Merge commit 'b2eaac1' into dtls

* commit 'b2eaac1':
  Stop assuming chars are signed
  Add tests for CBC record splitting
  Fix tests that were failing with record splitting
  Allow disabling record splitting at runtime
  Add 1/n-1 record splitting
  Enhance doc on ssl_write()

Conflicts:
	include/polarssl/ssl.h
	programs/ssl/ssl_client2.c
	programs/ssl/ssl_server2.c
This commit is contained in:
Manuel Pégourié-Gonnard 2015-01-21 13:37:08 +00:00
commit 8fbb01ec84
8 changed files with 190 additions and 12 deletions

View file

@ -38,6 +38,7 @@ Features
* Add compile-time option POLARSSL_X509_MAX_INTERMEDIATE_CA to limit the
length of an X.509 verification chain.
* Support for renegotiation can now be disabled at compile-time
* Support for 1/n-1 record splitting, a countermeasure against BEAST.
Bugfix
* Stack buffer overflow if ctr_drbg_update() is called with too large

View file

@ -303,6 +303,11 @@
#error "POLARSSL_SSL_SESSION_TICKETS_C defined, but not all prerequisites"
#endif
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING) && \
!defined(POLARSSL_SSL_PROTO_SSL3) && !defined(POLARSSL_SSL_PROTO_TLS1)
#error "POLARSSL_SSL_CBC_RECORD_SPLITTING defined, but not all prerequisites"
#endif
#if defined(POLARSSL_SSL_SERVER_NAME_INDICATION) && \
!defined(POLARSSL_X509_CRT_PARSE_C)
#error "POLARSSL_SSL_SERVER_NAME_INDICATION defined, but not all prerequisites"

View file

@ -886,6 +886,18 @@
*/
//#define POLARSSL_SSL_HW_RECORD_ACCEL
/**
* \def POLARSSL_SSL_CBC_RECORD_SPLITTING
*
* Enable 1/n-1 record splitting for CBC mode in SSLv3 and TLS 1.0.
*
* This is a countermeasure to the BEAST attack, which also minimizes the risk
* of interoperability issues compared to sending 0-length records.
*
* Comment this macro to disable 1/n-1 record splitting.
*/
#define POLARSSL_SSL_CBC_RECORD_SPLITTING
/**
* \def POLARSSL_SSL_DISABLE_RENEGOTIATION
*

View file

@ -265,6 +265,9 @@
#define SSL_SESSION_TICKETS_DISABLED 0
#define SSL_SESSION_TICKETS_ENABLED 1
#define SSL_CBC_RECORD_SPLITTING_DISABLED -1
#define SSL_CBC_RECORD_SPLITTING_ENABLED 0
/*
* DTLS retransmission states, see RFC 6347 4.2.4
*
@ -943,6 +946,10 @@ struct _ssl_context
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
unsigned char mfl_code; /*!< MaxFragmentLength chosen by us */
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
char split_done; /*!< flag for record splitting:
-1 disabled, 0 todo, 1 done */
#endif
/*
* PKI layer
@ -1857,6 +1864,21 @@ int ssl_set_max_frag_len( ssl_context *ssl, unsigned char mfl_code );
int ssl_set_truncated_hmac( ssl_context *ssl, int truncate );
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
/**
* \brief Enable / Disable 1/n-1 record splitting
* (Default: SSL_CBC_RECORD_SPLITTING_ENABLED)
*
* \note Only affects SSLv3 and TLS 1.0, not higher versions.
* Does not affect non-CBC ciphersuites in any version.
*
* \param ssl SSL context
* \param split SSL_CBC_RECORD_SPLITTING_ENABLED or
* SSL_CBC_RECORD_SPLITTING_DISABLED
*/
void ssl_set_cbc_record_splitting( ssl_context *ssl, char split );
#endif /* POLARSSL_SSL_CBC_RECORD_SPLITTING */
#if defined(POLARSSL_SSL_SESSION_TICKETS)
/**
* \brief Enable / Disable session tickets
@ -2147,11 +2169,13 @@ int ssl_read( ssl_context *ssl, unsigned char *buf, size_t len );
* it must be called later with the *same* arguments,
* until it returns a positive value.
*
* \note When DTLS is in use, and a maximum fragment length was
* either set with \c ssl_set_max_frag_len() or negotiated by
* the peer, len must not not be greater than the maximum
* fragment length, or POLARSSL_ERR_SSL_BAD_INPUT_DATA is
* returned.
* \note If the requested length is greater than the maximum
* fragment length (either the built-in limit or the one set
* or negotiated with the peer), then:
* - with TLS, less bytes than requested are written. (In
* order to write larger messages, this function should be
* called in a loop.)
* - with DTLS, POLARSSL_ERR_SSL_BAD_INPUT_DATA is returned.
*/
int ssl_write( ssl_context *ssl, const unsigned char *buf, size_t len );

View file

@ -5027,6 +5027,10 @@ int ssl_session_reset( ssl_context *ssl )
ssl->out_msgtype = 0;
ssl->out_msglen = 0;
ssl->out_left = 0;
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
if( ssl->split_done != SSL_CBC_RECORD_SPLITTING_DISABLED )
ssl->split_done = 0;
#endif
ssl->transform_in = NULL;
ssl->transform_out = NULL;
@ -5697,6 +5701,13 @@ int ssl_set_truncated_hmac( ssl_context *ssl, int truncate )
}
#endif /* POLARSSL_SSL_TRUNCATED_HMAC */
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
void ssl_set_cbc_record_splitting( ssl_context *ssl, char split )
{
ssl->split_done = split;
}
#endif
void ssl_legacy_renegotiation( ssl_context *ssl, int allow_legacy )
{
ssl->allow_legacy_renegotiation = allow_legacy;
@ -6309,7 +6320,11 @@ int ssl_read( ssl_context *ssl, unsigned char *buf, size_t len )
/*
* Send application data to be encrypted by the SSL layer
*/
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
static int ssl_write_real( ssl_context *ssl, const unsigned char *buf, size_t len )
#else
int ssl_write( ssl_context *ssl, const unsigned char *buf, size_t len )
#endif
{
int ret;
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
@ -6392,6 +6407,45 @@ int ssl_write( ssl_context *ssl, const unsigned char *buf, size_t len )
return( (int) len );
}
/*
* Write application data, doing 1/n-1 splitting if necessary.
*
* With non-blocking I/O, ssl_write_real() may return WANT_WRITE,
* then the caller will call us again with the same arguments, so
* remember wether we already did the split or not.
*/
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
int ssl_write( ssl_context *ssl, const unsigned char *buf, size_t len )
{
int ret;
if( ssl->split_done == SSL_CBC_RECORD_SPLITTING_DISABLED ||
len <= 1 ||
ssl->minor_ver > SSL_MINOR_VERSION_1 ||
cipher_get_cipher_mode( &ssl->transform_out->cipher_ctx_enc )
!= POLARSSL_MODE_CBC )
{
return( ssl_write_real( ssl, buf, len ) );
}
if( ssl->split_done == 0 )
{
ssl->split_done = 1;
if( ( ret = ssl_write_real( ssl, buf, 1 ) ) < 0 )
return( ret );
}
if( ssl->split_done == 1 )
{
ssl->split_done = 0;
if( ( ret = ssl_write_real( ssl, buf + 1, len - 1 ) ) < 0 )
return( ret );
}
return( ret + 1 );
}
#endif /* POLARSSL_SSL_CBC_RECORD_SPLITTING */
/*
* Notify the peer that the connection is being closed
*/

View file

@ -93,6 +93,7 @@ int main( int argc, char *argv[] )
#define DFL_AUTH_MODE SSL_VERIFY_REQUIRED
#define DFL_MFL_CODE SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC 0
#define DFL_RECSPLIT -1
#define DFL_RECONNECT 0
#define DFL_RECO_DELAY 0
#define DFL_TICKETS SSL_SESSION_TICKETS_ENABLED
@ -138,6 +139,7 @@ struct options
int auth_mode; /* verify mode for connection */
unsigned char mfl_code; /* code for maximum fragment length */
int trunc_hmac; /* negotiate truncated hmac or not */
int recsplit; /* enable record splitting? */
int reconnect; /* attempt to resume session */
int reco_delay; /* delay in seconds before resuming session */
int tickets; /* enable / disable session tickets */
@ -285,6 +287,13 @@ static int my_verify( void *data, x509_crt *crt, int depth, int *flags )
#define USAGE_MAX_FRAG_LEN ""
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
#define USAGE_RECSPLIT \
" recplit=%%d default: (library default)\n"
#else
#define USAGE_RECSPLIT
#endif
#if defined(POLARSSL_TIMING_C)
#define USAGE_TIME \
" reco_delay=%%d default: 0 seconds\n"
@ -373,6 +382,7 @@ static int my_verify( void *data, x509_crt *crt, int depth, int *flags )
USAGE_FALLBACK \
USAGE_EMS \
USAGE_ETM \
USAGE_RECSPLIT \
"\n" \
" min_version=%%s default: \"\" (ssl3)\n" \
" max_version=%%s default: \"\" (tls1_2)\n" \
@ -471,6 +481,7 @@ int main( int argc, char *argv[] )
opt.auth_mode = DFL_AUTH_MODE;
opt.mfl_code = DFL_MFL_CODE;
opt.trunc_hmac = DFL_TRUNC_HMAC;
opt.recsplit = DFL_RECSPLIT;
opt.reconnect = DFL_RECONNECT;
opt.reco_delay = DFL_RECO_DELAY;
opt.tickets = DFL_TICKETS;
@ -743,6 +754,12 @@ int main( int argc, char *argv[] )
if( opt.hs_to_min == 0 || opt.hs_to_max < opt.hs_to_min )
goto usage;
}
else if( strcmp( p, "recsplit" ) == 0 )
{
opt.recsplit = atoi( q );
if( opt.recsplit < 0 || opt.recsplit > 1 )
goto usage;
}
else
goto usage;
}
@ -1058,6 +1075,13 @@ int main( int argc, char *argv[] )
ssl_set_encrypt_then_mac( &ssl, opt.etm );
#endif
#if defined(POLARSSL_SSL_CBC_RECORD_SPLITTING)
if( opt.recsplit != DFL_RECSPLIT )
ssl_set_cbc_record_splitting( &ssl, opt.recsplit
? SSL_CBC_RECORD_SPLITTING_ENABLED
: SSL_CBC_RECORD_SPLITTING_DISABLED );
#endif
#if defined(POLARSSL_SSL_ALPN)
if( opt.alpn_string != NULL )
if( ( ret = ssl_set_alpn_protocols( &ssl, alpn_list ) ) != 0 )

View file

@ -192,14 +192,14 @@ struct options
char *sni; /* string describing sni information */
const char *alpn_string; /* ALPN supported protocols */
const char *dhm_file; /* the file with the DH parameters */
int extended_ms; /* allow negotiation of extended MS? */
int etm; /* allow negotiation of encrypt-then-MAC? */
int transport; /* TLS or DTLS? */
int cookies; /* Use cookies for DTLS? -1 to break them */
int anti_replay; /* Use anti-replay for DTLS? -1 for default */
uint32_t hs_to_min; /* Initial value of DTLS handshake timer */
uint32_t hs_to_max; /* Max value of DTLS handshake timer */
int badmac_limit; /* Limit of records with bad MAC */
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 )

View file

@ -791,6 +791,62 @@ run_test "Fallback SCSV: enabled, max version, openssl client" \
-s "received FALLBACK_SCSV" \
-S "inapropriate fallback"
# Tests for CBC 1/n-1 record splitting
run_test "CBC Record splitting: TLS 1.2, no splitting" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
request_size=123 force_version=tls1_2" \
0 \
-s "Read from client: 123 bytes read" \
-S "Read from client: 1 bytes read" \
-S "122 bytes read"
run_test "CBC Record splitting: TLS 1.1, no splitting" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
request_size=123 force_version=tls1_1" \
0 \
-s "Read from client: 123 bytes read" \
-S "Read from client: 1 bytes read" \
-S "122 bytes read"
run_test "CBC Record splitting: TLS 1.0, splitting" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
request_size=123 force_version=tls1" \
0 \
-S "Read from client: 123 bytes read" \
-s "Read from client: 1 bytes read" \
-s "122 bytes read"
run_test "CBC Record splitting: SSLv3, splitting" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
request_size=123 force_version=ssl3" \
0 \
-S "Read from client: 123 bytes read" \
-s "Read from client: 1 bytes read" \
-s "122 bytes read"
run_test "CBC Record splitting: TLS 1.0 RC4, no splitting" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA \
request_size=123 force_version=tls1" \
0 \
-s "Read from client: 123 bytes read" \
-S "Read from client: 1 bytes read" \
-S "122 bytes read"
run_test "CBC Record splitting: TLS 1.0, splitting disabled" \
"$P_SRV" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
request_size=123 force_version=tls1 recsplit=0" \
0 \
-s "Read from client: 123 bytes read" \
-S "Read from client: 1 bytes read" \
-S "122 bytes read"
# Tests for Session Tickets
run_test "Session resume using tickets: basic" \
@ -2283,7 +2339,8 @@ run_test "Small packet TLS 1.2 BlockCipher without EtM" \
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" \
"$P_CLI request_size=1 force_version=tls1_2 \
force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
0 \
-s "Read from client: 1 bytes read"
@ -2328,7 +2385,7 @@ run_test "Small packet TLS 1.2 AEAD shorter tag" \
run_test "Large packet SSLv3 BlockCipher" \
"$P_SRV" \
"$P_CLI request_size=16384 force_version=ssl3 \
"$P_CLI request_size=16384 force_version=ssl3 recsplit=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
0 \
-s "Read from client: 16384 bytes read"
@ -2342,14 +2399,14 @@ run_test "Large packet SSLv3 StreamCipher" \
run_test "Large packet TLS 1.0 BlockCipher" \
"$P_SRV" \
"$P_CLI request_size=16384 force_version=tls1 \
"$P_CLI request_size=16384 force_version=tls1 recsplit=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
0 \
-s "Read from client: 16384 bytes read"
run_test "Large packet TLS 1.0 BlockCipher truncated MAC" \
"$P_SRV" \
"$P_CLI request_size=16384 force_version=tls1 \
"$P_CLI request_size=16384 force_version=tls1 recsplit=0 \
force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA \
trunc_hmac=1" \
0 \
@ -2402,7 +2459,8 @@ run_test "Large packet TLS 1.2 BlockCipher" \
run_test "Large packet TLS 1.2 BlockCipher larger MAC" \
"$P_SRV" \
"$P_CLI request_size=16384 force_version=tls1_2 force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
"$P_CLI request_size=16384 force_version=tls1_2 \
force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
0 \
-s "Read from client: 16384 bytes read"