crypto/ex_data.c

   1 /*
   2  * Copyright 1995-2018 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 "internal/cryptlib_int.h"
  11 #include "internal/thread_once.h"
  12
  13 /*
  14  * Each structure type (sometimes called a class), that supports
  15  * exdata has a stack of callbacks for each instance.
  16  */
  17 struct ex_callback_st {
  18     long argl;                  /* Arbitrary long */
  19     void *argp;                 /* Arbitrary void * */
  20     CRYPTO_EX_new *new_func;
  21     CRYPTO_EX_free *free_func;
  22     CRYPTO_EX_dup *dup_func;
  23 };
  24
  25 /*
  26  * The state for each class.  This could just be a typedef, but
  27  * a structure allows future changes.
  28  */
  29 typedef struct ex_callbacks_st {
  30     STACK_OF(EX_CALLBACK) *meth;
  31 } EX_CALLBACKS;
  32
  33 static EX_CALLBACKS ex_data[CRYPTO_EX_INDEX__COUNT];
  34
  35 static CRYPTO_RWLOCK *ex_data_lock = NULL;
  36 static CRYPTO_ONCE ex_data_init = CRYPTO_ONCE_STATIC_INIT;
  37
  38 DEFINE_RUN_ONCE_STATIC(do_ex_data_init)
  39 {
  40     if (!OPENSSL_init_crypto(0, NULL))
  41         return 0;
  42     ex_data_lock = CRYPTO_THREAD_lock_new();
  43     return ex_data_lock != NULL;
  44 }
  45
  46 /*
  47  * Return the EX_CALLBACKS from the |ex_data| array that corresponds to
  48  * a given class.  On success, *holds the lock.*
  49  */
  50 static EX_CALLBACKS *get_and_lock(int class_index)
  51 {
  52     EX_CALLBACKS *ip;
  53
  54     if (class_index < 0 || class_index >= CRYPTO_EX_INDEX__COUNT) {
  55         CRYPTOerr(CRYPTO_F_GET_AND_LOCK, ERR_R_PASSED_INVALID_ARGUMENT);
  56         return NULL;
  57     }
  58
  59     if (!RUN_ONCE(&ex_data_init, do_ex_data_init)) {
  60         CRYPTOerr(CRYPTO_F_GET_AND_LOCK, ERR_R_MALLOC_FAILURE);
  61         return NULL;
  62     }
  63
  64     if (ex_data_lock == NULL) {
  65         /*
  66          * This can happen in normal operation when using CRYPTO_mem_leaks().
  67          * The CRYPTO_mem_leaks() function calls OPENSSL_cleanup() which cleans
  68          * up the locks. Subsequently the BIO that CRYPTO_mem_leaks() uses gets
  69          * freed, which also attempts to free the ex_data. However
  70          * CRYPTO_mem_leaks() ensures that the ex_data is freed early (i.e.
  71          * before OPENSSL_cleanup() is called), so if we get here we can safely
  72          * ignore this operation. We just treat it as an error.
  73          */
  74          return NULL;
  75     }
  76
  77     ip = &ex_data[class_index];
  78     CRYPTO_THREAD_write_lock(ex_data_lock);
  79     return ip;
  80 }
  81
  82 static void cleanup_cb(EX_CALLBACK *funcs)
  83 {
  84     OPENSSL_free(funcs);
  85 }
  86
  87 /*
  88  * Release all "ex_data" state to prevent memory leaks. This can't be made
  89  * thread-safe without overhauling a lot of stuff, and shouldn't really be
  90  * called under potential race-conditions anyway (it's for program shutdown
  91  * after all).
  92  */
  93 void crypto_cleanup_all_ex_data_int(void)
  94 {
  95     int i;
  96
  97     for (i = 0; i < CRYPTO_EX_INDEX__COUNT; ++i) {
  98         EX_CALLBACKS *ip = &ex_data[i];
  99
 100         sk_EX_CALLBACK_pop_free(ip->meth, cleanup_cb);
 101         ip->meth = NULL;
 102     }
 103
 104     CRYPTO_THREAD_lock_free(ex_data_lock);
 105     ex_data_lock = NULL;
 106 }
 107
 108
 109 /*
 110  * Unregister a new index by replacing the callbacks with no-ops.
 111  * Any in-use instances are leaked.
 112  */
 113 static void dummy_new(void *parent, void *ptr, CRYPTO_EX_DATA *ad, int idx,
 114                      long argl, void *argp)
 115 {
 116 }
 117
 118 static void dummy_free(void *parent, void *ptr, CRYPTO_EX_DATA *ad, int idx,
 119                        long argl, void *argp)
 120 {
 121 }
 122
 123 static int dummy_dup(CRYPTO_EX_DATA *to, const CRYPTO_EX_DATA *from,
 124                      void *from_d, int idx,
 125                      long argl, void *argp)
 126 {
 127     return 1;
 128 }
 129
 130 int CRYPTO_free_ex_index(int class_index, int idx)
 131 {
 132     EX_CALLBACKS *ip = get_and_lock(class_index);
 133     EX_CALLBACK *a;
 134     int toret = 0;
 135
 136     if (ip == NULL)
 137         return 0;
 138     if (idx < 0 || idx >= sk_EX_CALLBACK_num(ip->meth))
 139         goto err;
 140     a = sk_EX_CALLBACK_value(ip->meth, idx);
 141     if (a == NULL)
 142         goto err;
 143     a->new_func = dummy_new;
 144     a->dup_func = dummy_dup;
 145     a->free_func = dummy_free;
 146     toret = 1;
 147 err:
 148     CRYPTO_THREAD_unlock(ex_data_lock);
 149     return toret;
 150 }
 151
 152 /*
 153  * Register a new index.
 154  */
 155 int CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,
 156                             CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 157                             CRYPTO_EX_free *free_func)
 158 {
 159     int toret = -1;
 160     EX_CALLBACK *a;
 161     EX_CALLBACKS *ip = get_and_lock(class_index);
 162
 163     if (ip == NULL)
 164         return -1;
 165
 166     if (ip->meth == NULL) {
 167         ip->meth = sk_EX_CALLBACK_new_null();
 168         /* We push an initial value on the stack because the SSL
 169          * "app_data" routines use ex_data index zero.  See RT 3710. */
 170         if (ip->meth == NULL
 171             || !sk_EX_CALLBACK_push(ip->meth, NULL)) {
 172             CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);
 173             goto err;
 174         }
 175     }
 176
 177     a = (EX_CALLBACK *)OPENSSL_malloc(sizeof(*a));
 178     if (a == NULL) {
 179         CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);
 180         goto err;
 181     }
 182     a->argl = argl;
 183     a->argp = argp;
 184     a->new_func = new_func;
 185     a->dup_func = dup_func;
 186     a->free_func = free_func;
 187
 188     if (!sk_EX_CALLBACK_push(ip->meth, NULL)) {
 189         CRYPTOerr(CRYPTO_F_CRYPTO_GET_EX_NEW_INDEX, ERR_R_MALLOC_FAILURE);
 190         OPENSSL_free(a);
 191         goto err;
 192     }
 193     toret = sk_EX_CALLBACK_num(ip->meth) - 1;
 194     (void)sk_EX_CALLBACK_set(ip->meth, toret, a);
 195
 196  err:
 197     CRYPTO_THREAD_unlock(ex_data_lock);
 198     return toret;
 199 }
 200
 201 /*
 202  * Initialise a new CRYPTO_EX_DATA for use in a particular class - including
 203  * calling new() callbacks for each index in the class used by this variable
 204  * Thread-safe by copying a class's array of "EX_CALLBACK" entries
 205  * in the lock, then using them outside the lock. Note this only applies
 206  * to the global "ex_data" state (ie. class definitions), not 'ad' itself.
 207  */
 208 int CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 209 {
 210     int mx, i;
 211     void *ptr;
 212     EX_CALLBACK **storage = NULL;
 213     EX_CALLBACK *stack[10];
 214     EX_CALLBACKS *ip = get_and_lock(class_index);
 215
 216     if (ip == NULL)
 217         return 0;
 218
 219     ad->sk = NULL;
 220
 221     mx = sk_EX_CALLBACK_num(ip->meth);
 222     if (mx > 0) {
 223         if (mx < (int)OSSL_NELEM(stack))
 224             storage = stack;
 225         else
 226             storage = OPENSSL_malloc(sizeof(*storage) * mx);
 227         if (storage != NULL)
 228             for (i = 0; i < mx; i++)
 229                 storage[i] = sk_EX_CALLBACK_value(ip->meth, i);
 230     }
 231     CRYPTO_THREAD_unlock(ex_data_lock);
 232
 233     if (mx > 0 && storage == NULL) {
 234         CRYPTOerr(CRYPTO_F_CRYPTO_NEW_EX_DATA, ERR_R_MALLOC_FAILURE);
 235         return 0;
 236     }
 237     for (i = 0; i < mx; i++) {
 238         if (storage[i] && storage[i]->new_func) {
 239             ptr = CRYPTO_get_ex_data(ad, i);
 240             storage[i]->new_func(obj, ptr, ad, i,
 241                                  storage[i]->argl, storage[i]->argp);
 242         }
 243     }
 244     if (storage != stack)
 245         OPENSSL_free(storage);
 246     return 1;
 247 }
 248
 249 /*
 250  * Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks
 251  * for each index in the class used by this variable
 252  */
 253 int CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
 254                        const CRYPTO_EX_DATA *from)
 255 {
 256     int mx, j, i;
 257     void *ptr;
 258     EX_CALLBACK *stack[10];
 259     EX_CALLBACK **storage = NULL;
 260     EX_CALLBACKS *ip;
 261     int toret = 0;
 262
 263     if (from->sk == NULL)
 264         /* Nothing to copy over */
 265         return 1;
 266     if ((ip = get_and_lock(class_index)) == NULL)
 267         return 0;
 268
 269     mx = sk_EX_CALLBACK_num(ip->meth);
 270     j = sk_void_num(from->sk);
 271     if (j < mx)
 272         mx = j;
 273     if (mx > 0) {
 274         if (mx < (int)OSSL_NELEM(stack))
 275             storage = stack;
 276         else
 277             storage = OPENSSL_malloc(sizeof(*storage) * mx);
 278         if (storage != NULL)
 279             for (i = 0; i < mx; i++)
 280                 storage[i] = sk_EX_CALLBACK_value(ip->meth, i);
 281     }
 282     CRYPTO_THREAD_unlock(ex_data_lock);
 283
 284     if (mx == 0)
 285         return 1;
 286     if (storage == NULL) {
 287         CRYPTOerr(CRYPTO_F_CRYPTO_DUP_EX_DATA, ERR_R_MALLOC_FAILURE);
 288         return 0;
 289     }
 290     /*
 291      * Make sure the ex_data stack is at least |mx| elements long to avoid
 292      * issues in the for loop that follows; so go get the |mx|'th element
 293      * (if it does not exist CRYPTO_get_ex_data() returns NULL), and assign
 294      * to itself. This is normally a no-op; but ensures the stack is the
 295      * proper size
 296      */
 297     if (!CRYPTO_set_ex_data(to, mx - 1, CRYPTO_get_ex_data(to, mx - 1)))
 298         goto err;
 299
 300     for (i = 0; i < mx; i++) {
 301         ptr = CRYPTO_get_ex_data(from, i);
 302         if (storage[i] && storage[i]->dup_func)
 303             if (!storage[i]->dup_func(to, from, &ptr, i,
 304                                       storage[i]->argl, storage[i]->argp))
 305                 goto err;
 306         CRYPTO_set_ex_data(to, i, ptr);
 307     }
 308     toret = 1;
 309  err:
 310     if (storage != stack)
 311         OPENSSL_free(storage);
 312     return toret;
 313 }
 314
 315
 316 /*
 317  * Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for
 318  * each index in the class used by this variable
 319  */
 320 void CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 321 {
 322     int mx, i;
 323     EX_CALLBACKS *ip;
 324     void *ptr;
 325     EX_CALLBACK *f;
 326     EX_CALLBACK *stack[10];
 327     EX_CALLBACK **storage = NULL;
 328
 329     if ((ip = get_and_lock(class_index)) == NULL)
 330         goto err;
 331
 332     mx = sk_EX_CALLBACK_num(ip->meth);
 333     if (mx > 0) {
 334         if (mx < (int)OSSL_NELEM(stack))
 335             storage = stack;
 336         else
 337             storage = OPENSSL_malloc(sizeof(*storage) * mx);
 338         if (storage != NULL)
 339             for (i = 0; i < mx; i++)
 340                 storage[i] = sk_EX_CALLBACK_value(ip->meth, i);
 341     }
 342     CRYPTO_THREAD_unlock(ex_data_lock);
 343
 344     for (i = 0; i < mx; i++) {
 345         if (storage != NULL)
 346             f = storage[i];
 347         else {
 348             CRYPTO_THREAD_write_lock(ex_data_lock);
 349             f = sk_EX_CALLBACK_value(ip->meth, i);
 350             CRYPTO_THREAD_unlock(ex_data_lock);
 351         }
 352         if (f != NULL && f->free_func != NULL) {
 353             ptr = CRYPTO_get_ex_data(ad, i);
 354             f->free_func(obj, ptr, ad, i, f->argl, f->argp);
 355         }
 356     }
 357
 358     if (storage != stack)
 359         OPENSSL_free(storage);
 360  err:
 361     sk_void_free(ad->sk);
 362     ad->sk = NULL;
 363 }
 364
 365 /*
 366  * For a given CRYPTO_EX_DATA variable, set the value corresponding to a
 367  * particular index in the class used by this variable
 368  */
 369 int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)
 370 {
 371     int i;
 372
 373     if (ad->sk == NULL) {
 374         if ((ad->sk = sk_void_new_null()) == NULL) {
 375             CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);
 376             return 0;
 377         }
 378     }
 379
 380     for (i = sk_void_num(ad->sk); i <= idx; ++i) {
 381         if (!sk_void_push(ad->sk, NULL)) {
 382             CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);
 383             return 0;
 384         }
 385     }
 386     sk_void_set(ad->sk, idx, val);
 387     return 1;
 388 }
 389
 390 /*
 391  * For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a
 392  * particular index in the class used by this variable
 393  */
 394 void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
 395 {
 396     if (ad->sk == NULL || idx >= sk_void_num(ad->sk))
 397         return NULL;
 398     return sk_void_value(ad->sk, idx);
 399 }