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drivers entropy fake_native: Add option to seed generator randomly

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Add a command line option which will seed the random generator
from /dev/urandom.
This can be usefull for some particular tests in which we are
interested in having different random numbers in each run,
but we cannot provide a different random seed from command line.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>
This commit is contained in:
Alberto Escolar Piedras 2024-01-23 13:09:50 +01:00 committed by Carles Cufí
parent 3fc5d971fe
commit c6ed39e3ad
4 changed files with 83 additions and 14 deletions
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10
drivers/entropy/CMakeLists.txt
View file

@ -17,7 +17,15 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_SAM_RNG entropy_sam.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_SMARTBOND_TRNG entropy_smartbond.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_STM32_RNG entropy_stm32.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_LITEX_RNG entropy_litex.c)
zephyr_library_sources_ifdef(CONFIG_FAKE_ENTROPY_NATIVE_POSIX fake_entropy_native_posix.c)
if(CONFIG_FAKE_ENTROPY_NATIVE_POSIX)
zephyr_library_sources(fake_entropy_native_posix.c)
if(CONFIG_NATIVE_LIBRARY)
target_sources(native_simulator INTERFACE fake_entropy_native_bottom.c)
else()
zephyr_library_sources(fake_entropy_native_bottom.c)
endif()
endif()
zephyr_library_sources_ifdef(CONFIG_USERSPACE entropy_handlers.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_RV32M1_TRNG entropy_rv32m1_trng.c)
zephyr_library_sources_ifdef(CONFIG_ENTROPY_GECKO_TRNG entropy_gecko_trng.c)

34
drivers/entropy/fake_entropy_native_bottom.c Normal file
View file

@ -0,0 +1,34 @@
/*
* Copyright (c) 2024 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*
* Bottom/Linux side of the pseudo-random entropy generator for
* ARCH_POSIX architecture
*/
#include <stdbool.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/random.h>
#include "nsi_tracing.h"
void entropy_native_seed(unsigned int seed, bool seed_random)
{
if (seed_random == false) {
srandom(seed);
} else {
unsigned int buf;
int err = getrandom(&buf, sizeof(buf), 0);
if (err != sizeof(buf)) {
nsi_print_error_and_exit("Could not get random number (%i, %s)\n",
err, strerror(errno));
}
srandom(buf);
/* Let's print the seed so users can still reproduce the run if they need to */
nsi_print_trace("Random generator seeded with 0x%X\n", buf);
}
}

21
drivers/entropy/fake_entropy_native_bottom.h Normal file
View file

@ -0,0 +1,21 @@
/*
* Copyright (c) 2024 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef DRIVERS_ENTROPY_FAKE_ENTROPY_NATIVE_BOTTOM_H
#define DRIVERS_ENTROPY_FAKE_ENTROPY_NATIVE_BOTTOM_H
#ifdef __cplusplus
extern "C" {
#endif
void entropy_native_seed(unsigned int seed, bool seed_random);
#ifdef __cplusplus
}
#endif
#endif /* DRIVERS_ENTROPY_FAKE_ENTROPY_NATIVE_BOTTOM_H */

32
drivers/entropy/fake_entropy_native_posix.c
View file

@ -23,8 +23,10 @@
#include "soc.h"
#include "cmdline.h" /* native_posix command line options header */
#include "nsi_host_trampolines.h"
#include "fake_entropy_native_bottom.h"
static unsigned int seed = 0x5678;
static bool seed_random;
static int entropy_native_posix_get_entropy(const struct device *dev,
uint8_t *buffer,
@ -67,7 +69,7 @@ static int entropy_native_posix_get_entropy_isr(const struct device *dev,
static int entropy_native_posix_init(const struct device *dev)
{
ARG_UNUSED(dev);
nsi_host_srandom(seed);
entropy_native_seed(seed, seed_random);
posix_print_warning("WARNING: "
"Using a test - not safe - entropy source\n");
return 0;
@ -87,18 +89,22 @@ DEVICE_DT_INST_DEFINE(0,
static void add_fake_entropy_option(void)
{
static struct args_struct_t entropy_options[] = {
/*
* Fields:
* manual, mandatory, switch,
* option_name, var_name ,type,
* destination, callback,
* description
*/
{false, false, false,
"seed", "r_seed", 'u',
(void *)&seed, NULL,
"A 32-bit integer seed value for the entropy device, such as "
"97229 (decimal), 0x17BCD (hex), or 0275715 (octal)"},
{
.option = "seed",
.name = "r_seed",
.type = 'u',
.dest = (void *)&seed,
.descript = "A 32-bit integer seed value for the entropy device, such as "
"97229 (decimal), 0x17BCD (hex), or 0275715 (octal)"
},
{
.is_switch = true,
.option = "seed-random",
.type = 'b',
.dest = (void *)&seed_random,
.descript = "Seed the random generator from /dev/urandom. "
"Note your test may not be reproducible if you set this option"
},
ARG_TABLE_ENDMARKER
};