mirror of https://github.com/acidanthera/audk.git
113 lines
2.7 KiB
C
113 lines
2.7 KiB
C
/** @file
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Pseudorandom Number Generator Wrapper Implementation over OpenSSL.
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Copyright (c) 2012 - 2018, Intel Corporation. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "InternalCryptLib.h"
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#include <openssl/rand.h>
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#include <openssl/evp.h>
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#include <Library/PrintLib.h>
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/**
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Sets up the seed value for the pseudorandom number generator.
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This function sets up the seed value for the pseudorandom number generator.
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If Seed is not NULL, then the seed passed in is used.
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If Seed is NULL, then default seed is used.
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@param[in] Seed Pointer to seed value.
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If NULL, default seed is used.
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@param[in] SeedSize Size of seed value.
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If Seed is NULL, this parameter is ignored.
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@retval TRUE Pseudorandom number generator has enough entropy for random generation.
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@retval FALSE Pseudorandom number generator does not have enough entropy for random generation.
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**/
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BOOLEAN
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EFIAPI
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RandomSeed (
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IN CONST UINT8 *Seed OPTIONAL,
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IN UINTN SeedSize
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)
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{
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CHAR8 DefaultSeed[128];
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if (SeedSize > INT_MAX) {
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return FALSE;
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}
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//
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// The software PRNG implementation built in OpenSSL depends on message digest algorithm.
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// Make sure SHA-1 digest algorithm is available here.
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//
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if (EVP_add_digest (EVP_sha1 ()) == 0) {
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return FALSE;
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}
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//
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// Seed the pseudorandom number generator with user-supplied value.
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// NOTE: A cryptographic PRNG must be seeded with unpredictable data.
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//
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if (Seed != NULL) {
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RAND_seed (Seed, (UINT32) SeedSize);
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} else {
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//
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// Retrieve current time.
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//
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AsciiSPrint (
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DefaultSeed,
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sizeof (DefaultSeed),
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"UEFI Crypto Library default seed (%ld)",
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AsmReadTsc ()
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);
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RAND_seed (DefaultSeed, sizeof (DefaultSeed));
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}
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if (RAND_status () == 1) {
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return TRUE;
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}
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return FALSE;
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}
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/**
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Generates a pseudorandom byte stream of the specified size.
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If Output is NULL, then return FALSE.
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@param[out] Output Pointer to buffer to receive random value.
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@param[in] Size Size of random bytes to generate.
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@retval TRUE Pseudorandom byte stream generated successfully.
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@retval FALSE Pseudorandom number generator fails to generate due to lack of entropy.
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**/
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BOOLEAN
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EFIAPI
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RandomBytes (
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OUT UINT8 *Output,
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IN UINTN Size
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)
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{
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//
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// Check input parameters.
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//
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if (Output == NULL || Size > INT_MAX) {
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return FALSE;
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}
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//
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// Generate random data.
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//
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if (RAND_bytes (Output, (UINT32) Size) != 1) {
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return FALSE;
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}
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return TRUE;
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}
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