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240 lines
6.4 KiB
240 lines
6.4 KiB
/*
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* Platform-specific and custom entropy polling functions
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#if defined(__linux__) && !defined(_GNU_SOURCE)
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/* Ensure that syscall() is available even when compiling with -std=c99 */
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#define _GNU_SOURCE
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#endif
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#include "common.h"
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#ifndef CONFIG_SOCT_CIPHER_MBEDTLS_SUPPORT
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#include <string.h>
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#endif
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#if defined(MBEDTLS_ENTROPY_C)
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#include "mbedtls/entropy.h"
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#include "entropy_poll.h"
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#include "mbedtls/error.h"
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#if defined(MBEDTLS_TIMING_C)
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#include "mbedtls/timing.h"
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#endif
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#if defined(MBEDTLS_ENTROPY_NV_SEED)
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#include "mbedtls/platform.h"
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#endif
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#if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
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#if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
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!defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
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!defined(__HAIKU__) && !defined(__midipix__)
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#error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in mbedtls_config.h"
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#endif
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#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
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#if !defined(_WIN32_WINNT)
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#define _WIN32_WINNT 0x0400
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#endif
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#include <windows.h>
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#include <wincrypt.h>
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int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
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size_t *olen )
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{
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HCRYPTPROV provider;
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((void) data);
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*olen = 0;
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if( CryptAcquireContext( &provider, NULL, NULL,
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PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
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{
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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}
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if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
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{
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CryptReleaseContext( provider, 0 );
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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}
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CryptReleaseContext( provider, 0 );
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*olen = len;
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return( 0 );
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}
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#else /* _WIN32 && !EFIX64 && !EFI32 */
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/*
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* Test for Linux getrandom() support.
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* Since there is no wrapper in the libc yet, use the generic syscall wrapper
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* available in GNU libc and compatible libc's (eg uClibc).
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*/
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#if ((defined(__linux__) && defined(__GLIBC__)) || defined(__midipix__))
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#include <unistd.h>
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#include <sys/syscall.h>
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#if defined(SYS_getrandom)
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#define HAVE_GETRANDOM
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#include <errno.h>
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static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
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{
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/* MemSan cannot understand that the syscall writes to the buffer */
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#if defined(__has_feature)
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#if __has_feature(memory_sanitizer)
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memset( buf, 0, buflen );
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#endif
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#endif
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return( syscall( SYS_getrandom, buf, buflen, flags ) );
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}
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#endif /* SYS_getrandom */
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#endif /* __linux__ || __midipix__ */
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#if defined(__FreeBSD__) || defined(__DragonFly__)
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#include <sys/param.h>
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#if (defined(__FreeBSD__) && __FreeBSD_version >= 1200000) || \
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(defined(__DragonFly__) && __DragonFly_version >= 500700)
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#include <errno.h>
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#include <sys/random.h>
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#define HAVE_GETRANDOM
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static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
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{
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return getrandom( buf, buflen, flags );
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}
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#endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) ||
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(__DragonFly__ && __DragonFly_version >= 500700) */
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#endif /* __FreeBSD__ || __DragonFly__ */
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/*
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* Some BSD systems provide KERN_ARND.
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* This is equivalent to reading from /dev/urandom, only it doesn't require an
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* open file descriptor, and provides up to 256 bytes per call (basically the
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* same as getentropy(), but with a longer history).
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*
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* Documentation: https://netbsd.gw.com/cgi-bin/man-cgi?sysctl+7
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*/
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#if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(HAVE_GETRANDOM)
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#if defined(KERN_ARND)
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#define HAVE_SYSCTL_ARND
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static int sysctl_arnd_wrapper( unsigned char *buf, size_t buflen )
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{
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int name[2];
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size_t len;
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name[0] = CTL_KERN;
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name[1] = KERN_ARND;
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while( buflen > 0 )
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{
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len = buflen > 256 ? 256 : buflen;
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if( sysctl(name, 2, buf, &len, NULL, 0) == -1 )
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return( -1 );
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buflen -= len;
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buf += len;
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}
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return( 0 );
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}
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#endif /* KERN_ARND */
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#endif /* __FreeBSD__ || __NetBSD__ */
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#include <stdio.h>
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int mbedtls_platform_entropy_poll( void *data,
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unsigned char *output, size_t len, size_t *olen )
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{
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FILE *file;
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size_t read_len;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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((void) data);
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#if defined(HAVE_GETRANDOM)
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ret = getrandom_wrapper( output, len, 0 );
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if( ret >= 0 )
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{
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*olen = ret;
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return( 0 );
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}
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else if( errno != ENOSYS )
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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/* Fall through if the system call isn't known. */
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#else
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((void) ret);
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#endif /* HAVE_GETRANDOM */
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#if defined(HAVE_SYSCTL_ARND)
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((void) file);
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((void) read_len);
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if( sysctl_arnd_wrapper( output, len ) == -1 )
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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*olen = len;
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return( 0 );
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#else
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*olen = 0;
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file = fopen( "/dev/urandom", "rb" );
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if( file == NULL )
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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read_len = fread( output, 1, len, file );
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if( read_len != len )
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{
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fclose( file );
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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}
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fclose( file );
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*olen = len;
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return( 0 );
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#endif /* HAVE_SYSCTL_ARND */
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}
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#endif /* _WIN32 && !EFIX64 && !EFI32 */
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#endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
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#if defined(MBEDTLS_ENTROPY_NV_SEED)
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int mbedtls_nv_seed_poll( void *data,
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unsigned char *output, size_t len, size_t *olen )
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{
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unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
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size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
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((void) data);
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memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
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if( mbedtls_nv_seed_read( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 )
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return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
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if( len < use_len )
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use_len = len;
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memcpy( output, buf, use_len );
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*olen = use_len;
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return( 0 );
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}
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#endif /* MBEDTLS_ENTROPY_NV_SEED */
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#endif /* MBEDTLS_ENTROPY_C */
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