providers/implementations/encode_decode/encode_key2blob.c

   1 /*
   2  * Copyright 2021-2022 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * Low level APIs are deprecated for public use, but still ok for internal use.
  12  */
  13 #include "internal/deprecated.h"
  14
  15 #include <openssl/core.h>
  16 #include <openssl/core_dispatch.h>
  17 #include <openssl/core_names.h>
  18 #include <openssl/params.h>
  19 #include <openssl/err.h>
  20 #include <openssl/evp.h>
  21 #include <openssl/ec.h>
  22 #include "internal/passphrase.h"
  23 #include "internal/nelem.h"
  24 #include "prov/implementations.h"
  25 #include "prov/bio.h"
  26 #include "prov/provider_ctx.h"
  27 #include "endecoder_local.h"
  28
  29 static int write_blob(void *provctx, OSSL_CORE_BIO *cout,
  30                       void *data, int len)
  31 {
  32     BIO *out = ossl_bio_new_from_core_bio(provctx, cout);
  33     int ret;
  34
  35     if (out == NULL)
  36         return 0;
  37     ret = BIO_write(out, data, len);
  38
  39     BIO_free(out);
  40     return ret;
  41 }
  42
  43 static OSSL_FUNC_encoder_newctx_fn key2blob_newctx;
  44 static OSSL_FUNC_encoder_freectx_fn key2blob_freectx;
  45
  46 static void *key2blob_newctx(void *provctx)
  47 {
  48     return provctx;
  49 }
  50
  51 static void key2blob_freectx(void *vctx)
  52 {
  53 }
  54
  55 static int key2blob_check_selection(int selection, int selection_mask)
  56 {
  57     /*
  58      * The selections are kinda sorta "levels", i.e. each selection given
  59      * here is assumed to include those following.
  60      */
  61     int checks[] = {
  62         OSSL_KEYMGMT_SELECT_PRIVATE_KEY,
  63         OSSL_KEYMGMT_SELECT_PUBLIC_KEY,
  64         OSSL_KEYMGMT_SELECT_ALL_PARAMETERS
  65     };
  66     size_t i;
  67
  68     /* The decoder implementations made here support guessing */
  69     if (selection == 0)
  70         return 1;
  71
  72     for (i = 0; i < OSSL_NELEM(checks); i++) {
  73         int check1 = (selection & checks[i]) != 0;
  74         int check2 = (selection_mask & checks[i]) != 0;
  75
  76         /*
  77          * If the caller asked for the currently checked bit(s), return
  78          * whether the decoder description says it's supported.
  79          */
  80         if (check1)
  81             return check2;
  82     }
  83
  84     /* This should be dead code, but just to be safe... */
  85     return 0;
  86 }
  87
  88 static int key2blob_encode(void *vctx, const void *key, int selection,
  89                            OSSL_CORE_BIO *cout)
  90 {
  91     int pubkey_len = 0, ok = 0;
  92     unsigned char *pubkey = NULL;
  93
  94     pubkey_len = i2o_ECPublicKey(key, &pubkey);
  95     if (pubkey_len > 0 && pubkey != NULL)
  96         ok = write_blob(vctx, cout, pubkey, pubkey_len);
  97     OPENSSL_free(pubkey);
  98     return ok;
  99 }
 100
 101 /*
 102  * MAKE_BLOB_ENCODER() Makes an OSSL_DISPATCH table for a particular key->blob
 103  * encoder
 104  *
 105  * impl:                The keytype to encode
 106  * type:                The C structure type holding the key data
 107  * selection_name:      The acceptable selections.  This translates into
 108  *                      the macro EVP_PKEY_##selection_name.
 109  *
 110  * The selection is understood as a "level" rather than an exact set of
 111  * requests from the caller.  The encoder has to decide what contents fit
 112  * the encoded format.  For example, the EC public key blob will only contain
 113  * the encoded public key itself, no matter if the selection bits include
 114  * OSSL_KEYMGMT_SELECT_PARAMETERS or not.  However, if the selection includes
 115  * OSSL_KEYMGMT_SELECT_PRIVATE_KEY, the same encoder will simply refuse to
 116  * cooperate, because it cannot output the private key.
 117  *
 118  * EVP_PKEY_##selection_name are convenience macros that combine "typical"
 119  * OSSL_KEYMGMT_SELECT_ macros for a certain type of EVP_PKEY content.
 120  */
 121 #define MAKE_BLOB_ENCODER(impl, type, selection_name)                   \
 122     static OSSL_FUNC_encoder_import_object_fn                           \
 123     impl##2blob_import_object;                                          \
 124     static OSSL_FUNC_encoder_free_object_fn impl##2blob_free_object;    \
 125     static OSSL_FUNC_encoder_does_selection_fn                          \
 126     impl##2blob_does_selection;                                         \
 127     static OSSL_FUNC_encoder_encode_fn impl##2blob_encode;              \
 128                                                                         \
 129     static void *impl##2blob_import_object(void *ctx, int selection,    \
 130                                            const OSSL_PARAM params[])   \
 131     {                                                                   \
 132         return ossl_prov_import_key(ossl_##impl##_keymgmt_functions,    \
 133                                     ctx, selection, params);            \
 134     }                                                                   \
 135     static void impl##2blob_free_object(void *key)                      \
 136     {                                                                   \
 137         ossl_prov_free_key(ossl_##impl##_keymgmt_functions, key);       \
 138     }                                                                   \
 139     static int impl##2blob_does_selection(void *ctx, int selection)     \
 140     {                                                                   \
 141         return key2blob_check_selection(selection,                      \
 142                                         EVP_PKEY_##selection_name);     \
 143     }                                                                   \
 144     static int impl##2blob_encode(void *vctx, OSSL_CORE_BIO *cout,      \
 145                                   const void *key,                      \
 146                                   const OSSL_PARAM key_abstract[],      \
 147                                   int selection,                        \
 148                                   OSSL_PASSPHRASE_CALLBACK *cb,         \
 149                                   void *cbarg)                          \
 150     {                                                                   \
 151         /* We don't deal with abstract objects */                       \
 152         if (key_abstract != NULL) {                                     \
 153             ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_INVALID_ARGUMENT);     \
 154             return 0;                                                   \
 155         }                                                               \
 156         return key2blob_encode(vctx, key, selection, cout);             \
 157     }                                                                   \
 158     const OSSL_DISPATCH ossl_##impl##_to_blob_encoder_functions[] = {   \
 159         { OSSL_FUNC_ENCODER_NEWCTX,                                     \
 160           (void (*)(void))key2blob_newctx },                            \
 161         { OSSL_FUNC_ENCODER_FREECTX,                                    \
 162           (void (*)(void))key2blob_freectx },                           \
 163         { OSSL_FUNC_ENCODER_DOES_SELECTION,                             \
 164           (void (*)(void))impl##2blob_does_selection },                 \
 165         { OSSL_FUNC_ENCODER_IMPORT_OBJECT,                              \
 166           (void (*)(void))impl##2blob_import_object },                  \
 167         { OSSL_FUNC_ENCODER_FREE_OBJECT,                                \
 168           (void (*)(void))impl##2blob_free_object },                    \
 169         { OSSL_FUNC_ENCODER_ENCODE,                                     \
 170           (void (*)(void))impl##2blob_encode },                         \
 171         { 0, NULL }                                                     \
 172     }
 173
 174 #ifndef OPENSSL_NO_EC
 175 MAKE_BLOB_ENCODER(ec, ec, PUBLIC_KEY);
 176 # ifndef OPENSSL_NO_SM2
 177 MAKE_BLOB_ENCODER(sm2, ec, PUBLIC_KEY);
 178 # endif
 179 #endif