arch/x86/tools/insn_sanity.c

   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
  18 #define unlikely(cond) (cond)
  19 #define ARRAY_SIZE(a)   (sizeof(a)/sizeof(a[0]))
  20
  21 #include <asm/insn.h>
  22 #include <inat.c>
  23 #include <insn.c>
  24
  25 /*
  26  * Test of instruction analysis against tampering.
  27  * Feed random binary to instruction decoder and ensure not to
  28  * access out-of-instruction-buffer.
  29  */
  30
  31 #define DEFAULT_MAX_ITER        10000
  32 #define INSN_NOP 0x90
  33
  34 static const char       *prog;          /* Program name */
  35 static int              verbose;        /* Verbosity */
  36 static int              x86_64;         /* x86-64 bit mode flag */
  37 static unsigned int     seed;           /* Random seed */
  38 static unsigned long    iter_start;     /* Start of iteration number */
  39 static unsigned long    iter_end = DEFAULT_MAX_ITER;    /* End of iteration number */
  40 static FILE             *input_file;    /* Input file name */
  41
  42 static void usage(const char *err)
  43 {
  44         if (err)
  45                 fprintf(stderr, "%s: Error: %s\n\n", prog, err);
  46         fprintf(stderr, "Usage: %s [-y|-n|-v] [-s seed[,no]] [-m max] [-i input]\n", prog);
  47         fprintf(stderr, "\t-y   64bit mode\n");
  48         fprintf(stderr, "\t-n   32bit mode\n");
  49         fprintf(stderr, "\t-v   Verbosity(-vv dumps any decoded result)\n");
  50         fprintf(stderr, "\t-s   Give a random seed (and iteration number)\n");
  51         fprintf(stderr, "\t-m   Give a maximum iteration number\n");
  52         fprintf(stderr, "\t-i   Give an input file with decoded binary\n");
  53         exit(1);
  54 }
  55
  56 static void dump_field(FILE *fp, const char *name, const char *indent,
  57                        struct insn_field *field)
  58 {
  59         fprintf(fp, "%s.%s = {\n", indent, name);
  60         fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
  61                 indent, field->value, field->bytes[0], field->bytes[1],
  62                 field->bytes[2], field->bytes[3]);
  63         fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
  64                 field->got, field->nbytes);
  65 }
  66
  67 static void dump_insn(FILE *fp, struct insn *insn)
  68 {
  69         fprintf(fp, "Instruction = {\n");
  70         dump_field(fp, "prefixes", "\t",        &insn->prefixes);
  71         dump_field(fp, "rex_prefix", "\t",      &insn->rex_prefix);
  72         dump_field(fp, "vex_prefix", "\t",      &insn->vex_prefix);
  73         dump_field(fp, "opcode", "\t",          &insn->opcode);
  74         dump_field(fp, "modrm", "\t",           &insn->modrm);
  75         dump_field(fp, "sib", "\t",             &insn->sib);
  76         dump_field(fp, "displacement", "\t",    &insn->displacement);
  77         dump_field(fp, "immediate1", "\t",      &insn->immediate1);
  78         dump_field(fp, "immediate2", "\t",      &insn->immediate2);
  79         fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
  80                 insn->attr, insn->opnd_bytes, insn->addr_bytes);
  81         fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
  82                 insn->length, insn->x86_64, insn->kaddr);
  83 }
  84
  85 static void dump_stream(FILE *fp, const char *msg, unsigned long nr_iter,
  86                         unsigned char *insn_buff, struct insn *insn)
  87 {
  88         int i;
  89
  90         fprintf(fp, "%s:\n", msg);
  91
  92         dump_insn(fp, insn);
  93
  94         fprintf(fp, "You can reproduce this with below command(s);\n");
  95
  96         /* Input a decoded instruction sequence directly */
  97         fprintf(fp, " $ echo ");
  98         for (i = 0; i < MAX_INSN_SIZE; i++)
  99                 fprintf(fp, " %02x", insn_buff[i]);
 100         fprintf(fp, " | %s -i -\n", prog);
 101
 102         if (!input_file) {
 103                 fprintf(fp, "Or \n");
 104                 /* Give a seed and iteration number */
 105                 fprintf(fp, " $ %s -s 0x%x,%lu\n", prog, seed, nr_iter);
 106         }
 107 }
 108
 109 static void init_random_seed(void)
 110 {
 111         int fd;
 112
 113         fd = open("/dev/urandom", O_RDONLY);
 114         if (fd < 0)
 115                 goto fail;
 116
 117         if (read(fd, &seed, sizeof(seed)) != sizeof(seed))
 118                 goto fail;
 119
 120         close(fd);
 121         return;
 122 fail:
 123         usage("Failed to open /dev/urandom");
 124 }
 125
 126 /* Read given instruction sequence from the input file */
 127 static int read_next_insn(unsigned char *insn_buff)
 128 {
 129         char buf[256]  = "", *tmp;
 130         int i;
 131
 132         tmp = fgets(buf, ARRAY_SIZE(buf), input_file);
 133         if (tmp == NULL || feof(input_file))
 134                 return 0;
 135
 136         for (i = 0; i < MAX_INSN_SIZE; i++) {
 137                 insn_buff[i] = (unsigned char)strtoul(tmp, &tmp, 16);
 138                 if (*tmp != ' ')
 139                         break;
 140         }
 141
 142         return i;
 143 }
 144
 145 static int generate_insn(unsigned char *insn_buff)
 146 {
 147         int i;
 148
 149         if (input_file)
 150                 return read_next_insn(insn_buff);
 151
 152         /* Fills buffer with random binary up to MAX_INSN_SIZE */
 153         for (i = 0; i < MAX_INSN_SIZE - 1; i += 2)
 154                 *(unsigned short *)(&insn_buff[i]) = random() & 0xffff;
 155
 156         while (i < MAX_INSN_SIZE)
 157                 insn_buff[i++] = random() & 0xff;
 158
 159         return i;
 160 }
 161
 162 static void parse_args(int argc, char **argv)
 163 {
 164         int c;
 165         char *tmp = NULL;
 166         int set_seed = 0;
 167
 168         prog = argv[0];
 169         while ((c = getopt(argc, argv, "ynvs:m:i:")) != -1) {
 170                 switch (c) {
 171                 case 'y':
 172                         x86_64 = 1;
 173                         break;
 174                 case 'n':
 175                         x86_64 = 0;
 176                         break;
 177                 case 'v':
 178                         verbose++;
 179                         break;
 180                 case 'i':
 181                         if (strcmp("-", optarg) == 0)
 182                                 input_file = stdin;
 183                         else
 184                                 input_file = fopen(optarg, "r");
 185                         if (!input_file)
 186                                 usage("Failed to open input file");
 187                         break;
 188                 case 's':
 189                         seed = (unsigned int)strtoul(optarg, &tmp, 0);
 190                         if (*tmp == ',') {
 191                                 optarg = tmp + 1;
 192                                 iter_start = strtoul(optarg, &tmp, 0);
 193                         }
 194                         if (*tmp != '\0' || tmp == optarg)
 195                                 usage("Failed to parse seed");
 196                         set_seed = 1;
 197                         break;
 198                 case 'm':
 199                         iter_end = strtoul(optarg, &tmp, 0);
 200                         if (*tmp != '\0' || tmp == optarg)
 201                                 usage("Failed to parse max_iter");
 202                         break;
 203                 default:
 204                         usage(NULL);
 205                 }
 206         }
 207
 208         /* Check errors */
 209         if (iter_end < iter_start)
 210                 usage("Max iteration number must be bigger than iter-num");
 211
 212         if (set_seed && input_file)
 213                 usage("Don't use input file (-i) with random seed (-s)");
 214
 215         /* Initialize random seed */
 216         if (!input_file) {
 217                 if (!set_seed)  /* No seed is given */
 218                         init_random_seed();
 219                 srand(seed);
 220         }
 221 }
 222
 223 int main(int argc, char **argv)
 224 {
 225         struct insn insn;
 226         int insns = 0;
 227         int errors = 0;
 228         unsigned long i;
 229         unsigned char insn_buff[MAX_INSN_SIZE * 2];
 230
 231         parse_args(argc, argv);
 232
 233         /* Prepare stop bytes with NOPs */
 234         memset(insn_buff + MAX_INSN_SIZE, INSN_NOP, MAX_INSN_SIZE);
 235
 236         for (i = 0; i < iter_end; i++) {
 237                 if (generate_insn(insn_buff) <= 0)
 238                         break;
 239
 240                 if (i < iter_start)     /* Skip to given iteration number */
 241                         continue;
 242
 243                 /* Decode an instruction */
 244                 insn_init(&insn, insn_buff, sizeof(insn_buff), x86_64);
 245                 insn_get_length(&insn);
 246
 247                 if (insn.next_byte <= insn.kaddr ||
 248                     insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
 249                         /* Access out-of-range memory */
 250                         dump_stream(stderr, "Error: Found an access violation", i, insn_buff, &insn);
 251                         errors++;
 252                 } else if (verbose && !insn_complete(&insn))
 253                         dump_stream(stdout, "Info: Found an undecodable input", i, insn_buff, &insn);
 254                 else if (verbose >= 2)
 255                         dump_insn(stdout, &insn);
 256                 insns++;
 257         }
 258
 259         fprintf((errors) ? stderr : stdout,
 260                 "%s: %s: decoded and checked %d %s instructions with %d errors (seed:0x%x)\n",
 261                 prog,
 262                 (errors) ? "Failure" : "Success",
 263                 insns,
 264                 (input_file) ? "given" : "random",
 265                 errors,
 266                 seed);
 267
 268         return errors ? 1 : 0;
 269 }