | |
138 | int |
139 | audit_mac_syscall_enter(unsigned short code, proc_t p, struct uthread *uthread, |
140 | kauth_cred_t my_cred, au_event_t event) |
141 | { |
142 | int error; |
143 | |
144 | error = mac_audit_check_preselect(cred: my_cred, syscode: code, |
145 | args: (void *)uthread->uu_arg); |
146 | if (error == MAC_AUDIT_YES) { |
147 | uthread->uu_ar = audit_new(event, p, td: uthread); |
148 | if (uthread->uu_ar) { |
149 | uthread->uu_ar->k_ar.ar_forced_by_mac = 1; |
150 | } |
151 | return 1; |
152 | } else if (error == MAC_AUDIT_NO) { |
153 | return 0; |
154 | } else if (error == MAC_AUDIT_DEFAULT) { |
155 | return 1; |
156 | } |
157 | |
158 | return 0; |
159 | } |
160 | |
161 | int |
162 | audit_mac_syscall_exit(unsigned short code, struct uthread *uthread, int error, |
163 | int retval) |
164 | { |
165 | int mac_error; |
166 | |
167 | if (uthread->uu_ar == NULL) { /* syscall wasn't audited */ |
168 | return 1; |
169 | } |
170 | |
171 | /* |
172 | * Note, no other postselect mechanism exists. If |
173 | * mac_audit_check_postselect returns MAC_AUDIT_NO, the record will be |
174 | * suppressed. Other values at this point result in the audit record |
175 | * being committed. This suppression behavior will probably go away in |
176 | * the port to 10.3.4. |
177 | */ |
178 | mac_error = mac_audit_check_postselect(cred: kauth_cred_get(), syscode: code, |
179 | args: (void *) uthread->uu_arg, error, retval, |
180 | mac_forced: uthread->uu_ar->k_ar.ar_forced_by_mac); |
181 | |
182 | if (mac_error == MAC_AUDIT_YES) { |
183 | uthread->uu_ar->k_ar_commit |= AR_COMMIT_KERNEL; |
184 | } else if (mac_error == MAC_AUDIT_NO) { |
185 | audit_free(ar: uthread->uu_ar); |
186 | return 1; |
187 | } |
188 | return 0; |
189 | } |
190 | |
191 | /* |
192 | * This function is called by the MAC Framework to add audit data |
193 | * from a policy to the current audit record. |
194 | */ |
195 | int |
196 | audit_mac_data(int type, int len, u_char *data) |
197 | { |
198 | struct kaudit_record *cur; |
199 | struct mac_audit_record *record; |
200 | |
201 | if (audit_enabled == 0) { |
202 | zfree(mac_audit_data_zone, data); |
203 | return ENOTSUP; |
204 | } |
205 | |
206 | cur = currecord(); |
207 | if (cur == NULL) { |
208 | zfree(mac_audit_data_zone, data); |
209 | return ENOTSUP; |
210 | } |
211 | |
212 | /* |
213 | * XXX: Note that we silently drop the audit data if this |
214 | * allocation fails - this is consistent with the rest of the |
215 | * audit implementation. |
216 | */ |
217 | record = kalloc_type(struct mac_audit_record, Z_WAITOK | Z_NOFAIL); |
218 | |
219 | record->type = type; |
220 | record->length = len; |
221 | record->data = data; |
222 | LIST_INSERT_HEAD(cur->k_ar.ar_mac_records, record, records); |
223 | |
224 | return 0; |
225 | } |
226 | |
227 | void |
228 | audit_arg_mac_string(struct kaudit_record *ar, char *string) |
229 | { |
230 | if (ar->k_ar.ar_arg_mac_string == NULL) { |
231 | ar->k_ar.ar_arg_mac_string = kalloc_data(MAC_MAX_LABEL_BUF_LEN + MAC_ARG_PREFIX_LEN, Z_WAITOK); |
232 | } |
233 | |
234 | /* |
235 | * XXX This should be a rare event. If kalloc_data() returns NULL, |
236 | * the system is low on kernel virtual memory. To be |
237 | * consistent with the rest of audit, just return |
238 | * (may need to panic if required to for audit). |
239 | */ |
240 | if (ar->k_ar.ar_arg_mac_string == NULL) { |
241 | return; |
242 | } |
243 | |
244 | strlcpy(dst: ar->k_ar.ar_arg_mac_string, MAC_ARG_PREFIX, |
245 | MAC_ARG_PREFIX_LEN); |
246 | strlcpy(dst: ar->k_ar.ar_arg_mac_string + MAC_ARG_PREFIX_LEN, src: string, |
247 | MAC_MAX_LABEL_BUF_LEN); |
248 | ARG_SET_VALID(ar, ARG_MAC_STRING); |
249 | } |
250 | #endif /* MAC */ |
251 | |
252 | #endif /* CONFIG_AUDIT */ |
253 | |