xref: /freebsd/contrib/bc/src/dc_fuzzer.c (revision 24e4dcf4ba5e9dedcf89efd358ea3e1fe5867020)
1 /*
2  * *****************************************************************************
3  *
4  * SPDX-License-Identifier: BSD-2-Clause
5  *
6  * Copyright (c) 2018-2025 Gavin D. Howard and contributors.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * * Redistributions of source code must retain the above copyright notice, this
12  *   list of conditions and the following disclaimer.
13  *
14  * * Redistributions in binary form must reproduce the above copyright notice,
15  *   this list of conditions and the following disclaimer in the documentation
16  *   and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  *
30  * *****************************************************************************
31  *
32  * The entry point for libFuzzer when fuzzing dc.
33  *
34  */
35 
36 #include <setjmp.h>
37 #include <string.h>
38 
39 #include <status.h>
40 #include <ossfuzz.h>
41 #include <vm.h>
42 #include <bc.h>
43 #include <dc.h>
44 
45 uint8_t* bc_fuzzer_data;
46 
47 /// A boolean about whether we should use -c (false) or -C (true).
48 static bool dc_C;
49 
50 int
51 LLVMFuzzerInitialize(int* argc, char*** argv)
52 {
53 	BC_UNUSED(argc);
54 
55 	if (argv == NULL || *argv == NULL)
56 	{
57 		dc_C = false;
58 	}
59 	else
60 	{
61 		char* name;
62 
63 		// Get the basename
64 		name = strrchr((*argv)[0], BC_FILE_SEP);
65 		name = name == NULL ? (*argv)[0] : name + 1;
66 
67 		// Figure out which to use.
68 		dc_C = (strcmp(name, "dc_fuzzer_C") == 0);
69 	}
70 
71 	return 0;
72 }
73 
74 int
75 LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
76 {
77 	BcStatus s;
78 
79 	// I've already tested empty input, so just ignore.
80 	if (Size == 0 || Data[0] == '\0') return 0;
81 
82 	// Clear the global. This is to ensure a clean start.
83 	memset(vm, 0, sizeof(BcVm));
84 
85 	// Make sure to set the name.
86 	vm->name = "dc";
87 
88 	BC_SIG_LOCK;
89 
90 	// We *must* do this here. Otherwise, other code could not jump out all of
91 	// the way.
92 	bc_vec_init(&vm->jmp_bufs, sizeof(sigjmp_buf), BC_DTOR_NONE);
93 
94 	BC_SETJMP_LOCKED(vm, exit);
95 
96 	// Create a string with the data.
97 	bc_fuzzer_data = bc_vm_malloc(Size + 1);
98 	memcpy(bc_fuzzer_data, Data, Size);
99 	bc_fuzzer_data[Size] = '\0';
100 
101 	s = dc_main((int) (bc_fuzzer_args_len - 1),
102 	            dc_C ? dc_fuzzer_args_C : dc_fuzzer_args_c);
103 
104 exit:
105 
106 	BC_SIG_MAYLOCK;
107 
108 	free(bc_fuzzer_data);
109 
110 	return s == BC_STATUS_SUCCESS || s == BC_STATUS_QUIT ? 0 : -1;
111 }
112