hash: add support for nettle

configure

@@ -85,6 +85,7 @@ For better control, use the options below.
   --with-readline-library=DIR Specify where readline lib directory is
   --with-ncurses-library=DIR Specify where ncurses lib directory is
   --disable-sechash      Disable support for hashes other than MD5
+  --without-nettle       Don't use nettle even if it is available
   --without-nss          Don't use NSS even if it is available
   --without-tomcrypt     Don't use libtomcrypt even if it is available
   --disable-cmdmon       Disable command and monitoring support
@@ -198,6 +199,7 @@ feat_readline=1
 try_readline=1
 try_editline=1
 feat_sechash=1
+try_nettle=1
 try_nss=1
 try_tomcrypt=1
 feat_rtc=1
@@ -360,6 +362,9 @@ do
     --disable-sechash )
       feat_sechash=0
     ;;
+    --without-nettle )
+      try_nettle=0
+    ;;
     --without-nss )
       try_nss=0
     ;;
@@ -857,7 +862,22 @@ fi
 HASH_OBJ="hash_intmd5.o"
 HASH_LINK=""
 
-if [ $feat_sechash = "1" ] && [ $try_nss = "1" ]; then
+if [ $feat_sechash = "1" ] && [ "x$HASH_LINK" = "x" ]  && [ $try_nettle = "1" ]; then
+  test_cflags="`pkg_config --cflags nettle`"
+  test_link="`pkg_config --libs nettle`"
+  if test_code 'nettle' 'nettle/nettle-meta.h nettle/sha2.h' \
+    "$test_cflags" "$test_link" \
+    'return nettle_get_hashes()[0]->context_size;'
+  then
+    HASH_OBJ="hash_nettle.o"
+    HASH_LINK="$test_link"
+    LIBS="$LIBS $HASH_LINK"
+    MYCPPFLAGS="$MYCPPFLAGS $test_cflags"
+    add_def FEAT_SECHASH
+  fi
+fi
+
+if [ $feat_sechash = "1" ] && [ "x$HASH_LINK" = "x" ]  && [ $try_nss = "1" ]; then
   test_cflags="`pkg_config --cflags nss`"
   test_link="`pkg_config --libs-only-L nss` -lfreebl3"
   if test_code 'NSS' 'nss.h hasht.h nsslowhash.h' \

hash_nettle.c

@@ -0,0 +1,125 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2018
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Routines implementing crypto hashing using the nettle library.
+
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include <nettle/nettle-meta.h>
+
+#include "hash.h"
+#include "memory.h"
+
+struct hash {
+  const char *name;
+  const char *int_name;
+  const struct nettle_hash *nettle_hash;
+  void *context;
+};
+
+static struct hash hashes[] = {
+  { "MD5", "md5", NULL, NULL },
+  { "RMD160", "ripemd160", NULL, NULL },
+  { "SHA1", "sha1", NULL, NULL },
+  { "SHA256", "sha256", NULL, NULL },
+  { "SHA384", "sha384", NULL, NULL },
+  { "SHA512", "sha512", NULL, NULL },
+  { "SHA3-224", "sha3_224", NULL, NULL },
+  { "SHA3-256", "sha3_256", NULL, NULL },
+  { "SHA3-384", "sha3_384", NULL, NULL },
+  { "SHA3-512", "sha3_512", NULL, NULL },
+  { NULL, NULL, NULL, NULL }
+};
+
+int
+HSH_GetHashId(const char *name)
+{
+  const struct nettle_hash *const *nhashes;
+  int id, nid;
+
+  for (id = 0; hashes[id].name; id++) {
+    if (!strcmp(name, hashes[id].name))
+      break;
+  }
+
+  if (!hashes[id].name)
+    return -1;
+
+  if (hashes[id].context)
+    return id;
+
+  nhashes = nettle_get_hashes();
+  if (!nhashes)
+    return -1;
+
+  for (nid = 0; nhashes[nid]; nid++) {
+    if (!strcmp(hashes[id].int_name, nhashes[nid]->name))
+      break;
+  }
+
+  if (!nhashes[nid] || !nhashes[nid]->context_size || !nhashes[nid]->init)
+    return -1;
+
+  hashes[id].nettle_hash = nhashes[nid];
+  hashes[id].context = Malloc(hashes[id].nettle_hash->context_size);
+
+  return id;
+}
+
+unsigned int
+HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
+         const unsigned char *in2, unsigned int in2_len,
+         unsigned char *out, unsigned int out_len)
+{
+  const struct nettle_hash *hash;
+  void *context;
+
+  hash = hashes[id].nettle_hash;
+  context = hashes[id].context;
+
+  if (out_len > hash->digest_size)
+    out_len = hash->digest_size;
+
+  hash->init(context);
+  hash->update(context, in1_len, in1);
+  if (in2)
+    hash->update(context, in2_len, in2);
+  hash->digest(context, out_len, out);
+
+  return out_len;
+}
+
+void
+HSH_Finalise(void)
+{
+  int i;
+
+  for (i = 0; hashes[i].name; i++) {
+    if (hashes[i].context)
+      Free(hashes[i].context);
+  }
+}