c6ed39e3ad
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>
115 lines
2.9 KiB
C
115 lines
2.9 KiB
C
/*
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* Copyright (c) 2018 Oticon A/S
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Pseudo-random entropy generator for the ARCH_POSIX architecture:
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* Following the principle of reproducibility of the native_posix board
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* this entropy device will always generate the same random sequence when
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* initialized with the same seed
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*
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* This entropy source should only be used for testing.
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*/
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#define DT_DRV_COMPAT zephyr_native_posix_rng
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#include <zephyr/device.h>
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#include <zephyr/drivers/entropy.h>
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#include <zephyr/init.h>
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#include <zephyr/sys/util.h>
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#include <stdlib.h>
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#include <string.h>
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#include <zephyr/arch/posix/posix_trace.h>
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#include "soc.h"
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#include "cmdline.h" /* native_posix command line options header */
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#include "nsi_host_trampolines.h"
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#include "fake_entropy_native_bottom.h"
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static unsigned int seed = 0x5678;
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static bool seed_random;
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static int entropy_native_posix_get_entropy(const struct device *dev,
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uint8_t *buffer,
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uint16_t length)
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{
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ARG_UNUSED(dev);
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while (length) {
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/*
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* Note that only 1 thread (Zephyr thread or HW models), runs at
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* a time, therefore there is no need to use random_r()
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*/
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long value = nsi_host_random();
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size_t to_copy = MIN(length, sizeof(long int));
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memcpy(buffer, &value, to_copy);
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buffer += to_copy;
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length -= to_copy;
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}
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return 0;
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}
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static int entropy_native_posix_get_entropy_isr(const struct device *dev,
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uint8_t *buf,
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uint16_t len, uint32_t flags)
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{
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ARG_UNUSED(flags);
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/*
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* entropy_native_posix_get_entropy() is also safe for ISRs
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* and always produces data.
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*/
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entropy_native_posix_get_entropy(dev, buf, len);
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return len;
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}
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static int entropy_native_posix_init(const struct device *dev)
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{
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ARG_UNUSED(dev);
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entropy_native_seed(seed, seed_random);
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posix_print_warning("WARNING: "
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"Using a test - not safe - entropy source\n");
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return 0;
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}
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static const struct entropy_driver_api entropy_native_posix_api_funcs = {
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.get_entropy = entropy_native_posix_get_entropy,
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.get_entropy_isr = entropy_native_posix_get_entropy_isr
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};
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DEVICE_DT_INST_DEFINE(0,
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entropy_native_posix_init, NULL,
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NULL, NULL,
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PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY,
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&entropy_native_posix_api_funcs);
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static void add_fake_entropy_option(void)
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{
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static struct args_struct_t entropy_options[] = {
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{
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.option = "seed",
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.name = "r_seed",
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.type = 'u',
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.dest = (void *)&seed,
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.descript = "A 32-bit integer seed value for the entropy device, such as "
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"97229 (decimal), 0x17BCD (hex), or 0275715 (octal)"
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},
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{
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.is_switch = true,
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.option = "seed-random",
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.type = 'b',
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.dest = (void *)&seed_random,
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.descript = "Seed the random generator from /dev/urandom. "
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"Note your test may not be reproducible if you set this option"
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},
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ARG_TABLE_ENDMARKER
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};
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native_add_command_line_opts(entropy_options);
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}
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NATIVE_TASK(add_fake_entropy_option, PRE_BOOT_1, 10);
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