f6c95e46c0
Add a "where did this EVP_{CIPHER,MD} come from" flag: global, via fetch,
or via EVP_{CIPHER,MD}_meth_new. Update EVP_{CIPHER,MD}_free to handle all
three origins. The flag is deliberately right before some function pointers,
so that compile-time failures (int/pointer) will occur, as opposed to
taking a bit in the existing "flags" field. The "global variable" flag
is non-zero, so the default case of using OPENSSL_zalloc (for provider
ciphers), will do the right thing. Ref-counting is a no-op for
Make up_ref no-op for global MD and CIPHER objects
Deprecate EVP_MD_CTX_md(). Added EVP_MD_CTX_get0_md() (same semantics as
the deprecated function) and EVP_MD_CTX_get1_md(). Likewise, deprecate
EVP_CIPHER_CTX_cipher() in favor of EVP_CIPHER_CTX_get0_cipher(), and add
EVP_CIPHER_CTX_get1_CIPHER().
Refactor EVP_MD_free() and EVP_MD_meth_free() to call new common
evp_md_free_int() function.
Refactor EVP_CIPHER_free() and EVP_CIPHER_meth_free() to call new common
evp_cipher_free_int() function.
Also change some flags tests to explicit test == or != zero. E.g.,
if (flags & x) --> if ((flags & x) != 0)
if (!(flags & x)) --> if ((flags & x) == 0)
Only done for those lines where "get0_cipher" calls were made.
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14193)
|
||
|---|---|---|
| .. | ||
| 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.