Split WANT_READ in two error codes

This commit restricts WANT_READ to indicate that no data is available on the
underlying transport. To signal the need for further processing - which was
previously also handled through this error code - a new internal error code
MBEDTLS_ERR_SSL_CONTINUE_PROCESSING is introduced.
This commit is contained in:
Hanno Becker 2017-10-10 10:35:08 +01:00
parent 4cb1f4d49c
commit 8ec8102c9a
2 changed files with 53 additions and 14 deletions

View file

@ -102,13 +102,14 @@
#define MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED -0x6A80 /**< DTLS client must retry for hello verification */
#define MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL -0x6A00 /**< A buffer is too small to receive or write a message */
#define MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE -0x6980 /**< None of the common ciphersuites is usable (eg, no suitable certificate, see debug messages). */
#define MBEDTLS_ERR_SSL_WANT_READ -0x6900 /**< Connection requires a read call. */
#define MBEDTLS_ERR_SSL_WANT_READ -0x6900 /**< No data of requested type currently available on underlying transport. */
#define MBEDTLS_ERR_SSL_WANT_WRITE -0x6880 /**< Connection requires a write call. */
#define MBEDTLS_ERR_SSL_TIMEOUT -0x6800 /**< The operation timed out. */
#define MBEDTLS_ERR_SSL_CLIENT_RECONNECT -0x6780 /**< The client initiated a reconnect from the same port. */
#define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD -0x6700 /**< Record header looks valid but is not expected. */
#define MBEDTLS_ERR_SSL_NON_FATAL -0x6680 /**< The alert message received indicates a non-fatal error. */
#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 */
/*
* Various constants
@ -2397,6 +2398,19 @@ int mbedtls_ssl_get_session( const mbedtls_ssl_context *ssl, mbedtls_ssl_session
* MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED (see below), or
* a specific SSL error code.
*
* If MBEDTLS_ERR_SSL_WANT_READ is returned, the handshake is
* unfinished and no further data is available from the underlying
* transport. In this case, the function needs to be called again
* at some later stage.
*
* \note Remarks regarding event-driven DTLS:
* If the function returns MBEDTLS_ERR_SSL_WANT_READ, no datagram
* from the underlying transport layer is currently being processed,
* and it is safe to idle until the timer or the underlying transport
* signal a new event. This is not true for a successful handshake,
* in which case the currently processed underlying transport's datagram
* might or might not contain further DTLS records.
*
* \note If this function returns something other than 0 or
* MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
* becomes unusable, and you should either free it or call
@ -2460,20 +2474,20 @@ int mbedtls_ssl_renegotiate( mbedtls_ssl_context *ssl );
* \param buf buffer that will hold the data
* \param len maximum number of bytes to read
*
* \return the number of bytes read, or
* 0 for EOF, or
* MBEDTLS_ERR_SSL_WANT_READ or MBEDTLS_ERR_SSL_WANT_WRITE, or
* MBEDTLS_ERR_SSL_CLIENT_RECONNECT (see below), or
* another negative error code.
* \return One of the following:
* - 0 for EOF, or
* - the (positive) number of bytes read, or
* - a negative error code on failure.
*
* \note If this function returns something other than a positive
* value or MBEDTLS_ERR_SSL_WANT_READ/WRITE or
* MBEDTLS_ERR_SSL_CLIENT_RECONNECT, then the ssl context
* becomes unusable, and you should either free it or call
* \c mbedtls_ssl_session_reset() on it before re-using it for
* a new connection; the current connection must be closed.
* If MBEDTLS_ERR_SSL_WANT_READ is returned, no application data
* is available from the underlying transport. In this case,
* the function needs to be called again at some later stage.
*
* \note When this function return MBEDTLS_ERR_SSL_CLIENT_RECONNECT
* If MBEDTLS_ERR_SSL_WANT_WRITE is returned, a write is pending
* but the underlying transport isn't available for writing. In this
* case, the function needs to be called again at some later stage.
*
* When this function return MBEDTLS_ERR_SSL_CLIENT_RECONNECT
* (which can only happen server-side), it means that a client
* is initiating a new connection using the same source port.
* You can either treat that as a connection close and wait
@ -2486,6 +2500,29 @@ int mbedtls_ssl_renegotiate( mbedtls_ssl_context *ssl );
* again. WARNING: not validating the identity of the client
* again, or not transmitting the new identity to the
* application layer, would allow authentication bypass!
*
* If this function returns something other than a positive
* value or MBEDTLS_ERR_SSL_WANT_READ/WRITE or
* MBEDTLS_ERR_SSL_CLIENT_RECONNECT, then the ssl context
* becomes unusable, and you should either free it or call
* \c mbedtls_ssl_session_reset() on it before re-using it for
* a new connection; the current connection must be closed.
*
* \note Remarks regarding event-driven DTLS:
* - If the function returns MBEDTLS_ERR_SSL_WANT_READ, no datagram
* from the underlying transport layer is currently being processed,
* and it is safe to idle until the timer or the underlying transport
* signal a new event.
* - If the function returns MBEDTLS_ERR_SSL_WANT_READ this does not mean
* that no data was available from the underlying transport in the first place,
* as there might have been delayed or duplicated messages, or a renegotiation
* request from the peer. Therefore, the user must be prepared to receive
* MBEDTLS_ERR_SSL_WANT_READ even when reacting to an incoming-data event
* from the underlying transport.
* - On success, the currently processed underlying transport's datagram
* might or might not contain further DTLS records, and the user should
* consult \c mbedtls_ssl_check_pending in that regard.
*
*/
int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len );

View file

@ -426,7 +426,7 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen )
if( use_ret == -(MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE) )
mbedtls_snprintf( buf, buflen, "SSL - None of the common ciphersuites is usable (eg, no suitable certificate, see debug messages)" );
if( use_ret == -(MBEDTLS_ERR_SSL_WANT_READ) )
mbedtls_snprintf( buf, buflen, "SSL - Connection requires a read call" );
mbedtls_snprintf( buf, buflen, "SSL - No data of requested type currently available on underlying transport" );
if( use_ret == -(MBEDTLS_ERR_SSL_WANT_WRITE) )
mbedtls_snprintf( buf, buflen, "SSL - Connection requires a write call" );
if( use_ret == -(MBEDTLS_ERR_SSL_TIMEOUT) )
@ -439,6 +439,8 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen )
mbedtls_snprintf( buf, buflen, "SSL - The alert message received indicates a non-fatal error" );
if( use_ret == -(MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH) )
mbedtls_snprintf( buf, buflen, "SSL - Couldn't set the hash for verifying CertificateVerify" );
if( use_ret == -(MBEDTLS_ERR_SSL_CONTINUE_PROCESSING) )
mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signalling that further message-processing should be done" );
#endif /* MBEDTLS_SSL_TLS_C */
#if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)