When curl is built with libidn to handle International Domain Names (IDNA), it translates them to puny code for DNS resolving using the IDNA 2003 standard, while IDNA 2008 is the modern and up-to-date IDNA standard. This misalignment causes problems with for example domains using the German ß character (known as the Unicode Character 'LATIN SMALL LETTER SHARP S') which is used at times in the .de TLD and is translated differently in the two IDNA standards, leading to users potentially and unknowingly issuing network transfer requests to the wrong host. For example, `straße.de` is translated into `strasse.de` using IDNA 2003 but is translated into `xn--strae-oqa.de` using IDNA 2008. Needless to say, those host names could very well resolve to different addresses and be two completely independent servers. IDNA 2008 is mandatory for .de domains. curl is not alone with this problem, as there's currently a big flux in the world of network user-agents about which IDNA version to support and use. This name problem exists for DNS-using protocols in curl, but only when built to use libidn. External References: https://curl.haxx.se/docs/adv_20161102K.html
Created attachment 1213820 [details] Upstream patch
Created curl tracking bugs for this issue: Affects: fedora-all [bug 1390894]
Created mingw-curl tracking bugs for this issue: Affects: fedora-all [bug 1390895] Affects: epel-7 [bug 1390896]
I will postpone putting the upstream fix to stable Fedora because it does not seem to be fully ready. Some upstream test-cases started to fail after the switch to libidn2: http://pkgs.fedoraproject.org/cgit/rpms/curl.git/commit/?id=c8e19229 ... and there is an ongoing discussion upstream whether the patched version of libcurl works as expected: https://curl.haxx.se/mail/lib-2016-11/0033.html
(In reply to Kamil Dudka from comment #4) > I will postpone putting the upstream fix to stable Fedora because it does > not seem to be fully ready. Some upstream test-cases started to fail after > the switch to libidn2: > > http://pkgs.fedoraproject.org/cgit/rpms/curl.git/commit/?id=c8e19229 > > ... and there is an ongoing discussion upstream whether the patched version > of libcurl works as expected: > > https://curl.haxx.se/mail/lib-2016-11/0033.html This sounds like a good decision. Latest discussion on oss-security seems to head in the direction of disabling IDN completely. http://seclists.org/oss-sec/2016/q4/333
This issue has been addressed in the following products: Red Hat JBoss Core Services Via RHSA-2018:2486 https://access.redhat.com/errata/RHSA-2018:2486
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS Via RHSA-2018:3558 https://access.redhat.com/errata/RHSA-2018:3558