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
map_signal_num(int sig)21 static 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 */
audit_signal_mask(u32 mask)38 static 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_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 */
audit_signal_cb(struct audit_buffer * ab,void * va)52 static void audit_signal_cb(struct audit_buffer *ab, void *va)
53 {
54 struct common_audit_data *sa = va;
55
56 if (aad(sa)->request & AA_SIGNAL_PERM_MASK) {
57 audit_log_format(ab, " requested_mask=\"%s\"",
58 audit_signal_mask(aad(sa)->request));
59 if (aad(sa)->denied & AA_SIGNAL_PERM_MASK) {
60 audit_log_format(ab, " denied_mask=\"%s\"",
61 audit_signal_mask(aad(sa)->denied));
62 }
63 }
64 if (aad(sa)->signal == SIGUNKNOWN)
65 audit_log_format(ab, "signal=unknown(%d)",
66 aad(sa)->unmappedsig);
67 else if (aad(sa)->signal < MAXMAPPED_SIGNAME)
68 audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]);
69 else
70 audit_log_format(ab, " signal=rtmin+%d",
71 aad(sa)->signal - SIGRT_BASE);
72 audit_log_format(ab, " peer=");
73 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
74 FLAGS_NONE, GFP_ATOMIC);
75 }
76
profile_signal_perm(struct aa_profile * profile,struct aa_label * peer,u32 request,struct common_audit_data * sa)77 static int profile_signal_perm(struct aa_profile *profile,
78 struct aa_label *peer, u32 request,
79 struct common_audit_data *sa)
80 {
81 struct aa_perms perms;
82 unsigned int state;
83
84 if (profile_unconfined(profile) ||
85 !PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL))
86 return 0;
87
88 aad(sa)->peer = peer;
89 /* TODO: secondary cache check <profile, profile, perm> */
90 state = aa_dfa_next(profile->policy.dfa,
91 profile->policy.start[AA_CLASS_SIGNAL],
92 aad(sa)->signal);
93 aa_label_match(profile, peer, state, false, request, &perms);
94 aa_apply_modes_to_perms(profile, &perms);
95 return aa_check_perms(profile, &perms, request, sa, audit_signal_cb);
96 }
97
aa_may_signal(struct aa_label * sender,struct aa_label * target,int sig)98 int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig)
99 {
100 struct aa_profile *profile;
101 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL);
102
103 aad(&sa)->signal = map_signal_num(sig);
104 aad(&sa)->unmappedsig = sig;
105 return xcheck_labels(sender, target, profile,
106 profile_signal_perm(profile, target, MAY_WRITE, &sa),
107 profile_signal_perm(profile, sender, MAY_READ, &sa));
108 }
109
