EVP_MAC: Add CMAC implementation

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7484)

crypto/cmac/build.info

@@ -1,2 +1,2 @@
 LIBS=../../libcrypto
-SOURCE[../../libcrypto]=cmac.c cm_ameth.c cm_pmeth.c
+SOURCE[../../libcrypto]=cmac.c cm_ameth.c cm_pmeth.c cm_meth.c

crypto/cmac/cm_meth.c

@@ -0,0 +1,164 @@
+/*
+ * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdio.h>
+#include "internal/cryptlib.h"
+#include <openssl/x509.h>
+#include <openssl/x509v3.h>
+#include <openssl/evp.h>
+#include <openssl/cmac.h>
+#include "internal/evp_int.h"
+
+/* local CMAC pkey structure */
+
+/* typedef EVP_MAC_IMPL */
+struct evp_mac_impl_st {
+    /* tmpcipher and tmpengine are set to NULL after a CMAC_Init call */
+    const EVP_CIPHER *tmpcipher; /* cached CMAC cipher */
+    const ENGINE *tmpengine;     /* cached CMAC cipher engine */
+    CMAC_CTX *ctx;
+};
+
+static EVP_MAC_IMPL *cmac_new(void)
+{
+    EVP_MAC_IMPL *cctx;
+
+    if ((cctx = OPENSSL_zalloc(sizeof(*cctx))) == NULL
+        || (cctx->ctx = CMAC_CTX_new()) == NULL) {
+        OPENSSL_free(cctx);
+        cctx = NULL;
+    }
+
+    return cctx;
+}
+
+static void cmac_free(EVP_MAC_IMPL *cctx)
+{
+    if (cctx != NULL) {
+        CMAC_CTX_free(cctx->ctx);
+        OPENSSL_free(cctx);
+    }
+}
+
+static int cmac_copy(EVP_MAC_IMPL *cdst, EVP_MAC_IMPL *csrc)
+{
+    if (!CMAC_CTX_copy(cdst->ctx, csrc->ctx))
+        return 0;
+
+    cdst->tmpengine = csrc->tmpengine;
+    cdst->tmpcipher = csrc->tmpcipher;
+    return 1;
+}
+
+static size_t cmac_size(EVP_MAC_IMPL *cctx)
+{
+    return EVP_CIPHER_CTX_block_size(CMAC_CTX_get0_cipher_ctx(cctx->ctx));
+}
+
+static int cmac_init(EVP_MAC_IMPL *cctx)
+{
+    int rv = CMAC_Init(cctx->ctx, NULL, 0, cctx->tmpcipher,
+                       (ENGINE *)cctx->tmpengine);
+    cctx->tmpcipher = NULL;
+    cctx->tmpengine = NULL;
+
+    return rv;
+}
+
+static int cmac_update(EVP_MAC_IMPL *cctx, const unsigned char *data,
+                       size_t datalen)
+{
+    return CMAC_Update(cctx->ctx, data, datalen);
+}
+
+static int cmac_final(EVP_MAC_IMPL *cctx, unsigned char *out)
+{
+    size_t hlen;
+
+    return CMAC_Final(cctx->ctx, out, &hlen);
+}
+
+static int cmac_ctrl(EVP_MAC_IMPL *cctx, int cmd, va_list args)
+{
+    switch (cmd) {
+    case EVP_MAC_CTRL_SET_KEY:
+        {
+            const unsigned char *key = va_arg(args, const unsigned char *);
+            size_t keylen = va_arg(args, size_t);
+            int rv = CMAC_Init(cctx->ctx, key, keylen, cctx->tmpcipher,
+                               (ENGINE *)cctx->tmpengine);
+
+            cctx->tmpcipher = NULL;
+            cctx->tmpengine = NULL;
+
+            return rv;
+        }
+        break;
+    case EVP_MAC_CTRL_SET_CIPHER:
+        cctx->tmpcipher = va_arg(args, const EVP_CIPHER *);
+        break;
+    case EVP_MAC_CTRL_SET_ENGINE:
+        cctx->tmpengine = va_arg(args, const ENGINE *);
+        break;
+    default:
+        return -2;
+    }
+    return 1;
+}
+
+static int cmac_ctrl_int(EVP_MAC_IMPL *hctx, int cmd, ...)
+{
+    int rv;
+    va_list args;
+
+    va_start(args, cmd);
+    rv = cmac_ctrl(hctx, cmd, args);
+    va_end(args);
+
+    return rv;
+}
+
+static int cmac_ctrl_str_cb(void *hctx, int cmd, void *buf, size_t buflen)
+{
+    return cmac_ctrl_int(hctx, cmd, buf, buflen);
+}
+
+static int cmac_ctrl_str(EVP_MAC_IMPL *cctx, const char *type,
+                         const char *value)
+{
+    if (!value)
+        return 0;
+    if (strcmp(type, "cipher") == 0) {
+        const EVP_CIPHER *c = EVP_get_cipherbyname(value);
+
+        if (c == NULL)
+            return 0;
+        return cmac_ctrl_int(cctx, EVP_MAC_CTRL_SET_CIPHER, c);
+    }
+    if (strcmp(type, "key") == 0)
+        return EVP_str2ctrl(cmac_ctrl_str_cb, cctx, EVP_MAC_CTRL_SET_KEY,
+                            value);
+    if (strcmp(type, "hexkey") == 0)
+        return EVP_hex2ctrl(cmac_ctrl_str_cb, cctx, EVP_MAC_CTRL_SET_KEY,
+                            value);
+    return -2;
+}
+
+const EVP_MAC cmac_meth = {
+    EVP_MAC_CMAC,
+    cmac_new,
+    cmac_copy,
+    cmac_free,
+    cmac_size,
+    cmac_init,
+    cmac_update,
+    cmac_final,
+    cmac_ctrl,
+    cmac_ctrl_str
+};

crypto/evp/c_allm.c

@@ -12,4 +12,7 @@
 
 void openssl_add_all_macs_int(void)
 {
+#ifndef OPENSSL_NO_CMAC
+    EVP_add_mac(&cmac_meth);
+#endif
 }

crypto/include/internal/evp_int.h

@@ -128,6 +128,8 @@ struct evp_mac_st {
     int (*ctrl_str) (EVP_MAC_IMPL *macctx, const char *type, const char *value);
 };
 
+extern const EVP_MAC cmac_meth;
+
 /*
  * This function is internal for now, but can be made external when needed.
  * The documentation would read:

doc/man3/EVP_MAC.pod

@@ -326,16 +326,8 @@ F<./foo>)
 
 =head1 SEE ALSO
 
-=begin comment
-
-Add links to existing implementations in this form:
-
 L<EVP_MAC_CMAC(7)>
 
-Make sure the documentation exists in doc/man7/
-
-=end comment
-
 =head1 COPYRIGHT
 
 Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.

doc/man7/EVP_MAC_CMAC.pod

@@ -0,0 +1,65 @@
+=pod
+
+=head1 NAME
+
+EVP_MAC_CMAC - The CMAC EVP_MAC implementation
+
+=head1 DESCRIPTION
+
+Support for computing CMAC MACs through the B<EVP_MAC> API.
+
+=head2 Numeric identity
+
+B<EVP_MAC_CMAC> is the numeric identity for this implementation, and
+can be used in functions like EVP_MAC_CTX_new_id() and
+EVP_get_macbynid().
+
+=head2 Supported controls
+
+The supported controls are:
+
+=over 4
+
+=item B<EVP_MAC_CTRL_SET_KEY>
+
+EVP_MAC_ctrl_str() takes to type string for this control:
+
+=over 4
+
+=item "key"
+
+The value string is used as is.
+
+=item "hexkey"
+
+The value string is expected to be a hexadecimal number, which will be
+decoded before passing on as control value.
+
+=back
+
+=item B<EVP_MAC_CTRL_SET_ENGINE>
+
+=item B<EVP_MAC_CTRL_SET_CIPHER>
+
+These work as described in L<EVP_MAC(3)/CONTROLS>.
+
+EVP_MAC_ctrl_str() type string for B<EVP_MAC_CTRL_SET_CIPHER>: "cipher"
+
+The value is expected to be the name of a cipher.
+
+=back
+
+=head1 SEE ALSO
+
+L<EVP_MAC_ctrl(3)>, L<EVP_MAC(3)/CONTROLS>
+
+=head1 COPYRIGHT
+
+Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut

include/openssl/evp.h

@@ -987,6 +987,8 @@ void EVP_MD_do_all_sorted(void (*fn)
 
 /* MAC stuff */
 
+# define EVP_MAC_CMAC   NID_cmac
+
 EVP_MAC_CTX *EVP_MAC_CTX_new(const EVP_MAC *mac);
 EVP_MAC_CTX *EVP_MAC_CTX_new_id(int nid);
 void EVP_MAC_CTX_free(EVP_MAC_CTX *ctx);