summaryrefslogtreecommitdiff
path: root/arch/x86/tools/insn_sanity.c
blob: 213f35f94feb12ae1a516ef90e0bc2290693ebcb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * x86 decoder sanity test - based on test_get_insn.c
 *
 * Copyright (C) IBM Corporation, 2009
 * Copyright (C) Hitachi, Ltd., 2011
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <asm/insn.h>
#include <inat.c>
#include <insn.c>

/*
 * Test of instruction analysis against tampering.
 * Feed random binary to instruction decoder and ensure not to
 * access out-of-instruction-buffer.
 */

#define DEFAULT_MAX_ITER	10000
#define INSN_NOP 0x90

static const char	*prog;		/* Program name */
static int		verbose;	/* Verbosity */
static int		x86_64;		/* x86-64 bit mode flag */
static unsigned int	seed;		/* Random seed */
static unsigned long	iter_start;	/* Start of iteration number */
static unsigned long	iter_end = DEFAULT_MAX_ITER;	/* End of iteration number */
static FILE		*input_file;	/* Input file name */

static void usage(const char *err)
{
	if (err)
		fprintf(stderr, "%s: Error: %s\n\n", prog, err);
	fprintf(stderr, "Usage: %s [-y|-n|-v] [-s seed[,no]] [-m max] [-i input]\n", prog);
	fprintf(stderr, "\t-y	64bit mode\n");
	fprintf(stderr, "\t-n	32bit mode\n");
	fprintf(stderr, "\t-v	Verbosity(-vv dumps any decoded result)\n");
	fprintf(stderr, "\t-s	Give a random seed (and iteration number)\n");
	fprintf(stderr, "\t-m	Give a maximum iteration number\n");
	fprintf(stderr, "\t-i	Give an input file with decoded binary\n");
	exit(1);
}

static void dump_field(FILE *fp, const char *name, const char *indent,
		       struct insn_field *field)
{
	fprintf(fp, "%s.%s = {\n", indent, name);
	fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
		indent, field->value, field->bytes[0], field->bytes[1],
		field->bytes[2], field->bytes[3]);
	fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
		field->got, field->nbytes);
}

static void dump_insn(FILE *fp, struct insn *insn)
{
	fprintf(fp, "Instruction = {\n");
	dump_field(fp, "prefixes", "\t",	&insn->prefixes);
	dump_field(fp, "rex_prefix", "\t",	&insn->rex_prefix);
	dump_field(fp, "vex_prefix", "\t",	&insn->vex_prefix);
	dump_field(fp, "opcode", "\t",		&insn->opcode);
	dump_field(fp, "modrm", "\t",		&insn->modrm);
	dump_field(fp, "sib", "\t",		&insn->sib);
	dump_field(fp, "displacement", "\t",	&insn->displacement);
	dump_field(fp, "immediate1", "\t",	&insn->immediate1);
	dump_field(fp, "immediate2", "\t",	&insn->immediate2);
	fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
		insn->attr, insn->opnd_bytes, insn->addr_bytes);
	fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
		insn->length, insn->x86_64, insn->kaddr);
}

static void dump_stream(FILE *fp, const char *msg, unsigned long nr_iter,
			unsigned char *insn_buff, struct insn *insn)
{
	int i;

	fprintf(fp, "%s:\n", msg);

	dump_insn(fp, insn);

	fprintf(fp, "You can reproduce this with below command(s);\n");

	/* Input a decoded instruction sequence directly */
	fprintf(fp, " $ echo ");
	for (i = 0; i < MAX_INSN_SIZE; i++)
		fprintf(fp, " %02x", insn_buff[i]);
	fprintf(fp, " | %s -i -\n", prog);

	if (!input_file) {
		fprintf(fp, "Or \n");
		/* Give a seed and iteration number */
		fprintf(fp, " $ %s -s 0x%x,%lu\n", prog, seed, nr_iter);
	}
}

static void init_random_seed(void)
{
	int fd;

	fd = open("/dev/urandom", O_RDONLY);
	if (fd < 0)
		goto fail;

	if (read(fd, &seed, sizeof(seed)) != sizeof(seed))
		goto fail;

	close(fd);
	return;
fail:
	usage("Failed to open /dev/urandom");
}

/* Read given instruction sequence from the input file */
static int read_next_insn(unsigned char *insn_buff)
{
	char buf[256]  = "", *tmp;
	int i;

	tmp = fgets(buf, ARRAY_SIZE(buf), input_file);
	if (tmp == NULL || feof(input_file))
		return 0;

	for (i = 0; i < MAX_INSN_SIZE; i++) {
		insn_buff[i] = (unsigned char)strtoul(tmp, &tmp, 16);
		if (*tmp != ' ')
			break;
	}

	return i;
}

static int generate_insn(unsigned char *insn_buff)
{
	int i;

	if (input_file)
		return read_next_insn(insn_buff);

	/* Fills buffer with random binary up to MAX_INSN_SIZE */
	for (i = 0; i < MAX_INSN_SIZE - 1; i += 2)
		*(unsigned short *)(&insn_buff[i]) = random() & 0xffff;

	while (i < MAX_INSN_SIZE)
		insn_buff[i++] = random() & 0xff;

	return i;
}

static void parse_args(int argc, char **argv)
{
	int c;
	char *tmp = NULL;
	int set_seed = 0;

	prog = argv[0];
	while ((c = getopt(argc, argv, "ynvs:m:i:")) != -1) {
		switch (c) {
		case 'y':
			x86_64 = 1;
			break;
		case 'n':
			x86_64 = 0;
			break;
		case 'v':
			verbose++;
			break;
		case 'i':
			if (strcmp("-", optarg) == 0)
				input_file = stdin;
			else
				input_file = fopen(optarg, "r");
			if (!input_file)
				usage("Failed to open input file");
			break;
		case 's':
			seed = (unsigned int)strtoul(optarg, &tmp, 0);
			if (*tmp == ',') {
				optarg = tmp + 1;
				iter_start = strtoul(optarg, &tmp, 0);
			}
			if (*tmp != '\0' || tmp == optarg)
				usage("Failed to parse seed");
			set_seed = 1;
			break;
		case 'm':
			iter_end = strtoul(optarg, &tmp, 0);
			if (*tmp != '\0' || tmp == optarg)
				usage("Failed to parse max_iter");
			break;
		default:
			usage(NULL);
		}
	}

	/* Check errors */
	if (iter_end < iter_start)
		usage("Max iteration number must be bigger than iter-num");

	if (set_seed && input_file)
		usage("Don't use input file (-i) with random seed (-s)");

	/* Initialize random seed */
	if (!input_file) {
		if (!set_seed)	/* No seed is given */
			init_random_seed();
		srand(seed);
	}
}

int main(int argc, char **argv)
{
	int insns = 0, ret;
	struct insn insn;
	int errors = 0;
	unsigned long i;
	unsigned char insn_buff[MAX_INSN_SIZE * 2];

	parse_args(argc, argv);

	/* Prepare stop bytes with NOPs */
	memset(insn_buff + MAX_INSN_SIZE, INSN_NOP, MAX_INSN_SIZE);

	for (i = 0; i < iter_end; i++) {
		if (generate_insn(insn_buff) <= 0)
			break;

		if (i < iter_start)	/* Skip to given iteration number */
			continue;

		/* Decode an instruction */
		ret = insn_decode(&insn, insn_buff, sizeof(insn_buff),
				  x86_64 ? INSN_MODE_64 : INSN_MODE_32);

		if (insn.next_byte <= insn.kaddr ||
		    insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
			/* Access out-of-range memory */
			dump_stream(stderr, "Error: Found an access violation", i, insn_buff, &insn);
			errors++;
		} else if (verbose && ret < 0)
			dump_stream(stdout, "Info: Found an undecodable input", i, insn_buff, &insn);
		else if (verbose >= 2)
			dump_insn(stdout, &insn);
		insns++;
	}

	fprintf((errors) ? stderr : stdout,
		"%s: %s: decoded and checked %d %s instructions with %d errors (seed:0x%x)\n",
		prog,
		(errors) ? "Failure" : "Success",
		insns,
		(input_file) ? "given" : "random",
		errors,
		seed);

	return errors ? 1 : 0;
}