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Merge support for Encrypt-then-MAC

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This commit is contained in:
Paul Bakker 2015-01-13 14:23:56 +01:00
commit d9e2dd2bb0
10 changed files with 544 additions and 37 deletions
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3
ChangeLog
View file

@ -2,11 +2,12 @@ PolarSSL ChangeLog (Sorted per branch, date)
= 1.3 branch
Reminder: bump SONAME for ABI change (FALLBACK_SCSV, session-hash)
Reminder: bump SONAME for ABI change (FALLBACK_SCSV, session-hash, EtM)
Features
* Add support for FALLBACK_SCSV (draft-ietf-tls-downgrade-scsv)
* Add support for Extended Master Secret (draft-ietf-tls-session-hash)
* Add support for Encrypt-then-MAC (RFC 7366)
= PolarSSL 1.3.9 released 2014-10-20
Security

7
include/polarssl/check_config.h
View file

@ -257,6 +257,13 @@
#error "Illegal protocol selection"
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC) && \
!defined(POLARSSL_SSL_PROTO_TLS1) && \
!defined(POLARSSL_SSL_PROTO_TLS1_1) && \
!defined(POLARSSL_SSL_PROTO_TLS1_2)
#error "POLARSSL_SSL_ENCRYPT_THEN_MAC defined, but not all prerequsites"
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET) && \
!defined(POLARSSL_SSL_PROTO_TLS1) && \
!defined(POLARSSL_SSL_PROTO_TLS1_1) && \

18
include/polarssl/config.h
View file

@ -811,6 +811,24 @@
*/
//#define POLARSSL_SSL_DEBUG_ALL
/** \def POLARSSL_SSL_ENCRYPT_THEN_MAC
*
* Enable support for Encrypt-then-MAC, RFC 7366.
*
* This allows peers that both support it to use a more robust protection for
* ciphersuites using CBC, providing deep resistance against timing attacks
* on the padding or underlying cipher.
*
* This only affects CBC ciphersuites, and is useless if none is defined.
*
* Requires: POLARSSL_SSL_PROTO_TLS1 or
* POLARSSL_SSL_PROTO_TLS1_1 or
* POLARSSL_SSL_PROTO_TLS1_2
*
* Comment this macro to disable support for Encrypt-then-MAC
*/
#define POLARSSL_SSL_ENCRYPT_THEN_MAC
/** \def POLARSSL_SSL_EXTENDED_MASTER_SECRET
*
* Enable support for Extended Master Secret, aka Session Hash

26
include/polarssl/ssl.h
View file

@ -212,6 +212,9 @@
#define SSL_EXTENDED_MS_DISABLED 0
#define SSL_EXTENDED_MS_ENABLED 1
#define SSL_ETM_DISABLED 0
#define SSL_ETM_ENABLED 1
#define SSL_COMPRESS_NULL 0
#define SSL_COMPRESS_DEFLATE 1
@ -409,6 +412,7 @@
#define TLS_EXT_ALPN 16
#define TLS_EXT_ENCRYPT_THEN_MAC 22 /* 0x16 */
#define TLS_EXT_EXTENDED_MASTER_SECRET 0x0017 /* 23 */
#define TLS_EXT_SESSION_TICKET 35
@ -548,6 +552,10 @@ struct _ssl_session
#if defined(POLARSSL_SSL_TRUNCATED_HMAC)
int trunc_hmac; /*!< flag for truncated hmac activation */
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
int encrypt_then_mac; /*!< flag for EtM activation */
#endif
};
/*
@ -713,6 +721,9 @@ struct _ssl_context
#if defined(POLARSSL_SSL_FALLBACK_SCSV) && defined(POLARSSL_SSL_CLI_C)
char fallback; /*!< flag for fallback connections */
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
char encrypt_then_mac; /*!< flag for encrypt-then-mac */
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
char extended_ms; /*!< flag for extended master secret */
#endif
@ -1425,6 +1436,21 @@ void ssl_set_min_version( ssl_context *ssl, int major, int minor );
void ssl_set_fallback( ssl_context *ssl, char fallback );
#endif /* POLARSSL_SSL_FALLBACK_SCSV && POLARSSL_SSL_CLI_C */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
/**
* \brief Enable or disable Encrypt-then-MAC
* (Default: SSL_ETM_ENABLED)
*
* \note This should always be enabled, it is a security
* improvement, and should not cause any interoperability
* issue (used only if the peer supports it too).
*
* \param ssl SSL context
* \param etm SSL_ETM_ENABLED or SSL_ETM_DISABLED
*/
void ssl_set_encrypt_then_mac( ssl_context *ssl, char etm );
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
/**
* \brief Enable or disable Extended Master Secret negotiation.

64
library/ssl_cli.c
View file

@ -359,6 +359,32 @@ static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
{
unsigned char *p = buf;
if( ssl->encrypt_then_mac == SSL_ETM_DISABLED ||
ssl->max_minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "client hello, adding encrypt_then_mac "
"extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( ssl_context *ssl,
unsigned char *buf, size_t *olen )
@ -688,6 +714,11 @@ static int ssl_write_client_hello( ssl_context *ssl )
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
@ -811,6 +842,26 @@ static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( ssl->encrypt_then_mac == SSL_ETM_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 ||
len != 0 )
{
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
}
((void) buf);
ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED;
return( 0 );
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_ext( ssl_context *ssl,
const unsigned char *buf,
@ -1203,6 +1254,19 @@ static int ssl_parse_server_hello( ssl_context *ssl )
break;
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
case TLS_EXT_ENCRYPT_THEN_MAC:
SSL_DEBUG_MSG( 3, ( "found encrypt_then_mac extension" ) );
if( ( ret = ssl_parse_encrypt_then_mac_ext( ssl,
ext + 4, ext_size ) ) != 0 )
{
return( ret );
}
break;
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
case TLS_EXT_EXTENDED_MASTER_SECRET:
SSL_DEBUG_MSG( 3, ( "found extended_master_secret extension" ) );

81
library/ssl_srv.c
View file

@ -635,6 +635,29 @@ static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( ssl_context *ssl,
const unsigned char *buf,
size_t len )
{
if( len != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
((void) buf);
if( ssl->encrypt_then_mac == SSL_ETM_ENABLED &&
ssl->minor_ver != SSL_MINOR_VERSION_0 )
{
ssl->session_negotiate->encrypt_then_mac = SSL_ETM_ENABLED;
}
return( 0 );
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static int ssl_parse_extended_ms_ext( ssl_context *ssl,
const unsigned char *buf,
@ -1523,6 +1546,16 @@ static int ssl_parse_client_hello( ssl_context *ssl )
break;
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
case TLS_EXT_ENCRYPT_THEN_MAC:
SSL_DEBUG_MSG( 3, ( "found encrypt then mac extension" ) );
ret = ssl_parse_encrypt_then_mac_ext( ssl, ext + 4, ext_size );
if( ret != 0 )
return( ret );
break;
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
case TLS_EXT_EXTENDED_MASTER_SECRET:
SSL_DEBUG_MSG( 3, ( "found extended master secret extension" ) );
@ -1682,6 +1715,49 @@ static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
static void ssl_write_encrypt_then_mac_ext( ssl_context *ssl,
unsigned char *buf,
size_t *olen )
{
unsigned char *p = buf;
const ssl_ciphersuite_t *suite = NULL;
const cipher_info_t *cipher = NULL;
if( ssl->session_negotiate->encrypt_then_mac == SSL_EXTENDED_MS_DISABLED ||
ssl->minor_ver == SSL_MINOR_VERSION_0 )
{
*olen = 0;
return;
}
/*
* RFC 7366: "If a server receives an encrypt-then-MAC request extension
* from a client and then selects a stream or Authenticated Encryption
* with Associated Data (AEAD) ciphersuite, it MUST NOT send an
* encrypt-then-MAC response extension back to the client."
*/
if( ( suite = ssl_ciphersuite_from_id(
ssl->session_negotiate->ciphersuite ) ) == NULL ||
( cipher = cipher_info_from_type( suite->cipher ) ) == NULL ||
cipher->mode != POLARSSL_MODE_CBC )
{
*olen = 0;
return;
}
SSL_DEBUG_MSG( 3, ( "server hello, adding encrypt then mac extension" ) );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( TLS_EXT_ENCRYPT_THEN_MAC ) & 0xFF );
*p++ = 0x00;
*p++ = 0x00;
*olen = 4;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
static void ssl_write_extended_ms_ext( ssl_context *ssl,
unsigned char *buf,
@ -2012,6 +2088,11 @@ static int ssl_write_server_hello( ssl_context *ssl )
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl_write_encrypt_then_mac_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
ext_len += olen;

221
library/ssl_tls.c
View file

@ -601,12 +601,23 @@ int ssl_derive_keys( ssl_context *ssl )
{
/*
* GenericBlockCipher:
* first multiple of blocklen greater than maclen
* + IV except for SSL3 and TLS 1.0
* 1. if EtM is in use: one block plus MAC
* otherwise: * first multiple of blocklen greater than maclen
* 2. IV except for SSL3 and TLS 1.0
*/
transform->minlen = transform->maclen
+ cipher_info->block_size
- transform->maclen % cipher_info->block_size;
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( session->encrypt_then_mac == SSL_ETM_ENABLED )
{
transform->minlen = transform->maclen
+ cipher_info->block_size;
}
else
#endif
{
transform->minlen = transform->maclen
+ cipher_info->block_size
- transform->maclen % cipher_info->block_size;
}
#if defined(POLARSSL_SSL_PROTO_SSL3) || defined(POLARSSL_SSL_PROTO_TLS1)
if( ssl->minor_ver == SSL_MINOR_VERSION_0 ||
@ -1060,25 +1071,41 @@ static void ssl_mac( md_context_t *md_ctx, unsigned char *secret,
}
#endif /* POLARSSL_SSL_PROTO_SSL3 */
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) || \
( defined(POLARSSL_CIPHER_MODE_CBC) && \
( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
#define POLARSSL_SOME_MODES_USE_MAC
#endif
/*
* Encryption/decryption functions
*/
static int ssl_encrypt_buf( ssl_context *ssl )
{
size_t i;
const cipher_mode_t mode = cipher_get_cipher_mode(
&ssl->transform_out->cipher_ctx_enc );
cipher_mode_t mode;
int auth_done = 0;
SSL_DEBUG_MSG( 2, ( "=> encrypt buf" ) );
if( ssl->session_out == NULL || ssl->transform_out == NULL )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
mode = cipher_get_cipher_mode( &ssl->transform_out->cipher_ctx_enc );
/*
* Add MAC before encrypt, except for AEAD modes
* Add MAC before if needed
*/
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) || \
( defined(POLARSSL_CIPHER_MODE_CBC) && \
( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
if( mode != POLARSSL_MODE_GCM &&
mode != POLARSSL_MODE_CCM )
#if defined(POLARSSL_SOME_MODES_USE_MAC)
if( mode == POLARSSL_MODE_STREAM ||
( mode == POLARSSL_MODE_CBC
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
&& ssl->session_out->encrypt_then_mac == SSL_ETM_DISABLED
#endif
) )
{
#if defined(POLARSSL_SSL_PROTO_SSL3)
if( ssl->minor_ver == SSL_MINOR_VERSION_0 )
@ -1113,6 +1140,7 @@ static int ssl_encrypt_buf( ssl_context *ssl )
ssl->transform_out->maclen );
ssl->out_msglen += ssl->transform_out->maclen;
auth_done++;
}
#endif /* AEAD not the only option */
@ -1224,6 +1252,7 @@ static int ssl_encrypt_buf( ssl_context *ssl )
}
ssl->out_msglen += taglen;
auth_done++;
SSL_DEBUG_BUF( 4, "after encrypt: tag", enc_msg + enc_msglen, taglen );
}
@ -1312,6 +1341,40 @@ static int ssl_encrypt_buf( ssl_context *ssl )
ssl->transform_out->ivlen );
}
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( auth_done == 0 )
{
/*
* MAC(MAC_write_key, seq_num +
* TLSCipherText.type +
* TLSCipherText.version +
* length_of( (IV +) ENC(...) ) +
* IV + // except for TLS 1.0
* ENC(content + padding + padding_length));
*/
unsigned char pseudo_hdr[13];
SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) );
memcpy( pseudo_hdr + 0, ssl->out_ctr, 8 );
memcpy( pseudo_hdr + 8, ssl->out_hdr, 3 );
pseudo_hdr[11] = (unsigned char)( ( ssl->out_msglen >> 8 ) & 0xFF );
pseudo_hdr[12] = (unsigned char)( ( ssl->out_msglen ) & 0xFF );
SSL_DEBUG_BUF( 4, "MAC'd meta-data", pseudo_hdr, 13 );
md_hmac_update( &ssl->transform_out->md_ctx_enc, pseudo_hdr, 13 );
md_hmac_update( &ssl->transform_out->md_ctx_enc,
ssl->out_iv, ssl->out_msglen );
md_hmac_finish( &ssl->transform_out->md_ctx_enc,
ssl->out_iv + ssl->out_msglen );
md_hmac_reset( &ssl->transform_out->md_ctx_enc );
ssl->out_msglen += ssl->transform_out->maclen;
auth_done++;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
}
else
#endif /* POLARSSL_CIPHER_MODE_CBC &&
@ -1321,6 +1384,13 @@ static int ssl_encrypt_buf( ssl_context *ssl )
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
/* Make extra sure authentication was performed, exactly once */
if( auth_done != 1 )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
for( i = 8; i > 0; i-- )
if( ++ssl->out_ctr[i - 1] != 0 )
break;
@ -1342,16 +1412,22 @@ static int ssl_encrypt_buf( ssl_context *ssl )
static int ssl_decrypt_buf( ssl_context *ssl )
{
size_t i;
const cipher_mode_t mode = cipher_get_cipher_mode(
&ssl->transform_in->cipher_ctx_dec );
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) || \
( defined(POLARSSL_CIPHER_MODE_CBC) && \
( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
cipher_mode_t mode;
int auth_done = 0;
#if defined(POLARSSL_SOME_MODES_USE_MAC)
size_t padlen = 0, correct = 1;
#endif
SSL_DEBUG_MSG( 2, ( "=> decrypt buf" ) );
if( ssl->session_in == NULL || ssl->transform_in == NULL )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
mode = cipher_get_cipher_mode( &ssl->transform_in->cipher_ctx_dec );
if( ssl->in_msglen < ssl->transform_in->minlen )
{
SSL_DEBUG_MSG( 1, ( "in_msglen (%d) < minlen (%d)",
@ -1448,6 +1524,7 @@ static int ssl_decrypt_buf( ssl_context *ssl )
return( ret );
}
auth_done++;
if( olen != dec_msglen )
{
@ -1474,13 +1551,6 @@ static int ssl_decrypt_buf( ssl_context *ssl )
/*
* Check immediate ciphertext sanity
*/
if( ssl->in_msglen % ssl->transform_in->ivlen != 0 )
{
SSL_DEBUG_MSG( 1, ( "msglen (%d) %% ivlen (%d) != 0",
ssl->in_msglen, ssl->transform_in->ivlen ) );
return( POLARSSL_ERR_SSL_INVALID_MAC );
}
#if defined(POLARSSL_SSL_PROTO_TLS1_1) || defined(POLARSSL_SSL_PROTO_TLS1_2)
if( ssl->minor_ver >= SSL_MINOR_VERSION_2 )
minlen += ssl->transform_in->ivlen;
@ -1500,6 +1570,59 @@ static int ssl_decrypt_buf( ssl_context *ssl )
dec_msg = ssl->in_msg;
dec_msg_result = ssl->in_msg;
/*
* Authenticate before decrypt if enabled
*/
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( ssl->session_in->encrypt_then_mac == SSL_ETM_ENABLED )
{
unsigned char computed_mac[POLARSSL_SSL_MAX_MAC_SIZE];
unsigned char pseudo_hdr[13];
SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) );
dec_msglen -= ssl->transform_in->maclen;
ssl->in_msglen -= ssl->transform_in->maclen;
memcpy( pseudo_hdr + 0, ssl->in_ctr, 8 );
memcpy( pseudo_hdr + 8, ssl->in_hdr, 3 );
pseudo_hdr[11] = (unsigned char)( ( ssl->in_msglen >> 8 ) & 0xFF );
pseudo_hdr[12] = (unsigned char)( ( ssl->in_msglen ) & 0xFF );
SSL_DEBUG_BUF( 4, "MAC'd meta-data", pseudo_hdr, 13 );
md_hmac_update( &ssl->transform_in->md_ctx_dec, pseudo_hdr, 13 );
md_hmac_update( &ssl->transform_in->md_ctx_dec,
ssl->in_iv, ssl->in_msglen );
md_hmac_finish( &ssl->transform_in->md_ctx_dec, computed_mac );
md_hmac_reset( &ssl->transform_in->md_ctx_dec );
SSL_DEBUG_BUF( 4, "message mac", ssl->in_iv + ssl->in_msglen,
ssl->transform_in->maclen );
SSL_DEBUG_BUF( 4, "computed mac", computed_mac,
ssl->transform_in->maclen );
if( safer_memcmp( ssl->in_iv + ssl->in_msglen, computed_mac,
ssl->transform_in->maclen ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "message mac does not match" ) );
return( POLARSSL_ERR_SSL_INVALID_MAC );
}
auth_done++;
}
#endif /* POLARSSL_SSL_ENCRYPT_THEN_MAC */
/*
* Check length sanity
*/
if( ssl->in_msglen % ssl->transform_in->ivlen != 0 )
{
SSL_DEBUG_MSG( 1, ( "msglen (%d) %% ivlen (%d) != 0",
ssl->in_msglen, ssl->transform_in->ivlen ) );
return( POLARSSL_ERR_SSL_INVALID_MAC );
}
#if defined(POLARSSL_SSL_PROTO_TLS1_1) || defined(POLARSSL_SSL_PROTO_TLS1_2)
/*
* Initialize for prepended IV for block cipher in TLS v1.1 and up
@ -1544,7 +1667,8 @@ static int ssl_decrypt_buf( ssl_context *ssl )
padlen = 1 + ssl->in_msg[ssl->in_msglen - 1];
if( ssl->in_msglen < ssl->transform_in->maclen + padlen )
if( ssl->in_msglen < ssl->transform_in->maclen + padlen &&
auth_done == 0 )
{
#if defined(POLARSSL_SSL_DEBUG_ALL)
SSL_DEBUG_MSG( 1, ( "msglen (%d) < maclen (%d) + padlen (%d)",
@ -1618,6 +1742,8 @@ static int ssl_decrypt_buf( ssl_context *ssl )
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
ssl->in_msglen -= padlen;
}
else
#endif /* POLARSSL_CIPHER_MODE_CBC &&
@ -1631,17 +1757,15 @@ static int ssl_decrypt_buf( ssl_context *ssl )
ssl->in_msg, ssl->in_msglen );
/*
* Always compute the MAC (RFC4346, CBCTIME), except for AEAD of course
* Authenticate if not done yet.
* Compute the MAC regardless of the padding result (RFC4346, CBCTIME).
*/
#if defined(POLARSSL_ARC4_C) || defined(POLARSSL_CIPHER_NULL_CIPHER) || \
( defined(POLARSSL_CIPHER_MODE_CBC) && \
( defined(POLARSSL_AES_C) || defined(POLARSSL_CAMELLIA_C) ) )
if( mode != POLARSSL_MODE_GCM &&
mode != POLARSSL_MODE_CCM )
#if defined(POLARSSL_SOME_MODES_USE_MAC)
if( auth_done == 0 )
{
unsigned char tmp[POLARSSL_SSL_MAX_MAC_SIZE];
ssl->in_msglen -= ( ssl->transform_in->maclen + padlen );
ssl->in_msglen -= ssl->transform_in->maclen;
ssl->in_hdr[3] = (unsigned char)( ssl->in_msglen >> 8 );
ssl->in_hdr[4] = (unsigned char)( ssl->in_msglen );
@ -1711,6 +1835,7 @@ static int ssl_decrypt_buf( ssl_context *ssl )
#endif
correct = 0;
}
auth_done++;
/*
* Finally check the correct flag
@ -1718,7 +1843,14 @@ static int ssl_decrypt_buf( ssl_context *ssl )
if( correct == 0 )
return( POLARSSL_ERR_SSL_INVALID_MAC );
}
#endif /* AEAD not the only option */
#endif /* POLARSSL_SOME_MODES_USE_MAC */
/* Make extra sure authentication was performed, exactly once */
if( auth_done != 1 )
{
SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( POLARSSL_ERR_SSL_INTERNAL_ERROR );
}
if( ssl->in_msglen == 0 )
{
@ -1754,6 +1886,10 @@ static int ssl_decrypt_buf( ssl_context *ssl )
return( 0 );
}
#undef MAC_NONE
#undef MAC_PLAINTEXT
#undef MAC_CIPHERTEXT
#if defined(POLARSSL_ZLIB_SUPPORT)
/*
* Compression/decompression functions
@ -3116,6 +3252,12 @@ void ssl_handshake_wrapup( ssl_context *ssl )
if( ssl->session )
{
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
/* RFC 7366 3.1: keep the EtM state */
ssl->session_negotiate->encrypt_then_mac =
ssl->session->encrypt_then_mac;
#endif
ssl_session_free( ssl->session );
polarssl_free( ssl->session );
}
@ -3474,6 +3616,10 @@ int ssl_init( ssl_context *ssl )
memset( ssl-> in_ctr, 0, SSL_BUFFER_LEN );
memset( ssl->out_ctr, 0, SSL_BUFFER_LEN );
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
ssl->encrypt_then_mac = SSL_ETM_ENABLED;
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
ssl->extended_ms = SSL_EXTENDED_MS_ENABLED;
#endif
@ -4025,6 +4171,13 @@ void ssl_set_fallback( ssl_context *ssl, char fallback )
}
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
void ssl_set_encrypt_then_mac( ssl_context *ssl, char etm )
{
ssl->encrypt_then_mac = etm;
}
#endif
#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
void ssl_set_extended_master_secret( ssl_context *ssl, char ems )
{

25
programs/ssl/ssl_client2.c
View file

@ -97,6 +97,7 @@ int main( int argc, char *argv[] )
#define DFL_ALPN_STRING NULL
#define DFL_FALLBACK -1
#define DFL_EXTENDED_MS -1
#define DFL_ETM -1
#define GET_REQUEST "GET %s HTTP/1.0\r\nExtra-header: "
#define GET_REQUEST_END "\r\n\r\n"
@ -136,6 +137,7 @@ struct options
const char *alpn_string; /* ALPN supported protocols */
int fallback; /* is this a fallback connection? */
int extended_ms; /* negotiate extended master secret? */
char etm; /* negotiate encrypt then mac? ? */
} opt;
static void my_debug( void *ctx, int level, const char *str )
@ -302,6 +304,13 @@ static int my_verify( void *data, x509_crt *crt, int depth, int *flags )
#define USAGE_EMS ""
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
#define USAGE_ETM \
" etm=0/1 default: (library default: on)\n"
#else
#define USAGE_ETM ""
#endif
#define USAGE \
"\n usage: ssl_client2 param=<>...\n" \
"\n acceptable parameters:\n" \
@ -333,6 +342,7 @@ static int my_verify( void *data, x509_crt *crt, int depth, int *flags )
USAGE_ALPN \
USAGE_FALLBACK \
USAGE_EMS \
USAGE_ETM \
"\n" \
" min_version=%%s default: \"\" (ssl3)\n" \
" max_version=%%s default: \"\" (tls1_2)\n" \
@ -435,6 +445,7 @@ int main( int argc, char *argv[] )
opt.alpn_string = DFL_ALPN_STRING;
opt.fallback = DFL_FALLBACK;
opt.extended_ms = DFL_EXTENDED_MS;
opt.etm = DFL_ETM;
for( i = 1; i < argc; i++ )
{
@ -559,6 +570,15 @@ int main( int argc, char *argv[] )
default: goto usage;
}
}
else if( strcmp( p, "etm" ) == 0 )
{
switch( atoi( q ) )
{
case 0: opt.etm = SSL_ETM_DISABLED; break;
case 1: opt.etm = SSL_ETM_ENABLED; break;
default: goto usage;
}
}
else if( strcmp( p, "min_version" ) == 0 )
{
if( strcmp( q, "ssl3" ) == 0 )
@ -927,6 +947,11 @@ int main( int argc, char *argv[] )
ssl_set_extended_master_secret( &ssl, opt.extended_ms );
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( opt.etm != DFL_ETM )
ssl_set_encrypt_then_mac( &ssl, opt.etm );
#endif
#if defined(POLARSSL_SSL_ALPN)
if( opt.alpn_string != NULL )
if( ( ret = ssl_set_alpn_protocols( &ssl, alpn_list ) ) != 0 )

25
programs/ssl/ssl_server2.c
View file

@ -117,6 +117,7 @@ int main( int argc, char *argv[] )
#define DFL_ALPN_STRING NULL
#define DFL_DHM_FILE NULL
#define DFL_EXTENDED_MS -1
#define DFL_ETM -1
#define LONG_RESPONSE "<p>01-blah-blah-blah-blah-blah-blah-blah-blah-blah\r\n" \
"02-blah-blah-blah-blah-blah-blah-blah-blah-blah-blah-blah-blah-blah\r\n" \
@ -178,6 +179,7 @@ struct options
const char *alpn_string; /* ALPN supported protocols */
const char *dhm_file; /* the file with the DH parameters */
char extended_ms; /* allow negotiation of extended MS? */
char etm; /* allow negotiation of encrypt-then-MAC? */
} opt;
static void my_debug( void *ctx, int level, const char *str )
@ -308,6 +310,13 @@ static int my_send( void *ctx, const unsigned char *buf, size_t len )
#define USAGE_EMS ""
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
#define USAGE_ETM \
" etm=0/1 default: (library default: on)\n"
#else
#define USAGE_ETM ""
#endif
#define USAGE \
"\n usage: ssl_server2 param=<>...\n" \
"\n acceptable parameters:\n" \
@ -334,6 +343,7 @@ static int my_send( void *ctx, const unsigned char *buf, size_t len )
USAGE_MAX_FRAG_LEN \
USAGE_ALPN \
USAGE_EMS \
USAGE_ETM \
"\n" \
" min_version=%%s default: \"ssl3\"\n" \
" max_version=%%s default: \"tls1_2\"\n" \
@ -724,6 +734,7 @@ int main( int argc, char *argv[] )
opt.alpn_string = DFL_ALPN_STRING;
opt.dhm_file = DFL_DHM_FILE;
opt.extended_ms = DFL_EXTENDED_MS;
opt.etm = DFL_ETM;
for( i = 1; i < argc; i++ )
{
@ -900,6 +911,15 @@ int main( int argc, char *argv[] )
default: goto usage;
}
}
else if( strcmp( p, "etm" ) == 0 )
{
switch( atoi( q ) )
{
case 0: opt.etm = SSL_ETM_DISABLED; break;
case 1: opt.etm = SSL_ETM_ENABLED; break;
default: goto usage;
}
}
else if( strcmp( p, "tickets" ) == 0 )
{
opt.tickets = atoi( q );
@ -1282,6 +1302,11 @@ int main( int argc, char *argv[] )
ssl_set_extended_master_secret( &ssl, opt.extended_ms );
#endif
#if defined(POLARSSL_SSL_ENCRYPT_THEN_MAC)
if( opt.etm != DFL_ETM )
ssl_set_encrypt_then_mac( &ssl, opt.etm );
#endif
#if defined(POLARSSL_SSL_ALPN)
if( opt.alpn_string != NULL )
if( ( ret = ssl_set_alpn_protocols( &ssl, alpn_list ) ) != 0 )

111
tests/ssl-opt.sh
View file

@ -248,14 +248,14 @@ run_test() {
if is_polar "$SRV_CMD"; then
if grep "Performing the SSL/TLS handshake" $SRV_OUT >/dev/null; then :;
else
fail "server failed to start"
fail "server or client failed to reach handshake stage"
return
fi
fi
if is_polar "$CLI_CMD"; then
if grep "Performing the SSL/TLS handshake" $CLI_OUT >/dev/null; then :;
else
fail "client failed to start"
fail "server or client failed to reach handshake stage"
return
fi
fi
@ -441,6 +441,92 @@ run_test "Truncated HMAC: actual test" \
0 \
-s "dumping 'computed mac' (10 bytes)"
# Tests for Encrypt-then-MAC extension
run_test "Encrypt then MAC: default" \
"$P_SRV debug_level=3 \
force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
"$P_CLI debug_level=3" \
0 \
-c "client hello, adding encrypt_then_mac extension" \
-s "found encrypt then mac extension" \
-s "server hello, adding encrypt then mac extension" \
-c "found encrypt_then_mac extension" \
-c "using encrypt then mac" \
-s "using encrypt then mac"
run_test "Encrypt then MAC: client enabled, server disabled" \
"$P_SRV debug_level=3 etm=0 \
force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
"$P_CLI debug_level=3 etm=1" \
0 \
-c "client hello, adding encrypt_then_mac extension" \
-s "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
run_test "Encrypt then MAC: client enabled, aead cipher" \
"$P_SRV debug_level=3 etm=1 \
force_ciphersuite=TLS-RSA-WITH-AES-128-GCM-SHA256" \
"$P_CLI debug_level=3 etm=1" \
0 \
-c "client hello, adding encrypt_then_mac extension" \
-s "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
run_test "Encrypt then MAC: client enabled, stream cipher" \
"$P_SRV debug_level=3 etm=1 \
force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
"$P_CLI debug_level=3 etm=1" \
0 \
-c "client hello, adding encrypt_then_mac extension" \
-s "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
run_test "Encrypt then MAC: client disabled, server enabled" \
"$P_SRV debug_level=3 etm=1 \
force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
"$P_CLI debug_level=3 etm=0" \
0 \
-C "client hello, adding encrypt_then_mac extension" \
-S "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
run_test "Encrypt then MAC: client SSLv3, server enabled" \
"$P_SRV debug_level=3 \
force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
"$P_CLI debug_level=3 force_version=ssl3" \
0 \
-C "client hello, adding encrypt_then_mac extension" \
-S "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
run_test "Encrypt then MAC: client enabled, server SSLv3" \
"$P_SRV debug_level=3 force_version=ssl3 \
force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
"$P_CLI debug_level=3" \
0 \
-c "client hello, adding encrypt_then_mac extension" \
-s "found encrypt then mac extension" \
-S "server hello, adding encrypt then mac extension" \
-C "found encrypt_then_mac extension" \
-C "using encrypt then mac" \
-S "using encrypt then mac"
# Tests for Extended Master Secret extension
run_test "Extended Master Secret: default" \
@ -1779,6 +1865,13 @@ run_test "Small packet TLS 1.0 BlockCipher" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.0 BlockCipher without EtM" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1 etm=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.0 BlockCipher truncated MAC" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1 \
@ -1802,6 +1895,13 @@ run_test "Small packet TLS 1.1 BlockCipher" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.1 BlockCipher without EtM" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1_1 etm=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.1 StreamCipher" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1_1 \
@ -1832,6 +1932,13 @@ run_test "Small packet TLS 1.2 BlockCipher" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.2 BlockCipher without EtM" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1_2 etm=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
0 \
-s "Read from client: 1 bytes read"
run_test "Small packet TLS 1.2 BlockCipher larger MAC" \
"$P_SRV" \
"$P_CLI request_size=1 force_version=tls1_2 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \