What changed in OpenSSL after heartbleed (opens in new tab)

I've been doing differential fuzzing of many major cryptographic libraries. It currently tests symmetric crypto, some elliptic curve crypto, bignum arithmetic, message digests and MACs, KDFs, but not TLS, X509, ASN1 etc (yet). The list of bugs it has found so far can be viewed here [1].

The bug count per library can not be used as an absolute metric and not all bugs are security vulnerabilities (though many can be under specific circumstances).

BoringSSL has fewer bugs than LibreSSL, which has fewer bugs than OpenSSL. One of the reasons for this could be that the bug count is proportional to the complexity/SLOC: BoringSSL is smaller in terms of functionality (# of message digests, ciphers, ...) than LibreSSL, which is smaller than OpenSSL. OpenSSL sometimes commits new buggy code whereas BoringSSL does not, but OpenSSL has a higher commit frequency than BoringSSL, and BoringSSL might be aiming for a production-safe master branch where OpenSSL might not.

So it's not easy to derive a reliable metric from this, but with that said, you can't really go wrong with BoringSSL if it offers what you need.

[1] https://github.com/guidovranken/cryptofuzz#bugs-found-by-cry...

I think the multiplatform support is an interesting criticism but misunderstood.

I happened to be reading some OpenSSL code around the time of heartbleed and statically linking some of it in a project. I found a lot of the portability ifdefs were poorly done even for the standards of the 90s. It wasn't portability itself that was the issue, it was actual quality and in many cases the wrong abstractions in place.

One example that sticks out in my memory... There was a logger that had a Win32 ifdef. If you ran on Win32 it fed log messages directly to MessageBox(). Unless it detected the current process was an NT service, in that case it used another logging mechanism without asking. It wasn't actually "windows portability" or "windows support". The whole thing wasn't appropriate for a library. It could have had a mechanism to give the log lines to the application as a C string and be done with it. Instead, it was mixing of library layer stuff and application layer stuff, or just ordinary library bloat.

The other huge example I recall was compliance with older configurations that were pre-C99. C99 is much more universal now vs 20 years ago, although there are a few things Microsoft still doesn't support. But again, a bunch of these things seemed to be handled with ifdefs at the call site, rather than put in a proper compatibility layer that only an older configuration gets.

It does seem that in the years since then, cruft has been removed not only in forks but also in the upstream project.

During a code review we found recently written Go code using SHA1, which has been functionally obsolete since 2005. It's a bit baffling why Google even included it in Go or at the very least didn't make it throw up a bunch of warnings to only use it for very special edge cases related to backward compatibility.

The developer didn't know what algorithm to pick so he just went with one at random, assuming it was ok since it was in the library. How many other security vulnerabilities are out there due to similar circumstances? It's a bit troubling.

Unused? Ha ha, good one. Our VAX will never die.

    $ set def [.openssl]
    $ run openssl
    WARNING: can't open config file: SSLROOT: 
    [000000]openssl.cnf
    OpenSSL> version
    OpenSSL 1.0.0r 19 Mar 2015
    OpenSSL> quit
    $

The platform-specific stuff is not where most of the bugs have been found, so your assertion is misguided. Portability is one of the greatest strengths "keeping crypto freely accessible for all" and the fact that e.g. with a suitable C89 compiler I can create a binary that will run on an original 8088 IBM PC and perform SHA256 or AES should not be underestimated.

To a first approximation, crypto is pure maths. The rest can be taken care of by the standard C library.

"dumping ground for their pet research projects, that are enabled by default, of course"

How does that work? How does anyone even approve it if it isn't going to be used?

Admittedly I'm out of the loop as far as contributing to such projects, maybe letting that stuff in is the norm?

As the LibreSSL devs have said, heartbleed was not the cause of the fork. They forked the project because they believed the OpenSSL project repeatedly made bad decisions.

From https://www.openbsd.org/papers/eurobsdcon2014-libressl.html

> Heartbleed can't even be considered the worst OpenSSL vuln. Previous bugs have resulted in remote code execution. Anybody remember the Slapper worm? That worm exploited an OpenSSL bug (which was apparently titled the SSLv2 client master key buffer overflow) which revealed not only encrypted data or your private key, but also gave up a remote shell on the server, and then it propogated itself. Yeah, I'd say that's worse. But no headlines.

> I mention this just to reinforce that LibreSSL is not the result of "the worst bug ever". I may call you dirty names, but I'm not going to fork your project on the basis of a missing bounds check.

> why fork

> Instead, libressl is here because of a tragic comedy of other errors. Let's start with the obvious. Why were heartbeats, a feature only useful for the DTLS protocol over UDP, built into the TLS protocol that runs over TCP? And why was this entirely useless feature enabled by default? Then there's some nonsense with the buffer allocator and freelists and exploit mitigation countermeasures, and we keep on digging and we keep on not liking what we're seeing. Bob's talk has all the gory details.

You can see "Bob's talk" here: https://www.openbsd.org/papers/bsdcan14-libressl/ though I think there is a YouTube video somewhere.

Also I would like to point out that Google also forked OpenSSL. So it seems that the LibreSSL folks are not the only ones who thought a fork was necessary.

It wasn't about one bad vulnerability. Heartbleed was just the last straw.

OpenSSL implemented its own memory management system instead of using malloc. It would allocate one pool of memory and then manipulate into that. This meant that static analysis, runtime analysis, fuzzers were incapable of finding memory bugs. Because all pointers into that pool were "valid". LibreSSL stripped out OpenSSL's memory system and replaced it with malloc() and free() as provided by libc. Suddenly, static analysis, valgrind, and fuzzers found something like 3 dozen memory errors.

That is bad on so many levels.

OpenSSL supports big endian x86_64. OpenSSL supports EBDIC paths, certs, encodings, etc. OpenSSL supports DOS and Windows for Workgroups 3.11. It had a config -D NO_OLD_ASN1 and NO_ASN1_OLD. These defs performed different things. Having more eyeballs on a project didn't help OpenSSL, because all of those eyeballs glazed over immediately and/or had forks stabbed into them.

In something like the first month, the LibreSSL project deleted something like 90,000 LOC and 60,000 lines of comments/whitespace. Not changed: deleted. Removed useless cruft like mentioned above, and dangerous cruft like SSL 3.0 support. The latest OpenSSL tarball is 9.4MB, the latest LibreSSL tarball is 3.6MB. It has fewer eyeballs, sure, but it's an order of magnitude easier to audit.

> jumping ship to a brand new one with less eyes and reputation

That doesn't sound like an accurate description of LibreSSL, what with it being a part of OpenBSD.

Eyes doesn't make a project, but the development process

Read this (from older to newer posts) https://opensslrampage.org/ it explains a lot of the bad stuff on OpenSSL

Example: "“Do you really want to build OpenSSL for 16-bit Windows? Well, we don’t.”"

https://opensslrampage.org/post/83952304402/do-you-really-wa...

OpenSSL recently changed licenses to Apache 2.0, which is a unacceptable in some of the BSDs, which made the LibreSSL fork more valuable from a licensing perspective for them.

Tink isn't really a rename, but an API wrapper to prevent misuse that happens to use BoringSSL internally.

BoringSSL is still alive, Tink is something completely separate.

Google Tink is an encryption library providing a high level API for common cryptography problems. Such as authenticated encryption with associated data (AEAD). In a similar vein to libsodium, it's designed to not let you shoot yourself.

OpenSSL and it's forks expose the primitives directly, but as is the usual advice, don't roll your own crypto and say "We're using RSA 2048" because you copied an example from stack overflow without padding.

The paper points to data showing that OpenSSL is still the dominant SSL implementation on the net, so it's the one that matters.

> It's sad to see that duplication of effort but it's also the force of open source

How's that a FOSS thing? Do you think there would be fewer TLS implementations running around if they were proprietary?

The duplicated effort is needed. The OpenSSLs mono-cultur was one of the reason Heartbleed, and other OpenSSL security issues, where such huge problems and affected so many.

there is also https://www.wolfssl.com/

It's just a PDF link. The paper mentions the existence of LibreSSL but that is pretty much it; the focus of the paper is on the extensive efforts to improve OpenSSL.

In case anyone is curious:

> The OMC voted this week to update our security policy [1] to include the option of us giving prenotification to companies with which we have a commercial relationship. (Edited to clarify: the vote was to allow notification to our Premium Support customers and this does not include lower support levels, sponsors, or GitHub sponsors.)

* https://www.openssl.org/blog/blog/2020/05/12/security-prenot...

* https://www.openssl.org/support/contracts.html#premium

So, being realistic here, that means the Chinese government is given 7 days advance notice?