Add a README-POSIX file with information about the stub functions

libxcrypt.spec

@@ -127,7 +127,7 @@ fi                                                             \
 
 Name:           libxcrypt
 Version:        4.4.3
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        Extended crypt library for descrypt, md5crypt, bcrypt, and others
 
 # For explicit license breakdown, see the
@@ -272,6 +272,24 @@ by the %{name}-compat package.
 %endif
 EOF
 %endif
+%if %{with enosys_stubs}
+%{__cat} << EOF >> README-POSIX
+This version of the libcrypt.so.1 library has entirely removed
+the functionality of the encrypt, encrypt_r, setkey, setkey_r,
+and fcrypt functions, while keeping fully binary compatibility
+with existing (third-party) applications possibly still using
+those funtions.  If such an application attemps to call one of
+these functions, the corresponding function will indicate that
+it is not supported by the system in a POSIX-compliant way.
+
+For security reasons, the encrypt and encrypt_r functions will
+also overwrite their data-block argument with random bits.
+
+All existing binary executables linked against glibc's libcrypt
+should work unmodified with the provided version of the
+libcrypt.so.1 library in place.
+EOF
+%endif
 %{__mkdir_p} %{_vpath_builddir}{,-compat}
 
 
@@ -331,6 +349,12 @@ if [ -f README%{distname} ]; then
     README%{distname}
 fi
 
+# Install README-POSIX file, if existing, to shared %%_pkgdocdir.
+if [ -f README-POSIX ]; then
+  %{__install} -Dpm 0644 -t %{buildroot}%{_pkgdocdir} \
+    README-POSIX
+fi
+
 
 %check
 %if %{with compat_pkg}
@@ -371,7 +395,13 @@ done
 %files
 %doc %dir %{_pkgdocdir}
 %doc %{_pkgdocdir}/NEWS
-%doc %{_pkgdocdir}/README*
+%doc %{_pkgdocdir}/README
+%if %{with new_api}
+%doc %{_pkgdocdir}/README%{distname}
+%endif
+%if %{with enosys_stubs} && %{without compat_pkg}
+%doc %{_pkgdocdir}/README-POSIX
+%endif
 %doc %{_pkgdocdir}/THANKS
 %license AUTHORS COPYING.LIB LICENSING
 /%{_lib}/.libcrypt.so.{%{soc},%{sov}}.hmac
@@ -381,6 +411,9 @@ done
 
 %if %{with compat_pkg}
 %files          compat
+%if %{with enosys_stubs}
+%doc %{_pkgdocdir}/README-POSIX
+%endif
 /%{_lib}/.libcrypt.so.{%{csoc},%{csov}}.hmac
 /%{_lib}/libcrypt.so.{%{csoc},%{csov}}
 %endif
@@ -404,6 +437,9 @@ done
 
 
 %changelog
+* Wed Jan 30 2019 Björn Esser <besser82@fedoraproject.org> - 4.4.3-4
+- Add a README-POSIX file with information about the stub functions
+
 * Wed Jan 30 2019 Björn Esser <besser82@fedoraproject.org> - 4.4.3-3
 - Replace unsafe functions in libxcrypt-compat with stubs (#1670735)