curl / Mailing Lists / curl-library / Single Mail


Problems with CURL_DOES_CONVERSIONS/HAVE_ICONV build on EBCDIC platform

From: Stephan Mühlstrasser <>
Date: Wed, 11 Apr 2018 12:59:52 +0200


we are using libcurl 7.32.0 for a while now successfully on several
platforms, including z/OS Unix System Services. For the z/OS build we
have CURL_DOES_CONVERSIONS and HAVE_ICONV defined because of the use of

We now did run into a problem that looks like a bug on non-ASCII
platforms in the host name check against subjectAltName for HTTPS
connections in the curl code that uses OpenSSL. My hope was that the
problem might be fixed in libcurl 7.59.0, but that was not the case, so
I developed a potential fix for the problem. But unfortunately after the
fix I did run into another problem that did not exist in 7.32.0.

So my question is, what is the state of curl support for platforms that
require CURL_DOES_CONVERSIONS and HAVE_ICONV? Are corresponding bug
reports looked at and are pull requests wanted?

Here is a brief description of the problems:

1) subjectAltName check for HTTPS connections

In lib/vtls/openssl.c in function verifyhost() two strings with
different encodings are passed to Curl_cert_hostcheck(), causing the
check to always fail. I have a potential fix for this.

2) ASCII-based character classification

The functions in curl_ctype.c work for ASCII only. After checking the
history if this file I found the following related GitHub pull request:

In the comment it says:

> I figure EBCDIC gets its own set of functions, or possibly even get to use the original functions. I don't intend to work on those versions since I don't have any such hardware to test on so it'll certainly end up wrong somewhere anyway.

So this apparently is a known problem for EBCDIC.

Thank you

Received on 2018-04-11