security/apparmor/ipc.c

   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
  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  */
  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  */
  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
  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
  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 }