crypto/engine/eng_rdrand.c

   1 /*
   2  * Copyright 2011-2023 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 /* We need to use some engine deprecated APIs */
  11 #define OPENSSL_SUPPRESS_DEPRECATED
  12
  13 #include <openssl/opensslconf.h>
  14
  15 #include <stdio.h>
  16 #include <string.h>
  17 #include "crypto/engine.h"
  18 #include "internal/cryptlib.h"
  19 #include <openssl/rand.h>
  20 #include <openssl/err.h>
  21 #include <openssl/crypto.h>
  22
  23 #if defined(__has_feature)
  24 # if __has_feature(memory_sanitizer)
  25 #  include <sanitizer/msan_interface.h>
  26 # endif
  27 #endif
  28
  29 #if (defined(__i386)   || defined(__i386__)   || defined(_M_IX86) || \
  30      defined(__x86_64) || defined(__x86_64__) || \
  31      defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
  32
  33 size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
  34
  35 static int get_random_bytes(unsigned char *buf, int num)
  36 {
  37     if (num < 0) {
  38         return 0;
  39     }
  40
  41 # if defined(__has_feature)
  42 #  if __has_feature(memory_sanitizer)
  43     /*
  44      * MemorySanitizer fails to understand asm and produces false positive
  45      * use-of-uninitialized-value warnings.
  46      */
  47     __msan_unpoison(buf, num);
  48 #  endif
  49 # endif
  50
  51     return (size_t)num == OPENSSL_ia32_rdrand_bytes(buf, (size_t)num);
  52 }
  53
  54 static int random_status(void)
  55 {
  56     return 1;
  57 }
  58
  59 static RAND_METHOD rdrand_meth = {
  60     NULL,                       /* seed */
  61     get_random_bytes,
  62     NULL,                       /* cleanup */
  63     NULL,                       /* add */
  64     get_random_bytes,
  65     random_status,
  66 };
  67
  68 static int rdrand_init(ENGINE *e)
  69 {
  70     return 1;
  71 }
  72
  73 static const char *engine_e_rdrand_id = "rdrand";
  74 static const char *engine_e_rdrand_name = "Intel RDRAND engine";
  75
  76 static int bind_helper(ENGINE *e)
  77 {
  78     if (!ENGINE_set_id(e, engine_e_rdrand_id) ||
  79         !ENGINE_set_name(e, engine_e_rdrand_name) ||
  80         !ENGINE_set_flags(e, ENGINE_FLAGS_NO_REGISTER_ALL) ||
  81         !ENGINE_set_init_function(e, rdrand_init) ||
  82         !ENGINE_set_RAND(e, &rdrand_meth))
  83         return 0;
  84
  85     return 1;
  86 }
  87
  88 static ENGINE *ENGINE_rdrand(void)
  89 {
  90     ENGINE *ret = ENGINE_new();
  91     if (ret == NULL)
  92         return NULL;
  93     if (!bind_helper(ret)) {
  94         ENGINE_free(ret);
  95         return NULL;
  96     }
  97     return ret;
  98 }
  99
 100 void engine_load_rdrand_int(void)
 101 {
 102     if (OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) {
 103         ENGINE *toadd = ENGINE_rdrand();
 104         if (!toadd)
 105             return;
 106         ERR_set_mark();
 107         ENGINE_add(toadd);
 108         /*
 109         * If the "add" worked, it gets a structural reference. So either way, we
 110         * release our just-created reference.
 111         */
 112         ENGINE_free(toadd);
 113         /*
 114         * If the "add" didn't work, it was probably a conflict because it was
 115         * already added (eg. someone calling ENGINE_load_blah then calling
 116         * ENGINE_load_builtin_engines() perhaps).
 117         */
 118         ERR_pop_to_mark();
 119     }
 120 }
 121 #else
 122 void engine_load_rdrand_int(void)
 123 {
 124 }
 125 #endif