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TLS/SSL and crypto library
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Nicola Tuveri b9a380f78c Make BN_num_bits() consttime upon BN_FLG_CONSTTIME 
This issue was partially addressed by commit
972c87dfc7, which hardened its callee
BN_num_bits_word() to avoid leaking the most-significant word of its
argument via branching and memory access pattern.
The commit message also reported:
> There are a few places where BN_num_bits is called on an input where
> the bit length is also secret. This does *not* fully resolve those
> cases as we still only look at the top word.

BN_num_bits() is called directly or indirectly (e.g., through
BN_num_bytes() or BN_bn2binpad() ) in various parts of the `crypto/ec`
code, notably in all the currently supported implementations of scalar
multiplication (in the generic path through ec_scalar_mul_ladder() as
well as in dedicated methods like ecp_nistp{224,256,521}.c and
ecp_nistz256.c).

Under the right conditions, a motivated SCA attacker could retrieve the
secret bitlength of a secret nonce through this vulnerability,
potentially leading, ultimately, to recover a long-term secret key.

With this commit, exclusively for BIGNUMs that are flagged with
BN_FLG_CONSTTIME, instead of accessing only bn->top, all the limbs of
the BIGNUM are accessed up to bn->dmax and bitwise masking is used to
avoid branching.

Memory access pattern still leaks bn->dmax, the size of the lazily
allocated buffer for representing the BIGNUM, which is inevitable with
the current BIGNUM architecture: reading past bn->dmax would be an
out-of-bound read.
As such, it's the caller responsibility to ensure that bn->dmax does not
leak secret information, by explicitly expanding the internal BIGNUM
buffer to a public value sufficient to avoid any lazy reallocation
while manipulating it: this should be already done at the top level
alongside setting the BN_FLG_CONSTTIME.

Thanks to David Schrammel and Samuel Weiser for reporting this issue
through responsible disclosure.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/9511)

(cherry picked from commit 8b44198b916015f77bef1befa26edb48ad8a0238)
2019-09-07 02:20:59 +03:00
.github Remind people to have 'Fixes #XXXX' in the commit message 2017-04-02 21:51:47 +02:00
apps Suppress 'No server certificate CA names sent' message 2019-09-04 16:48:49 +02:00
boringssl@2070f8ad91 Update ossl_config.json for later BoringSSL commit 2017-03-14 12:12:13 +00:00
Configurations Configurations/unit-Makefile.tmpl: Don't clean away dotted files 2019-08-12 12:06:44 +02:00
crypto Make BN_num_bits() consttime upon BN_FLG_CONSTTIME 2019-09-07 02:20:59 +03:00
demos Fix Typos 2019-07-31 19:48:30 +02:00
doc Correct documented return value for BIO_get_mem_data() 2019-08-20 22:01:02 +10:00
engines engines/build.info: if the padlock engine is disabled, don't build it! 2019-08-12 11:58:24 +02:00
external/perl Update copyright year 2018-09-11 13:45:17 +01:00
fuzz Fix GOST OID 2019-05-24 12:36:06 +03:00
include Change EVP_CIPHER_CTX_iv_length() to return current ivlen for some modes 2019-08-08 13:19:23 +10:00
krb5@b9ad6c4950 [extended tests] Enable krb5 tests in Travis 2017-04-18 19:10:25 +02:00
ms Update copyright year 2019-02-26 14:05:09 +00:00
os-dep Move Haiku configuration to separate config file to denote 2016-05-19 22:39:52 +02:00
pyca-cryptography@09403100de Update the pyca-cryptography submodule 2018-09-10 12:04:03 +01:00
ssl Don't send a status_request extension in a CertificateRequest message 2019-09-06 10:12:51 +01:00
test Teach TLSProxy how to parse CertificateRequest messages 2019-09-06 10:12:51 +01:00
tools Update copyright year 2018-03-20 13:08:46 +00:00
util Teach TLSProxy how to parse CertificateRequest messages 2019-09-06 10:12:51 +01:00
VMS Simplify the handling of shared library version numbers 2017-07-26 22:53:03 +02:00
.gitattributes Don't export the submodules 'boringssl', 'krb5' and 'pyca-cryptography' 2018-11-24 18:43:54 +01:00
.gitignore Add a compile time test to verify that openssl/rsa.h and complex.h can 2018-09-17 09:44:45 +10:00
.gitmodules [extended tests] Enable krb5 tests in Travis 2017-04-18 19:10:25 +02:00
.travis-apt-pin.preferences Fix travis clang-3.9 builds 2017-06-23 17:57:02 +01:00
.travis-create-release.sh Remove all 'make dist' artifacts 2018-11-23 12:42:21 +01:00
.travis.yml .travis.yml: Use travis_terminate on failure 2019-08-18 13:21:29 +02:00
ACKNOWLEDGEMENTS Refer to website for acknowledgements. 2015-12-08 16:07:09 -05:00
appveyor.yml CI config: no need to make both install and install_docs 2018-05-14 17:51:48 +02:00
AUTHORS Update AUTHORS list, add commentary 2018-07-08 20:32:04 -04:00
build.info Configurations/10-main.conf: replace -bexpall with explicit list on AIX. 2018-06-13 10:48:27 +02:00
CHANGES Remove duplicate CHANGES text. 2019-08-30 19:20:17 +10:00
config iOS build: Replace %20 with space in config script 2019-07-08 10:57:30 +02:00
config.com Update copyright year 2018-02-13 13:59:25 +00:00
Configure Remove last references to DEBUG_SAFESTACK 2019-06-04 07:18:33 +02:00
CONTRIBUTING Remove unnecessary trailing whitespace 2019-02-05 16:29:17 +01:00
e_os.h Don't include the DEVRANDOM being seeded logic on Android. 2019-08-30 08:02:33 +10:00
FAQ Move FAQ to the web. 2015-08-16 19:02:29 -04:00
INSTALL INSTALL: clarify documentation of the --api=x.y.z deprecation option 2019-08-15 14:58:32 +02:00
LICENSE Update copyright year 2019-02-26 14:05:09 +00:00
NEWS Fix Typos 2019-07-01 02:02:06 +08:00
NOTES.ANDROID Remove unnecessary trailing whitespace 2019-02-05 16:29:17 +01:00
NOTES.DJGPP Remove unnecessary trailing whitespace 2019-02-05 16:29:17 +01:00
NOTES.PERL Fix typo in NOTES.PERL 2019-05-16 11:47:53 +10:00
NOTES.UNIX NOTES.UNIX: add "Linking your application" paragraph 2018-06-26 12:28:06 +02:00
NOTES.VMS Remove unnecessary trailing whitespace 2019-02-05 16:29:17 +01:00
NOTES.WIN Fix default installation paths on mingw 2019-07-25 13:08:46 +02:00
README Prepare for 1.1.1d-dev 2019-05-28 15:12:39 +02:00
README.ENGINE Remove bsd_cryptodev engine 2017-06-19 09:31:45 -04:00
README.FIPS Remove more (rest?) of FIPS build stuff. 2016-01-06 12:07:26 -05:00

README 

 OpenSSL 1.1.1d-dev

 Copyright (c) 1998-2019 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 optimization 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'
    - Configuration data: output of 'perl configdata.pm --dump'
    - 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.