require OpenSSL >= 1.0.2 and LibreSSL >= 3.1

Clean up old version guards in preparation for the upcoming OpenSSL 3.0
support.

OpenSSL 1.0.1 reached its EOL on 2016-12-31. At that time, we decided
to keep 1.0.1 support because many major Linux distributions were still
shipped with 1.0.1. Now, nearly 4 years later, most Linux distributions
are reaching their EOL and it should be safe to assume nobody uses them
anymore. Major ones that were using 1.0.1:

 - Ubuntu 14.04 is EOL since 2019-04-30
 - RHEL 6 will reach EOL on 2020-11-30

LibreSSL 3.0 and older versions are no longer supported by the LibreSSL
team as of October 2020.

Note that OpenSSL 1.0.2 also reached EOL on 2019-12-31 and 1.1.0 also
did on 2018-08-31.

1 files changed, 25 insertions, 30 deletions

diff --git a/ext/openssl/extconf.rb b/ext/openssl/extconf.rb
index d5e0470c..73a4cdc3 100644
--- a/ext/openssl/extconf.rb
+++ b/ext/openssl/extconf.rb
@@ -33,9 +33,6 @@ if $mswin || $mingw
   have_library("ws2_32")
 end
 
-Logging::message "=== Checking for required stuff... ===\n"
-result = pkg_config("openssl") && have_header("openssl/ssl.h")
-
 if $mingw
   append_cflags '-D_FORTIFY_SOURCE=2'
   append_ldflags '-fstack-protector'
@@ -92,19 +89,32 @@ def find_openssl_library
   return false
 end
 
-unless result
-  unless find_openssl_library
-    Logging::message "=== Checking for required stuff failed. ===\n"
-    Logging::message "Makefile wasn't created. Fix the errors above.\n"
-    raise "OpenSSL library could not be found. You might want to use " \
-      "--with-openssl-dir=<dir> option to specify the prefix where OpenSSL " \
-      "is installed."
-  end
+Logging::message "=== Checking for required stuff... ===\n"
+pkg_config_found = pkg_config("openssl") && have_header("openssl/ssl.h")
+
+if !pkg_config_found && !find_openssl_library
+  Logging::message "=== Checking for required stuff failed. ===\n"
+  Logging::message "Makefile wasn't created. Fix the errors above.\n"
+  raise "OpenSSL library could not be found. You might want to use " \
+    "--with-openssl-dir=<dir> option to specify the prefix where OpenSSL " \
+    "is installed."
+end
+
+version_ok = if have_macro("LIBRESSL_VERSION_NUMBER", "openssl/opensslv.h")
+  is_libressl = true
+  checking_for("LibreSSL version >= 3.1.0") {
+    try_static_assert("LIBRESSL_VERSION_NUMBER >= 0x30100000L", "openssl/opensslv.h") }
+else
+  checking_for("OpenSSL version >= 1.0.2") {
+    try_static_assert("OPENSSL_VERSION_NUMBER >= 0x10002000L", "openssl/opensslv.h") }
+end
+unless version_ok
+  raise "OpenSSL >= 1.0.2 or LibreSSL >= 3.1.0 is required"
 end
 
-unless checking_for("OpenSSL version is 1.0.1 or later") {
-    try_static_assert("OPENSSL_VERSION_NUMBER >= 0x10001000L", "openssl/opensslv.h") }
-  raise "OpenSSL >= 1.0.1 or LibreSSL is required"
+# Prevent wincrypt.h from being included, which defines conflicting macro with openssl/x509.h
+if is_libressl && ($mswin || $mingw)
+  $defs.push("-DNOCRYPT")
 end
 
 Logging::message "=== Checking for OpenSSL features... ===\n"
@@ -116,23 +126,8 @@ engines.each { |name|
   have_func("ENGINE_load_#{name}()", "openssl/engine.h")
 }
 
-if ($mswin || $mingw) && have_macro("LIBRESSL_VERSION_NUMBER", "openssl/opensslv.h")
-  $defs.push("-DNOCRYPT")
-end
-
-# added in 1.0.2
-have_func("EC_curve_nist2nid")
-have_func("X509_REVOKED_dup")
-have_func("X509_STORE_CTX_get0_store")
-have_func("SSL_CTX_set_alpn_select_cb")
-have_func("SSL_CTX_set1_curves_list(NULL, NULL)", "openssl/ssl.h")
-have_func("SSL_CTX_set_ecdh_auto(NULL, 0)", "openssl/ssl.h")
-have_func("SSL_get_server_tmp_key(NULL, NULL)", "openssl/ssl.h")
-have_func("SSL_is_server")
-
 # added in 1.1.0
-if !have_struct_member("SSL", "ctx", "openssl/ssl.h") ||
-    try_static_assert("LIBRESSL_VERSION_NUMBER >= 0x2070000fL", "openssl/opensslv.h")
+if !have_struct_member("SSL", "ctx", "openssl/ssl.h") || is_libressl
   $defs.push("-DHAVE_OPAQUE_OPENSSL")
 end
 have_func("CRYPTO_lock") || $defs.push("-DHAVE_OPENSSL_110_THREADING_API")