Implement the NULL cipher in the default provider

Libssl uses the null cipher in certain situations. It should be
converted to a provided cipher.

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10865)

crypto/evp/evp_enc.c

@@ -142,6 +142,7 @@ int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
 
     if (tmpcipher->prov == NULL) {
         switch(tmpcipher->nid) {
+        case NID_undef:
         case NID_aes_256_ecb:
         case NID_aes_192_ecb:
         case NID_aes_128_ecb:
@@ -326,7 +327,10 @@ int EVP_CipherInit_ex(EVP_CIPHER_CTX *ctx, const EVP_CIPHER *cipher,
         return 0;
 #else
         EVP_CIPHER *provciph =
-            EVP_CIPHER_fetch(NULL, OBJ_nid2sn(cipher->nid), "");
+            EVP_CIPHER_fetch(NULL,
+                             cipher->nid == NID_undef ? "NULL"
+                                                      : OBJ_nid2sn(cipher->nid),
+                             "");
 
         if (provciph == NULL) {
             EVPerr(EVP_F_EVP_CIPHERINIT_EX, EVP_R_INITIALIZATION_ERROR);

providers/defltprov.c

@@ -138,6 +138,7 @@ static const OSSL_ALGORITHM deflt_digests[] = {
 };
 
 static const OSSL_ALGORITHM_CAPABLE deflt_ciphers[] = {
+    ALG("NULL", null_functions),
     ALG("AES-256-ECB", aes256ecb_functions),
     ALG("AES-192-ECB", aes192ecb_functions),
     ALG("AES-128-ECB", aes128ecb_functions),

providers/implementations/ciphers/build.info

@@ -7,6 +7,7 @@
 
 $COMMON_GOAL=../../libcommon.a
 
+$NULL_GOAL=../../libimplementations.a
 $AES_GOAL=../../libimplementations.a
 $TDES_1_GOAL=../../libimplementations.a
 $TDES_2_GOAL=../../libimplementations.a
@@ -35,6 +36,9 @@ IF[{- !$disabled{des} -}]
   SOURCE[$TDES_1_GOAL]=cipher_tdes.c cipher_tdes_hw.c
 ENDIF
 
+SOURCE[$NULL_GOAL]=\
+        cipher_null.c
+
 SOURCE[$AES_GOAL]=\
         cipher_aes.c cipher_aes_hw.c \
         cipher_aes_xts.c cipher_aes_xts_hw.c \

providers/implementations/ciphers/cipher_null.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (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 <string.h>
+#include <openssl/crypto.h>
+#include <openssl/core_numbers.h>
+#include "prov/implementations.h"
+#include "prov/ciphercommon.h"
+#include "prov/providercommonerr.h"
+
+static OSSL_OP_cipher_newctx_fn null_newctx;
+static void *null_newctx(void *provctx)
+{
+    static int dummy = 0;
+
+    return &dummy;
+}
+
+static OSSL_OP_cipher_freectx_fn null_freectx;
+static void null_freectx(void *vctx)
+{
+}
+
+static OSSL_OP_cipher_encrypt_init_fn null_init;
+static int null_init(void *vctx, const unsigned char *key, size_t keylen,
+                     const unsigned char *iv, size_t ivlen)
+{
+    return 1;
+}
+
+static OSSL_OP_cipher_cipher_fn null_cipher;
+static int null_cipher(void *vctx, unsigned char *out, size_t *outl,
+                       size_t outsize, const unsigned char *in, size_t inl)
+{
+    if (outsize < inl)
+        return 0;
+    if (in != out)
+        memcpy(out, in, inl);
+    *outl = inl;
+    return 1;
+}
+
+static OSSL_OP_cipher_final_fn null_final;
+static int null_final(void *vctx, unsigned char *out, size_t *outl,
+                      size_t outsize)
+{
+    *outl = 0;
+    return 1;
+}
+
+static OSSL_OP_cipher_get_params_fn null_get_params;
+static int null_get_params(OSSL_PARAM params[])
+{
+    return cipher_generic_get_params(params, 0, 0, 0, 8, 0);
+}
+
+static const OSSL_PARAM null_known_gettable_ctx_params[] = {
+    OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_KEYLEN, NULL),
+    OSSL_PARAM_size_t(OSSL_CIPHER_PARAM_IVLEN, NULL),
+    OSSL_PARAM_END
+};
+
+static OSSL_OP_cipher_gettable_ctx_params_fn null_gettable_ctx_params;
+static const OSSL_PARAM *null_gettable_ctx_params(void)
+{
+    return null_known_gettable_ctx_params;
+}
+
+static OSSL_OP_cipher_get_ctx_params_fn null_get_ctx_params;
+static int null_get_ctx_params(void *vctx, OSSL_PARAM params[])
+{
+    OSSL_PARAM *p;
+
+    p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_IVLEN);
+    if (p != NULL && !OSSL_PARAM_set_size_t(p, 0)) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
+        return 0;
+    }
+    p = OSSL_PARAM_locate(params, OSSL_CIPHER_PARAM_KEYLEN);
+    if (p != NULL && !OSSL_PARAM_set_size_t(p, 0)) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
+        return 0;
+    }
+    return 1;
+}
+
+const OSSL_DISPATCH null_functions[] = {
+    { OSSL_FUNC_CIPHER_NEWCTX,
+      (void (*)(void)) null_newctx },
+    { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void)) null_freectx },
+    { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void)) null_newctx },
+    { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))null_init },
+    { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))null_init },
+    { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))null_cipher },
+    { OSSL_FUNC_CIPHER_FINAL, (void (*)(void))null_final },
+    { OSSL_FUNC_CIPHER_CIPHER, (void (*)(void))null_cipher },
+    { OSSL_FUNC_CIPHER_GET_PARAMS, (void (*)(void)) null_get_params },
+    { OSSL_FUNC_CIPHER_GETTABLE_PARAMS,
+        (void (*)(void))cipher_generic_gettable_params },
+    { OSSL_FUNC_CIPHER_GET_CTX_PARAMS, (void (*)(void))null_get_ctx_params },
+    { OSSL_FUNC_CIPHER_GETTABLE_CTX_PARAMS,
+      (void (*)(void))null_gettable_ctx_params },
+    { 0, NULL }
+};

providers/implementations/include/prov/implementations.h

@@ -35,6 +35,7 @@ extern const OSSL_DISPATCH wp_functions[];
 extern const OSSL_DISPATCH ripemd160_functions[];
 
 /* Ciphers */
+extern const OSSL_DISPATCH null_functions[];
 extern const OSSL_DISPATCH aes256ecb_functions[];
 extern const OSSL_DISPATCH aes192ecb_functions[];
 extern const OSSL_DISPATCH aes128ecb_functions[];