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