1 /* Copyright 2020 Google LLC
2 Licensed under the Apache License, Version 2.0 (the "License");
3 you may not use this file except in compliance with the License.
4 You may obtain a copy of the License at
5
6 http://www.apache.org/licenses/LICENSE-2.0
7
8 Unless required by applicable law or agreed to in writing, software
9 distributed under the License is distributed on an "AS IS" BASIS,
10 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 See the License for the specific language governing permissions and
12 limitations under the License.
13 */
14
15
16 #define lua_c
17
18 #include "lprefix.h"
19
20
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <stdint.h>
25
26 #include <signal.h>
27
28 #include "lua.h"
29
30 #include "lauxlib.h"
31 #include "lualib.h"
32
33
34 #if !defined(LUA_PROGNAME)
35 #define LUA_PROGNAME "lua"
36 #endif
37
38 #if !defined(LUA_INIT_VAR)
39 #define LUA_INIT_VAR "LUA_INIT"
40 #endif
41
42 #define LUA_INITVARVERSION LUA_INIT_VAR LUA_VERSUFFIX
43
44
45 static lua_State *globalL = NULL;
46
47 static const char *progname = LUA_PROGNAME;
48
49
50 /*
51 ** Hook set by signal function to stop the interpreter.
52 */
lstop(lua_State * L,lua_Debug * ar)53 static void lstop (lua_State *L, lua_Debug *ar) {
54 (void)ar; /* unused arg. */
55 lua_sethook(L, NULL, 0, 0); /* reset hook */
56 luaL_error(L, "interrupted!");
57 }
58
59
60 /*
61 ** Function to be called at a C signal. Because a C signal cannot
62 ** just change a Lua state (as there is no proper synchronization),
63 ** this function only sets a hook that, when called, will stop the
64 ** interpreter.
65 */
laction(int i)66 static void laction (int i) {
67 int flag = LUA_MASKCALL | LUA_MASKRET | LUA_MASKLINE | LUA_MASKCOUNT;
68 signal(i, SIG_DFL); /* if another SIGINT happens, terminate process */
69 lua_sethook(globalL, lstop, flag, 1);
70 }
71
72
73
74 /*
75 ** Prints an error message, adding the program name in front of it
76 ** (if present)
77 */
l_message(const char * pname,const char * msg)78 static void l_message (const char *pname, const char *msg) {
79 if (pname) lua_writestringerror("%s: ", pname);
80 lua_writestringerror("%s\n", msg);
81 }
82
83
84 /*
85 ** Check whether 'status' is not OK and, if so, prints the error
86 ** message on the top of the stack. It assumes that the error object
87 ** is a string, as it was either generated by Lua or by 'msghandler'.
88 */
report(lua_State * L,int status)89 static int report (lua_State *L, int status) {
90 if (status != LUA_OK) {
91 const char *msg = lua_tostring(L, -1);
92 l_message(progname, msg);
93 lua_pop(L, 1); /* remove message */
94 }
95 return status;
96 }
97
98 /*
99 ** Message handler used to run all chunks
100 */
msghandler(lua_State * L)101 static int msghandler (lua_State *L) {
102 const char *msg = lua_tostring(L, 1);
103 if (msg == NULL) { /* is error object not a string? */
104 if (luaL_callmeta(L, 1, "__tostring") && /* does it have a metamethod */
105 lua_type(L, -1) == LUA_TSTRING) /* that produces a string? */
106 return 1; /* that is the message */
107 else
108 msg = lua_pushfstring(L, "(error object is a %s value)",
109 luaL_typename(L, 1));
110 }
111 luaL_traceback(L, L, msg, 1); /* append a standard traceback */
112 return 1; /* return the traceback */
113 }
114
115
116 /*
117 ** Interface to 'lua_pcall', which sets appropriate message function
118 ** and C-signal handler. Used to run all chunks.
119 */
docall(lua_State * L,int narg,int nres)120 static int docall (lua_State *L, int narg, int nres) {
121 int status;
122 int base = lua_gettop(L) - narg; /* function index */
123 lua_pushcfunction(L, msghandler); /* push message handler */
124 lua_insert(L, base); /* put it under function and args */
125 globalL = L; /* to be available to 'laction' */
126 signal(SIGINT, laction); /* set C-signal handler */
127 status = lua_pcall(L, narg, nres, base);
128 signal(SIGINT, SIG_DFL); /* reset C-signal handler */
129 lua_remove(L, base); /* remove message handler from the stack */
130 return status;
131 }
132
133
dochunk(lua_State * L,int status)134 static int dochunk (lua_State *L, int status) {
135 if (status == LUA_OK) status = docall(L, 0, 0);
136 return report(L, status);
137 }
138
139
140 /* mark in error messages for incomplete statements */
141 #define EOFMARK "<eof>"
142 #define marklen (sizeof(EOFMARK)/sizeof(char) - 1)
143
144 int
LLVMFuzzerTestOneInput(const uint8_t * data,size_t size)145 LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
146 lua_State *L = luaL_newstate();
147 if (L == NULL) {
148 return 0;
149 }
150 dochunk(L, luaL_loadbufferx(L, data, size, "test", "t"));
151
152 lua_close(L);
153 return 0;
154 }
155