text: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   *
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   *
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   *
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.] */
  
  #include <openssl/mem.h>
  
  #include <assert.h>
  #include <stdarg.h>
  #include <stdio.h>
  
  #include <openssl/err.h>
  
  #if defined(OPENSSL_WINDOWS)
  OPENSSL_MSVC_PRAGMA(warning(push, 3))
  #include <windows.h>
  OPENSSL_MSVC_PRAGMA(warning(pop))
  #endif
  
  #include "internal.h"
  
  
  #define OPENSSL_MALLOC_PREFIX 8
  OPENSSL_STATIC_ASSERT(OPENSSL_MALLOC_PREFIX >= sizeof(size_t),
                        size_t_too_large)
  
  #if defined(OPENSSL_ASAN)
  void __asan_poison_memory_region(const volatile void *addr, size_t size);
  void __asan_unpoison_memory_region(const volatile void *addr, size_t size);
  #else
  static void __asan_poison_memory_region(const void *addr, size_t size) {}
  static void __asan_unpoison_memory_region(const void *addr, size_t size) {}
  #endif
  
  // Windows doesn't really support weak symbols as of May 2019, and Clang on
  // Windows will emit strong symbols instead. See
  // https://bugs.llvm.org/show_bug.cgi?id=37598
  #if defined(__ELF__) && defined(__GNUC__)
  #define WEAK_SYMBOL_FUNC(rettype, name, args) \
    rettype name args __attribute__((weak));
  #else
  #define WEAK_SYMBOL_FUNC(rettype, name, args) static rettype(*name) args = NULL;
  #endif
  
  #if defined(BORINGSSL_SDALLOCX)
  // sdallocx is a sized |free| function. By passing the size (which we happen to
  // always know in BoringSSL), the malloc implementation can save work.
  //
  // This is guarded by BORINGSSL_SDALLOCX, rather than being a weak symbol,
  // because it can work poorly if there are two malloc implementations in the
  // address space. (Which probably isn't valid, ODR etc, but
  // https://github.com/grpc/grpc/issues/25450). In that situation, |malloc| can
  // come from one allocator but |sdallocx| from another and crashes quickly
  // result. We can't match |sdallocx| with |mallocx| because tcmalloc only
  // provides the former, so a mismatch can still happen.
  void sdallocx(void *ptr, size_t size, int flags);
  #endif
  
  // The following three functions can be defined to override default heap
  // allocation and freeing. If defined, it is the responsibility of
  // |OPENSSL_memory_free| to zero out the memory before returning it to the
  // system. |OPENSSL_memory_free| will not be passed NULL pointers.
  //
  // WARNING: These functions are called on every allocation and free in
  // BoringSSL across the entire process. They may be called by any code in the
  // process which calls BoringSSL, including in process initializers and thread
  // destructors. When called, BoringSSL may hold pthreads locks. Any other code
  // in the process which, directly or indirectly, calls BoringSSL may be on the
  // call stack and may itself be using arbitrary synchronization primitives.
  //
  // As a result, these functions may not have the usual programming environment
  // available to most C or C++ code. In particular, they may not call into
  // BoringSSL, or any library which depends on BoringSSL. Any synchronization
  // primitives used must tolerate every other synchronization primitive linked
  // into the process, including pthreads locks. Failing to meet these constraints
  // may result in deadlocks, crashes, or memory corruption.
  WEAK_SYMBOL_FUNC(void*, OPENSSL_memory_alloc, (size_t size))
  WEAK_SYMBOL_FUNC(void, OPENSSL_memory_free, (void *ptr))
  WEAK_SYMBOL_FUNC(size_t, OPENSSL_memory_get_size, (void *ptr))
  
  void *OPENSSL_malloc(size_t size) {
    if (OPENSSL_memory_alloc != NULL) {
      assert(OPENSSL_memory_free != NULL);
      assert(OPENSSL_memory_get_size != NULL);
      return OPENSSL_memory_alloc(size);
    }
  
    if (size + OPENSSL_MALLOC_PREFIX < size) {
      return NULL;
    }
  
    void *ptr = malloc(size + OPENSSL_MALLOC_PREFIX);
    if (ptr == NULL) {
      return NULL;
    }
  
    *(size_t *)ptr = size;
  
    __asan_poison_memory_region(ptr, OPENSSL_MALLOC_PREFIX);
    return ((uint8_t *)ptr) + OPENSSL_MALLOC_PREFIX;
  }
  
  void OPENSSL_free(void *orig_ptr) {
    if (orig_ptr == NULL) {
      return;
    }
  
    if (OPENSSL_memory_free != NULL) {
      OPENSSL_memory_free(orig_ptr);
      return;
    }
  
    void *ptr = ((uint8_t *)orig_ptr) - OPENSSL_MALLOC_PREFIX;
    __asan_unpoison_memory_region(ptr, OPENSSL_MALLOC_PREFIX);
  
    size_t size = *(size_t *)ptr;
    OPENSSL_cleanse(ptr, size + OPENSSL_MALLOC_PREFIX);
  #if defined(BORINGSSL_SDALLOCX)
    sdallocx(ptr, size + OPENSSL_MALLOC_PREFIX, 0 /* flags */);
  #else
    free(ptr);
  #endif
  }
  
  void *OPENSSL_realloc(void *orig_ptr, size_t new_size) {
    if (orig_ptr == NULL) {
      return OPENSSL_malloc(new_size);
    }
  
    size_t old_size;
    if (OPENSSL_memory_get_size != NULL) {
      old_size = OPENSSL_memory_get_size(orig_ptr);
    } else {
      void *ptr = ((uint8_t *)orig_ptr) - OPENSSL_MALLOC_PREFIX;
      __asan_unpoison_memory_region(ptr, OPENSSL_MALLOC_PREFIX);
      old_size = *(size_t *)ptr;
      __asan_poison_memory_region(ptr, OPENSSL_MALLOC_PREFIX);
    }
  
    void *ret = OPENSSL_malloc(new_size);
    if (ret == NULL) {
      return NULL;
    }
  
    size_t to_copy = new_size;
    if (old_size < to_copy) {
      to_copy = old_size;
    }
  
    memcpy(ret, orig_ptr, to_copy);
    OPENSSL_free(orig_ptr);
  
    return ret;
  }
  
  void OPENSSL_cleanse(void *ptr, size_t len) {
  #if defined(OPENSSL_WINDOWS)
    SecureZeroMemory(ptr, len);
  #else
    OPENSSL_memset(ptr, 0, len);
  
  #if !defined(OPENSSL_NO_ASM)
    /* As best as we can tell, this is sufficient to break any optimisations that
       might try to eliminate "superfluous" memsets. If there's an easy way to
       detect memset_s, it would be better to use that. */
    __asm__ __volatile__("" : : "r"(ptr) : "memory");
  #endif
  #endif  // !OPENSSL_NO_ASM
  }
  
  void OPENSSL_clear_free(void *ptr, size_t unused) {
    OPENSSL_free(ptr);
  }
  
  int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len) {
    const uint8_t *a = in_a;
    const uint8_t *b = in_b;
    uint8_t x = 0;
  
    for (size_t i = 0; i < len; i++) {
      x |= a[i] ^ b[i];
    }
  
    return x;
  }
  
  uint32_t OPENSSL_hash32(const void *ptr, size_t len) {
    // These are the FNV-1a parameters for 32 bits.
    static const uint32_t kPrime = 16777619u;
    static const uint32_t kOffsetBasis = 2166136261u;
  
    const uint8_t *in = ptr;
    uint32_t h = kOffsetBasis;
  
    for (size_t i = 0; i < len; i++) {
      h ^= in[i];
      h *= kPrime;
    }
  
    return h;
  }
  
  uint32_t OPENSSL_strhash(const char *s) { return OPENSSL_hash32(s, strlen(s)); }
  
  size_t OPENSSL_strnlen(const char *s, size_t len) {
    for (size_t i = 0; i < len; i++) {
      if (s[i] == 0) {
        return i;
      }
    }
  
    return len;
  }
  
  char *OPENSSL_strdup(const char *s) {
    if (s == NULL) {
      return NULL;
    }
    const size_t len = strlen(s) + 1;
    char *ret = OPENSSL_malloc(len);
    if (ret == NULL) {
      return NULL;
    }
    OPENSSL_memcpy(ret, s, len);
    return ret;
  }
  
  int OPENSSL_tolower(int c) {
    if (c >= 'A' && c <= 'Z') {
      return c + ('a' - 'A');
    }
    return c;
  }
  
  int OPENSSL_strcasecmp(const char *a, const char *b) {
    for (size_t i = 0;; i++) {
      const int aa = OPENSSL_tolower(a[i]);
      const int bb = OPENSSL_tolower(b[i]);
  
      if (aa < bb) {
        return -1;
      } else if (aa > bb) {
        return 1;
      } else if (aa == 0) {
        return 0;
      }
    }
  }
  
  int OPENSSL_strncasecmp(const char *a, const char *b, size_t n) {
    for (size_t i = 0; i < n; i++) {
      const int aa = OPENSSL_tolower(a[i]);
      const int bb = OPENSSL_tolower(b[i]);
  
      if (aa < bb) {
        return -1;
      } else if (aa > bb) {
        return 1;
      } else if (aa == 0) {
        return 0;
      }
    }
  
    return 0;
  }
  
  int BIO_snprintf(char *buf, size_t n, const char *format, ...) {
    va_list args;
    va_start(args, format);
    int ret = BIO_vsnprintf(buf, n, format, args);
    va_end(args);
    return ret;
  }
  
  int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args) {
    return vsnprintf(buf, n, format, args);
  }
  
  char *OPENSSL_strndup(const char *str, size_t size) {
    size = OPENSSL_strnlen(str, size);
  
    size_t alloc_size = size + 1;
    if (alloc_size < size) {
      // overflow
      OPENSSL_PUT_ERROR(CRYPTO, ERR_R_MALLOC_FAILURE);
      return NULL;
    }
    char *ret = OPENSSL_malloc(alloc_size);
    if (ret == NULL) {
      OPENSSL_PUT_ERROR(CRYPTO, ERR_R_MALLOC_FAILURE);
      return NULL;
    }
  
    OPENSSL_memcpy(ret, str, size);
    ret[size] = '\0';
    return ret;
  }
  
  size_t OPENSSL_strlcpy(char *dst, const char *src, size_t dst_size) {
    size_t l = 0;
  
    for (; dst_size > 1 && *src; dst_size--) {
      *dst++ = *src++;
      l++;
    }
  
    if (dst_size) {
      *dst = 0;
    }
  
    return l + strlen(src);
  }
  
  size_t OPENSSL_strlcat(char *dst, const char *src, size_t dst_size) {
    size_t l = 0;
    for (; dst_size > 0 && *dst; dst_size--, dst++) {
      l++;
    }
    return l + OPENSSL_strlcpy(dst, src, dst_size);
  }
  
  void *OPENSSL_memdup(const void *data, size_t size) {
    if (size == 0) {
      return NULL;
    }
  
    void *ret = OPENSSL_malloc(size);
    if (ret == NULL) {
      OPENSSL_PUT_ERROR(CRYPTO, ERR_R_MALLOC_FAILURE);
      return NULL;
    }
  
    OPENSSL_memcpy(ret, data, size);
    return ret;
  }
  