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/*
* Copyright (C) 2012 Martin Willi
* Copyright (C) 2012 revosec AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "rdrand_plugin.h"
#include "rdrand_rng.h"
#include <stdio.h>
#include <library.h>
#include <utils/debug.h>
typedef struct private_rdrand_plugin_t private_rdrand_plugin_t;
typedef enum cpuid_feature_t cpuid_feature_t;
/**
* private data of rdrand_plugin
*/
struct private_rdrand_plugin_t {
/**
* public functions
*/
rdrand_plugin_t public;
};
/**
* CPU feature flags, returned via cpuid(1)
*/
enum cpuid_feature_t {
CPUID_RDRAND = (1<<30),
};
/**
* Get cpuid for info, return eax, ebx, ecx and edx.
* -fPIC requires to save ebx on IA-32.
*/
static void cpuid(u_int op, u_int *a, u_int *b, u_int *c, u_int *d)
{
#ifdef __x86_64__
asm("cpuid" : "=a" (*a), "=b" (*b), "=c" (*c), "=d" (*d) : "a" (op));
#else /* __i386__ */
asm("pushl %%ebx;"
"cpuid;"
"movl %%ebx, %1;"
"popl %%ebx;"
: "=a" (*a), "=r" (*b), "=c" (*c), "=d" (*d) : "a" (op));
#endif /* __x86_64__ / __i386__*/
}
/**
* Check if we have RDRAND instruction
*/
static bool have_rdrand()
{
char vendor[3 * sizeof(u_int32_t) + 1];
u_int a, b, c, d;
cpuid(0, &a, &b, &c, &d);
/* VendorID string is in b-d-c (yes, in this order) */
snprintf(vendor, sizeof(vendor), "%.4s%.4s%.4s", &b, &d, &c);
/* check if we have an Intel CPU */
if (streq(vendor, "GenuineIntel"))
{
cpuid(1, &a, &b, &c, &d);
if (c & CPUID_RDRAND)
{
DBG2(DBG_LIB, "detected RDRAND support on %s CPU", vendor);
return TRUE;
}
}
DBG2(DBG_LIB, "no RDRAND support on %s CPU, disabled", vendor);
return FALSE;
}
METHOD(plugin_t, get_name, char*,
private_rdrand_plugin_t *this)
{
return "rdrand";
}
METHOD(plugin_t, get_features, int,
private_rdrand_plugin_t *this, plugin_feature_t *features[])
{
static plugin_feature_t f[] = {
PLUGIN_REGISTER(RNG, rdrand_rng_create),
PLUGIN_PROVIDE(RNG, RNG_WEAK),
PLUGIN_PROVIDE(RNG, RNG_STRONG),
PLUGIN_PROVIDE(RNG, RNG_TRUE),
PLUGIN_DEPENDS(CRYPTER, ENCR_AES_CBC, 16),
};
*features = f;
if (have_rdrand())
{
return countof(f);
}
return 0;
}
METHOD(plugin_t, destroy, void,
private_rdrand_plugin_t *this)
{
free(this);
}
/*
* see header file
*/
plugin_t *rdrand_plugin_create()
{
private_rdrand_plugin_t *this;
INIT(this,
.public = {
.plugin = {
.get_name = _get_name,
.get_features = _get_features,
.reload = (void*)return_false,
.destroy = _destroy,
},
},
);
return &this->public.plugin;
}
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