mirror of
https://github.com/openssl/openssl.git
synced 2024-12-09 05:51:54 +08:00
6b1bb98fad
Provide a callback interface that gives the application the ability to adjust the nascent SSL object at the earliest stage of ClientHello processing, immediately after extensions have been collected but before they have been processed. This is akin to BoringSSL's "select_certificate_cb" (though it is not API compatible), and as the name indicates, one major use is to examine the supplied server name indication and select what certificate to present to the client. However, it can also be used to make more sweeping configuration changes to the SSL object according to the selected server identity and configuration. That may include adjusting the permitted TLS versions, swapping out the SSL_CTX object (as is traditionally done in a tlsext_servername_callback), changing the server's cipher list, and more. We also wish to allow an early callback to indicate that it needs to perform additional work asynchronously and resume processing later. To that effect, refactor the second half of tls_process_client_hello() into a subroutine to be called at the post-processing stage (including the early callback itself), to allow the callback to result in remaining in the same work stage for a later call to succeed. This requires allocating for and storing the CLIENTHELLO_MSG in the SSL object to be preserved across such calls, but the storage is reclaimed after ClientHello processing finishes. Information about the CliehtHello is available to the callback by means of accessor functions that can only be used from the early callback. This allows extensions to make use of the existing internal parsing machinery without exposing structure internals (e.g., of PACKET), so that applications do not have to write fragile parsing code. Applications are encouraged to utilize an early callback and not use a servername_callback, in order to avoid unexpected behavior that occurs due to the relative order of processing between things like session resumption and the historical servername callback. Also tidy up nearby style by removing unnecessary braces around one-line conditional bodies. Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/2279) |
||
|---|---|---|
| .github | ||
| apps | ||
| boringssl@490469f850 | ||
| Configurations | ||
| crypto | ||
| demos | ||
| doc | ||
| engines | ||
| external/perl | ||
| fuzz | ||
| include | ||
| ms | ||
| os-dep | ||
| ssl | ||
| test | ||
| tools | ||
| util | ||
| VMS | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| .travis-create-release.sh | ||
| .travis.yml | ||
| ACKNOWLEDGEMENTS | ||
| appveyor.yml | ||
| AUTHORS | ||
| build.info | ||
| CHANGES | ||
| config | ||
| config.com | ||
| Configure | ||
| CONTRIBUTING | ||
| e_os.h | ||
| FAQ | ||
| INSTALL | ||
| LICENSE | ||
| Makefile.shared | ||
| NEWS | ||
| NOTES.DJGPP | ||
| NOTES.PERL | ||
| NOTES.VMS | ||
| NOTES.WIN | ||
| README | ||
| README.ECC | ||
| README.ENGINE | ||
| README.FIPS | ||
OpenSSL 1.1.1-dev
Copyright (c) 1998-2016 The OpenSSL Project
Copyright (c) 1995-1998 Eric A. Young, Tim J. Hudson
All rights reserved.
DESCRIPTION
-----------
The OpenSSL Project is a collaborative effort to develop a robust,
commercial-grade, fully featured, and Open Source toolkit implementing the
Transport Layer Security (TLS) protocols (including SSLv3) as well as a
full-strength general purpose cryptographic library.
OpenSSL is descended from the SSLeay library developed by Eric A. Young
and Tim J. Hudson. The OpenSSL toolkit is licensed under a dual-license (the
OpenSSL license plus the SSLeay license), which means that you are free to
get and use it for commercial and non-commercial purposes as long as you
fulfill the conditions of both licenses.
OVERVIEW
--------
The OpenSSL toolkit includes:
libssl (with platform specific naming):
Provides the client and server-side implementations for SSLv3 and TLS.
libcrypto (with platform specific naming):
Provides general cryptographic and X.509 support needed by SSL/TLS but
not logically part of it.
openssl:
A command line tool that can be used for:
Creation of key parameters
Creation of X.509 certificates, CSRs and CRLs
Calculation of message digests
Encryption and decryption
SSL/TLS client and server tests
Handling of S/MIME signed or encrypted mail
And more...
INSTALLATION
------------
See the appropriate file:
INSTALL Linux, Unix, Windows, OpenVMS, ...
NOTES.* INSTALL addendums for different platforms
SUPPORT
-------
See the OpenSSL website www.openssl.org for details on how to obtain
commercial technical support. Free community support is available through the
openssl-users email list (see
https://www.openssl.org/community/mailinglists.html for further details).
If you have any problems with OpenSSL then please take the following steps
first:
- Download the latest version from the repository
to see if the problem has already been addressed
- Configure with no-asm
- Remove compiler optimisation flags
If you wish to report a bug then please include the following information
and create an issue on GitHub:
- OpenSSL version: output of 'openssl version -a'
- Any "Configure" options that you selected during compilation of the
library if applicable (see INSTALL)
- OS Name, Version, Hardware platform
- Compiler Details (name, version)
- Application Details (name, version)
- Problem Description (steps that will reproduce the problem, if known)
- Stack Traceback (if the application dumps core)
Just because something doesn't work the way you expect does not mean it
is necessarily a bug in OpenSSL. Use the openssl-users email list for this type
of query.
HOW TO CONTRIBUTE TO OpenSSL
----------------------------
See CONTRIBUTING
LEGALITIES
----------
A number of nations restrict the use or export of cryptography. If you
are potentially subject to such restrictions you should seek competent
professional legal advice before attempting to develop or distribute
cryptographic code.