[Qemu-devel] [PATCH v3 05/10] crypto: add a gcrypt cipher implementation

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

If we are linking to gnutls already and gnutls is built against
gcrypt, then we should use gcrypt as a cipher backend in
preference to our built-in backend.

This will be used when linking against GNUTLS 1.x and many
GNUTLS 2.x versions.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 configure              |  29 ++++++++
 crypto/cipher-gcrypt.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++++
 crypto/cipher.c        |  19 +++++
 crypto/init.c          |  90 +++++++++++++++++++++++
 4 files changed, 333 insertions(+)
 create mode 100644 crypto/cipher-gcrypt.c

diff --git a/configure b/configure
index a85917c..28f4172 100755
--- a/configure
+++ b/configure
@@ -2169,6 +2169,7 @@ fi
 ##########################################
 # GNUTLS probe
 
+gnutls_gcrypt=no
 if test "$gnutls" != "no"; then
     if $pkg_config --exists "gnutls"; then
         gnutls_cflags=`$pkg_config --cflags gnutls`
@@ -2184,6 +2185,18 @@ if test "$gnutls" != "no"; then
 	else
 	    gnutls_hash="no"
 	fi
+
+	if $pkg_config --exists 'gnutls >= 3.0'; then
+	    gnutls_gcrypt=no
+	elif $pkg_config --exists 'gnutls >= 2.12'; then
+	    case `$pkg_config --libs --static gnutls` in
+		*gcrypt*) gnutls_gcrypt=yes     ;;
+		*nettle*) gnutls_gcrypt=no      ;;
+		*)        gnutls_gcrypt=yes     ;;
+	    esac
+	else
+	    gnutls_gcrypt=yes
+	fi
     elif test "$gnutls" = "yes"; then
 	feature_not_found "gnutls" "Install gnutls devel"
     else
@@ -2194,6 +2207,18 @@ else
     gnutls_hash="no"
 fi
 
+if test "$gnutls_gcrypt" != "no"; then
+    if has "libgcrypt-config"; then
+        gcrypt_cflags=`libgcrypt-config --cflags`
+        gcrypt_libs=`libgcrypt-config --libs`
+        libs_softmmu="$gcrypt_libs $libs_softmmu"
+        libs_tools="$gcrypt_libs $libs_tools"
+        QEMU_CFLAGS="$QEMU_CFLAGS $gcrypt_cflags"
+    else
+        feature_not_found "gcrypt" "Install gcrypt devel"
+    fi
+fi
+
 
 ##########################################
 # VTE probe
@@ -4456,6 +4481,7 @@ echo "SDL support       $sdl"
 echo "GTK support       $gtk"
 echo "GNUTLS support    $gnutls"
 echo "GNUTLS hash       $gnutls_hash"
+echo "GNUTLS gcrypt     $gnutls_gcrypt"
 echo "VTE support       $vte"
 echo "curses support    $curses"
 echo "curl support      $curl"
@@ -4811,6 +4837,9 @@ fi
 if test "$gnutls_hash" = "yes" ; then
   echo "CONFIG_GNUTLS_HASH=y" >> $config_host_mak
 fi
+if test "$gnutls_gcrypt" = "yes" ; then
+  echo "CONFIG_GNUTLS_GCRYPT=y" >> $config_host_mak
+fi
 if test "$vte" = "yes" ; then
   echo "CONFIG_VTE=y" >> $config_host_mak
   echo "VTE_CFLAGS=$vte_cflags" >> $config_host_mak
diff --git a/crypto/cipher-gcrypt.c b/crypto/cipher-gcrypt.c
new file mode 100644
index 0000000..8cfc562
--- /dev/null
+++ b/crypto/cipher-gcrypt.c
@@ -0,0 +1,195 @@
+/*
+ * QEMU Crypto cipher libgcrypt algorithms
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <gcrypt.h>
+
+
+bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
+{
+    switch (alg) {
+    case QCRYPTO_CIPHER_ALG_DES_RFB:
+    case QCRYPTO_CIPHER_ALG_AES_128:
+    case QCRYPTO_CIPHER_ALG_AES_192:
+    case QCRYPTO_CIPHER_ALG_AES_256:
+        return true;
+    default:
+        return false;
+    }
+}
+
+
+QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
+                                  QCryptoCipherMode mode,
+                                  const uint8_t *key, size_t nkey,
+                                  Error **errp)
+{
+    QCryptoCipher *cipher;
+    gcry_cipher_hd_t handle;
+    gcry_error_t err;
+    int gcryalg, gcrymode;
+
+    switch (mode) {
+    case QCRYPTO_CIPHER_MODE_ECB:
+        gcrymode = GCRY_CIPHER_MODE_ECB;
+        break;
+    case QCRYPTO_CIPHER_MODE_CBC:
+        gcrymode = GCRY_CIPHER_MODE_CBC;
+        break;
+    default:
+        error_setg(errp, "Unsupported cipher mode %d", mode);
+        return NULL;
+    }
+
+    if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
+        return NULL;
+    }
+
+    switch (alg) {
+    case QCRYPTO_CIPHER_ALG_DES_RFB:
+        gcryalg = GCRY_CIPHER_DES;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_AES_128:
+        gcryalg = GCRY_CIPHER_AES128;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_AES_192:
+        gcryalg = GCRY_CIPHER_AES192;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_AES_256:
+        gcryalg = GCRY_CIPHER_AES256;
+        break;
+
+    default:
+        error_setg(errp, "Unsupported cipher algorithm %d", alg);
+        return NULL;
+    }
+
+    cipher = g_new0(QCryptoCipher, 1);
+    cipher->alg = alg;
+    cipher->mode = mode;
+
+    err = gcry_cipher_open(&handle, gcryalg, gcrymode, 0);
+    if (err != 0) {
+        error_setg(errp, "Cannot initialize cipher: %s",
+                   gcry_strerror(err));
+        goto error;
+    }
+
+    if (cipher->alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
+        /* We're using standard DES cipher from gcrypt, so we need
+         * to munge the key so that the results are the same as the
+         * bizarre RFB variant of DES :-)
+         */
+        uint8_t *rfbkey = qcrypto_cipher_munge_des_rfb_key(key, nkey);
+        err = gcry_cipher_setkey(handle, rfbkey, nkey);
+        g_free(rfbkey);
+    } else {
+        err = gcry_cipher_setkey(handle, key, nkey);
+    }
+    if (err != 0) {
+        error_setg(errp, "Cannot set key: %s",
+                   gcry_strerror(err));
+        goto error;
+    }
+
+    cipher->opaque = handle;
+    return cipher;
+
+ error:
+    gcry_cipher_close(handle);
+    g_free(cipher);
+    return NULL;
+}
+
+
+void qcrypto_cipher_free(QCryptoCipher *cipher)
+{
+    gcry_cipher_hd_t handle;
+    if (!cipher) {
+        return;
+    }
+    handle = cipher->opaque;
+    gcry_cipher_close(handle);
+    g_free(cipher);
+}
+
+
+int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
+                           const void *in,
+                           void *out,
+                           size_t len,
+                           Error **errp)
+{
+    gcry_cipher_hd_t handle = cipher->opaque;
+    gcry_error_t err;
+
+    err = gcry_cipher_encrypt(handle,
+                              out, len,
+                              in, len);
+    if (err != 0) {
+        error_setg(errp, "Cannot encrypt data: %s",
+                   gcry_strerror(err));
+        return -1;
+    }
+
+    return 0;
+}
+
+
+int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
+                           const void *in,
+                           void *out,
+                           size_t len,
+                           Error **errp)
+{
+    gcry_cipher_hd_t handle = cipher->opaque;
+    gcry_error_t err;
+
+    err = gcry_cipher_decrypt(handle,
+                              out, len,
+                              in, len);
+    if (err != 0) {
+        error_setg(errp, "Cannot decrypt data: %s",
+                   gcry_strerror(err));
+        return -1;
+    }
+
+    return 0;
+}
+
+int qcrypto_cipher_setiv(QCryptoCipher *cipher,
+                         const uint8_t *iv, size_t niv,
+                         Error **errp)
+{
+    gcry_cipher_hd_t handle = cipher->opaque;
+    gcry_error_t err;
+
+    gcry_cipher_reset(handle);
+    err = gcry_cipher_setiv(handle, iv, niv);
+    if (err != 0) {
+        error_setg(errp, "Cannot set IV: %s",
+                   gcry_strerror(err));
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/crypto/cipher.c b/crypto/cipher.c
index 8b05de8..02bcda3 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -20,7 +20,11 @@
 
 #include "crypto/cipher-internal.h"
 
+#ifdef CONFIG_GNUTLS_GCRYPT
+#include "crypto/cipher-gcrypt.c"
+#else
 #include "crypto/cipher-builtin.c"
+#endif
 
 
 static size_t alg_key_len[QCRYPTO_CIPHER_ALG_LAST] = {
@@ -48,3 +52,18 @@ bool qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
     }
     return true;
 }
+
+uint8_t *qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
+                                          size_t nkey)
+{
+    uint8_t *ret = g_new0(uint8_t, nkey);
+    size_t i;
+    for (i = 0; i < nkey; i++) {
+        uint8_t r = key[i];
+        r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
+        r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
+        r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
+        ret[i] = r;
+    }
+    return ret;
+}
diff --git a/crypto/init.c b/crypto/init.c
index 40f3d6e..7447882 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -19,13 +19,48 @@
  */
 
 #include "crypto/init.h"
+#include "qemu/thread.h"
 
 #ifdef CONFIG_GNUTLS
 #include <gnutls/gnutls.h>
 #include <gnutls/crypto.h>
 
+#ifdef CONFIG_GNUTLS_GCRYPT
+#include <gcrypt.h>
+#endif
+
 /* #define DEBUG_GNUTLS */
 
+/*
+ * If GNUTLS is built against GCrypt then
+ *
+ *  - When GNUTLS >= 2.12, we must not initialize gcrypt threading
+ *    because GNUTLS will do that itself
+ *  - When GNUTLS < 2.12 we must always initialize gcrypt threading
+ *
+ * But....
+ *
+ *    When gcrypt >= 1.6.0 we must not initialize gcrypt threading
+ *    because gcrypt will do that itself.
+ *
+ * So we need to init gcrypt threading if
+ *
+ *   - gcrypt < 1.6.0
+ * AND
+ *   - gnutls < 2.12
+ *
+ */
+
+#if (defined(CONFIG_GNUTLS_GCRYPT) &&           \
+     (!defined(GNUTLS_VERSION_NUMBER) ||        \
+      (GNUTLS_VERSION_NUMBER < 0x020c00)) &&    \
+     (!defined(GCRYPT_VERSION_NUMBER) ||        \
+      (GCRYPT_VERSION_NUMBER < 0x010600)))
+#define QCRYPTO_INIT_GCRYPT_THREADS
+#else
+#undef QCRYPTO_INIT_GCRYPT_THREADS
+#endif
+
 #ifdef DEBUG_GNUTLS
 static void qcrypto_gnutls_log(int level, const char *str)
 {
@@ -33,6 +68,49 @@ static void qcrypto_gnutls_log(int level, const char *str)
 }
 #endif
 
+#ifdef QCRYPTO_INIT_GCRYPT_THREADS
+static int qcrypto_gcrypt_mutex_init(void **priv)
+{                                                                             \
+    QemuMutex *lock = NULL;
+    lock = g_new0(QemuMutex, 1);
+    qemu_mutex_init(lock);
+    *priv = lock;
+    return 0;
+}
+
+static int qcrypto_gcrypt_mutex_destroy(void **priv)
+{
+    QemuMutex *lock = *priv;
+    qemu_mutex_destroy(lock);
+    g_free(lock);
+    return 0;
+}
+
+static int qcrypto_gcrypt_mutex_lock(void **priv)
+{
+    QemuMutex *lock = *priv;
+    qemu_mutex_lock(lock);
+    return 0;
+}
+
+static int qcrypto_gcrypt_mutex_unlock(void **priv)
+{
+    QemuMutex *lock = *priv;
+    qemu_mutex_unlock(lock);
+    return 0;
+}
+
+static struct gcry_thread_cbs qcrypto_gcrypt_thread_impl = {
+    (GCRY_THREAD_OPTION_PTHREAD | (GCRY_THREAD_OPTION_VERSION << 8)),
+    NULL,
+    qcrypto_gcrypt_mutex_init,
+    qcrypto_gcrypt_mutex_destroy,
+    qcrypto_gcrypt_mutex_lock,
+    qcrypto_gcrypt_mutex_unlock,
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
+};
+#endif /* QCRYPTO_INIT_GCRYPT */
+
 int qcrypto_init(Error **errp)
 {
     int ret;
@@ -47,6 +125,18 @@ int qcrypto_init(Error **errp)
     gnutls_global_set_log_level(10);
     gnutls_global_set_log_function(qcrypto_gnutls_log);
 #endif
+
+#ifdef CONFIG_GNUTLS_GCRYPT
+    if (!gcry_check_version(GCRYPT_VERSION)) {
+        error_setg(errp, "Unable to initialize gcrypt");
+        return -1;
+    }
+#ifdef QCRYPTO_INIT_GCRYPT_THREADS
+    gcry_control(GCRYCTL_SET_THREAD_CBS, &qcrypto_gcrypt_thread_impl);
+#endif /* QCRYPTO_INIT_GCRYPT_THREADS */
+    gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
+#endif
+
     return 0;
 }
 
-- 
2.4.2