arch/x86/tools/insn_sanity.c

   1 /*
   2  * x86 decoder sanity test - based on test_get_insn.c
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright (C) IBM Corporation, 2009
  19  * Copyright (C) Hitachi, Ltd., 2011
  20  */
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <assert.h>
  26 #include <unistd.h>
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <fcntl.h>
  30
  31 #define unlikely(cond) (cond)
  32 #define ARRAY_SIZE(a)   (sizeof(a)/sizeof(a[0]))
  33
  34 #include <asm/insn.h>
  35 #include <inat.c>
  36 #include <insn.c>
  37
  38 /*
  39  * Test of instruction analysis against tampering.
  40  * Feed random binary to instruction decoder and ensure not to
  41  * access out-of-instruction-buffer.
  42  */
  43
  44 #define DEFAULT_MAX_ITER        10000
  45 #define INSN_NOP 0x90
  46
  47 static const char       *prog;          /* Program name */
  48 static int              verbose;        /* Verbosity */
  49 static int              x86_64;         /* x86-64 bit mode flag */
  50 static unsigned int     seed;           /* Random seed */
  51 static unsigned long    iter_start;     /* Start of iteration number */
  52 static unsigned long    iter_end = DEFAULT_MAX_ITER;    /* End of iteration number */
  53 static FILE             *input_file;    /* Input file name */
  54
  55 static void usage(const char *err)
  56 {
  57         if (err)
  58                 fprintf(stderr, "%s: Error: %s\n\n", prog, err);
  59         fprintf(stderr, "Usage: %s [-y|-n|-v] [-s seed[,no]] [-m max] [-i input]\n", prog);
  60         fprintf(stderr, "\t-y   64bit mode\n");
  61         fprintf(stderr, "\t-n   32bit mode\n");
  62         fprintf(stderr, "\t-v   Verbosity(-vv dumps any decoded result)\n");
  63         fprintf(stderr, "\t-s   Give a random seed (and iteration number)\n");
  64         fprintf(stderr, "\t-m   Give a maximum iteration number\n");
  65         fprintf(stderr, "\t-i   Give an input file with decoded binary\n");
  66         exit(1);
  67 }
  68
  69 static void dump_field(FILE *fp, const char *name, const char *indent,
  70                        struct insn_field *field)
  71 {
  72         fprintf(fp, "%s.%s = {\n", indent, name);
  73         fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
  74                 indent, field->value, field->bytes[0], field->bytes[1],
  75                 field->bytes[2], field->bytes[3]);
  76         fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
  77                 field->got, field->nbytes);
  78 }
  79
  80 static void dump_insn(FILE *fp, struct insn *insn)
  81 {
  82         fprintf(fp, "Instruction = {\n");
  83         dump_field(fp, "prefixes", "\t",        &insn->prefixes);
  84         dump_field(fp, "rex_prefix", "\t",      &insn->rex_prefix);
  85         dump_field(fp, "vex_prefix", "\t",      &insn->vex_prefix);
  86         dump_field(fp, "opcode", "\t",          &insn->opcode);
  87         dump_field(fp, "modrm", "\t",           &insn->modrm);
  88         dump_field(fp, "sib", "\t",             &insn->sib);
  89         dump_field(fp, "displacement", "\t",    &insn->displacement);
  90         dump_field(fp, "immediate1", "\t",      &insn->immediate1);
  91         dump_field(fp, "immediate2", "\t",      &insn->immediate2);
  92         fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
  93                 insn->attr, insn->opnd_bytes, insn->addr_bytes);
  94         fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
  95                 insn->length, insn->x86_64, insn->kaddr);
  96 }
  97
  98 static void dump_stream(FILE *fp, const char *msg, unsigned long nr_iter,
  99                         unsigned char *insn_buf, struct insn *insn)
 100 {
 101         int i;
 102
 103         fprintf(fp, "%s:\n", msg);
 104
 105         dump_insn(fp, insn);
 106
 107         fprintf(fp, "You can reproduce this with below command(s);\n");
 108
 109         /* Input a decoded instruction sequence directly */
 110         fprintf(fp, " $ echo ");
 111         for (i = 0; i < MAX_INSN_SIZE; i++)
 112                 fprintf(fp, " %02x", insn_buf[i]);
 113         fprintf(fp, " | %s -i -\n", prog);
 114
 115         if (!input_file) {
 116                 fprintf(fp, "Or \n");
 117                 /* Give a seed and iteration number */
 118                 fprintf(fp, " $ %s -s 0x%x,%lu\n", prog, seed, nr_iter);
 119         }
 120 }
 121
 122 static void init_random_seed(void)
 123 {
 124         int fd;
 125
 126         fd = open("/dev/urandom", O_RDONLY);
 127         if (fd < 0)
 128                 goto fail;
 129
 130         if (read(fd, &seed, sizeof(seed)) != sizeof(seed))
 131                 goto fail;
 132
 133         close(fd);
 134         return;
 135 fail:
 136         usage("Failed to open /dev/urandom");
 137 }
 138
 139 /* Read given instruction sequence from the input file */
 140 static int read_next_insn(unsigned char *insn_buf)
 141 {
 142         char buf[256]  = "", *tmp;
 143         int i;
 144
 145         tmp = fgets(buf, ARRAY_SIZE(buf), input_file);
 146         if (tmp == NULL || feof(input_file))
 147                 return 0;
 148
 149         for (i = 0; i < MAX_INSN_SIZE; i++) {
 150                 insn_buf[i] = (unsigned char)strtoul(tmp, &tmp, 16);
 151                 if (*tmp != ' ')
 152                         break;
 153         }
 154
 155         return i;
 156 }
 157
 158 static int generate_insn(unsigned char *insn_buf)
 159 {
 160         int i;
 161
 162         if (input_file)
 163                 return read_next_insn(insn_buf);
 164
 165         /* Fills buffer with random binary up to MAX_INSN_SIZE */
 166         for (i = 0; i < MAX_INSN_SIZE - 1; i += 2)
 167                 *(unsigned short *)(&insn_buf[i]) = random() & 0xffff;
 168
 169         while (i < MAX_INSN_SIZE)
 170                 insn_buf[i++] = random() & 0xff;
 171
 172         return i;
 173 }
 174
 175 static void parse_args(int argc, char **argv)
 176 {
 177         int c;
 178         char *tmp = NULL;
 179         int set_seed = 0;
 180
 181         prog = argv[0];
 182         while ((c = getopt(argc, argv, "ynvs:m:i:")) != -1) {
 183                 switch (c) {
 184                 case 'y':
 185                         x86_64 = 1;
 186                         break;
 187                 case 'n':
 188                         x86_64 = 0;
 189                         break;
 190                 case 'v':
 191                         verbose++;
 192                         break;
 193                 case 'i':
 194                         if (strcmp("-", optarg) == 0)
 195                                 input_file = stdin;
 196                         else
 197                                 input_file = fopen(optarg, "r");
 198                         if (!input_file)
 199                                 usage("Failed to open input file");
 200                         break;
 201                 case 's':
 202                         seed = (unsigned int)strtoul(optarg, &tmp, 0);
 203                         if (*tmp == ',') {
 204                                 optarg = tmp + 1;
 205                                 iter_start = strtoul(optarg, &tmp, 0);
 206                         }
 207                         if (*tmp != '\0' || tmp == optarg)
 208                                 usage("Failed to parse seed");
 209                         set_seed = 1;
 210                         break;
 211                 case 'm':
 212                         iter_end = strtoul(optarg, &tmp, 0);
 213                         if (*tmp != '\0' || tmp == optarg)
 214                                 usage("Failed to parse max_iter");
 215                         break;
 216                 default:
 217                         usage(NULL);
 218                 }
 219         }
 220
 221         /* Check errors */
 222         if (iter_end < iter_start)
 223                 usage("Max iteration number must be bigger than iter-num");
 224
 225         if (set_seed && input_file)
 226                 usage("Don't use input file (-i) with random seed (-s)");
 227
 228         /* Initialize random seed */
 229         if (!input_file) {
 230                 if (!set_seed)  /* No seed is given */
 231                         init_random_seed();
 232                 srand(seed);
 233         }
 234 }
 235
 236 int main(int argc, char **argv)
 237 {
 238         struct insn insn;
 239         int insns = 0;
 240         int errors = 0;
 241         unsigned long i;
 242         unsigned char insn_buf[MAX_INSN_SIZE * 2];
 243
 244         parse_args(argc, argv);
 245
 246         /* Prepare stop bytes with NOPs */
 247         memset(insn_buf + MAX_INSN_SIZE, INSN_NOP, MAX_INSN_SIZE);
 248
 249         for (i = 0; i < iter_end; i++) {
 250                 if (generate_insn(insn_buf) <= 0)
 251                         break;
 252
 253                 if (i < iter_start)     /* Skip to given iteration number */
 254                         continue;
 255
 256                 /* Decode an instruction */
 257                 insn_init(&insn, insn_buf, x86_64);
 258                 insn_get_length(&insn);
 259
 260                 if (insn.next_byte <= insn.kaddr ||
 261                     insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
 262                         /* Access out-of-range memory */
 263                         dump_stream(stderr, "Error: Found an access violation", i, insn_buf, &insn);
 264                         errors++;
 265                 } else if (verbose && !insn_complete(&insn))
 266                         dump_stream(stdout, "Info: Found an undecodable input", i, insn_buf, &insn);
 267                 else if (verbose >= 2)
 268                         dump_insn(stdout, &insn);
 269                 insns++;
 270         }
 271
 272         fprintf(stdout, "%s: %s: decoded and checked %d %s instructions with %d errors (seed:0x%x)\n",
 273                 prog,
 274                 (errors) ? "Failure" : "Success",
 275                 insns,
 276                 (input_file) ? "given" : "random",
 277                 errors,
 278                 seed);
 279
 280         return errors ? 1 : 0;
 281 }