yuzu-emu/mbedtls
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Improve comments/documentation

Browse source 
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
This commit is contained in:
Ronald Cron 2024-02-21 13:45:52 +01:00
parent 49221900b0
commit d4069247b8
3 changed files with 48 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
include/mbedtls/ssl.h
View file

@ -5199,17 +5199,43 @@ int mbedtls_ssl_read_early_data(mbedtls_ssl_context *ssl,
* \brief Try to write exactly 'len' application data bytes while
* performing the handshake (early data).
*
* \warning Early data is defined in the TLS 1.3 specification, RFC 8446.
* IMPORTANT NOTE from section 2.3 of the specification:
*
* The security properties for 0-RTT data are weaker than
* those for other kinds of TLS data. Specifically:
* - This data is not forward secret, as it is encrypted
* solely under keys derived using the offered PSK.
* - There are no guarantees of non-replay between connections.
* Protection against replay for ordinary TLS 1.3 1-RTT data
* is provided via the server's Random value, but 0-RTT data
* does not depend on the ServerHello and therefore has
* weaker guarantees. This is especially relevant if the
* data is authenticated either with TLS client
* authentication or inside the application protocol. The
* same warnings apply to any use of the
* early_exporter_master_secret.
*
* \note This function behaves mainly as mbedtls_ssl_write(). The
* specification of mbedtls_ssl_write() relevant to TLS 1.3
* (thus not the parts specific to (D)TLS1.2) applies to this
* function and the present documentation is restricted to the
* differences with mbedtls_ssl_write().
* function and the present documentation is mainly restricted
* to the differences with mbedtls_ssl_write(). One noticeable
* difference though is that mbedtls_ssl_write() aims to
* complete the handshake before to write application data
* while mbedtls_ssl_write_early() aims to drive the handshake
* just past the point where it is not possible to send early
* data anymore.
*
* \param ssl SSL context
* \param buf buffer holding the data
* \param len how many bytes must be written
*
* \return One additional specific return value:
* \return The (non-negative) number of bytes actually written if
* successful (may be less than \p len).
*
* \return One additional specific error code compared to
* mbedtls_ssl_write():
* #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA.
*
* #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA is returned when it

19
library/ssl_msg.c
View file

@ -6087,14 +6087,17 @@ int mbedtls_ssl_write_early_data(mbedtls_ssl_context *ssl,
}
/*
* If we are at the beginning of the handshake, advance the handshake just
* If we are at the beginning of the handshake, the early data status being
* equal to MBEDTLS_SSL_EARLY_DATA_STATUS_UNKNOWN or
* MBEDTLS_SSL_EARLY_DATA_STATUS_SENT advance the handshake just
* enough to be able to send early data if possible. That way, we can
* guarantee that when starting the handshake with this function we will
* send at least one record of early data.
* Otherwise, resume the handshake and if the handshake sequence stops
* waiting for some message from the server, send early data if we can.
* send at least one record of early data. Note that when the status is
* MBEDTLS_SSL_EARLY_DATA_STATUS_SENT and not yet
* MBEDTLS_SSL_EARLY_DATA_STATUS_CAN_WRITE, we cannot send early data yet
* as the early data outbound transform has not been set as we may have to
* first send a dummy CCS in clear.
*/
if ((ssl->early_data_status == MBEDTLS_SSL_EARLY_DATA_STATUS_UNKNOWN) ||
(ssl->early_data_status == MBEDTLS_SSL_EARLY_DATA_STATUS_SENT)) {
while ((ssl->early_data_status == MBEDTLS_SSL_EARLY_DATA_STATUS_UNKNOWN) ||
@ -6112,6 +6115,12 @@ int mbedtls_ssl_write_early_data(mbedtls_ssl_context *ssl,
}
}
} else {
/*
* If we are past the point where we can send early data, return
* immediatly. Otherwise, progress the handshake as much as possible to
* not delay it too much. If we reach a point where we can still send
* early data, then we will send some.
*/
if ((ssl->early_data_status != MBEDTLS_SSL_EARLY_DATA_STATUS_CAN_WRITE) &&
(ssl->early_data_status != MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED)) {
return MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA;

7
tests/suites/test_suite_ssl.function
View file

@ -4217,8 +4217,11 @@ void tls13_write_early_data(int scenario)
TEST_EQUAL(ret, 0);
/*
* Run handshakes and test the writing of early data in each possible
* state.
* Run handshakes going one state further in the handshake sequence at each
* loop up to the point where we reach the MBEDTLS_SSL_HANDSHAKE_OVER
* state. For each reached handshake state, check the result of the call
* to mbedtls_ssl_write_early_data() and then restart the handshake from
* scratch (see reset label).
*/
previous_client_state = MBEDTLS_SSL_HELLO_REQUEST;
client_state = MBEDTLS_SSL_HELLO_REQUEST;