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