1 /*
2 * Copyright (C) 2022 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <errno.h>
30 #include <signal.h>
31 #include <stdint.h>
32 #include <string.h>
33 #include <sys/types.h>
34 #include <unistd.h>
35
36 #include <atomic>
37 #include <string>
38
39 #include <memunreachable/memunreachable.h>
40 #include <platform/bionic/macros.h>
41
42 #include "Config.h"
43 #include "Unreachable.h"
44 #include "debug_log.h"
45
46 std::atomic_bool Unreachable::do_check_;
47
EnableUnreachableCheck(int,struct siginfo *,void *)48 static void EnableUnreachableCheck(int, struct siginfo*, void*) {
49 Unreachable::EnableCheck();
50 }
51
CheckIfRequested(const Config & config)52 void Unreachable::CheckIfRequested(const Config& config) {
53 if ((config.options() & CHECK_UNREACHABLE_ON_SIGNAL) && do_check_.exchange(false)) {
54 info_log("Starting to check for unreachable memory.");
55 if (!LogUnreachableMemory(false, 100)) {
56 error_log("Unreachable check failed, run setenforce 0 and try again.");
57 }
58 }
59 }
60
Initialize(const Config & config)61 bool Unreachable::Initialize(const Config& config) {
62 if (!(config.options() & CHECK_UNREACHABLE_ON_SIGNAL)) {
63 return true;
64 }
65
66 struct sigaction64 unreachable_act = {};
67 unreachable_act.sa_sigaction = EnableUnreachableCheck;
68 unreachable_act.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
69 if (sigaction64(config.check_unreachable_signal(), &unreachable_act, nullptr) != 0) {
70 error_log("Unable to set up check unreachable signal function: %s", strerror(errno));
71 return false;
72 }
73
74 if (config.options() & VERBOSE) {
75 info_log("%s: Run: 'kill -%d %d' to check for unreachable memory.", getprogname(),
76 config.check_unreachable_signal(), getpid());
77 }
78
79 return true;
80 }
81