crypto: require gnutls >= 3.1.18 for building QEMU

gnutls 3.0.0 was released in 2011 and all the distros that are build
target platforms for QEMU [1] include it:

  RHEL-7: 3.1.18
  Debian (Stretch): 3.5.8
  Debian (Jessie): 3.3.8
  OpenBSD (ports): 3.5.18
  FreeBSD (ports): 3.5.18
  OpenSUSE Leap 15: 3.6.2
  Ubuntu (Xenial): 3.4.10
  macOS (Homebrew): 3.5.19

Based on this, it is reasonable to require gnutls >= 3.1.18 in QEMU
which allows for all conditional version checks in the code to be
removed.

[1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 40 insertions, 95 deletions

diff --git a/configure b/configure
index 9138af3..008f666 100755
--- a/configure
+++ b/configure
@@ -457,7 +457,6 @@ gtk=""
 gtk_gl="no"
 tls_priority="NORMAL"
 gnutls=""
-gnutls_rnd=""
 nettle=""
 nettle_kdf="no"
 gcrypt=""
@@ -2666,79 +2665,28 @@ fi
 ##########################################
 # GNUTLS probe
 
-gnutls_works() {
-    # Unfortunately some distros have bad pkg-config information for gnutls
-    # such that it claims to exist but you get a compiler error if you try
-    # to use the options returned by --libs. Specifically, Ubuntu for --static
-    # builds doesn't work:
-    # https://bugs.launchpad.net/ubuntu/+source/gnutls26/+bug/1478035
-    #
-    # So sanity check the cflags/libs before assuming gnutls can be used.
-    if ! $pkg_config --exists "gnutls"; then
-        return 1
-    fi
-
-    write_c_skeleton
-    compile_prog "$($pkg_config --cflags gnutls)" "$($pkg_config --libs gnutls)"
-}
-
-gnutls_gcrypt=no
-gnutls_nettle=no
 if test "$gnutls" != "no"; then
-    if gnutls_works; then
+    if $pkg_config --exists "gnutls >= 3.1.18"; then
         gnutls_cflags=$($pkg_config --cflags gnutls)
         gnutls_libs=$($pkg_config --libs gnutls)
         libs_softmmu="$gnutls_libs $libs_softmmu"
         libs_tools="$gnutls_libs $libs_tools"
 	QEMU_CFLAGS="$QEMU_CFLAGS $gnutls_cflags"
         gnutls="yes"
-
-	# gnutls_rnd requires >= 2.11.0
-	if $pkg_config --exists "gnutls >= 2.11.0"; then
-	    gnutls_rnd="yes"
-	else
-	    gnutls_rnd="no"
-	fi
-
-	if $pkg_config --exists 'gnutls >= 3.0'; then
-	    gnutls_gcrypt=no
-	    gnutls_nettle=yes
-	elif $pkg_config --exists 'gnutls >= 2.12'; then
-	    case $($pkg_config --libs --static gnutls) in
-		*gcrypt*)
-		    gnutls_gcrypt=yes
-		    gnutls_nettle=no
-		    ;;
-		*nettle*)
-		    gnutls_gcrypt=no
-		    gnutls_nettle=yes
-		    ;;
-		*)
-		    gnutls_gcrypt=yes
-		    gnutls_nettle=no
-		    ;;
-	    esac
-	else
-	    gnutls_gcrypt=yes
-	    gnutls_nettle=no
-	fi
     elif test "$gnutls" = "yes"; then
-	feature_not_found "gnutls" "Install gnutls devel"
+	feature_not_found "gnutls" "Install gnutls devel >= 3.1.18"
     else
         gnutls="no"
-        gnutls_rnd="no"
     fi
-else
-    gnutls_rnd="no"
 fi
 
 
 # If user didn't give a --disable/enable-gcrypt flag,
 # then mark as disabled if user requested nettle
-# explicitly, or if gnutls links to nettle
+# explicitly
 if test -z "$gcrypt"
 then
-    if test "$nettle" = "yes" || test "$gnutls_nettle" = "yes"
+    if test "$nettle" = "yes"
     then
         gcrypt="no"
     fi
@@ -2746,10 +2694,10 @@ fi
 
 # If user didn't give a --disable/enable-nettle flag,
 # then mark as disabled if user requested gcrypt
-# explicitly, or if gnutls links to gcrypt
+# explicitly
 if test -z "$nettle"
 then
-    if test "$gcrypt" = "yes" || test "$gnutls_gcrypt" = "yes"
+    if test "$gcrypt" = "yes"
     then
         nettle="no"
     fi
@@ -2773,6 +2721,40 @@ has_libgcrypt_config() {
     return 0
 }
 
+
+if test "$nettle" != "no"; then
+    if $pkg_config --exists "nettle"; then
+        nettle_cflags=$($pkg_config --cflags nettle)
+        nettle_libs=$($pkg_config --libs nettle)
+        nettle_version=$($pkg_config --modversion nettle)
+        libs_softmmu="$nettle_libs $libs_softmmu"
+        libs_tools="$nettle_libs $libs_tools"
+        QEMU_CFLAGS="$QEMU_CFLAGS $nettle_cflags"
+        nettle="yes"
+
+        cat > $TMPC << EOF
+#include <stddef.h>
+#include <nettle/pbkdf2.h>
+int main(void) {
+     pbkdf2_hmac_sha256(8, NULL, 1000, 8, NULL, 8, NULL);
+     return 0;
+}
+EOF
+        if test -z "$gcrypt"; then
+           gcrypt="no"
+        fi
+        if compile_prog "$nettle_cflags" "$nettle_libs" ; then
+            nettle_kdf=yes
+        fi
+    else
+        if test "$nettle" = "yes"; then
+            feature_not_found "nettle" "Install nettle devel"
+        else
+            nettle="no"
+        fi
+    fi
+fi
+
 if test "$gcrypt" != "no"; then
     if has_libgcrypt_config; then
         gcrypt_cflags=$(libgcrypt-config --cflags)
@@ -2788,9 +2770,6 @@ if test "$gcrypt" != "no"; then
         libs_tools="$gcrypt_libs $libs_tools"
         QEMU_CFLAGS="$QEMU_CFLAGS $gcrypt_cflags"
         gcrypt="yes"
-        if test -z "$nettle"; then
-           nettle="no"
-        fi
 
         cat > $TMPC << EOF
 #include <gcrypt.h>
@@ -2827,36 +2806,6 @@ EOF
 fi
 
 
-if test "$nettle" != "no"; then
-    if $pkg_config --exists "nettle"; then
-        nettle_cflags=$($pkg_config --cflags nettle)
-        nettle_libs=$($pkg_config --libs nettle)
-        nettle_version=$($pkg_config --modversion nettle)
-        libs_softmmu="$nettle_libs $libs_softmmu"
-        libs_tools="$nettle_libs $libs_tools"
-        QEMU_CFLAGS="$QEMU_CFLAGS $nettle_cflags"
-        nettle="yes"
-
-        cat > $TMPC << EOF
-#include <stddef.h>
-#include <nettle/pbkdf2.h>
-int main(void) {
-     pbkdf2_hmac_sha256(8, NULL, 1000, 8, NULL, 8, NULL);
-     return 0;
-}
-EOF
-        if compile_prog "$nettle_cflags" "$nettle_libs" ; then
-            nettle_kdf=yes
-        fi
-    else
-        if test "$nettle" = "yes"; then
-            feature_not_found "nettle" "Install nettle devel"
-        else
-            nettle="no"
-        fi
-    fi
-fi
-
 if test "$gcrypt" = "yes" && test "$nettle" = "yes"
 then
     error_exit "Only one of gcrypt & nettle can be enabled"
@@ -5961,7 +5910,6 @@ echo "GTK GL support    $gtk_gl"
 echo "VTE support       $vte $(echo_version $vte $vteversion)"
 echo "TLS priority      $tls_priority"
 echo "GNUTLS support    $gnutls"
-echo "GNUTLS rnd        $gnutls_rnd"
 echo "libgcrypt         $gcrypt"
 echo "libgcrypt kdf     $gcrypt_kdf"
 echo "nettle            $nettle $(echo_version $nettle $nettle_version)"
@@ -6401,9 +6349,6 @@ echo "CONFIG_TLS_PRIORITY=\"$tls_priority\"" >> $config_host_mak
 if test "$gnutls" = "yes" ; then
   echo "CONFIG_GNUTLS=y" >> $config_host_mak
 fi
-if test "$gnutls_rnd" = "yes" ; then
-  echo "CONFIG_GNUTLS_RND=y" >> $config_host_mak
-fi
 if test "$gcrypt" = "yes" ; then
   echo "CONFIG_GCRYPT=y" >> $config_host_mak
   if test "$gcrypt_hmac" = "yes" ; then