[Qemu-devel] [PATCH] crypto: do an explicit check for nettle pbkdf functions

["Daniel P. Berrange" <berrange@redhat.com>]

Support for the PBKDF functions in nettle was not introduced
until version 2.6. Some distros QEMU targets have older
versions and thus lack PBKDF support. Address this by doing
a check in configure for the desired function and then skipping
compilation of the nettle-pbkdf.o module

Reported-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 configure            | 16 ++++++++++++++++
 crypto/Makefile.objs |  4 ++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index f4a03b8..2d78bcd 100755
--- a/configure
+++ b/configure
@@ -308,6 +308,7 @@ gnutls=""
 gnutls_hash=""
 gnutls_rnd=""
 nettle=""
+nettle_kdf="no"
 gcrypt=""
 gcrypt_kdf="no"
 vte=""
@@ -2335,6 +2336,17 @@ if test "$nettle" != "no"; then
         libs_tools="$nettle_libs $libs_tools"
         QEMU_CFLAGS="$QEMU_CFLAGS $nettle_cflags"
         nettle="yes"
+
+        cat > $TMPC << EOF
+#include <nettle/pbkdf2.h>
+int main(void) {
+     pbkdf2_hmac_sha256(8, NULL, 1000, 8, NULL, 8, NULL);
+     return 0;
+}
+EOF
+        if compile_prog "$nettle_cflags" "$nettle_libs" ; then
+            nettle_kdf=yes
+        fi
     else
         if test "$nettle" = "yes"; then
             feature_not_found "nettle" "Install nettle devel"
@@ -4746,6 +4758,7 @@ if test "$nettle" = "yes"; then
 else
     echo "nettle            $nettle"
 fi
+echo "nettle kdf        $nettle_kdf"
 echo "libtasn1          $tasn1"
 echo "VTE support       $vte"
 echo "curses support    $curses"
@@ -5130,6 +5143,9 @@ fi
 if test "$nettle" = "yes" ; then
   echo "CONFIG_NETTLE=y" >> $config_host_mak
   echo "CONFIG_NETTLE_VERSION_MAJOR=${nettle_version%%.*}" >> $config_host_mak
+  if test "$nettle_kdf" = "yes" ; then
+    echo "CONFIG_NETTLE_KDF=y" >> $config_host_mak
+  fi
 fi
 if test "$tasn1" = "yes" ; then
   echo "CONFIG_TASN1=y" >> $config_host_mak
diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index 9f2c87e..0737f48 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -11,8 +11,8 @@ crypto-obj-y += secret.o
 crypto-obj-$(CONFIG_GCRYPT) += random-gcrypt.o
 crypto-obj-$(if $(CONFIG_GCRYPT),n,$(CONFIG_GNUTLS_RND)) += random-gnutls.o
 crypto-obj-y += pbkdf.o
-crypto-obj-$(CONFIG_NETTLE) += pbkdf-nettle.o
-crypto-obj-$(if $(CONFIG_NETTLE),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o
+crypto-obj-$(CONFIG_NETTLE_KDF) += pbkdf-nettle.o
+crypto-obj-$(if $(CONFIG_NETTLE_KDF),n,$(CONFIG_GCRYPT_KDF)) += pbkdf-gcrypt.o
 crypto-obj-y += ivgen.o
 crypto-obj-y += ivgen-essiv.o
 crypto-obj-y += ivgen-plain.o
-- 
2.5.5