1 /*
2 * Copyright (c) 2022 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 #include "dfx_signal_hook.h"
17
18 #include <dlfcn.h>
19 #include <libunwind_i-ohos.h>
20 #include <map_info.h>
21 #include <securec.h>
22 #include <signal.h>
23 #include <stdio.h>
24 #include <unistd.h>
25 #include "dfx_define.h"
26 #include "dfx_log.h"
27 #include "hilog_base/log_base.h"
28 #include "libunwind-arm.h"
29 #include "libunwind_i.h"
30 #include "pthread.h"
31 #include "stdbool.h"
32 #include "stdlib.h"
33
34 #include "dfx_hook_utils.h"
35
36 #ifdef LOG_DOMAIN
37 #undef LOG_DOMAIN
38 #define LOG_DOMAIN 0xD002D11
39 #endif
40
41 #ifdef LOG_TAG
42 #undef LOG_TAG
43 #define LOG_TAG "DfxSigHook"
44 #endif
45
46 #ifndef SIGDUMP
47 #define SIGDUMP 35
48 #endif
49
50 #define MIN_FRAME 4
51 #define MAX_FRAME 64
52 #define BUF_SZ 512
53 #define MAPINFO_SIZE 256
54 #define MAX_SIGNO 63
55
InitHook(void)56 void __attribute__((constructor)) InitHook(void)
57 {
58 StartHookFunc();
59 }
60
61 typedef int (*SigactionFunc)(int sig, const struct sigaction *restrict act, struct sigaction *restrict oact);
62 typedef int (*SigprocmaskFunc)(int how, const sigset_t *restrict set, sigset_t *restrict oldset);
63 typedef int (*PthreadSigmaskFunc)(int how, const sigset_t *restrict set, sigset_t *restrict oldset);
64 typedef sighandler_t (*SignalFunc)(int signum, sighandler_t handler);
65 static SigactionFunc g_hookedSigaction = NULL;
66 static SigprocmaskFunc g_hookedSigprocmask = NULL;
67 static SignalFunc g_hookedSignal = NULL;
68 static PthreadSigmaskFunc g_hookedPthreadSigmask = NULL;
69
IsPlatformHandleSignal(int sig)70 bool IsPlatformHandleSignal(int sig)
71 {
72 int platformSignals[] = {
73 SIGABRT, SIGBUS, SIGILL, SIGSEGV, SIGDUMP
74 };
75 for (size_t i = 0; i < sizeof(platformSignals) / sizeof(platformSignals[0]); i++) {
76 if (platformSignals[i] == sig) {
77 return true;
78 }
79 }
80 return false;
81 }
82
pthread_sigmask(int how,const sigset_t * restrict set,sigset_t * restrict oldset)83 int pthread_sigmask(int how, const sigset_t *restrict set, sigset_t *restrict oldset)
84 {
85 if (set != NULL) {
86 for (int i = 1; i < MAX_SIGNO; i++) {
87 if (sigismember(set, i) && (IsPlatformHandleSignal(i)) &&
88 ((how == SIG_BLOCK) || (how == SIG_SETMASK))) {
89 LOGI("%d:%d pthread_sigmask signal(%d)\n", getpid(), gettid(), i);
90 LogBacktrace();
91 }
92 }
93 }
94
95 if (g_hookedPthreadSigmask == NULL) {
96 LOGE("hooked procmask is NULL?\n");
97 return -1;
98 }
99 return g_hookedPthreadSigmask(how, set, oldset);
100 }
101
sigprocmask(int how,const sigset_t * restrict set,sigset_t * restrict oldset)102 int sigprocmask(int how, const sigset_t *restrict set, sigset_t *restrict oldset)
103 {
104 if (set != NULL) {
105 for (int i = 1; i < MAX_SIGNO; i++) {
106 if (sigismember(set, i) && (IsPlatformHandleSignal(i)) &&
107 ((how == SIG_BLOCK) || (how == SIG_SETMASK))) {
108 LOGI("%d:%d sigprocmask signal(%d)\n", getpid(), gettid(), i);
109 LogBacktrace();
110 }
111 }
112 }
113 if (g_hookedSigprocmask == NULL) {
114 LOGE("hooked procmask is NULL?\n");
115 return -1;
116 }
117 return g_hookedSigprocmask(how, set, oldset);
118 }
119
signal(int signum,sighandler_t handler)120 sighandler_t signal(int signum, sighandler_t handler)
121 {
122 if (IsPlatformHandleSignal(signum)) {
123 LOGI("%d register signal handler for signal(%d)\n", getpid(), signum);
124 LogBacktrace();
125 }
126
127 if (g_hookedSignal == NULL) {
128 LOGE("hooked signal is NULL?\n");
129 return NULL;
130 }
131 return g_hookedSignal(signum, handler);
132 }
133
IsSigactionAddr(uintptr_t sigactionAddr)134 static bool IsSigactionAddr(uintptr_t sigactionAddr)
135 {
136 bool ret = false;
137 char path[NAME_LEN] = {0};
138 if (snprintf_s(path, sizeof(path), sizeof(path) - 1, "/proc/self/maps") <= 0) {
139 LOGW("Fail to print path.");
140 return false;
141 }
142
143 FILE *fp = fopen(path, "r");
144 if (fp == NULL) {
145 LOGW("Fail to open maps info.");
146 return false;
147 }
148
149 char mapInfo[MAPINFO_SIZE] = {0};
150 int pos = 0;
151 uint64_t begin = 0;
152 uint64_t end = 0;
153 uint64_t offset = 0;
154 char perms[5] = {0}; // 5:rwxp
155 while (fgets(mapInfo, sizeof(mapInfo), fp) != NULL) {
156 // f79d6000-f7a62000 r-xp 0004b000 b3:06 1605 /system/lib/ld-musl-arm.so.1
157 if (sscanf_s(mapInfo, "%" SCNxPTR "-%" SCNxPTR " %4s %" SCNxPTR " %*x:%*x %*d%n", &begin, &end,
158 &perms, sizeof(perms), &offset, &pos) != 4) { // 4:scan size
159 LOGW("Fail to parse maps info.");
160 continue;
161 }
162
163 if ((strstr(mapInfo, "r-xp") != NULL) && (strstr(mapInfo, "ld-musl") != NULL)) {
164 LOGI("begin: %lu, end: %lu, sigactionAddr: %lu", begin, end, sigactionAddr);
165 if ((sigactionAddr >= begin) && (sigactionAddr <= end)) {
166 ret = true;
167 break;
168 }
169 } else {
170 continue;
171 }
172 }
173 if (fclose(fp) != 0) {
174 LOGW("Fail to close maps info.");
175 }
176 return ret;
177 }
178
sigaction(int sig,const struct sigaction * restrict act,struct sigaction * restrict oact)179 int sigaction(int sig, const struct sigaction *restrict act, struct sigaction *restrict oact)
180 {
181 if (g_hookedSigaction == NULL) {
182 LOGE("hooked sigaction is NULL?");
183 return -1;
184 }
185
186 if (IsPlatformHandleSignal(sig) && ((act == NULL) ||
187 ((act != NULL) && (IsSigactionAddr((uintptr_t)(act->sa_sigaction)))))) {
188 LOGI("%d call sigaction and signo is %d\n", getpid(), sig);
189 LogBacktrace();
190 }
191
192 return g_hookedSigaction(sig, act, oact);
193 }
194
195 GenHookFunc(StartHookSigactionFunction, SigactionFunc, "sigaction", g_hookedSigaction)
196 GenHookFunc(StartHookSignalFunction, SignalFunc, "signal", g_hookedSignal)
197 GenHookFunc(StartHookSigprocmaskFunction, SigprocmaskFunc, "sigprocmask", g_hookedSigprocmask)
198 GenHookFunc(StartHookPthreadSigmaskFunction, PthreadSigmaskFunc, "pthread_sigmask", g_hookedPthreadSigmask)
199
StartHookFunc(void)200 void StartHookFunc(void)
201 {
202 StartHookSigactionFunction();
203 StartHookSignalFunction();
204 StartHookSigprocmaskFunction();
205 StartHookPthreadSigmaskFunction();
206 }
207