1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * x86 decoder sanity test - based on test_get_insn.c
4 *
5 * Copyright (C) IBM Corporation, 2009
6 * Copyright (C) Hitachi, Ltd., 2011
7 */
8
9#include <stdlib.h>
10#include <stdio.h>
11#include <string.h>
12#include <assert.h>
13#include <unistd.h>
14#include <sys/types.h>
15#include <sys/stat.h>
16#include <fcntl.h>
17#include <asm/insn.h>
18#include <inat.c>
19#include <insn.c>
20
21/*
22 * Test of instruction analysis against tampering.
23 * Feed random binary to instruction decoder and ensure not to
24 * access out-of-instruction-buffer.
25 */
26
27#define DEFAULT_MAX_ITER	10000
28#define INSN_NOP 0x90
29
30static const char	*prog;		/* Program name */
31static int		verbose;	/* Verbosity */
32static int		x86_64;		/* x86-64 bit mode flag */
33static unsigned int	seed;		/* Random seed */
34static unsigned long	iter_start;	/* Start of iteration number */
35static unsigned long	iter_end = DEFAULT_MAX_ITER;	/* End of iteration number */
36static FILE		*input_file;	/* Input file name */
37
38static void usage(const char *err)
39{
40	if (err)
41		fprintf(stderr, "%s: Error: %s\n\n", prog, err);
42	fprintf(stderr, "Usage: %s [-y|-n|-v] [-s seed[,no]] [-m max] [-i input]\n", prog);
43	fprintf(stderr, "\t-y	64bit mode\n");
44	fprintf(stderr, "\t-n	32bit mode\n");
45	fprintf(stderr, "\t-v	Verbosity(-vv dumps any decoded result)\n");
46	fprintf(stderr, "\t-s	Give a random seed (and iteration number)\n");
47	fprintf(stderr, "\t-m	Give a maximum iteration number\n");
48	fprintf(stderr, "\t-i	Give an input file with decoded binary\n");
49	exit(1);
50}
51
52static void dump_field(FILE *fp, const char *name, const char *indent,
53		       struct insn_field *field)
54{
55	fprintf(fp, "%s.%s = {\n", indent, name);
56	fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
57		indent, field->value, field->bytes[0], field->bytes[1],
58		field->bytes[2], field->bytes[3]);
59	fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
60		field->got, field->nbytes);
61}
62
63static void dump_insn(FILE *fp, struct insn *insn)
64{
65	fprintf(fp, "Instruction = {\n");
66	dump_field(fp, "prefixes", "\t",	&insn->prefixes);
67	dump_field(fp, "rex_prefix", "\t",	&insn->rex_prefix);
68	dump_field(fp, "vex_prefix", "\t",	&insn->vex_prefix);
69	dump_field(fp, "opcode", "\t",		&insn->opcode);
70	dump_field(fp, "modrm", "\t",		&insn->modrm);
71	dump_field(fp, "sib", "\t",		&insn->sib);
72	dump_field(fp, "displacement", "\t",	&insn->displacement);
73	dump_field(fp, "immediate1", "\t",	&insn->immediate1);
74	dump_field(fp, "immediate2", "\t",	&insn->immediate2);
75	fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
76		insn->attr, insn->opnd_bytes, insn->addr_bytes);
77	fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
78		insn->length, insn->x86_64, insn->kaddr);
79}
80
81static void dump_stream(FILE *fp, const char *msg, unsigned long nr_iter,
82			unsigned char *insn_buff, struct insn *insn)
83{
84	int i;
85
86	fprintf(fp, "%s:\n", msg);
87
88	dump_insn(fp, insn);
89
90	fprintf(fp, "You can reproduce this with below command(s);\n");
91
92	/* Input a decoded instruction sequence directly */
93	fprintf(fp, " $ echo ");
94	for (i = 0; i < MAX_INSN_SIZE; i++)
95		fprintf(fp, " %02x", insn_buff[i]);
96	fprintf(fp, " | %s -i -\n", prog);
97
98	if (!input_file) {
99		fprintf(fp, "Or \n");
100		/* Give a seed and iteration number */
101		fprintf(fp, " $ %s -s 0x%x,%lu\n", prog, seed, nr_iter);
102	}
103}
104
105static void init_random_seed(void)
106{
107	int fd;
108
109	fd = open("/dev/urandom", O_RDONLY);
110	if (fd < 0)
111		goto fail;
112
113	if (read(fd, &seed, sizeof(seed)) != sizeof(seed))
114		goto fail;
115
116	close(fd);
117	return;
118fail:
119	usage("Failed to open /dev/urandom");
120}
121
122/* Read given instruction sequence from the input file */
123static int read_next_insn(unsigned char *insn_buff)
124{
125	char buf[256]  = "", *tmp;
126	int i;
127
128	tmp = fgets(buf, ARRAY_SIZE(buf), input_file);
129	if (tmp == NULL || feof(input_file))
130		return 0;
131
132	for (i = 0; i < MAX_INSN_SIZE; i++) {
133		insn_buff[i] = (unsigned char)strtoul(tmp, &tmp, 16);
134		if (*tmp != ' ')
135			break;
136	}
137
138	return i;
139}
140
141static int generate_insn(unsigned char *insn_buff)
142{
143	int i;
144
145	if (input_file)
146		return read_next_insn(insn_buff);
147
148	/* Fills buffer with random binary up to MAX_INSN_SIZE */
149	for (i = 0; i < MAX_INSN_SIZE - 1; i += 2)
150		*(unsigned short *)(&insn_buff[i]) = random() & 0xffff;
151
152	while (i < MAX_INSN_SIZE)
153		insn_buff[i++] = random() & 0xff;
154
155	return i;
156}
157
158static void parse_args(int argc, char **argv)
159{
160	int c;
161	char *tmp = NULL;
162	int set_seed = 0;
163
164	prog = argv[0];
165	while ((c = getopt(argc, argv, "ynvs:m:i:")) != -1) {
166		switch (c) {
167		case 'y':
168			x86_64 = 1;
169			break;
170		case 'n':
171			x86_64 = 0;
172			break;
173		case 'v':
174			verbose++;
175			break;
176		case 'i':
177			if (strcmp("-", optarg) == 0)
178				input_file = stdin;
179			else
180				input_file = fopen(optarg, "r");
181			if (!input_file)
182				usage("Failed to open input file");
183			break;
184		case 's':
185			seed = (unsigned int)strtoul(optarg, &tmp, 0);
186			if (*tmp == ',') {
187				optarg = tmp + 1;
188				iter_start = strtoul(optarg, &tmp, 0);
189			}
190			if (*tmp != '\0' || tmp == optarg)
191				usage("Failed to parse seed");
192			set_seed = 1;
193			break;
194		case 'm':
195			iter_end = strtoul(optarg, &tmp, 0);
196			if (*tmp != '\0' || tmp == optarg)
197				usage("Failed to parse max_iter");
198			break;
199		default:
200			usage(NULL);
201		}
202	}
203
204	/* Check errors */
205	if (iter_end < iter_start)
206		usage("Max iteration number must be bigger than iter-num");
207
208	if (set_seed && input_file)
209		usage("Don't use input file (-i) with random seed (-s)");
210
211	/* Initialize random seed */
212	if (!input_file) {
213		if (!set_seed)	/* No seed is given */
214			init_random_seed();
215		srand(seed);
216	}
217}
218
219int main(int argc, char **argv)
220{
221	int insns = 0, ret;
222	struct insn insn;
223	int errors = 0;
224	unsigned long i;
225	unsigned char insn_buff[MAX_INSN_SIZE * 2];
226
227	parse_args(argc, argv);
228
229	/* Prepare stop bytes with NOPs */
230	memset(insn_buff + MAX_INSN_SIZE, INSN_NOP, MAX_INSN_SIZE);
231
232	for (i = 0; i < iter_end; i++) {
233		if (generate_insn(insn_buff) <= 0)
234			break;
235
236		if (i < iter_start)	/* Skip to given iteration number */
237			continue;
238
239		/* Decode an instruction */
240		ret = insn_decode(&insn, insn_buff, sizeof(insn_buff),
241				  x86_64 ? INSN_MODE_64 : INSN_MODE_32);
242
243		if (insn.next_byte <= insn.kaddr ||
244		    insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
245			/* Access out-of-range memory */
246			dump_stream(stderr, "Error: Found an access violation", i, insn_buff, &insn);
247			errors++;
248		} else if (verbose && ret < 0)
249			dump_stream(stdout, "Info: Found an undecodable input", i, insn_buff, &insn);
250		else if (verbose >= 2)
251			dump_insn(stdout, &insn);
252		insns++;
253	}
254
255	fprintf((errors) ? stderr : stdout,
256		"%s: %s: decoded and checked %d %s instructions with %d errors (seed:0x%x)\n",
257		prog,
258		(errors) ? "Failure" : "Success",
259		insns,
260		(input_file) ? "given" : "random",
261		errors,
262		seed);
263
264	return errors ? 1 : 0;
265}
266