1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AppArmor security module
4  *
5  * This file contains AppArmor auditing functions
6  *
7  * Copyright (C) 1998-2008 Novell/SUSE
8  * Copyright 2009-2010 Canonical Ltd.
9  */
10 
11 #include <linux/audit.h>
12 #include <linux/socket.h>
13 
14 #include "include/apparmor.h"
15 #include "include/audit.h"
16 #include "include/policy.h"
17 #include "include/policy_ns.h"
18 #include "include/secid.h"
19 
20 const char *const audit_mode_names[] = {
21 	"normal",
22 	"quiet_denied",
23 	"quiet",
24 	"noquiet",
25 	"all"
26 };
27 
28 static const char *const aa_audit_type[] = {
29 	"AUDIT",
30 	"ALLOWED",
31 	"DENIED",
32 	"HINT",
33 	"STATUS",
34 	"ERROR",
35 	"KILLED",
36 	"AUTO"
37 };
38 
39 /*
40  * Currently AppArmor auditing is fed straight into the audit framework.
41  *
42  * TODO:
43  * netlink interface for complain mode
44  * user auditing, - send user auditing to netlink interface
45  * system control of whether user audit messages go to system log
46  */
47 
48 /**
49  * audit_base - core AppArmor function.
50  * @ab: audit buffer to fill (NOT NULL)
51  * @ca: audit structure containing data to audit (NOT NULL)
52  *
53  * Record common AppArmor audit data from @sa
54  */
audit_pre(struct audit_buffer * ab,void * ca)55 static void audit_pre(struct audit_buffer *ab, void *ca)
56 {
57 	struct common_audit_data *sa = ca;
58 
59 	if (aa_g_audit_header) {
60 		audit_log_format(ab, "apparmor=\"%s\"",
61 				 aa_audit_type[aad(sa)->type]);
62 	}
63 
64 	if (aad(sa)->op) {
65 		audit_log_format(ab, " operation=\"%s\"", aad(sa)->op);
66 	}
67 
68 	if (aad(sa)->info) {
69 		audit_log_format(ab, " info=\"%s\"", aad(sa)->info);
70 		if (aad(sa)->error)
71 			audit_log_format(ab, " error=%d", aad(sa)->error);
72 	}
73 
74 	if (aad(sa)->label) {
75 		struct aa_label *label = aad(sa)->label;
76 
77 		if (label_isprofile(label)) {
78 			struct aa_profile *profile = labels_profile(label);
79 
80 			if (profile->ns != root_ns) {
81 				audit_log_format(ab, " namespace=");
82 				audit_log_untrustedstring(ab,
83 						       profile->ns->base.hname);
84 			}
85 			audit_log_format(ab, " profile=");
86 			audit_log_untrustedstring(ab, profile->base.hname);
87 		} else {
88 			audit_log_format(ab, " label=");
89 			aa_label_xaudit(ab, root_ns, label, FLAG_VIEW_SUBNS,
90 					GFP_ATOMIC);
91 		}
92 	}
93 
94 	if (aad(sa)->name) {
95 		audit_log_format(ab, " name=");
96 		audit_log_untrustedstring(ab, aad(sa)->name);
97 	}
98 }
99 
100 /**
101  * aa_audit_msg - Log a message to the audit subsystem
102  * @sa: audit event structure (NOT NULL)
103  * @cb: optional callback fn for type specific fields (MAYBE NULL)
104  */
aa_audit_msg(int type,struct common_audit_data * sa,void (* cb)(struct audit_buffer *,void *))105 void aa_audit_msg(int type, struct common_audit_data *sa,
106 		  void (*cb) (struct audit_buffer *, void *))
107 {
108 	aad(sa)->type = type;
109 	common_lsm_audit(sa, audit_pre, cb);
110 }
111 
112 /**
113  * aa_audit - Log a profile based audit event to the audit subsystem
114  * @type: audit type for the message
115  * @profile: profile to check against (NOT NULL)
116  * @sa: audit event (NOT NULL)
117  * @cb: optional callback fn for type specific fields (MAYBE NULL)
118  *
119  * Handle default message switching based off of audit mode flags
120  *
121  * Returns: error on failure
122  */
aa_audit(int type,struct aa_profile * profile,struct common_audit_data * sa,void (* cb)(struct audit_buffer *,void *))123 int aa_audit(int type, struct aa_profile *profile, struct common_audit_data *sa,
124 	     void (*cb) (struct audit_buffer *, void *))
125 {
126 	AA_BUG(!profile);
127 
128 	if (type == AUDIT_APPARMOR_AUTO) {
129 		if (likely(!aad(sa)->error)) {
130 			if (AUDIT_MODE(profile) != AUDIT_ALL)
131 				return 0;
132 			type = AUDIT_APPARMOR_AUDIT;
133 		} else if (COMPLAIN_MODE(profile))
134 			type = AUDIT_APPARMOR_ALLOWED;
135 		else
136 			type = AUDIT_APPARMOR_DENIED;
137 	}
138 	if (AUDIT_MODE(profile) == AUDIT_QUIET ||
139 	    (type == AUDIT_APPARMOR_DENIED &&
140 	     AUDIT_MODE(profile) == AUDIT_QUIET_DENIED))
141 		return aad(sa)->error;
142 
143 	if (KILL_MODE(profile) && type == AUDIT_APPARMOR_DENIED)
144 		type = AUDIT_APPARMOR_KILL;
145 
146 	aad(sa)->label = &profile->label;
147 
148 	aa_audit_msg(type, sa, cb);
149 
150 	if (aad(sa)->type == AUDIT_APPARMOR_KILL)
151 		(void)send_sig_info(SIGKILL, NULL,
152 			sa->type == LSM_AUDIT_DATA_TASK && sa->u.tsk ?
153 				    sa->u.tsk : current);
154 
155 	if (aad(sa)->type == AUDIT_APPARMOR_ALLOWED)
156 		return complain_error(aad(sa)->error);
157 
158 	return aad(sa)->error;
159 }
160 
161 struct aa_audit_rule {
162 	struct aa_label *label;
163 };
164 
aa_audit_rule_free(void * vrule)165 void aa_audit_rule_free(void *vrule)
166 {
167 	struct aa_audit_rule *rule = vrule;
168 
169 	if (rule) {
170 		if (!IS_ERR(rule->label))
171 			aa_put_label(rule->label);
172 		kfree(rule);
173 	}
174 }
175 
aa_audit_rule_init(u32 field,u32 op,char * rulestr,void ** vrule)176 int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
177 {
178 	struct aa_audit_rule *rule;
179 
180 	switch (field) {
181 	case AUDIT_SUBJ_ROLE:
182 		if (op != Audit_equal && op != Audit_not_equal)
183 			return -EINVAL;
184 		break;
185 	default:
186 		return -EINVAL;
187 	}
188 
189 	rule = kzalloc(sizeof(struct aa_audit_rule), GFP_KERNEL);
190 
191 	if (!rule)
192 		return -ENOMEM;
193 
194 	/* Currently rules are treated as coming from the root ns */
195 	rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr,
196 				     GFP_KERNEL, true, false);
197 	if (IS_ERR(rule->label)) {
198 		int err = PTR_ERR(rule->label);
199 		aa_audit_rule_free(rule);
200 		return err;
201 	}
202 
203 	*vrule = rule;
204 	return 0;
205 }
206 
aa_audit_rule_known(struct audit_krule * rule)207 int aa_audit_rule_known(struct audit_krule *rule)
208 {
209 	int i;
210 
211 	for (i = 0; i < rule->field_count; i++) {
212 		struct audit_field *f = &rule->fields[i];
213 
214 		switch (f->type) {
215 		case AUDIT_SUBJ_ROLE:
216 			return 1;
217 		}
218 	}
219 
220 	return 0;
221 }
222 
aa_audit_rule_match(u32 sid,u32 field,u32 op,void * vrule)223 int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
224 {
225 	struct aa_audit_rule *rule = vrule;
226 	struct aa_label *label;
227 	int found = 0;
228 
229 	label = aa_secid_to_label(sid);
230 
231 	if (!label)
232 		return -ENOENT;
233 
234 	if (aa_label_is_subset(label, rule->label))
235 		found = 1;
236 
237 	switch (field) {
238 	case AUDIT_SUBJ_ROLE:
239 		switch (op) {
240 		case Audit_equal:
241 			return found;
242 		case Audit_not_equal:
243 			return !found;
244 		}
245 	}
246 	return 0;
247 }
248