1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.]
56  */
57 /* ====================================================================
58  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
59  *
60  * Redistribution and use in source and binary forms, with or without
61  * modification, are permitted provided that the following conditions
62  * are met:
63  *
64  * 1. Redistributions of source code must retain the above copyright
65  *    notice, this list of conditions and the following disclaimer.
66  *
67  * 2. Redistributions in binary form must reproduce the above copyright
68  *    notice, this list of conditions and the following disclaimer in
69  *    the documentation and/or other materials provided with the
70  *    distribution.
71  *
72  * 3. All advertising materials mentioning features or use of this
73  *    software must display the following acknowledgment:
74  *    "This product includes software developed by the OpenSSL Project
75  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76  *
77  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78  *    endorse or promote products derived from this software without
79  *    prior written permission. For written permission, please contact
80  *    openssl-core@openssl.org.
81  *
82  * 5. Products derived from this software may not be called "OpenSSL"
83  *    nor may "OpenSSL" appear in their names without prior written
84  *    permission of the OpenSSL Project.
85  *
86  * 6. Redistributions of any form whatsoever must retain the following
87  *    acknowledgment:
88  *    "This product includes software developed by the OpenSSL Project
89  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90  *
91  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
95  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102  * OF THE POSSIBILITY OF SUCH DAMAGE.
103  * ====================================================================
104  *
105  * This product includes cryptographic software written by Eric Young
106  * (eay@cryptsoft.com).  This product includes software written by Tim
107  * Hudson (tjh@cryptsoft.com). */
108 
109 #ifndef OPENSSL_HEADER_CRYPTO_INTERNAL_H
110 #define OPENSSL_HEADER_CRYPTO_INTERNAL_H
111 
112 #include <openssl/ex_data.h>
113 #include <openssl/stack.h>
114 #include <openssl/thread.h>
115 
116 #include <assert.h>
117 #include <string.h>
118 
119 #if defined(BORINGSSL_CONSTANT_TIME_VALIDATION)
120 #include <valgrind/memcheck.h>
121 #endif
122 
123 #if !defined(__cplusplus)
124 #if defined(_MSC_VER)
125 #define alignas(x) __declspec(align(x))
126 #define alignof __alignof
127 #else
128 #include <stdalign.h>
129 #endif
130 #endif
131 
132 #if defined(OPENSSL_THREADS) && \
133     (!defined(OPENSSL_WINDOWS) || defined(__MINGW32__))
134 #include <pthread.h>
135 #define OPENSSL_PTHREADS
136 #endif
137 
138 #if defined(OPENSSL_THREADS) && !defined(OPENSSL_PTHREADS) && \
139     defined(OPENSSL_WINDOWS)
140 #define OPENSSL_WINDOWS_THREADS
141 OPENSSL_MSVC_PRAGMA(warning(push, 3))
142 #include <windows.h>
OPENSSL_MSVC_PRAGMA(warning (pop))143 OPENSSL_MSVC_PRAGMA(warning(pop))
144 #endif
145 
146 #if defined(__cplusplus)
147 extern "C" {
148 #endif
149 
150 
151 #if defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || defined(OPENSSL_ARM) || \
152     defined(OPENSSL_AARCH64) || defined(OPENSSL_PPC64LE)
153 // OPENSSL_cpuid_setup initializes the platform-specific feature cache.
154 void OPENSSL_cpuid_setup(void);
155 #endif
156 
157 #if (defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64)) && \
158     !defined(OPENSSL_STATIC_ARMCAP)
159 // OPENSSL_get_armcap_pointer_for_test returns a pointer to |OPENSSL_armcap_P|
160 // for unit tests. Any modifications to the value must be made after
161 // |CRYPTO_library_init| but before any other function call in BoringSSL.
162 OPENSSL_EXPORT uint32_t *OPENSSL_get_armcap_pointer_for_test(void);
163 #endif
164 
165 
166 #if (!defined(_MSC_VER) || defined(__clang__)) && defined(OPENSSL_64_BIT)
167 #define BORINGSSL_HAS_UINT128
168 typedef __int128_t int128_t;
169 typedef __uint128_t uint128_t;
170 
171 // clang-cl supports __uint128_t but modulus and division don't work.
172 // https://crbug.com/787617.
173 #if !defined(_MSC_VER) || !defined(__clang__)
174 #define BORINGSSL_CAN_DIVIDE_UINT128
175 #endif
176 #endif
177 
178 #define OPENSSL_ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
179 
180 // Have a generic fall-through for different versions of C/C++.
181 #if defined(__cplusplus) && __cplusplus >= 201703L
182 #define OPENSSL_FALLTHROUGH [[fallthrough]]
183 #elif defined(__cplusplus) && __cplusplus >= 201103L && defined(__clang__)
184 #define OPENSSL_FALLTHROUGH [[clang::fallthrough]]
185 #elif defined(__cplusplus) && __cplusplus >= 201103L && defined(__GNUC__) && \
186     __GNUC__ >= 7
187 #define OPENSSL_FALLTHROUGH [[gnu::fallthrough]]
188 #elif defined(__GNUC__) && __GNUC__ >= 7 // gcc 7
189 #define OPENSSL_FALLTHROUGH __attribute__ ((fallthrough))
190 #else // C++11 on gcc 6, and all other cases
191 #define OPENSSL_FALLTHROUGH
192 #endif
193 
194 // buffers_alias returns one if |a| and |b| alias and zero otherwise.
195 static inline int buffers_alias(const uint8_t *a, size_t a_len,
196                                 const uint8_t *b, size_t b_len) {
197   // Cast |a| and |b| to integers. In C, pointer comparisons between unrelated
198   // objects are undefined whereas pointer to integer conversions are merely
199   // implementation-defined. We assume the implementation defined it in a sane
200   // way.
201   uintptr_t a_u = (uintptr_t)a;
202   uintptr_t b_u = (uintptr_t)b;
203   return a_u + a_len > b_u && b_u + b_len > a_u;
204 }
205 
206 
207 // Constant-time utility functions.
208 //
209 // The following methods return a bitmask of all ones (0xff...f) for true and 0
210 // for false. This is useful for choosing a value based on the result of a
211 // conditional in constant time. For example,
212 //
213 // if (a < b) {
214 //   c = a;
215 // } else {
216 //   c = b;
217 // }
218 //
219 // can be written as
220 //
221 // crypto_word_t lt = constant_time_lt_w(a, b);
222 // c = constant_time_select_w(lt, a, b);
223 
224 // crypto_word_t is the type that most constant-time functions use. Ideally we
225 // would like it to be |size_t|, but NaCl builds in 64-bit mode with 32-bit
226 // pointers, which means that |size_t| can be 32 bits when |BN_ULONG| is 64
227 // bits. Since we want to be able to do constant-time operations on a
228 // |BN_ULONG|, |crypto_word_t| is defined as an unsigned value with the native
229 // word length.
230 #if defined(OPENSSL_64_BIT)
231 typedef uint64_t crypto_word_t;
232 #elif defined(OPENSSL_32_BIT)
233 typedef uint32_t crypto_word_t;
234 #else
235 #error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
236 #endif
237 
238 #define CONSTTIME_TRUE_W ~((crypto_word_t)0)
239 #define CONSTTIME_FALSE_W ((crypto_word_t)0)
240 #define CONSTTIME_TRUE_8 ((uint8_t)0xff)
241 #define CONSTTIME_FALSE_8 ((uint8_t)0)
242 
243 // constant_time_msb_w returns the given value with the MSB copied to all the
244 // other bits.
245 static inline crypto_word_t constant_time_msb_w(crypto_word_t a) {
246   return 0u - (a >> (sizeof(a) * 8 - 1));
247 }
248 
249 // constant_time_lt_w returns 0xff..f if a < b and 0 otherwise.
250 static inline crypto_word_t constant_time_lt_w(crypto_word_t a,
251                                                crypto_word_t b) {
252   // Consider the two cases of the problem:
253   //   msb(a) == msb(b): a < b iff the MSB of a - b is set.
254   //   msb(a) != msb(b): a < b iff the MSB of b is set.
255   //
256   // If msb(a) == msb(b) then the following evaluates as:
257   //   msb(a^((a^b)|((a-b)^a))) ==
258   //   msb(a^((a-b) ^ a))       ==   (because msb(a^b) == 0)
259   //   msb(a^a^(a-b))           ==   (rearranging)
260   //   msb(a-b)                      (because ∀x. x^x == 0)
261   //
262   // Else, if msb(a) != msb(b) then the following evaluates as:
263   //   msb(a^((a^b)|((a-b)^a))) ==
264   //   msb(a^(�� | ((a-b)^a)))   ==   (because msb(a^b) == 1 and ��
265   //                                  represents a value s.t. msb(��) = 1)
266   //   msb(a^��)                 ==   (because ORing with 1 results in 1)
267   //   msb(b)
268   //
269   //
270   // Here is an SMT-LIB verification of this formula:
271   //
272   // (define-fun lt ((a (_ BitVec 32)) (b (_ BitVec 32))) (_ BitVec 32)
273   //   (bvxor a (bvor (bvxor a b) (bvxor (bvsub a b) a)))
274   // )
275   //
276   // (declare-fun a () (_ BitVec 32))
277   // (declare-fun b () (_ BitVec 32))
278   //
279   // (assert (not (= (= #x00000001 (bvlshr (lt a b) #x0000001f)) (bvult a b))))
280   // (check-sat)
281   // (get-model)
282   return constant_time_msb_w(a^((a^b)|((a-b)^a)));
283 }
284 
285 // constant_time_lt_8 acts like |constant_time_lt_w| but returns an 8-bit
286 // mask.
287 static inline uint8_t constant_time_lt_8(crypto_word_t a, crypto_word_t b) {
288   return (uint8_t)(constant_time_lt_w(a, b));
289 }
290 
291 // constant_time_ge_w returns 0xff..f if a >= b and 0 otherwise.
292 static inline crypto_word_t constant_time_ge_w(crypto_word_t a,
293                                                crypto_word_t b) {
294   return ~constant_time_lt_w(a, b);
295 }
296 
297 // constant_time_ge_8 acts like |constant_time_ge_w| but returns an 8-bit
298 // mask.
299 static inline uint8_t constant_time_ge_8(crypto_word_t a, crypto_word_t b) {
300   return (uint8_t)(constant_time_ge_w(a, b));
301 }
302 
303 // constant_time_is_zero returns 0xff..f if a == 0 and 0 otherwise.
304 static inline crypto_word_t constant_time_is_zero_w(crypto_word_t a) {
305   // Here is an SMT-LIB verification of this formula:
306   //
307   // (define-fun is_zero ((a (_ BitVec 32))) (_ BitVec 32)
308   //   (bvand (bvnot a) (bvsub a #x00000001))
309   // )
310   //
311   // (declare-fun a () (_ BitVec 32))
312   //
313   // (assert (not (= (= #x00000001 (bvlshr (is_zero a) #x0000001f)) (= a #x00000000))))
314   // (check-sat)
315   // (get-model)
316   return constant_time_msb_w(~a & (a - 1));
317 }
318 
319 // constant_time_is_zero_8 acts like |constant_time_is_zero_w| but returns an
320 // 8-bit mask.
321 static inline uint8_t constant_time_is_zero_8(crypto_word_t a) {
322   return (uint8_t)(constant_time_is_zero_w(a));
323 }
324 
325 // constant_time_eq_w returns 0xff..f if a == b and 0 otherwise.
326 static inline crypto_word_t constant_time_eq_w(crypto_word_t a,
327                                                crypto_word_t b) {
328   return constant_time_is_zero_w(a ^ b);
329 }
330 
331 // constant_time_eq_8 acts like |constant_time_eq_w| but returns an 8-bit
332 // mask.
333 static inline uint8_t constant_time_eq_8(crypto_word_t a, crypto_word_t b) {
334   return (uint8_t)(constant_time_eq_w(a, b));
335 }
336 
337 // constant_time_eq_int acts like |constant_time_eq_w| but works on int
338 // values.
339 static inline crypto_word_t constant_time_eq_int(int a, int b) {
340   return constant_time_eq_w((crypto_word_t)(a), (crypto_word_t)(b));
341 }
342 
343 // constant_time_eq_int_8 acts like |constant_time_eq_int| but returns an 8-bit
344 // mask.
345 static inline uint8_t constant_time_eq_int_8(int a, int b) {
346   return constant_time_eq_8((crypto_word_t)(a), (crypto_word_t)(b));
347 }
348 
349 // constant_time_select_w returns (mask & a) | (~mask & b). When |mask| is all
350 // 1s or all 0s (as returned by the methods above), the select methods return
351 // either |a| (if |mask| is nonzero) or |b| (if |mask| is zero).
352 static inline crypto_word_t constant_time_select_w(crypto_word_t mask,
353                                                    crypto_word_t a,
354                                                    crypto_word_t b) {
355   return (mask & a) | (~mask & b);
356 }
357 
358 // constant_time_select_8 acts like |constant_time_select| but operates on
359 // 8-bit values.
360 static inline uint8_t constant_time_select_8(uint8_t mask, uint8_t a,
361                                              uint8_t b) {
362   return (uint8_t)(constant_time_select_w(mask, a, b));
363 }
364 
365 // constant_time_select_int acts like |constant_time_select| but operates on
366 // ints.
367 static inline int constant_time_select_int(crypto_word_t mask, int a, int b) {
368   return (int)(constant_time_select_w(mask, (crypto_word_t)(a),
369                                       (crypto_word_t)(b)));
370 }
371 
372 #if defined(BORINGSSL_CONSTANT_TIME_VALIDATION)
373 
374 // CONSTTIME_SECRET takes a pointer and a number of bytes and marks that region
375 // of memory as secret. Secret data is tracked as it flows to registers and
376 // other parts of a memory. If secret data is used as a condition for a branch,
377 // or as a memory index, it will trigger warnings in valgrind.
378 #define CONSTTIME_SECRET(x, y) VALGRIND_MAKE_MEM_UNDEFINED(x, y)
379 
380 // CONSTTIME_DECLASSIFY takes a pointer and a number of bytes and marks that
381 // region of memory as public. Public data is not subject to constant-time
382 // rules.
383 #define CONSTTIME_DECLASSIFY(x, y) VALGRIND_MAKE_MEM_DEFINED(x, y)
384 
385 #else
386 
387 #define CONSTTIME_SECRET(x, y)
388 #define CONSTTIME_DECLASSIFY(x, y)
389 
390 #endif  // BORINGSSL_CONSTANT_TIME_VALIDATION
391 
392 
393 // Thread-safe initialisation.
394 
395 #if !defined(OPENSSL_THREADS)
396 typedef uint32_t CRYPTO_once_t;
397 #define CRYPTO_ONCE_INIT 0
398 #elif defined(OPENSSL_WINDOWS_THREADS)
399 typedef INIT_ONCE CRYPTO_once_t;
400 #define CRYPTO_ONCE_INIT INIT_ONCE_STATIC_INIT
401 #elif defined(OPENSSL_PTHREADS)
402 typedef pthread_once_t CRYPTO_once_t;
403 #define CRYPTO_ONCE_INIT PTHREAD_ONCE_INIT
404 #else
405 #error "Unknown threading library"
406 #endif
407 
408 // CRYPTO_once calls |init| exactly once per process. This is thread-safe: if
409 // concurrent threads call |CRYPTO_once| with the same |CRYPTO_once_t| argument
410 // then they will block until |init| completes, but |init| will have only been
411 // called once.
412 //
413 // The |once| argument must be a |CRYPTO_once_t| that has been initialised with
414 // the value |CRYPTO_ONCE_INIT|.
415 OPENSSL_EXPORT void CRYPTO_once(CRYPTO_once_t *once, void (*init)(void));
416 
417 
418 // Reference counting.
419 
420 // CRYPTO_REFCOUNT_MAX is the value at which the reference count saturates.
421 #define CRYPTO_REFCOUNT_MAX 0xffffffff
422 
423 // CRYPTO_refcount_inc atomically increments the value at |*count| unless the
424 // value would overflow. It's safe for multiple threads to concurrently call
425 // this or |CRYPTO_refcount_dec_and_test_zero| on the same
426 // |CRYPTO_refcount_t|.
427 OPENSSL_EXPORT void CRYPTO_refcount_inc(CRYPTO_refcount_t *count);
428 
429 // CRYPTO_refcount_dec_and_test_zero tests the value at |*count|:
430 //   if it's zero, it crashes the address space.
431 //   if it's the maximum value, it returns zero.
432 //   otherwise, it atomically decrements it and returns one iff the resulting
433 //       value is zero.
434 //
435 // It's safe for multiple threads to concurrently call this or
436 // |CRYPTO_refcount_inc| on the same |CRYPTO_refcount_t|.
437 OPENSSL_EXPORT int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *count);
438 
439 
440 // Locks.
441 //
442 // Two types of locks are defined: |CRYPTO_MUTEX|, which can be used in
443 // structures as normal, and |struct CRYPTO_STATIC_MUTEX|, which can be used as
444 // a global lock. A global lock must be initialised to the value
445 // |CRYPTO_STATIC_MUTEX_INIT|.
446 //
447 // |CRYPTO_MUTEX| can appear in public structures and so is defined in
448 // thread.h as a structure large enough to fit the real type. The global lock is
449 // a different type so it may be initialized with platform initializer macros.
450 
451 #if !defined(OPENSSL_THREADS)
452 struct CRYPTO_STATIC_MUTEX {
453   char padding;  // Empty structs have different sizes in C and C++.
454 };
455 #define CRYPTO_STATIC_MUTEX_INIT { 0 }
456 #elif defined(OPENSSL_WINDOWS_THREADS)
457 struct CRYPTO_STATIC_MUTEX {
458   SRWLOCK lock;
459 };
460 #define CRYPTO_STATIC_MUTEX_INIT { SRWLOCK_INIT }
461 #elif defined(OPENSSL_PTHREADS)
462 struct CRYPTO_STATIC_MUTEX {
463   pthread_rwlock_t lock;
464 };
465 #define CRYPTO_STATIC_MUTEX_INIT { PTHREAD_RWLOCK_INITIALIZER }
466 #else
467 #error "Unknown threading library"
468 #endif
469 
470 // CRYPTO_MUTEX_init initialises |lock|. If |lock| is a static variable, use a
471 // |CRYPTO_STATIC_MUTEX|.
472 OPENSSL_EXPORT void CRYPTO_MUTEX_init(CRYPTO_MUTEX *lock);
473 
474 // CRYPTO_MUTEX_lock_read locks |lock| such that other threads may also have a
475 // read lock, but none may have a write lock.
476 OPENSSL_EXPORT void CRYPTO_MUTEX_lock_read(CRYPTO_MUTEX *lock);
477 
478 // CRYPTO_MUTEX_lock_write locks |lock| such that no other thread has any type
479 // of lock on it.
480 OPENSSL_EXPORT void CRYPTO_MUTEX_lock_write(CRYPTO_MUTEX *lock);
481 
482 // CRYPTO_MUTEX_unlock_read unlocks |lock| for reading.
483 OPENSSL_EXPORT void CRYPTO_MUTEX_unlock_read(CRYPTO_MUTEX *lock);
484 
485 // CRYPTO_MUTEX_unlock_write unlocks |lock| for writing.
486 OPENSSL_EXPORT void CRYPTO_MUTEX_unlock_write(CRYPTO_MUTEX *lock);
487 
488 // CRYPTO_MUTEX_cleanup releases all resources held by |lock|.
489 OPENSSL_EXPORT void CRYPTO_MUTEX_cleanup(CRYPTO_MUTEX *lock);
490 
491 // CRYPTO_STATIC_MUTEX_lock_read locks |lock| such that other threads may also
492 // have a read lock, but none may have a write lock. The |lock| variable does
493 // not need to be initialised by any function, but must have been statically
494 // initialised with |CRYPTO_STATIC_MUTEX_INIT|.
495 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_read(
496     struct CRYPTO_STATIC_MUTEX *lock);
497 
498 // CRYPTO_STATIC_MUTEX_lock_write locks |lock| such that no other thread has
499 // any type of lock on it.  The |lock| variable does not need to be initialised
500 // by any function, but must have been statically initialised with
501 // |CRYPTO_STATIC_MUTEX_INIT|.
502 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_write(
503     struct CRYPTO_STATIC_MUTEX *lock);
504 
505 // CRYPTO_STATIC_MUTEX_unlock_read unlocks |lock| for reading.
506 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_unlock_read(
507     struct CRYPTO_STATIC_MUTEX *lock);
508 
509 // CRYPTO_STATIC_MUTEX_unlock_write unlocks |lock| for writing.
510 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_unlock_write(
511     struct CRYPTO_STATIC_MUTEX *lock);
512 
513 #if defined(__cplusplus)
514 extern "C++" {
515 
516 BSSL_NAMESPACE_BEGIN
517 
518 namespace internal {
519 
520 // MutexLockBase is a RAII helper for CRYPTO_MUTEX locking.
521 template <void (*LockFunc)(CRYPTO_MUTEX *), void (*ReleaseFunc)(CRYPTO_MUTEX *)>
522 class MutexLockBase {
523  public:
524   explicit MutexLockBase(CRYPTO_MUTEX *mu) : mu_(mu) {
525     assert(mu_ != nullptr);
526     LockFunc(mu_);
527   }
528   ~MutexLockBase() { ReleaseFunc(mu_); }
529   MutexLockBase(const MutexLockBase<LockFunc, ReleaseFunc> &) = delete;
530   MutexLockBase &operator=(const MutexLockBase<LockFunc, ReleaseFunc> &) =
531       delete;
532 
533  private:
534   CRYPTO_MUTEX *const mu_;
535 };
536 
537 }  // namespace internal
538 
539 using MutexWriteLock =
540     internal::MutexLockBase<CRYPTO_MUTEX_lock_write, CRYPTO_MUTEX_unlock_write>;
541 using MutexReadLock =
542     internal::MutexLockBase<CRYPTO_MUTEX_lock_read, CRYPTO_MUTEX_unlock_read>;
543 
544 BSSL_NAMESPACE_END
545 
546 }  // extern "C++"
547 #endif  // defined(__cplusplus)
548 
549 
550 // Thread local storage.
551 
552 // thread_local_data_t enumerates the types of thread-local data that can be
553 // stored.
554 typedef enum {
555   OPENSSL_THREAD_LOCAL_ERR = 0,
556   OPENSSL_THREAD_LOCAL_RAND,
557   OPENSSL_THREAD_LOCAL_TEST,
558   NUM_OPENSSL_THREAD_LOCALS,
559 } thread_local_data_t;
560 
561 // thread_local_destructor_t is the type of a destructor function that will be
562 // called when a thread exits and its thread-local storage needs to be freed.
563 typedef void (*thread_local_destructor_t)(void *);
564 
565 // CRYPTO_get_thread_local gets the pointer value that is stored for the
566 // current thread for the given index, or NULL if none has been set.
567 OPENSSL_EXPORT void *CRYPTO_get_thread_local(thread_local_data_t value);
568 
569 // CRYPTO_set_thread_local sets a pointer value for the current thread at the
570 // given index. This function should only be called once per thread for a given
571 // |index|: rather than update the pointer value itself, update the data that
572 // is pointed to.
573 //
574 // The destructor function will be called when a thread exits to free this
575 // thread-local data. All calls to |CRYPTO_set_thread_local| with the same
576 // |index| should have the same |destructor| argument. The destructor may be
577 // called with a NULL argument if a thread that never set a thread-local
578 // pointer for |index|, exits. The destructor may be called concurrently with
579 // different arguments.
580 //
581 // This function returns one on success or zero on error. If it returns zero
582 // then |destructor| has been called with |value| already.
583 OPENSSL_EXPORT int CRYPTO_set_thread_local(
584     thread_local_data_t index, void *value,
585     thread_local_destructor_t destructor);
586 
587 
588 // ex_data
589 
590 typedef struct crypto_ex_data_func_st CRYPTO_EX_DATA_FUNCS;
591 
592 DECLARE_STACK_OF(CRYPTO_EX_DATA_FUNCS)
593 
594 // CRYPTO_EX_DATA_CLASS tracks the ex_indices registered for a type which
595 // supports ex_data. It should defined as a static global within the module
596 // which defines that type.
597 typedef struct {
598   struct CRYPTO_STATIC_MUTEX lock;
599   STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
600   // num_reserved is one if the ex_data index zero is reserved for legacy
601   // |TYPE_get_app_data| functions.
602   uint8_t num_reserved;
603 } CRYPTO_EX_DATA_CLASS;
604 
605 #define CRYPTO_EX_DATA_CLASS_INIT {CRYPTO_STATIC_MUTEX_INIT, NULL, 0}
606 #define CRYPTO_EX_DATA_CLASS_INIT_WITH_APP_DATA \
607     {CRYPTO_STATIC_MUTEX_INIT, NULL, 1}
608 
609 // CRYPTO_get_ex_new_index allocates a new index for |ex_data_class| and writes
610 // it to |*out_index|. Each class of object should provide a wrapper function
611 // that uses the correct |CRYPTO_EX_DATA_CLASS|. It returns one on success and
612 // zero otherwise.
613 OPENSSL_EXPORT int CRYPTO_get_ex_new_index(CRYPTO_EX_DATA_CLASS *ex_data_class,
614                                            int *out_index, long argl,
615                                            void *argp,
616                                            CRYPTO_EX_free *free_func);
617 
618 // CRYPTO_set_ex_data sets an extra data pointer on a given object. Each class
619 // of object should provide a wrapper function.
620 OPENSSL_EXPORT int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int index, void *val);
621 
622 // CRYPTO_get_ex_data returns an extra data pointer for a given object, or NULL
623 // if no such index exists. Each class of object should provide a wrapper
624 // function.
625 OPENSSL_EXPORT void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int index);
626 
627 // CRYPTO_new_ex_data initialises a newly allocated |CRYPTO_EX_DATA|.
628 OPENSSL_EXPORT void CRYPTO_new_ex_data(CRYPTO_EX_DATA *ad);
629 
630 // CRYPTO_free_ex_data frees |ad|, which is embedded inside |obj|, which is an
631 // object of the given class.
632 OPENSSL_EXPORT void CRYPTO_free_ex_data(CRYPTO_EX_DATA_CLASS *ex_data_class,
633                                         void *obj, CRYPTO_EX_DATA *ad);
634 
635 
636 // Endianness conversions.
637 
638 #if defined(__GNUC__) && __GNUC__ >= 2
639 static inline uint32_t CRYPTO_bswap4(uint32_t x) {
640   return __builtin_bswap32(x);
641 }
642 
643 static inline uint64_t CRYPTO_bswap8(uint64_t x) {
644   return __builtin_bswap64(x);
645 }
646 #elif defined(_MSC_VER)
647 OPENSSL_MSVC_PRAGMA(warning(push, 3))
648 #include <stdlib.h>
649 OPENSSL_MSVC_PRAGMA(warning(pop))
650 #pragma intrinsic(_byteswap_uint64, _byteswap_ulong)
651 static inline uint32_t CRYPTO_bswap4(uint32_t x) {
652   return _byteswap_ulong(x);
653 }
654 
655 static inline uint64_t CRYPTO_bswap8(uint64_t x) {
656   return _byteswap_uint64(x);
657 }
658 #else
659 static inline uint32_t CRYPTO_bswap4(uint32_t x) {
660   x = (x >> 16) | (x << 16);
661   x = ((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8);
662   return x;
663 }
664 
665 static inline uint64_t CRYPTO_bswap8(uint64_t x) {
666   return CRYPTO_bswap4(x >> 32) | (((uint64_t)CRYPTO_bswap4(x)) << 32);
667 }
668 #endif
669 
670 
671 // Language bug workarounds.
672 //
673 // Most C standard library functions are undefined if passed NULL, even when the
674 // corresponding length is zero. This gives them (and, in turn, all functions
675 // which call them) surprising behavior on empty arrays. Some compilers will
676 // miscompile code due to this rule. See also
677 // https://www.imperialviolet.org/2016/06/26/nonnull.html
678 //
679 // These wrapper functions behave the same as the corresponding C standard
680 // functions, but behave as expected when passed NULL if the length is zero.
681 //
682 // Note |OPENSSL_memcmp| is a different function from |CRYPTO_memcmp|.
683 
684 // C++ defines |memchr| as a const-correct overload.
685 #if defined(__cplusplus)
686 extern "C++" {
687 
688 static inline const void *OPENSSL_memchr(const void *s, int c, size_t n) {
689   if (n == 0) {
690     return NULL;
691   }
692 
693   return memchr(s, c, n);
694 }
695 
696 static inline void *OPENSSL_memchr(void *s, int c, size_t n) {
697   if (n == 0) {
698     return NULL;
699   }
700 
701   return memchr(s, c, n);
702 }
703 
704 }  // extern "C++"
705 #else  // __cplusplus
706 
707 static inline void *OPENSSL_memchr(const void *s, int c, size_t n) {
708   if (n == 0) {
709     return NULL;
710   }
711 
712   return memchr(s, c, n);
713 }
714 
715 #endif  // __cplusplus
716 
717 static inline int OPENSSL_memcmp(const void *s1, const void *s2, size_t n) {
718   if (n == 0) {
719     return 0;
720   }
721 
722   return memcmp(s1, s2, n);
723 }
724 
725 static inline void *OPENSSL_memcpy(void *dst, const void *src, size_t n) {
726   if (n == 0) {
727     return dst;
728   }
729 
730   return memcpy(dst, src, n);
731 }
732 
733 static inline void *OPENSSL_memmove(void *dst, const void *src, size_t n) {
734   if (n == 0) {
735     return dst;
736   }
737 
738   return memmove(dst, src, n);
739 }
740 
741 static inline void *OPENSSL_memset(void *dst, int c, size_t n) {
742   if (n == 0) {
743     return dst;
744   }
745 
746   return memset(dst, c, n);
747 }
748 
749 #if defined(BORINGSSL_FIPS)
750 // BORINGSSL_FIPS_abort is called when a FIPS power-on or continuous test
751 // fails. It prevents any further cryptographic operations by the current
752 // process.
753 void BORINGSSL_FIPS_abort(void) __attribute__((noreturn));
754 #endif
755 
756 #if defined(__cplusplus)
757 }  // extern C
758 #endif
759 
760 #endif  // OPENSSL_HEADER_CRYPTO_INTERNAL_H
761