linux-imx

/*

 * PRNG: Pseudo Random Number Generator

 *       Based on NIST Recommended PRNG From ANSI X9.31 Appendix A.2.4 using

 *       AES 128 cipher

 *

 *  (C) Neil Horman <nhorman@tuxdriver.com>

 *

 *  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

 *  any later version.

 *

 *

 */

​

#include <crypto/internal/rng.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/string.h>

​

#define DEFAULT_PRNG_KEY "0123456789abcdef"

#define DEFAULT_PRNG_KSZ 16

#define DEFAULT_BLK_SZ 16

#define DEFAULT_V_SEED "zaybxcwdveuftgsh"

​

/*

 * Flags for the prng_context flags field

 */

​

#define PRNG_FIXED_SIZE 0x1

#define PRNG_NEED_RESET 0x2

​

/*

 * Note: DT is our counter value

 *   I is our intermediate value

 *   V is our seed vector

 * See http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf

 * for implementation details

 */

​

​

struct prng_context {

    spinlock_t prng_lock;

    unsigned char rand_data[DEFAULT_BLK_SZ];

    unsigned char last_rand_data[DEFAULT_BLK_SZ];

    unsigned char DT[DEFAULT_BLK_SZ];

    unsigned char I[DEFAULT_BLK_SZ];

    unsigned char V[DEFAULT_BLK_SZ];

    u32 rand_data_valid;

    struct crypto_cipher *tfm;

    u32 flags;

};

​

static int dbg;

​

static void hexdump(char *note, unsigned char *buf, unsigned int len)

{

    if (dbg) {

        printk(KERN_CRIT "%s", note);

        print_hex_dump(KERN_CONT, "", DUMP_PREFIX_OFFSET,

                16, 1,

                buf, len, false);

    }

}

​

#define dbgprint(format, args...) do {\

if (dbg)\

    printk(format, ##args);\

} while (0)

​

static void xor_vectors(unsigned char *in1, unsigned char *in2,

            unsigned char *out, unsigned int size)

{

    int i;

​

    for (i = 0; i < size; i++)

        out[i] = in1[i] ^ in2[i];

​

}

/*

 * Returns DEFAULT_BLK_SZ bytes of random data per call

 * returns 0 if generation succeeded, <0 if something went wrong

 */

static int _get_more_prng_bytes(struct prng_context *ctx, int cont_test)

{

    int i;

    unsigned char tmp[DEFAULT_BLK_SZ];

    unsigned char *output = NULL;

​

​