Re: [PATCH] imap-send: Fix compilation without deprecated OpenSSL APIs

From: Rosen Penev <rosenp@gmail.com>
Date: Dec 27, 2018, 17:55 UTC
Message-ID: <CAKxU2N9egn6MbJeWUWFsyYpnwOCj4=mckmkJJtVJGhmQUt36aw@mail.gmail.com>
In-Reply-To: <xmqqwonvpjiy.fsf@gitster-ct.c.googlers.com>

On Wed, Dec 26, 2018 at 10:32 PM Junio C Hamano <gitster@pobox.com> wrote:

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>
> Rosen Penev <rosenp@gmail.com> writes:
>
> > Initialization in OpenSSL has been deprecated in version 1.1.
>
> https://www.openssl.org/docs/man1.0.2/ssl/SSL_library_init.html says
>
>         SSL_library_init() must be called before any other action takes
>         place.
>
> https://www.openssl.org/docs/man1.1.0/ssl/SSL_library_init.html says
> the same.

Later on in the document it mentions that it is deprecated.

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>
> Which makes it necessary for us to defend the following claim
>
> > This makes
> > compilation fail when deprecated APIs for OpenSSL are compile-time
> > disabled.
>
> as a valid problem description more rigorously.  To me, the cursory
> web-serfing I did above makes me suspect that an OpenSSL
> implementation with such a compile-time disabling _is_ buggy, as it
> forbids the API users to call an API function they are told to call
> before doing anything else.

I agree the man page is misleading. The changelog for 1.1.0 is very clear though:

Added support for auto-initialisation and de-initialisation of the library.
     OpenSSL no longer requires explicit init or deinit routines to be called,
     except in certain circumstances. See the OPENSSL_init_crypto() and
     OPENSSL_init_ssl() man pages for further information.
     [Matt Caswell]

https://www.openssl.org/news/changelog.html#x12

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>
> > Signed-off-by: Rosen Penev <rosenp@gmail.com>
> > ---
> >  imap-send.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/imap-send.c b/imap-send.c
> > index b4eb886e2..21f741c8c 100644
> > --- a/imap-send.c
> > +++ b/imap-send.c
> > @@ -284,8 +284,10 @@ static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int ve
> >       int ret;
> >       X509 *cert;
> >
> > +#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
>
> https://www.openssl.org/docs/man1.1.0/crypto/OPENSSL_VERSION_NUMBER.html
>
> says that OPENSSL_VERSION_NUMBER is of form 0xMNNFFPPS where M is
> major, NN is minor, FF is fix, PP is patch and S is status, and
> gives an example that 0x00906023 stands for 0.9.6.b beta 3 (M=0,
> NN=09, FF=06, PP=02 and S=3).  So "< 0x10000000L" means "anything
> with M smaller than 1".  IOW, we would no longer call _init() for
> e.g. "version 1.0.0 beta 0".  That contradicts with the first claim
> of the proposed log message ("deprecated in 1.1" implying that it is
> not yet deprecated in say 1.0.2).

This is a mistake. I will send a v2 to fix.

Oh I see what I did wrong. I mistakenly copied the above OPENSSL_VERSION_NUMBER check without looking carefully at the number.

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>
>
>
> >       SSL_library_init();
> >       SSL_load_error_strings();
> > +#endif
> >
> >       meth = SSLv23_method();
> >       if (!meth) {