IABSD.fr/src/lib/libssl/ssl_transcript.c

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• Author : jsing
  Date : 2020-02-05 16:47:34
  Hash : 3213f5ab
  Message : Provide tls1_transcript_unfreeze() to avoid the need for manual flags mangling. ok tb@

• lib/libssl/ssl_transcript.c

• /* $OpenBSD: ssl_transcript.c,v 1.2 2020/02/05 16:47:34 jsing Exp $ */
  /*
   * Copyright (c) 2017 Joel Sing <jsing@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include "ssl_locl.h"
  
  #include <openssl/ssl.h>
  
  int
  tls1_transcript_hash_init(SSL *s)
  {
  	const unsigned char *data;
  	const EVP_MD *md;
  	size_t len;
  
  	tls1_transcript_hash_free(s);
  
  	if (!ssl_get_handshake_evp_md(s, &md)) {
  		SSLerrorx(ERR_R_INTERNAL_ERROR);
  		goto err;
  	}
  
  	if ((S3I(s)->handshake_hash = EVP_MD_CTX_new()) == NULL) {
  		SSLerror(s, ERR_R_MALLOC_FAILURE);
  		goto err;
  	}
  	if (!EVP_DigestInit_ex(S3I(s)->handshake_hash, md, NULL)) {
  		SSLerror(s, ERR_R_EVP_LIB);
  		goto err;
  	}
  
  	if (!tls1_transcript_data(s, &data, &len)) {
  		SSLerror(s, SSL_R_BAD_HANDSHAKE_LENGTH);
  		goto err;
  	}
  	if (!tls1_transcript_hash_update(s, data, len)) {
  		SSLerror(s, ERR_R_EVP_LIB);
  		goto err;
  	}
  		
  	return 1;
  
   err:
  	tls1_transcript_hash_free(s);
  
  	return 0;
  }
  
  int
  tls1_transcript_hash_update(SSL *s, const unsigned char *buf, size_t len)
  {
  	if (S3I(s)->handshake_hash == NULL)
  		return 1;
  
  	return EVP_DigestUpdate(S3I(s)->handshake_hash, buf, len);
  }
  
  int
  tls1_transcript_hash_value(SSL *s, const unsigned char *out, size_t len,
      size_t *outlen)
  {
  	EVP_MD_CTX *mdctx = NULL;
  	unsigned int mdlen;
  	int ret = 0;
  
  	if (EVP_MD_CTX_size(S3I(s)->handshake_hash) > len)
  		goto err;
  
  	if ((mdctx = EVP_MD_CTX_new()) == NULL) {
  		SSLerror(s, ERR_R_MALLOC_FAILURE);
  		goto err;
  	}
  	if (!EVP_MD_CTX_copy_ex(mdctx, S3I(s)->handshake_hash)) {
  		SSLerror(s, ERR_R_EVP_LIB);
  		goto err;
  	}
  	if (!EVP_DigestFinal_ex(mdctx, (unsigned char *)out, &mdlen)) {
  		SSLerror(s, ERR_R_EVP_LIB);
  		goto err;
  	}
  	if (outlen != NULL)
  		*outlen = mdlen;
  
  	ret = 1;
  
   err:
  	EVP_MD_CTX_free(mdctx);
  
  	return (ret);
  }
  
  void
  tls1_transcript_hash_free(SSL *s)
  {
  	EVP_MD_CTX_free(S3I(s)->handshake_hash);
  	S3I(s)->handshake_hash = NULL;
  }
  
  int
  tls1_transcript_init(SSL *s)
  {
  	if (S3I(s)->handshake_transcript != NULL)
  		return 0;
  
  	if ((S3I(s)->handshake_transcript = BUF_MEM_new()) == NULL)
  		return 0;
  
  	tls1_transcript_reset(s);
  
  	return 1;
  }
  
  void
  tls1_transcript_free(SSL *s)
  {
  	BUF_MEM_free(S3I(s)->handshake_transcript);
  	S3I(s)->handshake_transcript = NULL;
  }
  
  void
  tls1_transcript_reset(SSL *s)
  {
  	/*
  	 * We should check the return value of BUF_MEM_grow_clean(), however
  	 * due to yet another bad API design, when called with a length of zero
  	 * it is impossible to tell if it succeeded (returning a length of zero)
  	 * or if it failed (and returned zero)... our implementation never
  	 * fails with a length of zero, so we trust all is okay...
  	 */ 
  	(void)BUF_MEM_grow_clean(S3I(s)->handshake_transcript, 0);
  
  	tls1_transcript_unfreeze(s);
  }
  
  int
  tls1_transcript_append(SSL *s, const unsigned char *buf, size_t len)
  {
  	size_t olen, nlen;
  
  	if (S3I(s)->handshake_transcript == NULL)
  		return 1;
  
  	if (s->s3->flags & TLS1_FLAGS_FREEZE_TRANSCRIPT)
  		return 1;
  
  	olen = S3I(s)->handshake_transcript->length;
  	nlen = olen + len;
  
  	if (nlen < olen)
  		return 0;
  
  	if (BUF_MEM_grow(S3I(s)->handshake_transcript, nlen) == 0)
  		return 0;
  
  	memcpy(S3I(s)->handshake_transcript->data + olen, buf, len);
  
  	return 1;
  }
  
  int
  tls1_transcript_data(SSL *s, const unsigned char **data, size_t *len)
  {
  	if (S3I(s)->handshake_transcript == NULL)
  		return 0;
  
  	*data = S3I(s)->handshake_transcript->data;
  	*len = S3I(s)->handshake_transcript->length;
  
  	return 1;
  }
  
  void
  tls1_transcript_freeze(SSL *s)
  {
  	s->s3->flags |= TLS1_FLAGS_FREEZE_TRANSCRIPT;
  }
  
  void
  tls1_transcript_unfreeze(SSL *s)
  {
  	s->s3->flags &= ~TLS1_FLAGS_FREEZE_TRANSCRIPT;
  }
  
  int
  tls1_transcript_record(SSL *s, const unsigned char *buf, size_t len)
  {
  	if (!tls1_transcript_hash_update(s, buf, len))
  		return 0;
  
  	if (!tls1_transcript_append(s, buf, len))
  		return 0;
  
  	return 1;
  }