crypto/mem.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <limits.h>
  13 #include <openssl/crypto.h>
  14 #include "internal/cryptlib.h"
  15 #include "internal/cryptlib_int.h"
  16 #ifndef OPENSSL_NO_CRYPTO_MDEBUG_BACKTRACE
  17 # include <execinfo.h>
  18 #endif
  19
  20 /*
  21  * the following pointers may be changed as long as 'allow_customize' is set
  22  */
  23 static int allow_customize = 1;
  24
  25 static void *(*malloc_impl)(size_t, const char *, int)
  26     = CRYPTO_malloc;
  27 static void *(*realloc_impl)(void *, size_t, const char *, int)
  28     = CRYPTO_realloc;
  29 static void (*free_impl)(void *, const char *, int)
  30     = CRYPTO_free;
  31
  32 #ifndef OPENSSL_NO_CRYPTO_MDEBUG
  33 static char *md_failstring;
  34 static long md_count;
  35 static int md_fail_percent = 0;
  36 static int md_tracefd = -1;
  37 static int call_malloc_debug = 1;
  38
  39 static void parseit(void);
  40 static int shouldfail(void);
  41
  42 # define FAILTEST() if (shouldfail()) return NULL
  43
  44 #else
  45 static int call_malloc_debug = 0;
  46
  47 # define FAILTEST() /* empty */
  48 #endif
  49
  50 int CRYPTO_set_mem_functions(
  51         void *(*m)(size_t, const char *, int),
  52         void *(*r)(void *, size_t, const char *, int),
  53         void (*f)(void *, const char *, int))
  54 {
  55     if (!allow_customize)
  56         return 0;
  57     if (m)
  58         malloc_impl = m;
  59     if (r)
  60         realloc_impl = r;
  61     if (f)
  62         free_impl = f;
  63     return 1;
  64 }
  65
  66 int CRYPTO_set_mem_debug(int flag)
  67 {
  68     if (!allow_customize)
  69         return 0;
  70     call_malloc_debug = flag;
  71     return 1;
  72 }
  73
  74 void CRYPTO_get_mem_functions(
  75         void *(**m)(size_t, const char *, int),
  76         void *(**r)(void *, size_t, const char *, int),
  77         void (**f)(void *, const char *, int))
  78 {
  79     if (m != NULL)
  80         *m = malloc_impl;
  81     if (r != NULL)
  82         *r = realloc_impl;
  83     if (f != NULL)
  84         *f = free_impl;
  85 }
  86
  87 #ifndef OPENSSL_NO_CRYPTO_MDEBUG
  88 /*
  89  * Parse a "malloc failure spec" string.  This likes like a set of fields
  90  * separated by semicolons.  Each field has a count and an optional failure
  91  * percentage.  For example:
  92  *          100@0;100@25;0@0
  93  *    or    100;100@25;0
  94  * This means 100 mallocs succeed, then next 100 fail 25% of the time, and
  95  * all remaining (count is zero) succeed.
  96  */
  97 static void parseit(void)
  98 {
  99     char *semi = strchr(md_failstring, ';');
 100     char *atsign;
 101
 102     if (semi != NULL)
 103         *semi++ = '\0';
 104
 105     /* Get the count (atol will stop at the @ if there), and percentage */
 106     md_count = atol(md_failstring);
 107     atsign = strchr(md_failstring, '@');
 108     md_fail_percent = atsign == NULL ? 0 : atoi(atsign + 1);
 109
 110     if (semi != NULL)
 111         md_failstring = semi;
 112 }
 113
 114 /*
 115  * Windows doesn't have random(), but it has rand()
 116  * Some rand() implementations aren't good, but we're not
 117  * dealing with secure randomness here.
 118  */
 119 #ifdef _WIN32
 120 # define random() rand()
 121 #endif
 122 /*
 123  * See if the current malloc should fail.
 124  */
 125 static int shouldfail(void)
 126 {
 127     int roll = (int)(random() % 100);
 128     int shoulditfail = roll < md_fail_percent;
 129     char buff[80];
 130
 131     if (md_tracefd > 0) {
 132         BIO_snprintf(buff, sizeof(buff),
 133                      "%c C%ld %%%d R%d\n",
 134                      shoulditfail ? '-' : '+', md_count, md_fail_percent, roll);
 135         write(md_tracefd, buff, strlen(buff));
 136 #ifndef OPENSSL_NO_CRYPTO_MDEBUG_BACKTRACE
 137         if (shoulditfail) {
 138             void *addrs[30];
 139             int num = backtrace(addrs, OSSL_NELEM(addrs));
 140
 141             backtrace_symbols_fd(addrs, num, md_tracefd);
 142         }
 143 #endif
 144     }
 145
 146     if (md_count) {
 147         /* If we used up this one, go to the next. */
 148         if (--md_count == 0)
 149             parseit();
 150     }
 151
 152     return shoulditfail;
 153 }
 154
 155 void ossl_malloc_setup_failures(void)
 156 {
 157     const char *cp = getenv("OPENSSL_MALLOC_FAILURES");
 158
 159     if (cp != NULL && (md_failstring = strdup(cp)) != NULL)
 160         parseit();
 161     if ((cp = getenv("OPENSSL_MALLOC_FD")) != NULL)
 162         md_tracefd = atoi(cp);
 163 }
 164 #endif
 165
 166 void *CRYPTO_malloc(size_t num, const char *file, int line)
 167 {
 168     void *ret = NULL;
 169
 170     if (malloc_impl != NULL && malloc_impl != CRYPTO_malloc)
 171         return malloc_impl(num, file, line);
 172
 173     if (num == 0)
 174         return NULL;
 175
 176     FAILTEST();
 177     allow_customize = 0;
 178 #ifndef OPENSSL_NO_CRYPTO_MDEBUG
 179     if (call_malloc_debug) {
 180         CRYPTO_mem_debug_malloc(NULL, num, 0, file, line);
 181         ret = malloc(num);
 182         CRYPTO_mem_debug_malloc(ret, num, 1, file, line);
 183     } else {
 184         ret = malloc(num);
 185     }
 186 #else
 187     osslargused(file); osslargused(line);
 188     ret = malloc(num);
 189 #endif
 190
 191     return ret;
 192 }
 193
 194 void *CRYPTO_zalloc(size_t num, const char *file, int line)
 195 {
 196     void *ret = CRYPTO_malloc(num, file, line);
 197
 198     FAILTEST();
 199     if (ret != NULL)
 200         memset(ret, 0, num);
 201     return ret;
 202 }
 203
 204 void *CRYPTO_realloc(void *str, size_t num, const char *file, int line)
 205 {
 206     if (realloc_impl != NULL && realloc_impl != &CRYPTO_realloc)
 207         return realloc_impl(str, num, file, line);
 208
 209     FAILTEST();
 210     if (str == NULL)
 211         return CRYPTO_malloc(num, file, line);
 212
 213     if (num == 0) {
 214         CRYPTO_free(str, file, line);
 215         return NULL;
 216     }
 217
 218     allow_customize = 0;
 219 #ifndef OPENSSL_NO_CRYPTO_MDEBUG
 220     if (call_malloc_debug) {
 221         void *ret;
 222         CRYPTO_mem_debug_realloc(str, NULL, num, 0, file, line);
 223         ret = realloc(str, num);
 224         CRYPTO_mem_debug_realloc(str, ret, num, 1, file, line);
 225         return ret;
 226     }
 227 #else
 228     osslargused(file); osslargused(line);
 229 #endif
 230     return realloc(str, num);
 231
 232 }
 233
 234 void *CRYPTO_clear_realloc(void *str, size_t old_len, size_t num,
 235                            const char *file, int line)
 236 {
 237     void *ret = NULL;
 238
 239     if (str == NULL)
 240         return CRYPTO_malloc(num, file, line);
 241
 242     if (num == 0) {
 243         CRYPTO_clear_free(str, old_len, file, line);
 244         return NULL;
 245     }
 246
 247     /* Can't shrink the buffer since memcpy below copies |old_len| bytes. */
 248     if (num < old_len) {
 249         OPENSSL_cleanse((char*)str + num, old_len - num);
 250         return str;
 251     }
 252
 253     ret = CRYPTO_malloc(num, file, line);
 254     if (ret != NULL) {
 255         memcpy(ret, str, old_len);
 256         CRYPTO_clear_free(str, old_len, file, line);
 257     }
 258     return ret;
 259 }
 260
 261 void CRYPTO_free(void *str, const char *file, int line)
 262 {
 263     if (free_impl != NULL && free_impl != &CRYPTO_free) {
 264         free_impl(str, file, line);
 265         return;
 266     }
 267
 268 #ifndef OPENSSL_NO_CRYPTO_MDEBUG
 269     if (call_malloc_debug) {
 270         CRYPTO_mem_debug_free(str, 0, file, line);
 271         free(str);
 272         CRYPTO_mem_debug_free(str, 1, file, line);
 273     } else {
 274         free(str);
 275     }
 276 #else
 277     free(str);
 278 #endif
 279 }
 280
 281 void CRYPTO_clear_free(void *str, size_t num, const char *file, int line)
 282 {
 283     if (str == NULL)
 284         return;
 285     if (num)
 286         OPENSSL_cleanse(str, num);
 287     CRYPTO_free(str, file, line);
 288 }