Diff: source/entropy_poll.c

Revision:

1:24750b9ad5ef

diff -r 000000000000 -r 24750b9ad5ef source/entropy_poll.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/source/entropy_poll.c	Fri Jan 22 16:44:49 2016 -0600
@@ -0,0 +1,216 @@
+/*
+ *  Platform-specific and custom entropy polling functions
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_ENTROPY_C)
+
+#include "mbedtls/entropy.h"
+#include "mbedtls/entropy_poll.h"
+
+#if defined(MBEDTLS_TIMING_C)
+#include <string.h>
+#include "mbedtls/timing.h"
+#endif
+#if defined(MBEDTLS_HAVEGE_C)
+#include "mbedtls/havege.h"
+#endif
+
+#if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
+
+#if !defined(_WIN32_WINNT)
+#define _WIN32_WINNT 0x0400
+#endif
+#include <windows.h>
+#include <wincrypt.h>
+
+int mbedtls_platform_entropy_poll( void *data, unsigned char *output, size_t len,
+                           size_t *olen )
+{
+    HCRYPTPROV provider;
+    ((void) data);
+    *olen = 0;
+
+    if( CryptAcquireContext( &provider, NULL, NULL,
+                              PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == FALSE )
+    {
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+    }
+
+    if( CryptGenRandom( provider, (DWORD) len, output ) == FALSE )
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+
+    CryptReleaseContext( provider, 0 );
+    *olen = len;
+
+    return( 0 );
+}
+#else /* _WIN32 && !EFIX64 && !EFI32 */
+
+/*
+ * Test for Linux getrandom() support.
+ * Since there is no wrapper in the libc yet, use the generic syscall wrapper
+ * available in GNU libc and compatible libc's (eg uClibc).
+ */
+#if defined(__linux__) && defined(__GLIBC__)
+#include <unistd.h>
+#include <sys/syscall.h>
+#if defined(SYS_getrandom)
+#define HAVE_GETRANDOM
+
+static int getrandom_wrapper( void *buf, size_t buflen, unsigned int flags )
+{
+    /* MemSan cannot understand that the syscall writes to the buffer */
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+    memset( buf, 0, buflen );
+#endif
+#endif
+
+    return( syscall( SYS_getrandom, buf, buflen, flags ) );
+}
+
+#include <sys/utsname.h>
+/* Check if version is at least 3.17.0 */
+static int check_version_3_17_plus( void )
+{
+    int minor;
+    struct utsname un;
+    const char *ver;
+
+    /* Get version information */
+    uname(&un);
+    ver = un.release;
+
+    /* Check major version; assume a single digit */
+    if( ver[0] < '3' || ver[0] > '9' || ver [1] != '.' )
+        return( -1 );
+
+    if( ver[0] - '0' > 3 )
+        return( 0 );
+
+    /* Ok, so now we know major == 3, check minor.
+     * Assume 1 or 2 digits. */
+    if( ver[2] < '0' || ver[2] > '9' )
+        return( -1 );
+
+    minor = ver[2] - '0';
+
+    if( ver[3] >= '0' && ver[3] <= '9' )
+        minor = 10 * minor + ver[3] - '0';
+    else if( ver [3] != '.' )
+        return( -1 );
+
+    if( minor < 17 )
+        return( -1 );
+
+    return( 0 );
+}
+static int has_getrandom = -1;
+#endif /* SYS_getrandom */
+#endif /* __linux__ */
+
+#include <stdio.h>
+
+int mbedtls_platform_entropy_poll( void *data,
+                           unsigned char *output, size_t len, size_t *olen )
+{
+    FILE *file;
+    size_t read_len;
+    ((void) data);
+
+#if defined(HAVE_GETRANDOM)
+    if( has_getrandom == -1 )
+        has_getrandom = ( check_version_3_17_plus() == 0 );
+
+    if( has_getrandom )
+    {
+        int ret;
+
+        if( ( ret = getrandom_wrapper( output, len, 0 ) ) < 0 )
+            return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+
+        *olen = ret;
+        return( 0 );
+    }
+#endif /* HAVE_GETRANDOM */
+
+    *olen = 0;
+
+    file = fopen( "/dev/urandom", "rb" );
+    if( file == NULL )
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+
+    read_len = fread( output, 1, len, file );
+    if( read_len != len )
+    {
+        fclose( file );
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+    }
+
+    fclose( file );
+    *olen = len;
+
+    return( 0 );
+}
+#endif /* _WIN32 && !EFIX64 && !EFI32 */
+#endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
+
+#if defined(MBEDTLS_TIMING_C)
+int mbedtls_hardclock_poll( void *data,
+                    unsigned char *output, size_t len, size_t *olen )
+{
+    unsigned long timer = mbedtls_timing_hardclock();
+    ((void) data);
+    *olen = 0;
+
+    if( len < sizeof(unsigned long) )
+        return( 0 );
+
+    memcpy( output, &timer, sizeof(unsigned long) );
+    *olen = sizeof(unsigned long);
+
+    return( 0 );
+}
+#endif /* MBEDTLS_TIMING_C */
+
+#if defined(MBEDTLS_HAVEGE_C)
+int mbedtls_havege_poll( void *data,
+                 unsigned char *output, size_t len, size_t *olen )
+{
+    mbedtls_havege_state *hs = (mbedtls_havege_state *) data;
+    *olen = 0;
+
+    if( mbedtls_havege_random( hs, output, len ) != 0 )
+        return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
+
+    *olen = len;
+
+    return( 0 );
+}
+#endif /* MBEDTLS_HAVEGE_C */
+
+#endif /* MBEDTLS_ENTROPY_C */