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/bio.h>
  
  #include <assert.h>
  #include <errno.h>
  #include <limits.h>
  #include <string.h>
  
  #include <openssl/asn1.h>
  #include <openssl/err.h>
  #include <openssl/mem.h>
  #include <openssl/thread.h>
  
  #include "../internal.h"
  
  
  BIO *BIO_new(const BIO_METHOD *method) {
    BIO *ret = OPENSSL_malloc(sizeof(BIO));
    if (ret == NULL) {
      OPENSSL_PUT_ERROR(BIO, ERR_R_MALLOC_FAILURE);
      return NULL;
    }
  
    OPENSSL_memset(ret, 0, sizeof(BIO));
    ret->method = method;
    ret->shutdown = 1;
    ret->references = 1;
  
    if (method->create != NULL && !method->create(ret)) {
      OPENSSL_free(ret);
      return NULL;
    }
  
    return ret;
  }
  
  int BIO_free(BIO *bio) {
    BIO *next_bio;
  
    for (; bio != NULL; bio = next_bio) {
      if (!CRYPTO_refcount_dec_and_test_zero(&bio->references)) {
        return 0;
      }
  
      next_bio = BIO_pop(bio);
  
      if (bio->method != NULL && bio->method->destroy != NULL) {
        bio->method->destroy(bio);
      }
  
      OPENSSL_free(bio);
    }
    return 1;
  }
  
  int BIO_up_ref(BIO *bio) {
    CRYPTO_refcount_inc(&bio->references);
    return 1;
  }
  
  void BIO_vfree(BIO *bio) {
    BIO_free(bio);
  }
  
  void BIO_free_all(BIO *bio) {
    BIO_free(bio);
  }
  
  int BIO_read(BIO *bio, void *buf, int len) {
    if (bio == NULL || bio->method == NULL || bio->method->bread == NULL) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
      return -2;
    }
    if (!bio->init) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNINITIALIZED);
      return -2;
    }
    if (len <= 0) {
      return 0;
    }
    int ret = bio->method->bread(bio, buf, len);
    if (ret > 0) {
      bio->num_read += ret;
    }
    return ret;
  }
  
  int BIO_gets(BIO *bio, char *buf, int len) {
    if (bio == NULL || bio->method == NULL || bio->method->bgets == NULL) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
      return -2;
    }
    if (!bio->init) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNINITIALIZED);
      return -2;
    }
    if (len <= 0) {
      return 0;
    }
    int ret = bio->method->bgets(bio, buf, len);
    if (ret > 0) {
      bio->num_read += ret;
    }
    return ret;
  }
  
  int BIO_write(BIO *bio, const void *in, int inl) {
    if (bio == NULL || bio->method == NULL || bio->method->bwrite == NULL) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
      return -2;
    }
    if (!bio->init) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNINITIALIZED);
      return -2;
    }
    if (inl <= 0) {
      return 0;
    }
    int ret = bio->method->bwrite(bio, in, inl);
    if (ret > 0) {
      bio->num_write += ret;
    }
    return ret;
  }
  
  int BIO_write_all(BIO *bio, const void *data, size_t len) {
    const uint8_t *data_u8 = data;
    while (len > 0) {
      int ret = BIO_write(bio, data_u8, len > INT_MAX ? INT_MAX : (int)len);
      if (ret <= 0) {
        return 0;
      }
      data_u8 += ret;
      len -= ret;
    }
    return 1;
  }
  
  int BIO_puts(BIO *bio, const char *in) {
    return BIO_write(bio, in, strlen(in));
  }
  
  int BIO_flush(BIO *bio) {
    return BIO_ctrl(bio, BIO_CTRL_FLUSH, 0, NULL);
  }
  
  long BIO_ctrl(BIO *bio, int cmd, long larg, void *parg) {
    if (bio == NULL) {
      return 0;
    }
  
    if (bio->method == NULL || bio->method->ctrl == NULL) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
      return -2;
    }
  
    return bio->method->ctrl(bio, cmd, larg, parg);
  }
  
  char *BIO_ptr_ctrl(BIO *b, int cmd, long larg) {
    char *p = NULL;
  
    if (BIO_ctrl(b, cmd, larg, (void *)&p) <= 0) {
      return NULL;
    }
  
    return p;
  }
  
  long BIO_int_ctrl(BIO *b, int cmd, long larg, int iarg) {
    int i = iarg;
  
    return BIO_ctrl(b, cmd, larg, (void *)&i);
  }
  
  int BIO_reset(BIO *bio) {
    return BIO_ctrl(bio, BIO_CTRL_RESET, 0, NULL);
  }
  
  int BIO_eof(BIO *bio) {
    return BIO_ctrl(bio, BIO_CTRL_EOF, 0, NULL);
  }
  
  void BIO_set_flags(BIO *bio, int flags) {
    bio->flags |= flags;
  }
  
  int BIO_test_flags(const BIO *bio, int flags) {
    return bio->flags & flags;
  }
  
  int BIO_should_read(const BIO *bio) {
    return BIO_test_flags(bio, BIO_FLAGS_READ);
  }
  
  int BIO_should_write(const BIO *bio) {
    return BIO_test_flags(bio, BIO_FLAGS_WRITE);
  }
  
  int BIO_should_retry(const BIO *bio) {
    return BIO_test_flags(bio, BIO_FLAGS_SHOULD_RETRY);
  }
  
  int BIO_should_io_special(const BIO *bio) {
    return BIO_test_flags(bio, BIO_FLAGS_IO_SPECIAL);
  }
  
  int BIO_get_retry_reason(const BIO *bio) { return bio->retry_reason; }
  
  void BIO_set_retry_reason(BIO *bio, int reason) { bio->retry_reason = reason; }
  
  void BIO_clear_flags(BIO *bio, int flags) {
    bio->flags &= ~flags;
  }
  
  void BIO_set_retry_read(BIO *bio) {
    bio->flags |= BIO_FLAGS_READ | BIO_FLAGS_SHOULD_RETRY;
  }
  
  void BIO_set_retry_write(BIO *bio) {
    bio->flags |= BIO_FLAGS_WRITE | BIO_FLAGS_SHOULD_RETRY;
  }
  
  static const int kRetryFlags = BIO_FLAGS_RWS | BIO_FLAGS_SHOULD_RETRY;
  
  int BIO_get_retry_flags(BIO *bio) {
    return bio->flags & kRetryFlags;
  }
  
  void BIO_clear_retry_flags(BIO *bio) {
    bio->flags &= ~kRetryFlags;
    bio->retry_reason = 0;
  }
  
  int BIO_method_type(const BIO *bio) { return bio->method->type; }
  
  void BIO_copy_next_retry(BIO *bio) {
    BIO_clear_retry_flags(bio);
    BIO_set_flags(bio, BIO_get_retry_flags(bio->next_bio));
    bio->retry_reason = bio->next_bio->retry_reason;
  }
  
  long BIO_callback_ctrl(BIO *bio, int cmd, bio_info_cb fp) {
    if (bio == NULL) {
      return 0;
    }
  
    if (bio->method == NULL || bio->method->callback_ctrl == NULL) {
      OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
      return 0;
    }
  
    return bio->method->callback_ctrl(bio, cmd, fp);
  }
  
  size_t BIO_pending(const BIO *bio) {
    const long r = BIO_ctrl((BIO *) bio, BIO_CTRL_PENDING, 0, NULL);
    assert(r >= 0);
  
    if (r < 0) {
      return 0;
    }
    return r;
  }
  
  size_t BIO_ctrl_pending(const BIO *bio) {
    return BIO_pending(bio);
  }
  
  size_t BIO_wpending(const BIO *bio) {
    const long r = BIO_ctrl((BIO *) bio, BIO_CTRL_WPENDING, 0, NULL);
    assert(r >= 0);
  
    if (r < 0) {
      return 0;
    }
    return r;
  }
  
  int BIO_set_close(BIO *bio, int close_flag) {
    return BIO_ctrl(bio, BIO_CTRL_SET_CLOSE, close_flag, NULL);
  }
  
  OPENSSL_EXPORT size_t BIO_number_read(const BIO *bio) {
    return bio->num_read;
  }
  
  OPENSSL_EXPORT size_t BIO_number_written(const BIO *bio) {
    return bio->num_write;
  }
  
  BIO *BIO_push(BIO *bio, BIO *appended_bio) {
    BIO *last_bio;
  
    if (bio == NULL) {
      return bio;
    }
  
    last_bio = bio;
    while (last_bio->next_bio != NULL) {
      last_bio = last_bio->next_bio;
    }
  
    last_bio->next_bio = appended_bio;
    return bio;
  }
  
  BIO *BIO_pop(BIO *bio) {
    BIO *ret;
  
    if (bio == NULL) {
      return NULL;
    }
    ret = bio->next_bio;
    bio->next_bio = NULL;
    return ret;
  }
  
  BIO *BIO_next(BIO *bio) {
    if (!bio) {
      return NULL;
    }
    return bio->next_bio;
  }
  
  BIO *BIO_find_type(BIO *bio, int type) {
    int method_type, mask;
  
    if (!bio) {
      return NULL;
    }
    mask = type & 0xff;
  
    do {
      if (bio->method != NULL) {
        method_type = bio->method->type;
  
        if (!mask) {
          if (method_type & type) {
            return bio;
          }
        } else if (method_type == type) {
          return bio;
        }
      }
      bio = bio->next_bio;
    } while (bio != NULL);
  
    return NULL;
  }
  
  int BIO_indent(BIO *bio, unsigned indent, unsigned max_indent) {
    if (indent > max_indent) {
      indent = max_indent;
    }
  
    while (indent--) {
      if (BIO_puts(bio, " ") != 1) {
        return 0;
      }
    }
    return 1;
  }
  
  static int print_bio(const char *str, size_t len, void *bio) {
    return BIO_write((BIO *)bio, str, len);
  }
  
  void ERR_print_errors(BIO *bio) {
    ERR_print_errors_cb(print_bio, bio);
  }
  
  // bio_read_all reads everything from |bio| and prepends |prefix| to it. On
  // success, |*out| is set to an allocated buffer (which should be freed with
  // |OPENSSL_free|), |*out_len| is set to its length and one is returned. The
  // buffer will contain |prefix| followed by the contents of |bio|. On failure,
  // zero is returned.
  //
  // The function will fail if the size of the output would equal or exceed
  // |max_len|.
  static int bio_read_all(BIO *bio, uint8_t **out, size_t *out_len,
                          const uint8_t *prefix, size_t prefix_len,
                          size_t max_len) {
    static const size_t kChunkSize = 4096;
  
    size_t len = prefix_len + kChunkSize;
    if (len > max_len) {
      len = max_len;
    }
    if (len < prefix_len) {
      return 0;
    }
    *out = OPENSSL_malloc(len);
    if (*out == NULL) {
      return 0;
    }
    OPENSSL_memcpy(*out, prefix, prefix_len);
    size_t done = prefix_len;
  
    for (;;) {
      if (done == len) {
        OPENSSL_free(*out);
        return 0;
      }
      const size_t todo = len - done;
      assert(todo < INT_MAX);
      const int n = BIO_read(bio, *out + done, todo);
      if (n == 0) {
        *out_len = done;
        return 1;
      } else if (n == -1) {
        OPENSSL_free(*out);
        return 0;
      }
  
      done += n;
      if (len < max_len && len - done < kChunkSize / 2) {
        len += kChunkSize;
        if (len < kChunkSize || len > max_len) {
          len = max_len;
        }
        uint8_t *new_buf = OPENSSL_realloc(*out, len);
        if (new_buf == NULL) {
          OPENSSL_free(*out);
          return 0;
        }
        *out = new_buf;
      }
    }
  }
  
  // bio_read_full reads |len| bytes |bio| and writes them into |out|. It
  // tolerates partial reads from |bio| and returns one on success or zero if a
  // read fails before |len| bytes are read. On failure, it additionally sets
  // |*out_eof_on_first_read| to whether the error was due to |bio| returning zero
  // on the first read. |out_eof_on_first_read| may be NULL to discard the value.
  static int bio_read_full(BIO *bio, uint8_t *out, int *out_eof_on_first_read,
                           size_t len) {
    int first_read = 1;
    while (len > 0) {
      int todo = len <= INT_MAX ? (int)len : INT_MAX;
      int ret = BIO_read(bio, out, todo);
      if (ret <= 0) {
        if (out_eof_on_first_read != NULL) {
          *out_eof_on_first_read = first_read && ret == 0;
        }
        return 0;
      }
      out += ret;
      len -= (size_t)ret;
      first_read = 0;
    }
  
    return 1;
  }
  
  // For compatibility with existing |d2i_*_bio| callers, |BIO_read_asn1| uses
  // |ERR_LIB_ASN1| errors.
  OPENSSL_DECLARE_ERROR_REASON(ASN1, ASN1_R_DECODE_ERROR)
  OPENSSL_DECLARE_ERROR_REASON(ASN1, ASN1_R_HEADER_TOO_LONG)
  OPENSSL_DECLARE_ERROR_REASON(ASN1, ASN1_R_NOT_ENOUGH_DATA)
  OPENSSL_DECLARE_ERROR_REASON(ASN1, ASN1_R_TOO_LONG)
  
  int BIO_read_asn1(BIO *bio, uint8_t **out, size_t *out_len, size_t max_len) {
    uint8_t header[6];
  
    static const size_t kInitialHeaderLen = 2;
    int eof_on_first_read;
    if (!bio_read_full(bio, header, &eof_on_first_read, kInitialHeaderLen)) {
      if (eof_on_first_read) {
        // Historically, OpenSSL returned |ASN1_R_HEADER_TOO_LONG| when
        // |d2i_*_bio| could not read anything. CPython conditions on this to
        // determine if |bio| was empty.
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_HEADER_TOO_LONG);
      } else {
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
      }
      return 0;
    }
  
    const uint8_t tag = header[0];
    const uint8_t length_byte = header[1];
  
    if ((tag & 0x1f) == 0x1f) {
      // Long form tags are not supported.
      OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);
      return 0;
    }
  
    size_t len, header_len;
    if ((length_byte & 0x80) == 0) {
      // Short form length.
      len = length_byte;
      header_len = kInitialHeaderLen;
    } else {
      const size_t num_bytes = length_byte & 0x7f;
  
      if ((tag & 0x20 /* constructed */) != 0 && num_bytes == 0) {
        // indefinite length.
        if (!bio_read_all(bio, out, out_len, header, kInitialHeaderLen,
                          max_len)) {
          OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
          return 0;
        }
        return 1;
      }
  
      if (num_bytes == 0 || num_bytes > 4) {
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);
        return 0;
      }
  
      if (!bio_read_full(bio, header + kInitialHeaderLen, NULL, num_bytes)) {
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
        return 0;
      }
      header_len = kInitialHeaderLen + num_bytes;
  
      uint32_t len32 = 0;
      for (unsigned i = 0; i < num_bytes; i++) {
        len32 <<= 8;
        len32 |= header[kInitialHeaderLen + i];
      }
  
      if (len32 < 128) {
        // Length should have used short-form encoding.
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);
        return 0;
      }
  
      if ((len32 >> ((num_bytes-1)*8)) == 0) {
        // Length should have been at least one byte shorter.
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_DECODE_ERROR);
        return 0;
      }
  
      len = len32;
    }
  
    if (len + header_len < len ||
        len + header_len > max_len ||
        len > INT_MAX) {
      OPENSSL_PUT_ERROR(ASN1, ASN1_R_TOO_LONG);
      return 0;
    }
    len += header_len;
    *out_len = len;
  
    *out = OPENSSL_malloc(len);
    if (*out == NULL) {
      OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
      return 0;
    }
    OPENSSL_memcpy(*out, header, header_len);
    if (!bio_read_full(bio, (*out) + header_len, NULL, len - header_len)) {
      OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
      OPENSSL_free(*out);
      return 0;
    }
  
    return 1;
  }
  
  void BIO_set_retry_special(BIO *bio) {
    bio->flags |= BIO_FLAGS_READ | BIO_FLAGS_IO_SPECIAL;
  }
  
  int BIO_set_write_buffer_size(BIO *bio, int buffer_size) { return 0; }
  
  static struct CRYPTO_STATIC_MUTEX g_index_lock = CRYPTO_STATIC_MUTEX_INIT;
  static int g_index = BIO_TYPE_START;
  
  int BIO_get_new_index(void) {
    CRYPTO_STATIC_MUTEX_lock_write(&g_index_lock);
    // If |g_index| exceeds 255, it will collide with the flags bits.
    int ret = g_index > 255 ? -1 : g_index++;
    CRYPTO_STATIC_MUTEX_unlock_write(&g_index_lock);
    return ret;
  }
  
  BIO_METHOD *BIO_meth_new(int type, const char *name) {
    BIO_METHOD *method = OPENSSL_malloc(sizeof(BIO_METHOD));
    if (method == NULL) {
      return NULL;
    }
    OPENSSL_memset(method, 0, sizeof(BIO_METHOD));
    method->type = type;
    method->name = name;
    return method;
  }
  
  void BIO_meth_free(BIO_METHOD *method) {
    OPENSSL_free(method);
  }
  
  int BIO_meth_set_create(BIO_METHOD *method,
                          int (*create)(BIO *)) {
    method->create = create;
    return 1;
  }
  
  int (*BIO_meth_get_create(const BIO_METHOD *method)) (BIO *) {
    return method->create;
  }
  
  int BIO_meth_set_destroy(BIO_METHOD *method,
                           int (*destroy)(BIO *)) {
    method->destroy = destroy;
    return 1;
  }
  
  int (*BIO_meth_get_destroy(const BIO_METHOD *method)) (BIO *) {
    return method->destroy;
  }
  
  int BIO_meth_set_write(BIO_METHOD *method,
                         int (*write)(BIO *, const char *, int)) {
    method->bwrite = write;
    return 1;
  }
  
  int BIO_meth_set_read(BIO_METHOD *method,
                        int (*read)(BIO *, char *, int)) {
    method->bread = read;
    return 1;
  }
  
  int BIO_meth_set_gets(BIO_METHOD *method,
                        int (*gets)(BIO *, char *, int)) {
    method->bgets = gets;
    return 1;
  }
  
  int (*BIO_meth_get_gets(const BIO_METHOD *method)) (BIO *, char *, int) {
    return method->bgets;
  }
  
  int BIO_meth_set_ctrl(BIO_METHOD *method,
                        long (*ctrl)(BIO *, int, long, void *)) {
    method->ctrl = ctrl;
    return 1;
  }
  
  long (*BIO_meth_get_ctrl(const BIO_METHOD *method)) (BIO *, int, long, void *) {
    return method->ctrl;
  }
  
  int BIO_meth_set_callback_ctrl(BIO_METHOD *method,
                                 long (*callback_ctrl)(BIO *, int, bio_info_cb)) {
    method->callback_ctrl = callback_ctrl;
    return 1;
  }
  
  long (*BIO_meth_get_callback_ctrl(const BIO_METHOD *method)) (BIO *, int, bio_info_cb) {
    return method->callback_ctrl;
  }
  
  void BIO_set_data(BIO *bio, void *ptr) { bio->ptr = ptr; }
  
  void *BIO_get_data(BIO *bio) { return bio->ptr; }
  
  void BIO_set_init(BIO *bio, int init) { bio->init = init; }
  
  int BIO_get_init(BIO *bio) { return bio->init; }
  
  void BIO_set_shutdown(BIO *bio, int shutdown) { bio->shutdown = shutdown; }
  
  int BIO_get_shutdown(BIO *bio) { return bio->shutdown; }
  
  int BIO_meth_set_puts(BIO_METHOD *method, int (*puts)(BIO *, const char *)) {
    // Ignore the parameter. We implement |BIO_puts| using |BIO_write|.
    return 1;
  }
  
  int (*BIO_meth_get_puts(const BIO_METHOD *method)) (BIO *, const char *) {
    return method->bputs;
  }
  