1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * AppArmor security module
4 *
5 * This file contains AppArmor ipc mediation
6 *
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2017 Canonical Ltd.
9 */
10
11#include <linux/gfp.h>
12
13#include "include/audit.h"
14#include "include/capability.h"
15#include "include/cred.h"
16#include "include/policy.h"
17#include "include/ipc.h"
18#include "include/sig_names.h"
19
20
21static inline int map_signal_num(int sig)
22{
23 if (sig > SIGRTMAX)
24 return SIGUNKNOWN;
25 else if (sig >= SIGRTMIN)
26 return sig - SIGRTMIN + SIGRT_BASE;
27 else if (sig < MAXMAPPED_SIG)
28 return sig_map[sig];
29 return SIGUNKNOWN;
30}
31
32/**
33 * audit_signal_mask - convert mask to permission string
34 * @mask: permission mask to convert
35 *
36 * Returns: pointer to static string
37 */
38static const char *audit_signal_mask(u32 mask)
39{
40 if (mask & MAY_READ)
41 return "receive";
42 if (mask & MAY_WRITE)
43 return "send";
44 return "";
45}
46
47/**
48 * audit_signal_cb() - call back for signal specific audit fields
49 * @ab: audit_buffer (NOT NULL)
50 * @va: audit struct to audit values of (NOT NULL)
51 */
52static void audit_signal_cb(struct audit_buffer *ab, void *va)
53{
54 struct common_audit_data *sa = va;
55 struct apparmor_audit_data *ad = aad(sa);
56
57 if (ad->request & AA_SIGNAL_PERM_MASK) {
58 audit_log_format(ab, fmt: " requested_mask=\"%s\"",
59 audit_signal_mask(mask: ad->request));
60 if (ad->denied & AA_SIGNAL_PERM_MASK) {
61 audit_log_format(ab, fmt: " denied_mask=\"%s\"",
62 audit_signal_mask(mask: ad->denied));
63 }
64 }
65 if (ad->signal == SIGUNKNOWN)
66 audit_log_format(ab, fmt: "signal=unknown(%d)",
67 ad->unmappedsig);
68 else if (ad->signal < MAXMAPPED_SIGNAME)
69 audit_log_format(ab, fmt: " signal=%s", sig_names[ad->signal]);
70 else
71 audit_log_format(ab, fmt: " signal=rtmin+%d",
72 ad->signal - SIGRT_BASE);
73 audit_log_format(ab, fmt: " peer=");
74 aa_label_xaudit(ab, labels_ns(ad->subj_label), label: ad->peer,
75 FLAGS_NONE, GFP_ATOMIC);
76}
77
78static int profile_signal_perm(const struct cred *cred,
79 struct aa_profile *profile,
80 struct aa_label *peer, u32 request,
81 struct apparmor_audit_data *ad)
82{
83 struct aa_ruleset *rules = profile->label.rules[0];
84 struct aa_perms perms;
85 aa_state_t state;
86
87 if (profile_unconfined(profile))
88 return 0;
89
90 ad->subj_cred = cred;
91 ad->peer = peer;
92 /* TODO: secondary cache check <profile, profile, perm> */
93 state = RULE_MEDIATES(rules, AA_CLASS_SIGNAL);
94 if (!state)
95 return 0;
96 state = aa_dfa_next(dfa: rules->policy->dfa, state, c: ad->signal);
97 aa_label_match(profile, rules, label: peer, state, subns: false, request, perms: &perms);
98 aa_apply_modes_to_perms(profile, perms: &perms);
99 return aa_check_perms(profile, perms: &perms, request, ad, cb: audit_signal_cb);
100}
101
102int aa_may_signal(const struct cred *subj_cred, struct aa_label *sender,
103 const struct cred *target_cred, struct aa_label *target,
104 int sig)
105{
106 struct aa_profile *profile;
107 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_NONE, AA_CLASS_SIGNAL, OP_SIGNAL);
108
109 ad.signal = map_signal_num(sig);
110 ad.unmappedsig = sig;
111 return xcheck_labels(sender, target, profile,
112 profile_signal_perm(subj_cred, profile, target,
113 MAY_WRITE, &ad),
114 profile_signal_perm(target_cred, profile, sender,
115 MAY_READ, &ad));
116}
117

source code of linux/security/apparmor/ipc.c