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Merge pull request Mbed-TLS#325 from hanno-arm/mps_remove_ext_rd_wr
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MPS: Remove extended reader/writer from MPS, part 2
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Hanno Becker authored Jul 29, 2021
2 parents 4ddebaf + fba6861 commit 471fc0e
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Showing 12 changed files with 629 additions and 1,147 deletions.
46 changes: 18 additions & 28 deletions include/mbedtls/mps/common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -290,8 +290,10 @@ typedef uint8_t mbedtls_mps_epoch_offset_t;

#else /* MBEDTLS_MPS_ENABLE_ASSERTIONS */

#define MBEDTLS_MPS_ASSERT( cond, string ) do {} while( 0 )
#define MBEDTLS_MPS_ASSERT_RAW( cond, string ) do {} while( 0 )
#define MBEDTLS_MPS_ASSERT( cond, string ) \
do { int val = (cond); ((void) val); } while( 0 )
#define MBEDTLS_MPS_ASSERT_RAW( cond, string ) \
do { int val = (cond); ((void) val); } while( 0 )

#endif /* MBEDTLS_MPS_ENABLE_ASSERTIONS */

Expand Down Expand Up @@ -376,41 +378,29 @@ typedef uint8_t mbedtls_mps_transport_type;
/* MBEDTLS_SSL_TRANSPORT_DATAGRAM */
#define MBEDTLS_MPS_MODE_DATAGRAM ((mbedtls_mps_transport_type) 1)

/* Helper macros to check whether TLS/DTLS are enabled. */
#if defined(MBEDTLS_MPS_PROTO_TLS)

#if defined(MBEDTLS_MPS_PROTO_BOTH)
#define MBEDTLS_MPS_IS_TLS( mode ) \
( (mode) == MBEDTLS_MPS_MODE_STREAM )
#define MBEDTLS_MPS_IS_TLS(mode) ((mode) == MBEDTLS_MPS_MODE_STREAM)
#else
/* Define `1` in a roundabout way using `mode` to avoid unused
* variable warnings. */
#define MBEDTLS_MPS_IS_TLS( mode ) ( ((void) mode), 1 )
#define MBEDTLS_MPS_IS_TLS(mode) (((void) mode), 1)
#endif /* MBEDTLS_MPS_PROTO_BOTH */

#define MBEDTLS_MPS_IF_TLS( mode ) if( MBEDTLS_MPS_IS_TLS( mode ) )

#else /* MBEDTLS_MPS_PROTO_TLS */

#define MBEDTLS_MPS_IS_TLS( mode ) 0

#else /* MBEDTLS_MPS_PROTO_TLS */
#define MBEDTLS_MPS_IS_TLS(mode) (((void) mode), 0)
#endif /* MBEDTLS_MPS_PROTO_TLS */

#define MBEDTLS_MPS_IF_TLS(mode) if( MBEDTLS_MPS_IS_TLS( mode ) )
#if defined(MBEDTLS_MPS_PROTO_DTLS)
#if defined(MBEDTLS_MPS_PROTO_BOTH)
#define MBEDTLS_MPS_IS_DTLS( mode ) \
( (mode) == MBEDTLS_MPS_MODE_DATAGRAM )
#define MBEDTLS_MPS_ELSE_IF_DTLS( mode ) \
else if( ((void)mode), 1 )
#else
/* Define `1` in a roundabout way using `mode` to avoid unused
* variable warnings. */
#define MBEDTLS_MPS_IS_DTLS( mode ) ( ((void) mode), 1 )
#define MBEDTLS_MPS_ELSE_IF_DTLS( mode ) \
if( MBEDTLS_MPS_IS_DTLS( mode ) )
#define MBEDTLS_MPS_IS_DTLS(mode) ((mode) == MBEDTLS_MPS_MODE_DATAGRAM)
#define MBEDTLS_MPS_ELSE_IF_DTLS(mode) else if(((void)mode), 1)
#else /* MBEDTLS_MPS_PROTO_BOTH */
#define MBEDTLS_MPS_IS_DTLS(mode) (((void) mode), 1)
#define MBEDTLS_MPS_ELSE_IF_DTLS( mode ) if( MBEDTLS_MPS_IS_DTLS( mode ) )
#endif /* MBEDTLS_MPS_PROTO_BOTH */

#define MBEDTLS_MPS_IF_DTLS( mode ) if( MBEDTLS_MPS_IS_DTLS( mode ) )
#else /* MBEDTLS_MPS_PROTO_DTLS */
#define MBEDTLS_MPS_IS_DTLS(mode) (((void) mode), 0 )
#endif /* MBEDTLS_MPS_PROTO_DTLS */
#define MBEDTLS_MPS_IF_DTLS( mode ) if(MBEDTLS_MPS_IS_DTLS(mode))

/*! The enumeration of record content types recognized by MPS.
*
Expand Down
94 changes: 38 additions & 56 deletions include/mbedtls/mps/layer3.h
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Original file line number Diff line number Diff line change
Expand Up @@ -92,39 +92,39 @@ typedef enum mps_l3_hs_state
} mps_l3_hs_state;

/**
* \brief This structure represents handles to
* outgoing handshake messages.
*
* It is used in the following way:
* When the user wants to prepare an outgoing
* handshake message, he creates an instance
* of this structure and sets fields indicating
* the intended epoch, handshake type, and
* handshake message length. The user then calls
* mps_l3_write_handshake() which, on success,
* sets the \c wr_ext within this struct to point
* to a valid writer that can be used to provide
* the actual message contents.
*
* When the writing is done, the user calls
* mps_l3_dispatch() to prepare the message for
* delivery; if the writing cannot be completed
* because the provided writer does not provide
* enough space for outgoing data, the write can
* be paused via mps_l3_pause_handshake(), and
* subsequently be continued via another call to
* mps_l3_write_handshake() which must use the
* the same epoch, handshake type and length
* parameters as the initial one.
*
* The handshake message length must be known
* in advance if pausing is needed for the message.
* If pausing is not needed, the length field can
* be set to #MBEDTLS_MPS_SIZE_UNKNOWN and will be
* be determined automatically on closing.
* \brief This structure represents handles to outgoing handshake messages.
*
* It is used in the following way: When users want to prepare
* an outgoing handshake message, they create an instance of this
* structure and set fields indicating the intended epoch,
* handshake type, and handshake message length. They then call
* mps_l3_write_handshake() which, on success, sets the \c wr
* within this struct to point to a valid writer that can be used
* to provide the actual message contents.
*
* When the writing is done, users call mps_l3_dispatch() to prepare
* the message for delivery; if the writing cannot be completed
* because the provided writer does not provide enough space for
* outgoing data, the write can be paused via mps_l3_pause_handshake()
* and subsequently be continued via another call to
* mps_l3_write_handshake() which must use the the same epoch,
* handshake type and length parameters as the initial one.
*
* The handshake message length must be known in advance if pausing
* is needed for the message. If pausing is not needed, the length
* field can be set to #MBEDTLS_MPS_SIZE_UNKNOWN and will be be
* determined automatically on closing.
*/
struct mps_l3_handshake_out
{
/*! The total length of the handshake message (regardless of fragmentation),
* or #MBEDTLS_MPS_SIZE_UNKNOWN if the length will be determined at
* write-time. In this case, pausing is not possible for the handshake
* message (because the headers for handshake fragments include the total
* length of the handshake message). This must be set by the user
* before calling mps_l3_write_handshake(). */
mbedtls_mps_stored_opt_size_t len;

/*! The epoch to use to protect the handshake message.
* This must be set by the user before calling mps_l3_write_handshake(). */
mbedtls_mps_stored_epoch_id epoch;
Expand All @@ -133,30 +133,24 @@ struct mps_l3_handshake_out
* the user before calling mps_l3_write_handshake().*/
mbedtls_mps_stored_hs_type type;

#if defined(MBEDTLS_MPS_PROTO_DTLS)
/*! The handshake sequence number. */
mbedtls_mps_stored_hs_seq_nr_t seq_nr;

/*! The total length of the handshake message (regardless of fragmentation),
* or #MBEDTLS_MPS_SIZE_UNKNOWN if the length will be determined at
* write-time. In this case, pausing is not possible for the handshake
* message (because the headers for handshake fragments include the total
* length of the handshake message). This must be set by the user
* before calling mps_l3_write_handshake(). */
mbedtls_mps_stored_opt_size_t len;

/*! The length of the current handshake fragment, or
* #MBEDTLS_MPS_SIZE_UNKNOWN if the will be determined at write-time. */
mbedtls_mps_stored_opt_size_t frag_len;

/*! The offset of the current fragment from the
* beginning of the handshake message.*/
mbedtls_mps_stored_size_t frag_offset;
#endif /* MBEDTLS_MPS_PROTO_DTLS */

/*! The extended writer providing buffers to which the message
/*! The writer providing buffers to which the message
* contents can be written, and keeping track of message bounds.
* This must be \c NULL when the user calls mps_l3_write_handshake(), which
* will modify it to point to a valid extended writer on success. */
mbedtls_writer_ext *wr_ext;
* will modify it to point to a valid writer on success. */
mbedtls_writer *wr;
};

/**
Expand Down Expand Up @@ -205,9 +199,8 @@ struct mps_l3_handshake_in
/*! The handshake sequence number.*/
mbedtls_mps_stored_hs_seq_nr_t seq_nr;

/*!< The extended reader giving access to the message contents, and
* keeping track of message bounds. */
mbedtls_mps_reader_ext *rd_ext;
/*!< The reader giving access to the message contents. */
mbedtls_mps_reader *rd;
};

/**
Expand Down Expand Up @@ -338,10 +331,6 @@ struct mps_l3_hs_in_internal

/*!< The handshake sequence number. */
mbedtls_mps_stored_hs_seq_nr_t seq_nr;

mbedtls_mps_reader_ext rd_ext; /*!< The extended reader giving access to
* the message contents, but also keeping
* track of message bounds. */
};

struct mps_l3_hs_out_internal
Expand Down Expand Up @@ -369,14 +358,7 @@ struct mps_l3_hs_out_internal
/*! The size of the header buffer. */
mbedtls_mps_stored_size_t hdr_len;

/*! The extended writer providing buffers to which the message
* contents can be written, and keeping track of message bounds. */

/* OPTIMIZATION:
* Consider removing the extended writer from Layer 3 and
* performing bounds checks for handshake messages at Layer 4.
* See the corresponding comment in mps.h. */
mbedtls_writer_ext wr_ext;
mbedtls_mps_stored_size_t hdr_offset;

/* DTLS-specific fields. */

Expand Down
36 changes: 17 additions & 19 deletions include/mbedtls/mps/mps.h
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Original file line number Diff line number Diff line change
Expand Up @@ -433,7 +433,7 @@ typedef void mbedtls_mps_write_cb_ctx_t;
* that was used to write the message in the first place.
*/
typedef int (*mbedtls_mps_write_cb_t)( mbedtls_mps_write_cb_ctx_t const *ctx,
mbedtls_writer_ext *writer );
mbedtls_writer *writer );

/*! Enumeration of states of ::mbedtls_mps_handshake_out_internal. */
typedef uint8_t mbedtls_mps_hs_state;
Expand All @@ -445,13 +445,14 @@ typedef uint8_t mbedtls_mps_hs_state;
writing-mode. */
#define MBEDTLS_MPS_HS_ACTIVE ( (mbedtls_mps_hs_state) 1 )
/*! This state indicates an initialized structure representing
* an outgoing handshake message whose user-facing writer is in
* providing mode. That's the case if the message is not yet
* completely written and another message buffer is needed to
* hold the next chunk of message contents; or it might be that
* the message has been entirely written, but parts or all of its
* content are still buffered and need to be dispatched. */
#define MBEDTLS_MPS_HS_PAUSED ( (mbedtls_mps_hs_state) 2 )
* an outgoing handshake message has been completely written
* by the user, but which still needs to be dispatched to
* Layer 3. */
#define MBEDTLS_MPS_HS_QUEUED ( (mbedtls_mps_hs_state) 2 )
/*! This state indicates an initialized structure representing
* an outgoing handshake message which has not yet been fully
* written by the user */
#define MBEDTLS_MPS_HS_PAUSED ( (mbedtls_mps_hs_state) 3 )

/*
* \brief Internal structure representing an outgoing handshake message.
Expand Down Expand Up @@ -542,8 +543,8 @@ struct mbedtls_mps_handshake_out_internal
* we'd safe a pointer to a raw writer here (which, however,
* might be removed due to the previous optimization
* opportunity). */
mbedtls_writer_ext *wr_ext_l3; /*!< The writer obtained from Layer 3 to
* write the next handshake fragment.*/
mbedtls_writer *wr_l3; /*!< The writer obtained from Layer 3 to
* write the next handshake fragment.*/

/*
* User-facing writers
Expand All @@ -554,9 +555,7 @@ struct mbedtls_mps_handshake_out_internal
* and one should be able to avoid duplicating them here. */
mbedtls_mps_stored_size_t queue_len;
unsigned char *queue;
mbedtls_writer wr;
mbedtls_writer_ext wr_ext; /*!< The write-handle to the handshake message
* content that's passed to the user. */
mbedtls_writer wr;

};

Expand Down Expand Up @@ -1043,8 +1042,7 @@ struct mbedtls_mps
*
* TODO: Document in which states this is valid.
*/
mbedtls_mps_reader rd;
mbedtls_mps_reader_ext rd_ext;
mbedtls_mps_reader rd;

/*! The array of structures representing future and/or
* partially received handshake messages. */
Expand Down Expand Up @@ -1089,7 +1087,7 @@ struct mbedtls_mps
/*! The extended reader owned by Layer 3 giving rise to the
* contents of the handshake message. This is valid if and
* only if \c status is #MPS_REASSEMBLY_NO_FRAGMENTATION */
mbedtls_mps_reader_ext *rd_ext_l3;
mbedtls_mps_reader *rd_l3;

/*! The reassembly buffer holding the partially received
* handshake message. This is valid if and only if
Expand Down Expand Up @@ -1290,7 +1288,7 @@ typedef struct
{
uint8_t type; /*!< Type of handshake message */
size_t length; /*!< Length of entire handshake message */
mbedtls_mps_reader_ext *handle; /*!< Reader to retrieve message contents */
mbedtls_mps_reader *handle; /*!< Reader to retrieve message contents */

uint8_t add[8]; /*!< Opaque, additional data to be used for
* checksum calculations. */
Expand Down Expand Up @@ -1405,7 +1403,7 @@ int mbedtls_mps_read_set_flags( mbedtls_mps *mps, mbedtls_mps_msg_flags flags );
* \brief Pause the reading of an incoming handshake message.
*
* When a handshake message has been received, the user of the
* MPS can query its contents through mbedtls_mps_reader_get_ext(),
* MPS can query its contents through mbedtls_mps_reader_get(),
* using the reader returned from mbedtls_mps_read_handshake().
* If the handshake message is only partially available - for
* example, because it was fragments on the TLS record layer -
Expand Down Expand Up @@ -1535,7 +1533,7 @@ struct mbedtls_mps_handshake_out
* calling mbedtls_mps_write_handshake(). */
mbedtls_mps_stored_opt_size_t length;

mbedtls_writer_ext *handle; /*!< Write-handle to handshake message content.
mbedtls_writer *handle; /*!< Write-handle to handshake message content.
*
* This field is set by the MPS implementation
* of mbedtls_mps_write_handshake(). Any
Expand Down
16 changes: 12 additions & 4 deletions include/mbedtls/mps/trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,8 +37,6 @@
#define mbedtls_vsnprintf vsnprintf
#endif /* MBEDTLS_PLATFORM_C */

#if defined(MBEDTLS_MPS_ENABLE_TRACE)

/*
* Adapt this to enable/disable tracing output
* from the various layers of the MPS.
Expand Down Expand Up @@ -115,6 +113,8 @@ typedef enum
MBEDTLS_MPS_TRACE_MASK_READER | \
MBEDTLS_MPS_TRACE_MASK_WRITER )

#if defined(MBEDTLS_MPS_ENABLE_TRACE)

/* We have to avoid globals because E-ACSL chokes on them...
* Wrap everything in stub functions. */
int mbedtls_mps_trace_get_depth( void );
Expand Down Expand Up @@ -163,8 +163,16 @@ void mbedtls_mps_trace_print_msg( int id, int line, const char *format, ... );

#else /* MBEDTLS_MPS_TRACE */

#define MBEDTLS_MPS_TRACE( type, ... ) do { } while( 0 )
#define MBEDTLS_MPS_TRACE_INIT( ... ) do { } while( 0 )
static inline void mps_trace_variable_sink( const char* fmt, ...)
{
((void) fmt);
}

/* Make sure to "use" arguments, to avoid unused variable warnings. */
#define MBEDTLS_MPS_TRACE( type, ... ) \
do { ((void) type); mps_trace_variable_sink( __VA_ARGS__ ); } while( 0 )
#define MBEDTLS_MPS_TRACE_INIT( ... ) \
do { mps_trace_variable_sink( __VA_ARGS__ ); } while( 0 )
#define MBEDTLS_MPS_TRACE_END do { } while( 0 )

#define MBEDTLS_MPS_TRACE_RETURN( val ) return( val );
Expand Down
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