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Re: Crash libCurl 7.76.1 32-bit build in H3 transfers

From: Daniel Stenberg via curl-library <>
Date: Thu, 6 May 2021 23:04:48 +0200 (CEST)

On Thu, 6 May 2021, Dmitry Karpov via curl-library wrote:

> So "size_t datalen" in libCurl is different from "uint64_t datalen" in the
> ngtcp2 library.

Fix pending:

> The crash was so obvious, so it was a bit surprising how it was able to
> escape pre-release testing. Maybe H3, as experimental feature, wasn't tested
> enough on 32-builds?

We don't test h3 at all yet on any platform, I'm sorry to say! :-O

We still lack a test server/proxy for this purpose and we have at least three
rather nasty-sounding HTTP/3 related bugs in KNOWN_BUGS:

I would prefer doing h3 tests with a h3 <=> h1 proxy front, a little like
stunnel but for h3, so that we could still serve the core stuff with our
existing h1 test server. But it's not a hard requirement.

I would love to get this going better and further but I've not had time for it
lately and no one has stepped up wanting to sponsor my work on h3.

> 32-bit builds are still widely used on embedded devices, so it will help a
> lot if you guys look at this issue and look for other potential pitfalls
> like this when switching from 64-bit builds to 32-bit builds.

Once we get a few h3-tests landed, I think it would make sense and be good to
have at least one set of them running on a 32 bit system, yes. The availablity
of convenient CI builds on 32 bit systems might be a bit limited though.

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Received on 2021-05-06