crypto: require libgcrypt >= 1.5.0 for building QEMU

libgcrypt 1.5.0 was released in 2011 and all the distros that are build
target platforms for QEMU [1] include it:

  RHEL-7: 1.5.3
  Debian (Stretch): 1.7.6
  Debian (Jessie): 1.6.3
  OpenBSD (ports): 1.8.2
  FreeBSD (ports): 1.8.3
  OpenSUSE Leap 15: 1.8.2
  Ubuntu (Xenial): 1.6.5
  macOS (Homebrew): 1.8.3

Based on this, it is reasonable to require libgcrypt >= 1.5.0 in QEMU
which allows for some conditional version checks in the code to be
removed.

[1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platformsReviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

configure

@@ -461,7 +461,6 @@ nettle=""
 nettle_kdf="no"
 gcrypt=""
 gcrypt_hmac="no"
-gcrypt_kdf="no"
 vte=""
 virglrenderer=""
 tpm="yes"
@@ -2703,7 +2702,7 @@ then
     fi
 fi
 
-has_libgcrypt_config() {
+has_libgcrypt() {
     if ! has "libgcrypt-config"
     then
 	return 1
@@ -2718,6 +2717,14 @@ has_libgcrypt_config() {
 	fi
     fi
 
+    maj=`libgcrypt-config --version | awk -F . '{print $1}'`
+    min=`libgcrypt-config --version | awk -F . '{print $2}'`
+
+    if test $maj != 1 || test $min -lt 5
+    then
+       return 1
+    fi
+
     return 0
 }
 
@@ -2756,7 +2763,7 @@ EOF
 fi
 
 if test "$gcrypt" != "no"; then
-    if has_libgcrypt_config; then
+    if has_libgcrypt; then
         gcrypt_cflags=$(libgcrypt-config --cflags)
         gcrypt_libs=$(libgcrypt-config --libs)
         # Debian has remove -lgpg-error from libgcrypt-config
@@ -2773,19 +2780,6 @@ if test "$gcrypt" != "no"; then
 
         cat > $TMPC << EOF
 #include <gcrypt.h>
-int main(void) {
-  gcry_kdf_derive(NULL, 0, GCRY_KDF_PBKDF2,
-                  GCRY_MD_SHA256,
-                  NULL, 0, 0, 0, NULL);
- return 0;
-}
-EOF
-        if compile_prog "$gcrypt_cflags" "$gcrypt_libs" ; then
-            gcrypt_kdf=yes
-        fi
-
-        cat > $TMPC << EOF
-#include <gcrypt.h>
 int main(void) {
   gcry_mac_hd_t handle;
   gcry_mac_open(&handle, GCRY_MAC_HMAC_MD5,
@@ -2798,7 +2792,7 @@ EOF
         fi
     else
         if test "$gcrypt" = "yes"; then
-            feature_not_found "gcrypt" "Install gcrypt devel"
+            feature_not_found "gcrypt" "Install gcrypt devel >= 1.5.0"
         else
             gcrypt="no"
         fi
@@ -5911,7 +5905,6 @@ echo "VTE support       $vte $(echo_version $vte $vteversion)"
 echo "TLS priority      $tls_priority"
 echo "GNUTLS support    $gnutls"
 echo "libgcrypt         $gcrypt"
-echo "libgcrypt kdf     $gcrypt_kdf"
 echo "nettle            $nettle $(echo_version $nettle $nettle_version)"
 echo "nettle kdf        $nettle_kdf"
 echo "libtasn1          $tasn1"
@@ -6354,9 +6347,6 @@ if test "$gcrypt" = "yes" ; then
   if test "$gcrypt_hmac" = "yes" ; then
     echo "CONFIG_GCRYPT_HMAC=y" >> $config_host_mak
   fi
-  if test "$gcrypt_kdf" = "yes" ; then
-    echo "CONFIG_GCRYPT_KDF=y" >> $config_host_mak
-  fi
 fi
 if test "$nettle" = "yes" ; then
   echo "CONFIG_NETTLE=y" >> $config_host_mak

crypto/Makefile.objs

@@ -24,7 +24,7 @@ crypto-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS)) += random-gnutls.o
 crypto-obj-$(if $(CONFIG_GCRYPT),n,$(if $(CONFIG_GNUTLS),n,y)) += random-platform.o
 crypto-obj-y += pbkdf.o
 crypto-obj-$(CONFIG_NETTLE_KDF) += pbkdf-nettle.o
-crypto-obj-$(if $(CONFIG_NETTLE_KDF),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o
+crypto-obj-$(if $(CONFIG_NETTLE_KDF),n,$(CONFIG_GCRYPT)) += pbkdf-gcrypt.o
 crypto-obj-y += ivgen.o
 crypto-obj-y += ivgen-essiv.o
 crypto-obj-y += ivgen-plain.o

crypto/init.c

@@ -44,8 +44,7 @@
  */
 
 #if (defined(CONFIG_GCRYPT) &&                  \
-     (!defined(GCRYPT_VERSION_NUMBER) ||        \
-      (GCRYPT_VERSION_NUMBER < 0x010600)))
+     (GCRYPT_VERSION_NUMBER < 0x010600))
 #define QCRYPTO_INIT_GCRYPT_THREADS
 #else
 #undef QCRYPTO_INIT_GCRYPT_THREADS

tests/Makefile.include

@@ -115,7 +115,7 @@ check-unit-$(CONFIG_GNUTLS) += tests/test-io-channel-tls$(EXESUF)
 check-unit-y += tests/test-io-channel-command$(EXESUF)
 check-unit-y += tests/test-io-channel-buffer$(EXESUF)
 check-unit-y += tests/test-base64$(EXESUF)
-check-unit-$(if $(CONFIG_NETTLE_KDF),y,$(CONFIG_GCRYPT_KDF)) += tests/test-crypto-pbkdf$(EXESUF)
+check-unit-$(if $(CONFIG_NETTLE_KDF),y,$(CONFIG_GCRYPT)) += tests/test-crypto-pbkdf$(EXESUF)
 check-unit-y += tests/test-crypto-ivgen$(EXESUF)
 check-unit-y += tests/test-crypto-afsplit$(EXESUF)
 check-unit-y += tests/test-crypto-xts$(EXESUF)

tests/test-crypto-block.c

@@ -29,7 +29,7 @@
 #endif
 
 #if (defined(_WIN32) || defined RUSAGE_THREAD) && \
-    (defined(CONFIG_NETTLE_KDF) || defined(CONFIG_GCRYPT_KDF))
+    (defined(CONFIG_NETTLE_KDF) || defined(CONFIG_GCRYPT))
 #define TEST_LUKS
 #else
 #undef TEST_LUKS