On Wed, Sep 21, 2016 at 09:24:10PM +0200, Ricardo Wurmus wrote:
> Leo Famulari <l...@famulari.name> writes:
> > On Tue, Sep 13, 2016 at 11:53:33PM +0200, Roel Janssen wrote:
> >> This patch was essential to me being able to interact with HTTPS urls in
> >> R.  As far as I understand, by default, R only looks for CURL_CA_BUNDLE
> >> on Windows, but with this patch it looks for CURL_CA_BUNDLE on GNU/Linux
> >> as well.  Is this correct?
> >> 
> >> I can confirm it works for me, so I'd like to see this patch pushed.
> >
> > It's good to hear that it works, but I still think we should run it by
> > the upstream maintainers. We are activating C code that they
> > specifically decided not to use on GNU / Linux. Why did they do that?
> The comments in the code indicate that on Windows they try to load the
> certs bundle that comes with R for Windows, i.e. in the R HOME’s “etc”
> directory.  There is no such file on GNU, so no special handling is
> needed.
> On GNU this is taken care of by libcurl.  It comes with a default path
> to the certs bundle, which can be overridden with configure flags
> (“--with-ca-bundle” or “--with-ca-path”).  In our Guix package we don’t
> do this (yet?), so by default SSL cert validation is broken.
> libcurl does not respect CURL_CA_BUNDLE; it assumes that the application
> will override the CA bundle path if it needs a special path, otherwise
> it assumes that the default path is fine (using Guix this is not the
> case).
> The maintainers of the R curl package made the special case for Windows
> because it is not needed on GNU systems following the FHS.  The best fix
> here would be to patch libcurl such that it checks the CURL_CA_BUNDLE
> environment variable invariably, just like the curl command line tool
> does.  Until this is done I think we should path packages such as
> r-curl to make them usable.  Once we have agreed on a fix to libcurl we
> can remove all patches to individual packages using libcurl.

That makes sense. Thank you for taking the time to explain.

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