1 /*
2 * AppArmor security module
3 *
4 * This file contains AppArmor capability mediation functions
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15 #include <linux/capability.h>
16 #include <linux/errno.h>
17 #include <linux/gfp.h>
18
19 #include "include/apparmor.h"
20 #include "include/capability.h"
21 #include "include/context.h"
22 #include "include/policy.h"
23 #include "include/audit.h"
24
25 /*
26 * Table of capability names: we generate it from capabilities.h.
27 */
28 #include "capability_names.h"
29
30 struct audit_cache {
31 struct aa_profile *profile;
32 kernel_cap_t caps;
33 };
34
35 static DEFINE_PER_CPU(struct audit_cache, audit_cache);
36
37 /**
38 * audit_cb - call back for capability components of audit struct
39 * @ab - audit buffer (NOT NULL)
40 * @va - audit struct to audit data from (NOT NULL)
41 */
audit_cb(struct audit_buffer * ab,void * va)42 static void audit_cb(struct audit_buffer *ab, void *va)
43 {
44 struct common_audit_data *sa = va;
45 audit_log_format(ab, " capname=");
46 audit_log_untrustedstring(ab, capability_names[sa->u.cap]);
47 }
48
49 /**
50 * audit_caps - audit a capability
51 * @profile: profile confining task (NOT NULL)
52 * @task: task capability test was performed against (NOT NULL)
53 * @cap: capability tested
54 * @error: error code returned by test
55 *
56 * Do auditing of capability and handle, audit/complain/kill modes switching
57 * and duplicate message elimination.
58 *
59 * Returns: 0 or sa->error on success, error code on failure
60 */
audit_caps(struct aa_profile * profile,struct task_struct * task,int cap,int error)61 static int audit_caps(struct aa_profile *profile, struct task_struct *task,
62 int cap, int error)
63 {
64 struct audit_cache *ent;
65 int type = AUDIT_APPARMOR_AUTO;
66 struct common_audit_data sa;
67 struct apparmor_audit_data aad = {0,};
68 COMMON_AUDIT_DATA_INIT(&sa, CAP);
69 sa.aad = &aad;
70 sa.tsk = task;
71 sa.u.cap = cap;
72 sa.aad->op = OP_CAPABLE;
73 sa.aad->error = error;
74
75 if (likely(!error)) {
76 /* test if auditing is being forced */
77 if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
78 !cap_raised(profile->caps.audit, cap)))
79 return 0;
80 type = AUDIT_APPARMOR_AUDIT;
81 } else if (KILL_MODE(profile) ||
82 cap_raised(profile->caps.kill, cap)) {
83 type = AUDIT_APPARMOR_KILL;
84 } else if (cap_raised(profile->caps.quiet, cap) &&
85 AUDIT_MODE(profile) != AUDIT_NOQUIET &&
86 AUDIT_MODE(profile) != AUDIT_ALL) {
87 /* quiet auditing */
88 return error;
89 }
90
91 /* Do simple duplicate message elimination */
92 ent = &get_cpu_var(audit_cache);
93 if (profile == ent->profile && cap_raised(ent->caps, cap)) {
94 put_cpu_var(audit_cache);
95 if (COMPLAIN_MODE(profile))
96 return complain_error(error);
97 return error;
98 } else {
99 aa_put_profile(ent->profile);
100 ent->profile = aa_get_profile(profile);
101 cap_raise(ent->caps, cap);
102 }
103 put_cpu_var(audit_cache);
104
105 return aa_audit(type, profile, GFP_ATOMIC, &sa, audit_cb);
106 }
107
108 /**
109 * profile_capable - test if profile allows use of capability @cap
110 * @profile: profile being enforced (NOT NULL, NOT unconfined)
111 * @cap: capability to test if allowed
112 *
113 * Returns: 0 if allowed else -EPERM
114 */
profile_capable(struct aa_profile * profile,int cap)115 static int profile_capable(struct aa_profile *profile, int cap)
116 {
117 return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
118 }
119
120 /**
121 * aa_capable - test permission to use capability
122 * @task: task doing capability test against (NOT NULL)
123 * @profile: profile confining @task (NOT NULL)
124 * @cap: capability to be tested
125 * @audit: whether an audit record should be generated
126 *
127 * Look up capability in profile capability set.
128 *
129 * Returns: 0 on success, or else an error code.
130 */
aa_capable(struct task_struct * task,struct aa_profile * profile,int cap,int audit)131 int aa_capable(struct task_struct *task, struct aa_profile *profile, int cap,
132 int audit)
133 {
134 int error = profile_capable(profile, cap);
135
136 if (!audit) {
137 if (COMPLAIN_MODE(profile))
138 return complain_error(error);
139 return error;
140 }
141
142 return audit_caps(profile, task, cap, error);
143 }
144