OpenSSL 1.1.0 Changes

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Revision as of 17:18, 16 February 2015 by Dwmw2 (talk | contribs)
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This is a parent page for discussion about API changes being done for OpenSSL version 1.1

The overall goal of this project is to make most data structures opaque to applications. This provides us with a number of benefits:

  • We can add fields without breaking binary compatibility
  • Applications are more robust and can be more assured about correctness
  • It helps us determine which (new) accessors and settors, for example, are needed

Please add sub-pages to discuss particular parts of the library as work progresses.

Major Changes so far

  • All structures in libssl public header files have been removed so that they are "opaque" to library users. You should use the provided accessor functions instead
  • The old DES API has been removed
  • bn, a sub library in libcrypto, has been made opaque
  • Access to deprecated functions/macros has been removed by default. To enable access you must do two things. 1) Build OpenSSL with deprecation support (pass "enable-deprecated" as an argument to config) 2) Applications must define "OPENSSL_USE_DEPRECATED" before including OpenSSL header files
  • HMAC_Init and HMAC_cleanup were previously stated in the docs and header files as being deprecated - but were not flagged in previous versions with OPENSSL_NO_DEPRECATED. This has been corrected in 1.1.0. Access to these functions/macros will be off by default in 1.1.0 as per the note above about deprecation.

Things that Broke in Qt

Here's what's broken in the dev branch of Qt when building openssl master as of 6 Feb 2015.

  • DH - we were directly accessing p and q to set the DH params to primes embedded in Qt. We can probably replace this with SSL_CTX_set_dh_auto(ctx, 1). Another option suggested by Steve Henson is to save the DHparams we're using at the moment then use d2i_DHparams to load them in. This is compatible with openssl versions that don't have the dh_auto option.
  • ctx->cert_store - we were directly accessing the cert_store field of SSL_CTX. We can probably replace this with X509_STORE *SSL_CTX_get_cert_store(SSL_CTX *ctx) [Fixed in dev]
  • session->tlsext_tick_lifetime_hint - we were directly accessing the lifetime hint of the session. [A new API to access this field has been added]
  • cipher->valid - we were directly accessing the valid field of SSL_CIPHER. No replacement found. [This turned out not to be needed and so will be removed].

Things that Broke in Curl

  • SSL_SESSION->ssl_version. Replaced with SSL_version(SSL *)

Things that Broke in wget

  • SSL->state. Replaced with SSL_state(SSL *)

Things that Broke in Apache Traffic Manager

  • Setting SSL->rbio without setting SSL->wbio. New function introduction in 1.1.0 to handle this: SSL_set_rbio()

Things that Broke in OpenConnect

In order to simulate "resume" of a DTLS session which never really existed but which was actually negotiated over the VPN control connection, this code in the OpenConnect VPN client needs to set the following fields in a new SSL_SESSION:

  • ->ssl_version
  • ->cipher{,_id}
  • ->master_key{,_length}
  • ->session_id{,_length}

It looks like using d2i_SSL_SESSION() might be a possible replacement, if the ASN.1 rendering of the SSL_SESSION is considered to be usable as a stable ABI feature. But it would need fixing to cope with the fact that the SSL version is Cisco's pre-standard DTLS1_BAD_VER abomination, which currently makes d2i_SSL_SESSION() fail with SSL_R_UNKNOWN_SSL_VERSION.

An alternative would be to introduce a new function to create a SSL_SESSION with the required parameters, vaguely equivalent to gnutls_session_set_premaster()

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