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- Don't unpad records, check the outer record type, or extract the inner record type from TLS 1.3 records handled by the kernel. KTLS performs all of these steps and returns the inner record type in the TLS header. - When checking the length of a received TLS 1.3 record don't allow for the extra byte for the nested record type when KTLS is used. - Pass a pointer to the record type in the TLS header to the SSL3_RT_INNER_CONTENT_TYPE message callback. For KTLS, the old pointer pointed to the last byte of payload rather than the record type. For the non-KTLS case, the TLS header has been updated with the inner type before this callback is invoked. Co-authored-by: John Baldwin <jhb@FreeBSD.org> Signed-off-by: Daiki Ueno <dueno@redhat.com> Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Tomas Mraz <tomas@openssl.org> (Merged from https://github.com/openssl/openssl/pull/17942) |
||
|---|---|---|
| .. | ||
| dtls1_bitmap.c | ||
| README.md | ||
| rec_layer_d1.c | ||
| rec_layer_s3.c | ||
| record_local.h | ||
| record.h | ||
| ssl3_buffer.c | ||
| ssl3_record_tls13.c | ||
| ssl3_record.c | ||
| tls_pad.c | ||
Record Layer Design
This file provides some guidance on the thinking behind the design of the record layer code to aid future maintenance.
The record layer is divided into a number of components. At the time of writing there are four: SSL3_RECORD, SSL3_BUFFER, DLTS1_BITMAP and RECORD_LAYER. Each of these components is defined by:
- A struct definition of the same name as the component
- A set of source files that define the functions for that component
- A set of accessor macros
All struct definitions are in record.h. The functions and macros are either defined in record.h or record_local.h dependent on whether they are intended to be private to the record layer, or whether they form part of the API to the rest of libssl.
The source files map to components as follows:
dtls1_bitmap.c -> DTLS1_BITMAP component
ssl3_buffer.c -> SSL3_BUFFER component
ssl3_record.c -> SSL3_RECORD component
rec_layer_s3.c, rec_layer_d1.c -> RECORD_LAYER component
The RECORD_LAYER component is a facade pattern, i.e. it provides a simplified interface to the record layer for the rest of libssl. The other 3 components are entirely private to the record layer and therefore should never be accessed directly by libssl.
Any component can directly access its own members - they are private to that component, e.g. ssl3_buffer.c can access members of the SSL3_BUFFER struct without using a macro. No component can directly access the members of another component, e.g. ssl3_buffer cannot reach inside the RECORD_LAYER component to directly access its members. Instead components use accessor macros, so if code in ssl3_buffer.c wants to access the members of the RECORD_LAYER it uses the RECORD_LAYER_* macros.
Conceptually it looks like this:
libssl
|
-------------------------|-----record.h------------------------------------
|
_______V______________
| |
| RECORD_LAYER |
| |
| rec_layer_s3.c |
| ^ |
| _________|__________ |
|| ||
|| DTLS1_RECORD_LAYER ||
|| ||
|| rec_layer_d1.c ||
||____________________||
|______________________|
record_local.h ^ ^ ^
_________________| | |_________________
| | |
_____V_________ ______V________ _______V________
| | | | | |
| SSL3_BUFFER | | SSL3_RECORD | | DTLS1_BITMAP |
| |--->| | | |
| ssl3_buffer.c | | ssl3_record.c | | dtls1_bitmap.c |
|_______________| |_______________| |________________|
The two RECORD_LAYER source files build on each other, i.e. the main one is rec_layer_s3.c which provides the core SSL/TLS layer. The second one is rec_layer_d1.c which builds off of the SSL/TLS code to provide DTLS specific capabilities. It uses some DTLS specific RECORD_LAYER component members which should only be accessed from rec_layer_d1.c. These are held in the DTLS1_RECORD_LAYER struct.