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[libvirt] [PATCH v3 1/2] qemu: Introduce new Secret IV API's



New APIs:

  qemuDomainGetIVKeyAlias:
    Generate/return the secret object alias for an initialization
    vector (IV) secret info type. This will be saved in the secret
    info block. This will be called from qemuDomainSecretIVSetup.

  qemuDomainSecretHaveEncrypt: (private)
    Boolean function to determine whether the underly encryption
    API is available. This function will utilize a similar mechanism
    as the 'gnutls_rnd' did in configure.ac.

  qemuDomainSecretIVSetup: (private)
    This API handles the details of the generation of the IV secret
    and saves the pieces that need to be passed to qemu in order for
    the secret to be decrypted. The encrypted secret based upon the
    domain master key, an initialization vector (16 byte random value),
    and the stored secret. Finally, the requirement from qemu is the IV
    and encrypted secret are to be base64 encoded. They can be passed
    either directly or within a file. This implementation chooses
    to pass directly rather than a file.

Signed-off-by: John Ferlan <jferlan redhat com>
---
 configure.ac           |   1 +
 src/qemu/qemu_alias.c  |  23 +++++++++
 src/qemu/qemu_alias.h  |   2 +
 src/qemu/qemu_domain.c | 137 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 163 insertions(+)

diff --git a/configure.ac b/configure.ac
index 88e2e20..3cabd5e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1264,6 +1264,7 @@ if test "x$with_gnutls" != "xno"; then
   ]])
 
   AC_CHECK_FUNCS([gnutls_rnd])
+  AC_CHECK_FUNCS([gnutls_cipher_encrypt])
 
   CFLAGS="$old_CFLAGS"
   LIBS="$old_LIBS"
diff --git a/src/qemu/qemu_alias.c b/src/qemu/qemu_alias.c
index ade2033..de9a74f 100644
--- a/src/qemu/qemu_alias.c
+++ b/src/qemu/qemu_alias.c
@@ -556,3 +556,26 @@ qemuDomainGetMasterKeyAlias(void)
 
     return alias;
 }
+
+
+/* qemuDomainGetIVKeyAlias:
+ *
+ * Generate and return an initialization vector alias
+ *
+ * Returns NULL or a string containing the IV key alias
+ */
+char *
+qemuDomainGetIVKeyAlias(const char *srcalias)
+{
+    char *alias;
+
+    if (!srcalias) {
+        virReportError(VIR_ERR_INVALID_ARG, "%s",
+                       _("secret iv alias requires valid source alias"));
+        return NULL;
+    }
+
+    ignore_value(virAsprintf(&alias, "%s-ivKey0", srcalias));
+
+    return alias;
+}
diff --git a/src/qemu/qemu_alias.h b/src/qemu/qemu_alias.h
index 2d7bc9b..435747e 100644
--- a/src/qemu/qemu_alias.h
+++ b/src/qemu/qemu_alias.h
@@ -69,4 +69,6 @@ char *qemuAliasFromDisk(const virDomainDiskDef *disk);
 
 char *qemuDomainGetMasterKeyAlias(void);
 
+char *qemuDomainGetIVKeyAlias(const char *srcalias);
+
 #endif /* __QEMU_ALIAS_H__*/
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index cae356c..b174caa 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -893,6 +893,143 @@ qemuDomainSecretPlainSetup(virConnectPtr conn,
 }
 
 
+/* qemuDomainSecretHaveEncypt:
+ *
+ * Returns true if we can support the encryption code, false otherwise
+ */
+static bool ATTRIBUTE_UNUSED
+qemuDomainSecretHaveEncrypt(void)
+{
+#ifdef HAVE_GNUTLS_CIPHER_ENCRYPT
+    return true;
+#else
+    return false;
+#endif
+}
+
+
+/* qemuDomainSecretIVSetup:
+ * @conn: Pointer to connection
+ * @priv: pointer to domain private object
+ * @secinfo: Pointer to secret info
+ * @srcalias: Alias of the disk/hostdev used to generate the secret alias
+ * @protocol: Protocol for secret
+ * @authdef: Pointer to auth data
+ *
+ * Taking a secinfo, fill in the initialization vector information
+ *
+ * Returns 0 on success, -1 on failure with error message
+ */
+static int ATTRIBUTE_UNUSED
+qemuDomainSecretIVSetup(virConnectPtr conn,
+                        qemuDomainObjPrivatePtr priv,
+                        qemuDomainSecretInfoPtr secinfo,
+                        const char *srcalias,
+                        virStorageNetProtocol protocol,
+                        virStorageAuthDefPtr authdef)
+{
+    int ret = -1;
+    int rc;
+    uint8_t *raw_iv = NULL;
+    char *secret = NULL;
+    uint8_t *ciphertext = NULL;
+    size_t secretlen = 0, ciphertextlen = 0, paddinglen;
+    int secretType = VIR_SECRET_USAGE_TYPE_ISCSI;
+    const char *protocolstr = virStorageNetProtocolTypeToString(protocol);
+    gnutls_cipher_hd_t handle = NULL;
+    gnutls_datum_t enc_key;
+    gnutls_datum_t iv_key;
+
+    secinfo->type = VIR_DOMAIN_SECRET_INFO_TYPE_IV;
+    if (VIR_STRDUP(secinfo->s.iv.username, authdef->username) < 0)
+        return -1;
+
+    if (protocol == VIR_STORAGE_NET_PROTOCOL_RBD)
+        secretType = VIR_SECRET_USAGE_TYPE_CEPH;
+
+    if (!(secinfo->s.iv.alias = qemuDomainGetIVKeyAlias(srcalias)))
+        return -1;
+
+    /* Create a random initialization vector */
+    if (!(raw_iv = qemuDomainGenerateRandomKey(QEMU_DOMAIN_IV_KEY_LEN)))
+        return -1;
+
+    /* Encode the IV and save that since qemu will need it */
+    base64_encode_alloc((const char *)raw_iv, QEMU_DOMAIN_IV_KEY_LEN,
+                        &secinfo->s.iv.iv);
+    if (!secinfo->s.iv.iv) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("failed to encode initialization vector"));
+        goto cleanup;
+    }
+
+    /* Grab the unencoded secret */
+    if (!(secret = virSecretGetSecretString(conn, protocolstr, false,
+                                            authdef, secretType)))
+        goto cleanup;
+
+    /* Allocate a padded buffer */
+    secretlen = strlen(secret);
+    paddinglen = 16 - (secretlen % 16);
+    ciphertextlen = secretlen + paddinglen;
+    if (VIR_ALLOC_N(ciphertext, ciphertextlen) < 0)
+        goto cleanup;
+    memcpy(ciphertext, secret, secretlen);
+    memset(ciphertext + secretlen, paddinglen, paddinglen);
+
+    /* clear secret so that it doesn't hang around */
+    memset(secret, 0, strlen(secret));
+
+    /* Initialize the gnutls cipher */
+    enc_key.size = QEMU_DOMAIN_MASTER_KEY_LEN;
+    enc_key.data = priv->masterKey;
+    iv_key.size = QEMU_DOMAIN_IV_KEY_LEN;
+    iv_key.data = raw_iv;
+    if ((rc = gnutls_cipher_init(&handle, GNUTLS_CIPHER_AES_256_CBC,
+                                 &enc_key, &iv_key)) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("failed to initialize cipher: '%s'"),
+                       gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    /* Encrypt the secret and free the memory for cipher operations */
+    rc = gnutls_cipher_encrypt(handle, ciphertext, ciphertextlen);
+    gnutls_cipher_deinit(handle);
+    if (rc < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("failed to encrypt the secret: '%s'"),
+                       gnutls_strerror(rc));
+        goto cleanup;
+    }
+
+    /* Now base64 encode the ciphertext and store to be passed to qemu */
+    base64_encode_alloc((const char *)ciphertext, ciphertextlen,
+                        &secinfo->s.iv.ciphertext);
+    if (!secinfo->s.iv.ciphertext) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("failed to encode ciphertext"));
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+
+    /* Clear and free the raw_iv, plaintext secret, and ciphertext */
+    memset(raw_iv, 0, QEMU_DOMAIN_IV_KEY_LEN);
+    VIR_FREE(raw_iv);
+
+    memset(secret, 0, secretlen);
+    VIR_FREE(secret);
+
+    memset(ciphertext, 0, ciphertextlen);
+    VIR_FREE(ciphertext);
+
+    return ret;
+}
+
+
 /* qemuDomainSecretDiskDestroy:
  * @disk: Pointer to a disk definition
  *
-- 
2.5.5


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