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[qemu-xen master] crypto: Add tls-cipher-suites object



commit 993aec27aa39aa90f89f227d8f82cc1f8062386e
Author:     Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
AuthorDate: Thu Oct 11 20:21:11 2018 +0200
Commit:     Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
CommitDate: Fri Jul 3 18:16:01 2020 +0200

    crypto: Add tls-cipher-suites object
    
    On the host OS, various aspects of TLS operation are configurable.
    In particular it is possible for the sysadmin to control the TLS
    cipher/protocol algorithms that applications are permitted to use.
    
    * Any given crypto library has a built-in default priority list
      defined by the distro maintainer of the library package (or by
      upstream).
    
    * The "crypto-policies" RPM (or equivalent host OS package)
      provides a config file such as "/etc/crypto-policies/config",
      where the sysadmin can set a high level (library-independent)
      policy.
    
      The "update-crypto-policies --set" command (or equivalent) is
      used to translate the global policy to individual library
      representations, producing files such as
      "/etc/crypto-policies/back-ends/*.config". The generated files,
      if present, are loaded by the various crypto libraries to
      override their own built-in defaults.
    
      For example, the GNUTLS library may read
      "/etc/crypto-policies/back-ends/gnutls.config".
    
    * A management application (or the QEMU user) may overide the
      system-wide crypto-policies config via their own config, if
      they need to diverge from the former.
    
    Thus the priority order is "QEMU user config" > "crypto-policies
    system config" > "library built-in config".
    
    Introduce the "tls-cipher-suites" object for exposing the ordered
    list of permitted TLS cipher suites from the host side to the
    guest firmware, via fw_cfg. The list is represented as an array
    of bytes.
    
    The priority at which the host-side policy is retrieved is given
    by the "priority" property of the new object type. For example,
    "priority=@SYSTEM" may be used to refer to
    "/etc/crypto-policies/back-ends/gnutls.config" (given that QEMU
    uses GNUTLS).
    
    The firmware uses the IANA_TLS_CIPHER array for configuring
    guest-side TLS, for example in UEFI HTTPS Boot.
    
    [Description from Daniel P. Berrangé, edited by Laszlo Ersek.]
    
    Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
    Reviewed-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
    Acked-by: Laszlo Ersek <lersek@xxxxxxxxxx>
    Message-Id: <20200623172726.21040-2-philmd@xxxxxxxxxx>
---
 crypto/Makefile.objs               |   1 +
 crypto/tls-cipher-suites.c         | 115 +++++++++++++++++++++++++++++++++++++
 crypto/trace-events                |   5 ++
 include/crypto/tls-cipher-suites.h |  39 +++++++++++++
 qemu-options.hx                    |  19 ++++++
 5 files changed, 179 insertions(+)

diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index 707c02ad37..f1965b1a68 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -13,6 +13,7 @@ crypto-obj-y += cipher.o
 crypto-obj-$(CONFIG_AF_ALG) += afalg.o
 crypto-obj-$(CONFIG_AF_ALG) += cipher-afalg.o
 crypto-obj-$(CONFIG_AF_ALG) += hash-afalg.o
+crypto-obj-$(CONFIG_GNUTLS) += tls-cipher-suites.o
 crypto-obj-y += tlscreds.o
 crypto-obj-y += tlscredsanon.o
 crypto-obj-y += tlscredspsk.o
diff --git a/crypto/tls-cipher-suites.c b/crypto/tls-cipher-suites.c
new file mode 100644
index 0000000000..a4e0f84307
--- /dev/null
+++ b/crypto/tls-cipher-suites.c
@@ -0,0 +1,115 @@
+/*
+ * QEMU TLS Cipher Suites
+ *
+ * Copyright (c) 2018-2020 Red Hat, Inc.
+ *
+ * Author: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qom/object_interfaces.h"
+#include "crypto/tlscreds.h"
+#include "crypto/tls-cipher-suites.h"
+#include "trace.h"
+
+/*
+ * IANA registered TLS ciphers:
+ * 
https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-4
+ */
+typedef struct {
+    uint8_t data[2];
+} QEMU_PACKED IANA_TLS_CIPHER;
+
+GByteArray *qcrypto_tls_cipher_suites_get_data(QCryptoTLSCipherSuites *obj,
+                                               Error **errp)
+{
+    QCryptoTLSCreds *creds = QCRYPTO_TLS_CREDS(obj);
+    gnutls_priority_t pcache;
+    GByteArray *byte_array;
+    const char *err;
+    size_t i;
+    int ret;
+
+    trace_qcrypto_tls_cipher_suite_priority(creds->priority);
+    ret = gnutls_priority_init(&pcache, creds->priority, &err);
+    if (ret < 0) {
+        error_setg(errp, "Syntax error using priority '%s': %s",
+                   creds->priority, gnutls_strerror(ret));
+        return NULL;
+    }
+
+    byte_array = g_byte_array_new();
+
+    for (i = 0;; i++) {
+        int ret;
+        unsigned idx;
+        const char *name;
+        IANA_TLS_CIPHER cipher;
+        gnutls_protocol_t protocol;
+        const char *version;
+
+        ret = gnutls_priority_get_cipher_suite_index(pcache, i, &idx);
+        if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
+            break;
+        }
+        if (ret == GNUTLS_E_UNKNOWN_CIPHER_SUITE) {
+            continue;
+        }
+
+        name = gnutls_cipher_suite_info(idx, (unsigned char *)&cipher,
+                                        NULL, NULL, NULL, &protocol);
+        if (name == NULL) {
+            continue;
+        }
+
+        version = gnutls_protocol_get_name(protocol);
+        g_byte_array_append(byte_array, cipher.data, 2);
+        trace_qcrypto_tls_cipher_suite_info(cipher.data[0],
+                                            cipher.data[1],
+                                            version, name);
+    }
+    trace_qcrypto_tls_cipher_suite_count(byte_array->len);
+    gnutls_priority_deinit(pcache);
+
+    return byte_array;
+}
+
+static void qcrypto_tls_cipher_suites_complete(UserCreatable *uc,
+                                               Error **errp)
+{
+    QCryptoTLSCreds *creds = QCRYPTO_TLS_CREDS(uc);
+
+    if (!creds->priority) {
+        error_setg(errp, "'priority' property is not set");
+        return;
+    }
+}
+
+static void qcrypto_tls_cipher_suites_class_init(ObjectClass *oc, void *data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+
+    ucc->complete = qcrypto_tls_cipher_suites_complete;
+}
+
+static const TypeInfo qcrypto_tls_cipher_suites_info = {
+    .parent = TYPE_QCRYPTO_TLS_CREDS,
+    .name = TYPE_QCRYPTO_TLS_CIPHER_SUITES,
+    .instance_size = sizeof(QCryptoTLSCreds),
+    .class_size = sizeof(QCryptoTLSCredsClass),
+    .class_init = qcrypto_tls_cipher_suites_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+static void qcrypto_tls_cipher_suites_register_types(void)
+{
+    type_register_static(&qcrypto_tls_cipher_suites_info);
+}
+
+type_init(qcrypto_tls_cipher_suites_register_types);
diff --git a/crypto/trace-events b/crypto/trace-events
index 9e594d30e8..798b6067ab 100644
--- a/crypto/trace-events
+++ b/crypto/trace-events
@@ -21,3 +21,8 @@ qcrypto_tls_creds_x509_load_cert_list(void *creds, const char 
*file) "TLS creds
 # tlssession.c
 qcrypto_tls_session_new(void *session, void *creds, const char *hostname, 
const char *authzid, int endpoint) "TLS session new session=%p creds=%p 
hostname=%s authzid=%s endpoint=%d"
 qcrypto_tls_session_check_creds(void *session, const char *status) "TLS 
session check creds session=%p status=%s"
+
+# tls-cipher-suites.c
+qcrypto_tls_cipher_suite_priority(const char *name) "priority: %s"
+qcrypto_tls_cipher_suite_info(uint8_t data0, uint8_t data1, const char 
*version, const char *name) "data=[0x%02x,0x%02x] version=%s name=%s"
+qcrypto_tls_cipher_suite_count(unsigned count) "count: %u"
diff --git a/include/crypto/tls-cipher-suites.h 
b/include/crypto/tls-cipher-suites.h
new file mode 100644
index 0000000000..28b3a73ce1
--- /dev/null
+++ b/include/crypto/tls-cipher-suites.h
@@ -0,0 +1,39 @@
+/*
+ * QEMU TLS Cipher Suites Registry (RFC8447)
+ *
+ * Copyright (c) 2018-2020 Red Hat, Inc.
+ *
+ * Author: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef QCRYPTO_TLSCIPHERSUITES_H
+#define QCRYPTO_TLSCIPHERSUITES_H
+
+#include "qom/object.h"
+#include "crypto/tlscreds.h"
+
+#define TYPE_QCRYPTO_TLS_CIPHER_SUITES "tls-cipher-suites"
+#define QCRYPTO_TLS_CIPHER_SUITES(obj) \
+    OBJECT_CHECK(QCryptoTLSCipherSuites, (obj), TYPE_QCRYPTO_TLS_CIPHER_SUITES)
+
+typedef struct QCryptoTLSCipherSuites {
+    /* <private> */
+    QCryptoTLSCreds parent_obj;
+    /* <public> */
+} QCryptoTLSCipherSuites;
+
+/**
+  * qcrypto_tls_cipher_suites_get_data:
+  * @obj: pointer to a TLS cipher suites object
+  * @errp: pointer to a NULL-initialized error object
+  *
+  * Returns: reference to a byte array containing the data.
+  * The caller should release the reference when no longer
+  * required.
+  */
+GByteArray *qcrypto_tls_cipher_suites_get_data(QCryptoTLSCipherSuites *obj,
+                                               Error **errp);
+
+#endif /* QCRYPTO_TLSCIPHERSUITES_H */
diff --git a/qemu-options.hx b/qemu-options.hx
index 196f468786..ecc4658e1f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4567,6 +4567,25 @@ SRST
         string as described at
         https://gnutls.org/manual/html_node/Priority-Strings.html.
 
+    ``-object tls-cipher-suites,id=id,priority=priority``
+        Creates a TLS cipher suites object, which can be used to control
+        the TLS cipher/protocol algorithms that applications are permitted
+        to use.
+
+        The ``id`` parameter is a unique ID which frontends will use to
+        access the ordered list of permitted TLS cipher suites from the
+        host.
+
+        The ``priority`` parameter allows to override the global default
+        priority used by gnutls. This can be useful if the system
+        administrator needs to use a weaker set of crypto priorities for
+        QEMU without potentially forcing the weakness onto all
+        applications. Or conversely if one wants wants a stronger
+        default for QEMU than for all other applications, they can do
+        this through this parameter. Its format is a gnutls priority
+        string as described at
+        https://gnutls.org/manual/html_node/Priority-Strings.html.
+
     ``-object 
filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]``
         Interval t can't be 0, this filter batches the packet delivery:
         all packets arriving in a given interval on netdev netdevid are
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#master



 


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