Merge branch 'datagram_packing' into message_reordering
diff --git a/ChangeLog b/ChangeLog
index 4bf4c8e..975b3ba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -41,6 +41,7 @@
Drozd. Fixes #1215 raised by randombit.
* Improve compatibility with some alternative CCM implementations by using
CCM test vectors from RAM.
+ * Add support for buffering of out-of-order handshake messages.
INTERNAL NOTE: need to bump soversion of libmbedtls:
- added new member 'mtu' to public 'mbedtls_ssl_conf' structure
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 70820be..70dd4be2 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3010,6 +3010,14 @@
*/
//#define MBEDTLS_SSL_OUT_CONTENT_LEN 16384
+/** \def MBEDTLS_SSL_DTLS_MAX_BUFFERING
+ *
+ * Maximum number of heap-allocated bytes for the purpose of
+ * DTLS handshake message reassembly and future message buffering.
+ *
+ */
+//#define MBEDTLS_SSL_DTLS_MAX_BUFFERING ( 2 * 16384 )
+
//#define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME 86400 /**< Lifetime of session tickets (if enabled) */
//#define MBEDTLS_PSK_MAX_LEN 32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
//#define MBEDTLS_SSL_COOKIE_TIMEOUT 60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index c86a0f9..b6700fc 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -121,6 +121,7 @@
#define MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH -0x6600 /**< Couldn't set the hash for verifying CertificateVerify */
#define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -0x6580 /**< Internal-only message signaling that further message-processing should be done */
#define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS -0x6500 /**< The asynchronous operation is not completed yet. */
+#define MBEDTLS_ERR_SSL_EARLY_MESSAGE -0x6480 /**< Internal-only message signaling that a message arrived early. */
/*
* Various constants
@@ -242,6 +243,10 @@
#define MBEDTLS_SSL_OUT_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
#endif
+#if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING)
+#define MBEDTLS_SSL_DTLS_MAX_BUFFERING ( 2 * MBEDTLS_SSL_IN_CONTENT_LEN )
+#endif
+
/* \} name SECTION: Module settings */
/*
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 65b1fc9..3f595a3 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -155,6 +155,9 @@
#define MBEDTLS_SSL_OUT_PAYLOAD_LEN ( MBEDTLS_SSL_PAYLOAD_OVERHEAD + \
( MBEDTLS_SSL_OUT_CONTENT_LEN ) )
+/* The maximum number of buffered handshake messages. */
+#define MBEDTLS_SSL_MAX_BUFFERED_HS 4
+
/* Maximum length we can advertise as our max content length for
RFC 6066 max_fragment_length extension negotiation purposes
(the lesser of both sizes, if they are unequal.)
@@ -294,8 +297,6 @@
unsigned char verify_cookie_len; /*!< Cli: cookie length
Srv: flag for sending a cookie */
- unsigned char *hs_msg; /*!< Reassembled handshake message */
-
uint32_t retransmit_timeout; /*!< Current value of timeout */
unsigned char retransmit_state; /*!< Retransmission state */
mbedtls_ssl_flight_item *flight; /*!< Current outgoing flight */
@@ -307,6 +308,33 @@
resending messages */
unsigned char alt_out_ctr[8]; /*!< Alternative record epoch/counter
for resending messages */
+
+ struct
+ {
+ size_t total_bytes_buffered; /*!< Cumulative size of heap allocated
+ * buffers used for message buffering. */
+
+ uint8_t seen_ccs; /*!< Indicates if a CCS message has
+ * been seen in the current flight. */
+
+ struct mbedtls_ssl_hs_buffer
+ {
+ uint8_t is_valid : 1;
+ uint8_t is_fragmented : 1;
+ uint8_t is_complete : 1;
+ unsigned char *data;
+ size_t data_len;
+ } hs[MBEDTLS_SSL_MAX_BUFFERED_HS];
+
+ struct
+ {
+ unsigned char *data;
+ size_t len;
+ unsigned epoch;
+ } future_record;
+
+ } buffering;
+
uint16_t mtu; /*!< Handshake mtu, used to fragment outgoing messages */
#endif /* MBEDTLS_SSL_PROTO_DTLS */
@@ -366,6 +394,8 @@
#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
};
+typedef struct mbedtls_ssl_hs_buffer mbedtls_ssl_hs_buffer;
+
/*
* This structure contains a full set of runtime transform parameters
* either in negotiation or active.
@@ -480,7 +510,6 @@
void mbedtls_ssl_reset_checksum( mbedtls_ssl_context *ssl );
int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl );
-int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl );
int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl );
int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl );
void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
@@ -492,7 +521,10 @@
* of the logic of (D)TLS from the implementation
* of the secure transport.
*
- * \param ssl SSL context to use
+ * \param ssl The SSL context to use.
+ * \param update_hs_digest This indicates if the handshake digest
+ * should be automatically updated in case
+ * a handshake message is found.
*
* \return 0 or non-zero error code.
*
@@ -558,7 +590,8 @@
* following the above definition.
*
*/
-int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl,
+ unsigned update_hs_digest );
int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want );
int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl );
diff --git a/library/error.c b/library/error.c
index 774244b..6c88689 100644
--- a/library/error.c
+++ b/library/error.c
@@ -515,6 +515,8 @@
mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that further message-processing should be done" );
if( use_ret == -(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) )
mbedtls_snprintf( buf, buflen, "SSL - The asynchronous operation is not completed yet" );
+ if( use_ret == -(MBEDTLS_ERR_SSL_EARLY_MESSAGE) )
+ mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that a message arrived early" );
#endif /* MBEDTLS_SSL_TLS_C */
#if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 73e4391..d160c42 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1500,7 +1500,7 @@
buf = ssl->in_msg;
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
/* No alert on a read error. */
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
@@ -2349,7 +2349,7 @@
#endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -2656,7 +2656,7 @@
return( 0 );
}
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -2808,7 +2808,7 @@
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) );
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -3297,7 +3297,7 @@
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) );
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 7101f46..84c83e3 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -3728,7 +3728,7 @@
}
else
#endif
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -4038,25 +4038,10 @@
}
/* Read the message without adding it to the checksum */
- do {
-
- do ret = mbedtls_ssl_read_record_layer( ssl );
- while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
-
- if( ret != 0 )
- {
- MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
- return( ret );
- }
-
- ret = mbedtls_ssl_handle_message_type( ssl );
-
- } while( MBEDTLS_ERR_SSL_NON_FATAL == ret ||
- MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret );
-
+ ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
if( 0 != ret )
{
- MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret );
+ MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
return( ret );
}
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 8cf7aa1..5fccedf 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -55,6 +55,7 @@
#endif
static void ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl );
+static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context *ssl );
/* Length of the "epoch" field in the record header */
static inline size_t ssl_ep_len( const mbedtls_ssl_context *ssl )
@@ -168,6 +169,11 @@
return( (int) remaining );
}
+static void ssl_buffering_free( mbedtls_ssl_context *ssl );
+
+static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl,
+ uint8_t slot );
+
/*
* Double the retransmit timeout value, within the allowed range,
* returning -1 if the maximum value has already been reached.
@@ -3079,6 +3085,12 @@
/* The next incoming flight will start with this msg_seq */
ssl->handshake->in_flight_start_seq = ssl->handshake->in_msg_seq;
+ /* We don't want to remember CCS's across flight boundaries. */
+ ssl->handshake->buffering.seen_ccs = 0;
+
+ /* Clear future message buffering structure. */
+ ssl_buffering_free( ssl );
+
/* Cancel timer */
ssl_set_timer( ssl, 0 );
@@ -3426,6 +3438,52 @@
}
#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl )
+{
+ if( ssl->in_msglen < ssl->in_hslen ||
+ memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 ||
+ memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 )
+ {
+ return( 1 );
+ }
+ return( 0 );
+}
+
+static uint32_t ssl_get_hs_frag_len( mbedtls_ssl_context *ssl )
+{
+ return( ( ssl->in_msg[9] << 16 ) |
+ ( ssl->in_msg[10] << 8 ) |
+ ssl->in_msg[11] );
+}
+
+static uint32_t ssl_get_hs_frag_off( mbedtls_ssl_context *ssl )
+{
+ return( ( ssl->in_msg[6] << 16 ) |
+ ( ssl->in_msg[7] << 8 ) |
+ ssl->in_msg[8] );
+}
+
+static int ssl_check_hs_header( mbedtls_ssl_context *ssl )
+{
+ uint32_t msg_len, frag_off, frag_len;
+
+ msg_len = ssl_get_hs_total_len( ssl );
+ frag_off = ssl_get_hs_frag_off( ssl );
+ frag_len = ssl_get_hs_frag_len( ssl );
+
+ if( frag_off > msg_len )
+ return( -1 );
+
+ if( frag_len > msg_len - frag_off )
+ return( -1 );
+
+ if( frag_len + 12 > ssl->in_msglen )
+ return( -1 );
+
+ return( 0 );
+}
+
/*
* Mark bits in bitmask (used for DTLS HS reassembly)
*/
@@ -3487,162 +3545,30 @@
return( 0 );
}
-/*
- * Reassemble fragmented DTLS handshake messages.
- *
- * Use a temporary buffer for reassembly, divided in two parts:
- * - the first holds the reassembled message (including handshake header),
- * - the second holds a bitmask indicating which parts of the message
- * (excluding headers) have been received so far.
- */
-static int ssl_reassemble_dtls_handshake( mbedtls_ssl_context *ssl )
+/* msg_len does not include the handshake header */
+static size_t ssl_get_reassembly_buffer_size( unsigned msg_len,
+ unsigned add_bitmap )
{
- unsigned char *msg, *bitmask;
- size_t frag_len, frag_off;
- size_t msg_len = ssl->in_hslen - 12; /* Without headers */
+ size_t alloc_len;
- if( ssl->handshake == NULL )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "not supported outside handshake (for now)" ) );
- return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
- }
+ alloc_len = 12; /* Handshake header */
+ alloc_len += msg_len; /* Content buffer */
- /*
- * For first fragment, check size and allocate buffer
- */
- if( ssl->handshake->hs_msg == NULL )
- {
- size_t alloc_len;
+ if( add_bitmap )
+ alloc_len += msg_len / 8 + ( msg_len % 8 != 0 ); /* Bitmap */
- MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d",
- msg_len ) );
-
- if( ssl->in_hslen > MBEDTLS_SSL_IN_CONTENT_LEN )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake message too large" ) );
- return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
- }
-
- /* The bitmask needs one bit per byte of message excluding header */
- alloc_len = 12 + msg_len + msg_len / 8 + ( msg_len % 8 != 0 );
-
- ssl->handshake->hs_msg = mbedtls_calloc( 1, alloc_len );
- if( ssl->handshake->hs_msg == NULL )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc failed (%d bytes)", alloc_len ) );
- return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
- }
-
- /* Prepare final header: copy msg_type, length and message_seq,
- * then add standardised fragment_offset and fragment_length */
- memcpy( ssl->handshake->hs_msg, ssl->in_msg, 6 );
- memset( ssl->handshake->hs_msg + 6, 0, 3 );
- memcpy( ssl->handshake->hs_msg + 9,
- ssl->handshake->hs_msg + 1, 3 );
- }
- else
- {
- /* Make sure msg_type and length are consistent */
- if( memcmp( ssl->handshake->hs_msg, ssl->in_msg, 4 ) != 0 )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "fragment header mismatch" ) );
- return( MBEDTLS_ERR_SSL_INVALID_RECORD );
- }
- }
-
- msg = ssl->handshake->hs_msg + 12;
- bitmask = msg + msg_len;
-
- /*
- * Check and copy current fragment
- */
- frag_off = ( ssl->in_msg[6] << 16 ) |
- ( ssl->in_msg[7] << 8 ) |
- ssl->in_msg[8];
- frag_len = ( ssl->in_msg[9] << 16 ) |
- ( ssl->in_msg[10] << 8 ) |
- ssl->in_msg[11];
-
- if( frag_off + frag_len > msg_len )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment offset/len: %d + %d > %d",
- frag_off, frag_len, msg_len ) );
- return( MBEDTLS_ERR_SSL_INVALID_RECORD );
- }
-
- if( frag_len + 12 > ssl->in_msglen )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment length: %d + 12 > %d",
- frag_len, ssl->in_msglen ) );
- return( MBEDTLS_ERR_SSL_INVALID_RECORD );
- }
-
- MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d",
- frag_off, frag_len ) );
-
- memcpy( msg + frag_off, ssl->in_msg + 12, frag_len );
- ssl_bitmask_set( bitmask, frag_off, frag_len );
-
- /*
- * Do we have the complete message by now?
- * If yes, finalize it, else ask to read the next record.
- */
- if( ssl_bitmask_check( bitmask, msg_len ) != 0 )
- {
- MBEDTLS_SSL_DEBUG_MSG( 2, ( "message is not complete yet" ) );
- return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
- }
-
- MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake message completed" ) );
-
- if( frag_len + 12 < ssl->in_msglen )
- {
- /*
- * We'got more handshake messages in the same record.
- * This case is not handled now because no know implementation does
- * that and it's hard to test, so we prefer to fail cleanly for now.
- */
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "last fragment not alone in its record" ) );
- return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
- }
-
- if( ssl->in_left > ssl->next_record_offset )
- {
- /*
- * We've got more data in the buffer after the current record,
- * that we don't want to overwrite. Move it before writing the
- * reassembled message, and adjust in_left and next_record_offset.
- */
- unsigned char *cur_remain = ssl->in_hdr + ssl->next_record_offset;
- unsigned char *new_remain = ssl->in_msg + ssl->in_hslen;
- size_t remain_len = ssl->in_left - ssl->next_record_offset;
-
- /* First compute and check new lengths */
- ssl->next_record_offset = new_remain - ssl->in_hdr;
- ssl->in_left = ssl->next_record_offset + remain_len;
-
- if( ssl->in_left > MBEDTLS_SSL_IN_BUFFER_LEN -
- (size_t)( ssl->in_hdr - ssl->in_buf ) )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "reassembled message too large for buffer" ) );
- return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
- }
-
- memmove( new_remain, cur_remain, remain_len );
- }
-
- memcpy( ssl->in_msg, ssl->handshake->hs_msg, ssl->in_hslen );
-
- mbedtls_free( ssl->handshake->hs_msg );
- ssl->handshake->hs_msg = NULL;
-
- MBEDTLS_SSL_DEBUG_BUF( 3, "reassembled handshake message",
- ssl->in_msg, ssl->in_hslen );
-
- return( 0 );
+ return( alloc_len );
}
+
#endif /* MBEDTLS_SSL_PROTO_DTLS */
+static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context *ssl )
+{
+ return( ( ssl->in_msg[1] << 16 ) |
+ ( ssl->in_msg[2] << 8 ) |
+ ssl->in_msg[3] );
+}
+
int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
{
if( ssl->in_msglen < mbedtls_ssl_hs_hdr_len( ssl ) )
@@ -3652,10 +3578,7 @@
return( MBEDTLS_ERR_SSL_INVALID_RECORD );
}
- ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + (
- ( ssl->in_msg[1] << 16 ) |
- ( ssl->in_msg[2] << 8 ) |
- ssl->in_msg[3] );
+ ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ssl_get_hs_total_len( ssl );
MBEDTLS_SSL_DEBUG_MSG( 3, ( "handshake message: msglen ="
" %d, type = %d, hslen = %d",
@@ -3667,12 +3590,26 @@
int ret;
unsigned int recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
+ if( ssl_check_hs_header( ssl ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid handshake header" ) );
+ return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+ }
+
if( ssl->handshake != NULL &&
( ( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER &&
recv_msg_seq != ssl->handshake->in_msg_seq ) ||
( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER &&
ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) )
{
+ if( recv_msg_seq > ssl->handshake->in_msg_seq )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)",
+ recv_msg_seq,
+ ssl->handshake->in_msg_seq ) );
+ return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+ }
+
/* Retransmit only on last message from previous flight, to avoid
* too many retransmissions.
* Besides, No sane server ever retransmits HelloVerifyRequest */
@@ -3702,20 +3639,14 @@
}
/* Wait until message completion to increment in_msg_seq */
- /* Reassemble if current message is fragmented or reassembly is
- * already in progress */
- if( ssl->in_msglen < ssl->in_hslen ||
- memcmp( ssl->in_msg + 6, "\0\0\0", 3 ) != 0 ||
- memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 ||
- ( ssl->handshake != NULL && ssl->handshake->hs_msg != NULL ) )
+ /* Message reassembly is handled alongside buffering of future
+ * messages; the commonality is that both handshake fragments and
+ * future messages cannot be forwarded immediately to the handshake
+ * handshake logic layer. */
+ if( ssl_hs_is_proper_fragment( ssl ) == 1 )
{
MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) );
-
- if( ( ret = ssl_reassemble_dtls_handshake( ssl ) ) != 0 )
- {
- MBEDTLS_SSL_DEBUG_RET( 1, "ssl_reassemble_dtls_handshake", ret );
- return( ret );
- }
+ return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
}
}
else
@@ -3732,9 +3663,9 @@
void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl )
{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
- if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER &&
- ssl->handshake != NULL )
+ if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && hs != NULL )
{
ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen );
}
@@ -3744,7 +3675,29 @@
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ssl->handshake != NULL )
{
- ssl->handshake->in_msg_seq++;
+ unsigned offset;
+ mbedtls_ssl_hs_buffer *hs_buf;
+
+ /* Increment handshake sequence number */
+ hs->in_msg_seq++;
+
+ /*
+ * Clear up handshake buffering and reassembly structure.
+ */
+
+ /* Free first entry */
+ ssl_buffering_free_slot( ssl, 0 );
+
+ /* Shift all other entries */
+ for( offset = 0, hs_buf = &hs->buffering.hs[0];
+ offset + 1 < MBEDTLS_SSL_MAX_BUFFERED_HS;
+ offset++, hs_buf++ )
+ {
+ *hs_buf = *(hs_buf + 1);
+ }
+
+ /* Create a fresh last entry */
+ memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) );
}
#endif
}
@@ -4145,7 +4098,16 @@
}
else
#endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */
+ {
+ /* Consider buffering the record. */
+ if( rec_epoch == (unsigned int) ssl->in_epoch + 1 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Consider record for buffering" ) );
+ return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+ }
+
return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
+ }
}
#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
@@ -4158,15 +4120,6 @@
}
#endif
- /* Drop unexpected ChangeCipherSpec messages */
- if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC &&
- ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC &&
- ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ChangeCipherSpec" ) );
- return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
- }
-
/* Drop unexpected ApplicationData records,
* except at the beginning of renegotiations */
if( ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA &&
@@ -4303,7 +4256,22 @@
* RFC 6347 4.1.2.7) and continue reading until a valid record is found.
*
*/
-int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
+
+/* Helper functions for mbedtls_ssl_read_record(). */
+static int ssl_consume_current_message( mbedtls_ssl_context *ssl );
+static int ssl_get_next_record( mbedtls_ssl_context *ssl );
+static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl );
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+static int ssl_load_buffered_message( mbedtls_ssl_context *ssl );
+static int ssl_load_buffered_record( mbedtls_ssl_context *ssl );
+static int ssl_buffer_message( mbedtls_ssl_context *ssl );
+static int ssl_buffer_future_record( mbedtls_ssl_context *ssl );
+static int ssl_another_record_in_datagram( mbedtls_ssl_context *ssl );
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl,
+ unsigned update_hs_digest )
{
int ret;
@@ -4313,17 +4281,53 @@
{
do {
- do ret = mbedtls_ssl_read_record_layer( ssl );
- while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
-
+ ret = ssl_consume_current_message( ssl );
if( ret != 0 )
- {
- MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
return( ret );
+
+ if( ssl_record_is_in_progress( ssl ) == 0 )
+ {
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ int have_buffered = 0;
+
+ /* We only check for buffered messages if the
+ * current datagram is fully consumed. */
+ if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+ ssl_another_record_in_datagram( ssl ) == 0 )
+ {
+ if( ssl_load_buffered_message( ssl ) == 0 )
+ have_buffered = 1;
+ }
+
+ if( have_buffered == 0 )
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+ {
+ ret = ssl_get_next_record( ssl );
+ if( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING )
+ continue;
+
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
+ return( ret );
+ }
+ }
}
ret = mbedtls_ssl_handle_message_type( ssl );
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE )
+ {
+ /* Buffer future message */
+ ret = ssl_buffer_message( ssl );
+ if( ret != 0 )
+ return( ret );
+
+ ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING;
+ }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
} while( MBEDTLS_ERR_SSL_NON_FATAL == ret ||
MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret );
@@ -4333,14 +4337,15 @@
return( ret );
}
- if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE )
+ if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
+ update_hs_digest == 1 )
{
mbedtls_ssl_update_handshake_status( ssl );
}
}
else
{
- MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= reuse previously read message" ) );
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "reuse previously read message" ) );
ssl->keep_current_message = 0;
}
@@ -4349,13 +4354,342 @@
return( 0 );
}
-int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl )
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+static int ssl_another_record_in_datagram( mbedtls_ssl_context *ssl )
{
- int ret;
+ if( ssl->in_left > ssl->next_record_offset )
+ return( 1 );
+ return( 0 );
+}
+
+static int ssl_load_buffered_message( mbedtls_ssl_context *ssl )
+{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+ mbedtls_ssl_hs_buffer * hs_buf;
+ int ret = 0;
+
+ if( hs == NULL )
+ return( -1 );
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_messsage" ) );
+
+ if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC ||
+ ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+ {
+ /* Check if we have seen a ChangeCipherSpec before.
+ * If yes, synthesize a CCS record. */
+ if( !hs->buffering.seen_ccs )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "CCS not seen in the current flight" ) );
+ ret = -1;
+ goto exit;
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Inject buffered CCS message" ) );
+ ssl->in_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC;
+ ssl->in_msglen = 1;
+ ssl->in_msg[0] = 1;
+
+ /* As long as they are equal, the exact value doesn't matter. */
+ ssl->in_left = 0;
+ ssl->next_record_offset = 0;
+
+ hs->buffering.seen_ccs = 0;
+ goto exit;
+ }
+
+ /* Debug only */
+ {
+ unsigned offset;
+ for( offset = 1; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ )
+ {
+ hs_buf = &hs->buffering.hs[offset];
+ if( hs_buf->is_valid == 1 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Future message with sequence number %u %s buffered.",
+ hs->in_msg_seq + offset,
+ hs_buf->is_complete ? "fully" : "partitially" ) );
+ }
+ }
+ }
+
+ /* Check if we have buffered and/or fully reassembled the
+ * next handshake message. */
+ hs_buf = &hs->buffering.hs[0];
+ if( ( hs_buf->is_valid == 1 ) && ( hs_buf->is_complete == 1 ) )
+ {
+ /* Synthesize a record containing the buffered HS message. */
+ size_t msg_len = ( hs_buf->data[1] << 16 ) |
+ ( hs_buf->data[2] << 8 ) |
+ hs_buf->data[3];
+
+ /* Double-check that we haven't accidentally buffered
+ * a message that doesn't fit into the input buffer. */
+ if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message has been buffered - load" ) );
+ MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered handshake message (incl. header)",
+ hs_buf->data, msg_len + 12 );
+
+ ssl->in_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
+ ssl->in_hslen = msg_len + 12;
+ ssl->in_msglen = msg_len + 12;
+ memcpy( ssl->in_msg, hs_buf->data, ssl->in_hslen );
+
+ ret = 0;
+ goto exit;
+ }
+ else
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message %u not or only partially bufffered",
+ hs->in_msg_seq ) );
+ }
+
+ ret = -1;
+
+exit:
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_message" ) );
+ return( ret );
+}
+
+static void ssl_free_buffered_record( mbedtls_ssl_context *ssl );
+static int ssl_buffer_make_space( mbedtls_ssl_context *ssl,
+ size_t desired )
+{
+ int offset;
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+
+ /* Get rid of future records epoch first, if such exist. */
+ ssl_free_buffered_record( ssl );
+
+ /* Check if we have enough space available now. */
+ if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+ hs->buffering.total_bytes_buffered ) )
+ {
+ return( 0 );
+ }
+
+ /* We don't have enough space to buffer the next expected
+ * handshake message. Remove buffers used for future msgs
+ * to gain space, starting with the most distant one. */
+ for( offset = MBEDTLS_SSL_MAX_BUFFERED_HS - 1;
+ offset >= 0; offset-- )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Free buffering slot %d to make space for reassembly of next handshake message",
+ offset ) );
+
+ ssl_buffering_free_slot( ssl, offset );
+
+ /* Check if we have enough space available now. */
+ if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+ hs->buffering.total_bytes_buffered ) )
+ {
+ return( 0 );
+ }
+ }
+
+ return( -1 );
+}
+
+static int ssl_buffer_message( mbedtls_ssl_context *ssl )
+{
+ int ret = 0;
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+
+ if( hs == NULL )
+ return( 0 );
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_buffer_message" ) );
+
+ switch( ssl->in_msgtype )
+ {
+ case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC:
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Remember CCS message" ) );
+
+ hs->buffering.seen_ccs = 1;
+ break;
+
+ case MBEDTLS_SSL_MSG_HANDSHAKE:
+ {
+ unsigned recv_msg_seq_offset;
+ unsigned recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
+ mbedtls_ssl_hs_buffer *hs_buf;
+ size_t msg_len = ssl->in_hslen - 12;
+
+ /* We should never receive an old handshake
+ * message - double-check nonetheless. */
+ if( recv_msg_seq < ssl->handshake->in_msg_seq )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ recv_msg_seq_offset = recv_msg_seq - ssl->handshake->in_msg_seq;
+ if( recv_msg_seq_offset >= MBEDTLS_SSL_MAX_BUFFERED_HS )
+ {
+ /* Silently ignore -- message too far in the future */
+ MBEDTLS_SSL_DEBUG_MSG( 2,
+ ( "Ignore future HS message with sequence number %u, "
+ "buffering window %u - %u",
+ recv_msg_seq, ssl->handshake->in_msg_seq,
+ ssl->handshake->in_msg_seq + MBEDTLS_SSL_MAX_BUFFERED_HS - 1 ) );
+
+ goto exit;
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering HS message with sequence number %u, offset %u ",
+ recv_msg_seq, recv_msg_seq_offset ) );
+
+ hs_buf = &hs->buffering.hs[ recv_msg_seq_offset ];
+
+ /* Check if the buffering for this seq nr has already commenced. */
+ if( !hs_buf->is_valid )
+ {
+ size_t reassembly_buf_sz;
+
+ hs_buf->is_fragmented =
+ ( ssl_hs_is_proper_fragment( ssl ) == 1 );
+
+ /* We copy the message back into the input buffer
+ * after reassembly, so check that it's not too large.
+ * This is an implementation-specific limitation
+ * and not one from the standard, hence it is not
+ * checked in ssl_check_hs_header(). */
+ if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN )
+ {
+ /* Ignore message */
+ goto exit;
+ }
+
+ /* Check if we have enough space to buffer the message. */
+ if( hs->buffering.total_bytes_buffered >
+ MBEDTLS_SSL_DTLS_MAX_BUFFERING )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ reassembly_buf_sz = ssl_get_reassembly_buffer_size( msg_len,
+ hs_buf->is_fragmented );
+
+ if( reassembly_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+ hs->buffering.total_bytes_buffered ) )
+ {
+ if( recv_msg_seq_offset > 0 )
+ {
+ /* If we can't buffer a future message because
+ * of space limitations -- ignore. */
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n",
+ (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+ (unsigned) hs->buffering.total_bytes_buffered ) );
+ goto exit;
+ }
+ else
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- attempt to make space by freeing buffered future messages\n",
+ (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+ (unsigned) hs->buffering.total_bytes_buffered ) );
+ }
+
+ if( ssl_buffer_make_space( ssl, reassembly_buf_sz ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reassembly of next message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- fail\n",
+ (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+ (unsigned) hs->buffering.total_bytes_buffered ) );
+ ret = MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
+ goto exit;
+ }
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d",
+ msg_len ) );
+
+ hs_buf->data = mbedtls_calloc( 1, reassembly_buf_sz );
+ if( hs_buf->data == NULL )
+ {
+ ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+ goto exit;
+ }
+ hs_buf->data_len = reassembly_buf_sz;
+
+ /* Prepare final header: copy msg_type, length and message_seq,
+ * then add standardised fragment_offset and fragment_length */
+ memcpy( hs_buf->data, ssl->in_msg, 6 );
+ memset( hs_buf->data + 6, 0, 3 );
+ memcpy( hs_buf->data + 9, hs_buf->data + 1, 3 );
+
+ hs_buf->is_valid = 1;
+
+ hs->buffering.total_bytes_buffered += reassembly_buf_sz;
+ }
+ else
+ {
+ /* Make sure msg_type and length are consistent */
+ if( memcmp( hs_buf->data, ssl->in_msg, 4 ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "Fragment header mismatch - ignore" ) );
+ /* Ignore */
+ goto exit;
+ }
+ }
+
+ if( !hs_buf->is_complete )
+ {
+ size_t frag_len, frag_off;
+ unsigned char * const msg = hs_buf->data + 12;
+
+ /*
+ * Check and copy current fragment
+ */
+
+ /* Validation of header fields already done in
+ * mbedtls_ssl_prepare_handshake_record(). */
+ frag_off = ssl_get_hs_frag_off( ssl );
+ frag_len = ssl_get_hs_frag_len( ssl );
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d",
+ frag_off, frag_len ) );
+ memcpy( msg + frag_off, ssl->in_msg + 12, frag_len );
+
+ if( hs_buf->is_fragmented )
+ {
+ unsigned char * const bitmask = msg + msg_len;
+ ssl_bitmask_set( bitmask, frag_off, frag_len );
+ hs_buf->is_complete = ( ssl_bitmask_check( bitmask,
+ msg_len ) == 0 );
+ }
+ else
+ {
+ hs_buf->is_complete = 1;
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "message %scomplete",
+ hs_buf->is_complete ? "" : "not yet " ) );
+ }
+
+ break;
+ }
+
+ default:
+ break;
+ }
+
+exit:
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_buffer_message" ) );
+ return( ret );
+}
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+static int ssl_consume_current_message( mbedtls_ssl_context *ssl )
+{
/*
- * Step A
- *
* Consume last content-layer message and potentially
* update in_msglen which keeps track of the contents'
* consumption state.
@@ -4437,20 +4771,161 @@
ssl->in_msglen = 0;
}
- /*
- * Step B
- *
- * Fetch and decode new record if current one is fully consumed.
- *
- */
+ return( 0 );
+}
+static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl )
+{
if( ssl->in_msglen > 0 )
+ return( 1 );
+
+ return( 0 );
+}
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+static void ssl_free_buffered_record( mbedtls_ssl_context *ssl )
+{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+ if( hs == NULL )
+ return;
+
+ if( hs->buffering.future_record.data != NULL )
{
- /* There's something left to be processed in the current record. */
+ hs->buffering.total_bytes_buffered -=
+ hs->buffering.future_record.len;
+
+ mbedtls_free( hs->buffering.future_record.data );
+ hs->buffering.future_record.data = NULL;
+ }
+}
+
+static int ssl_load_buffered_record( mbedtls_ssl_context *ssl )
+{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+ unsigned char * rec;
+ size_t rec_len;
+ unsigned rec_epoch;
+
+ if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+ return( 0 );
+
+ if( hs == NULL )
+ return( 0 );
+
+ rec = hs->buffering.future_record.data;
+ rec_len = hs->buffering.future_record.len;
+ rec_epoch = hs->buffering.future_record.epoch;
+
+ if( rec == NULL )
+ return( 0 );
+
+ /* Only consider loading future records if the
+ * input buffer is empty. */
+ if( ssl_another_record_in_datagram( ssl ) == 1 )
+ return( 0 );
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_record" ) );
+
+ if( rec_epoch != ssl->in_epoch )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffered record not from current epoch." ) );
+ goto exit;
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Found buffered record from current epoch - load" ) );
+
+ /* Double-check that the record is not too large */
+ if( rec_len > MBEDTLS_SSL_IN_BUFFER_LEN -
+ (size_t)( ssl->in_hdr - ssl->in_buf ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ memcpy( ssl->in_hdr, rec, rec_len );
+ ssl->in_left = rec_len;
+ ssl->next_record_offset = 0;
+
+ ssl_free_buffered_record( ssl );
+
+exit:
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_record" ) );
+ return( 0 );
+}
+
+static int ssl_buffer_future_record( mbedtls_ssl_context *ssl )
+{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+ size_t const rec_hdr_len = 13;
+ size_t const total_buf_sz = rec_hdr_len + ssl->in_msglen;
+
+ /* Don't buffer future records outside handshakes. */
+ if( hs == NULL )
+ return( 0 );
+
+ /* Only buffer handshake records (we are only interested
+ * in Finished messages). */
+ if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
+ return( 0 );
+
+ /* Don't buffer more than one future epoch record. */
+ if( hs->buffering.future_record.data != NULL )
+ return( 0 );
+
+ /* Don't buffer record if there's not enough buffering space remaining. */
+ if( total_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+ hs->buffering.total_bytes_buffered ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future epoch record of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n",
+ (unsigned) total_buf_sz, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+ (unsigned) hs->buffering.total_bytes_buffered ) );
return( 0 );
}
- /* Current record either fully processed or to be discarded. */
+ /* Buffer record */
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffer record from epoch %u",
+ ssl->in_epoch + 1 ) );
+ MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered record", ssl->in_hdr,
+ rec_hdr_len + ssl->in_msglen );
+
+ /* ssl_parse_record_header() only considers records
+ * of the next epoch as candidates for buffering. */
+ hs->buffering.future_record.epoch = ssl->in_epoch + 1;
+ hs->buffering.future_record.len = total_buf_sz;
+
+ hs->buffering.future_record.data =
+ mbedtls_calloc( 1, hs->buffering.future_record.len );
+ if( hs->buffering.future_record.data == NULL )
+ {
+ /* If we run out of RAM trying to buffer a
+ * record from the next epoch, just ignore. */
+ return( 0 );
+ }
+
+ memcpy( hs->buffering.future_record.data, ssl->in_hdr, total_buf_sz );
+
+ hs->buffering.total_bytes_buffered += total_buf_sz;
+ return( 0 );
+}
+
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+static int ssl_get_next_record( mbedtls_ssl_context *ssl )
+{
+ int ret;
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ /* We might have buffered a future record; if so,
+ * and if the epoch matches now, load it.
+ * On success, this call will set ssl->in_left to
+ * the length of the buffered record, so that
+ * the calls to ssl_fetch_input() below will
+ * essentially be no-ops. */
+ ret = ssl_load_buffered_record( ssl );
+ if( ret != 0 )
+ return( ret );
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
if( ( ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_hdr_len( ssl ) ) ) != 0 )
{
@@ -4464,6 +4939,16 @@
if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
ret != MBEDTLS_ERR_SSL_CLIENT_RECONNECT )
{
+ if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE )
+ {
+ ret = ssl_buffer_future_record( ssl );
+ if( ret != 0 )
+ return( ret );
+
+ /* Fall through to handling of unexpected records */
+ ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD;
+ }
+
if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_RECORD )
{
/* Skip unexpected record (but not whole datagram) */
@@ -4595,6 +5080,39 @@
}
}
+ if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
+ {
+ if( ssl->in_msglen != 1 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, len: %d",
+ ssl->in_msglen ) );
+ return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+ }
+
+ if( ssl->in_msg[0] != 1 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, content: %02x",
+ ssl->in_msg[0] ) );
+ return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+ }
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+ ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC &&
+ ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+ {
+ if( ssl->handshake == NULL )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping ChangeCipherSpec outside handshake" ) );
+ return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "received out-of-order ChangeCipherSpec - remember" ) );
+ return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+ }
+#endif
+ }
+
if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT )
{
if( ssl->in_msglen != 2 )
@@ -4920,7 +5438,7 @@
}
#endif
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
/* mbedtls_ssl_read_record may have sent an alert already. We
let it decide whether to alert. */
@@ -5295,7 +5813,7 @@
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) );
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -5309,13 +5827,8 @@
return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
}
- if( ssl->in_msglen != 1 || ssl->in_msg[0] != 1 )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
- mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
- MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
- return( MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC );
- }
+ /* CCS records are only accepted if they have length 1 and content '1',
+ * so we don't need to check this here. */
/*
* Switch to our negotiated transform and session parameters for inbound
@@ -5924,7 +6437,7 @@
ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 );
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
return( ret );
@@ -7691,7 +8204,7 @@
ssl_set_timer( ssl, ssl->conf->read_timeout );
}
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
return( 0 );
@@ -7706,7 +8219,7 @@
/*
* OpenSSL sends empty messages to randomize the IV
*/
- if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+ if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
{
if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
return( 0 );
@@ -8140,6 +8653,35 @@
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+static void ssl_buffering_free( mbedtls_ssl_context *ssl )
+{
+ unsigned offset;
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+
+ if( hs == NULL )
+ return;
+
+ for( offset = 0; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ )
+ ssl_buffering_free_slot( ssl, offset );
+}
+
+static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl,
+ uint8_t slot )
+{
+ mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+ mbedtls_ssl_hs_buffer * const hs_buf = &hs->buffering.hs[slot];
+ if( hs_buf->is_valid == 1 )
+ {
+ hs->buffering.total_bytes_buffered -= hs_buf->data_len;
+ mbedtls_free( hs_buf->data );
+ memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) );
+ }
+}
+
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
void mbedtls_ssl_handshake_free( mbedtls_ssl_context *ssl )
{
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
@@ -8219,8 +8761,9 @@
#if defined(MBEDTLS_SSL_PROTO_DTLS)
mbedtls_free( handshake->verify_cookie );
- mbedtls_free( handshake->hs_msg );
ssl_flight_free( handshake->flight );
+ ssl_buffering_free( ssl );
+ ssl_free_buffered_record( ssl );
#endif
mbedtls_platform_zeroize( handshake,
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 55e0f24..0428d28 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -40,6 +40,8 @@
#define mbedtls_time time
#define mbedtls_time_t time_t
#define mbedtls_printf printf
+#define mbedtls_calloc calloc
+#define mbedtls_free free
#define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif /* MBEDTLS_PLATFORM_C */
@@ -106,6 +108,21 @@
" delay=%%d default: 0 (no delayed packets)\n" \
" delay about 1:N packets randomly\n" \
" delay_ccs=0/1 default: 0 (don't delay ChangeCipherSpec)\n" \
+ " delay_cli=%%s Handshake message from client that should be\n"\
+ " delayed. Possible values are 'ClientHello',\n" \
+ " 'Certificate', 'CertificateVerify', and\n" \
+ " 'ClientKeyExchange'.\n" \
+ " May be used multiple times, even for the same\n"\
+ " message, in which case the respective message\n"\
+ " gets delayed multiple times.\n" \
+ " delay_srv=%%s Handshake message from server that should be\n"\
+ " delayed. Possible values are 'HelloRequest',\n"\
+ " 'ServerHello', 'ServerHelloDone', 'Certificate'\n"\
+ " 'ServerKeyExchange', 'NewSessionTicket',\n"\
+ " 'HelloVerifyRequest' and ''CertificateRequest'.\n"\
+ " May be used multiple times, even for the same\n"\
+ " message, in which case the respective message\n"\
+ " gets delayed multiple times.\n" \
" drop=%%d default: 0 (no dropped packets)\n" \
" drop about 1:N packets randomly\n" \
" mtu=%%d default: 0 (unlimited)\n" \
@@ -121,6 +138,9 @@
/*
* global options
*/
+
+#define MAX_DELAYED_HS 10
+
static struct options
{
const char *server_addr; /* address to forward packets to */
@@ -131,6 +151,12 @@
int duplicate; /* duplicate 1 in N packets (none if 0) */
int delay; /* delay 1 packet in N (none if 0) */
int delay_ccs; /* delay ChangeCipherSpec */
+ char* delay_cli[MAX_DELAYED_HS]; /* handshake types of messages from
+ * client that should be delayed. */
+ uint8_t delay_cli_cnt; /* Number of entries in delay_cli. */
+ char* delay_srv[MAX_DELAYED_HS]; /* handshake types of messages from
+ * server that should be delayed. */
+ uint8_t delay_srv_cnt; /* Number of entries in delay_srv. */
int drop; /* drop 1 packet in N (none if 0) */
int mtu; /* drop packets larger than this */
int bad_ad; /* inject corrupted ApplicationData record */
@@ -164,6 +190,11 @@
opt.pack = DFL_PACK;
/* Other members default to 0 */
+ opt.delay_cli_cnt = 0;
+ opt.delay_srv_cnt = 0;
+ memset( opt.delay_cli, 0, sizeof( opt.delay_cli ) );
+ memset( opt.delay_srv, 0, sizeof( opt.delay_srv ) );
+
for( i = 1; i < argc; i++ )
{
p = argv[i];
@@ -197,6 +228,43 @@
if( opt.delay_ccs < 0 || opt.delay_ccs > 1 )
exit_usage( p, q );
}
+ else if( strcmp( p, "delay_cli" ) == 0 ||
+ strcmp( p, "delay_srv" ) == 0 )
+ {
+ uint8_t *delay_cnt;
+ char **delay_list;
+ size_t len;
+ char *buf;
+
+ if( strcmp( p, "delay_cli" ) == 0 )
+ {
+ delay_cnt = &opt.delay_cli_cnt;
+ delay_list = opt.delay_cli;
+ }
+ else
+ {
+ delay_cnt = &opt.delay_srv_cnt;
+ delay_list = opt.delay_srv;
+ }
+
+ if( *delay_cnt == MAX_DELAYED_HS )
+ {
+ mbedtls_printf( " maximally %d uses of delay_cli argument allowed\n",
+ MAX_DELAYED_HS );
+ exit_usage( p, NULL );
+ }
+
+ len = strlen( q );
+ buf = mbedtls_calloc( 1, len + 1 );
+ if( buf == NULL )
+ {
+ mbedtls_printf( " Allocation failure\n" );
+ exit( 1 );
+ }
+ memcpy( buf, q, len + 1 );
+
+ delay_list[ (*delay_cnt)++ ] = buf;
+ }
else if( strcmp( p, "drop" ) == 0 )
{
opt.drop = atoi( q );
@@ -488,11 +556,37 @@
return( 0 );
}
-static packet prev;
+#define MAX_DELAYED_MSG 5
+static size_t prev_len;
+static packet prev[MAX_DELAYED_MSG];
void clear_pending( void )
{
memset( &prev, 0, sizeof( packet ) );
+ prev_len = 0;
+}
+
+void delay_packet( packet *delay )
+{
+ if( prev_len == MAX_DELAYED_MSG )
+ return;
+
+ memcpy( &prev[prev_len++], delay, sizeof( packet ) );
+}
+
+int send_delayed()
+{
+ uint8_t offset;
+ int ret;
+ for( offset = 0; offset < prev_len; offset++ )
+ {
+ ret = send_packet( &prev[offset], "delayed" );
+ if( ret != 0 )
+ return( ret );
+ }
+
+ clear_pending();
+ return( 0 );
}
/*
@@ -540,6 +634,10 @@
packet cur;
size_t id;
+ uint8_t delay_idx;
+ char ** delay_list;
+ uint8_t delay_list_len;
+
/* receive packet */
if( ( ret = mbedtls_net_recv( src, cur.buf, sizeof( cur.buf ) ) ) <= 0 )
{
@@ -555,6 +653,36 @@
id = cur.len % sizeof( dropped );
+ if( strcmp( way, "S <- C" ) == 0 )
+ {
+ delay_list = opt.delay_cli;
+ delay_list_len = opt.delay_cli_cnt;
+ }
+ else
+ {
+ delay_list = opt.delay_srv;
+ delay_list_len = opt.delay_srv_cnt;
+ }
+ /* Check if message type is in the list of messages
+ * that should be delayed */
+ for( delay_idx = 0; delay_idx < delay_list_len; delay_idx++ )
+ {
+ if( delay_list[ delay_idx ] == NULL )
+ continue;
+
+ if( strcmp( delay_list[ delay_idx ], cur.type ) == 0 )
+ {
+ /* Delay message */
+ delay_packet( &cur );
+
+ /* Remove entry from list */
+ mbedtls_free( delay_list[delay_idx] );
+ delay_list[delay_idx] = NULL;
+
+ return( 0 );
+ }
+ }
+
/* do we want to drop, delay, or forward it? */
if( ( opt.mtu != 0 &&
cur.len > (unsigned) opt.mtu ) ||
@@ -574,12 +702,11 @@
strcmp( cur.type, "ApplicationData" ) != 0 &&
! ( opt.protect_hvr &&
strcmp( cur.type, "HelloVerifyRequest" ) == 0 ) &&
- prev.dst == NULL &&
cur.len != (size_t) opt.protect_len &&
dropped[id] < DROP_MAX &&
rand() % opt.delay == 0 ) )
{
- memcpy( &prev, &cur, sizeof( packet ) );
+ delay_packet( &cur );
}
else
{
@@ -587,14 +714,10 @@
if( ( ret = send_packet( &cur, "forwarded" ) ) != 0 )
return( ret );
- /* send previously delayed message if any */
- if( prev.dst != NULL )
- {
- ret = send_packet( &prev, "delayed" );
- memset( &prev, 0, sizeof( packet ) );
- if( ret != 0 )
- return( ret );
- }
+ /* send previously delayed messages if any */
+ ret = send_delayed();
+ if( ret != 0 )
+ return( ret );
}
return( 0 );
@@ -604,6 +727,7 @@
{
int ret = 1;
int exit_code = MBEDTLS_EXIT_FAILURE;
+ uint8_t delay_idx;
mbedtls_net_context listen_fd, client_fd, server_fd;
@@ -798,6 +922,12 @@
}
#endif
+ for( delay_idx = 0; delay_idx < MAX_DELAYED_HS; delay_idx++ )
+ {
+ mbedtls_free( opt.delay_cli + delay_idx );
+ mbedtls_free( opt.delay_srv + delay_idx );
+ }
+
mbedtls_net_free( &client_fd );
mbedtls_net_free( &server_fd );
mbedtls_net_free( &listen_fd );
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index e63d45f..b77c096 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -5820,6 +5820,88 @@
-s "Extra-header:" \
-c "HTTP/1.0 200 OK"
+# Tests for reordering support with DTLS
+
+run_test "DTLS reordering: Buffer out-of-order handshake message on client" \
+ -p "$P_PXY delay_srv=ServerHello" \
+ "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -c "Buffering HS message" \
+ -c "Next handshake message has been buffered - load"\
+ -S "Buffering HS message" \
+ -S "Next handshake message has been buffered - load"\
+ -C "Inject buffered CCS message" \
+ -C "Remember CCS message" \
+ -S "Inject buffered CCS message" \
+ -S "Remember CCS message"
+
+run_test "DTLS reordering: Buffer out-of-order handshake message on client before reassembling next" \
+ -p "$P_PXY delay_srv=Certificate delay_srv=Certificate" \
+ "$P_SRV mtu=512 dgram_packing=0 cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -c "Buffering HS message" \
+ -c "Next handshake message has been buffered - load"\
+ -S "Buffering HS message" \
+ -S "Next handshake message has been buffered - load"\
+ -C "Inject buffered CCS message" \
+ -C "Remember CCS message" \
+ -S "Inject buffered CCS message" \
+ -S "Remember CCS message"
+
+run_test "DTLS reordering: Buffer out-of-order handshake message on server" \
+ -p "$P_PXY delay_cli=Certificate" \
+ "$P_SRV dgram_packing=0 auth_mode=required cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -C "Buffering HS message" \
+ -C "Next handshake message has been buffered - load"\
+ -s "Buffering HS message" \
+ -s "Next handshake message has been buffered - load" \
+ -C "Inject buffered CCS message" \
+ -C "Remember CCS message" \
+ -S "Inject buffered CCS message" \
+ -S "Remember CCS message"
+
+run_test "DTLS reordering: Buffer out-of-order CCS message on client"\
+ -p "$P_PXY delay_srv=NewSessionTicket" \
+ "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -C "Buffering HS message" \
+ -C "Next handshake message has been buffered - load"\
+ -S "Buffering HS message" \
+ -S "Next handshake message has been buffered - load" \
+ -c "Inject buffered CCS message" \
+ -c "Remember CCS message" \
+ -S "Inject buffered CCS message" \
+ -S "Remember CCS message"
+
+run_test "DTLS reordering: Buffer out-of-order CCS message on server"\
+ -p "$P_PXY delay_cli=ClientKeyExchange" \
+ "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -C "Buffering HS message" \
+ -C "Next handshake message has been buffered - load"\
+ -S "Buffering HS message" \
+ -S "Next handshake message has been buffered - load" \
+ -C "Inject buffered CCS message" \
+ -C "Remember CCS message" \
+ -s "Inject buffered CCS message" \
+ -s "Remember CCS message"
+
+run_test "DTLS reordering: Buffer record from future epoch (client and server)" \
+ -p "$P_PXY delay_ccs=1" \
+ "$P_SRV dgram_packing=0 cookies=0 dtls=1 debug_level=2" \
+ "$P_CLI dgram_packing=0 dtls=1 debug_level=2" \
+ 0 \
+ -s "Buffer record from epoch 1" \
+ -s "Found buffered record from current epoch - load" \
+ -c "Buffer record from epoch 1" \
+ -c "Found buffered record from current epoch - load"
+
# Tests for "randomly unreliable connection": try a variety of flows and peers
client_needs_more_time 2