view libtomcrypt/src/math/ltm_desc.c @ 1930:299f4f19ba19

Add /usr/sbin and /sbin to default root PATH When dropbear is used in a very restricted environment (such as in a initrd), the default user shell is often also very restricted and doesn't take care of setting the PATH so the user ends up with the PATH set by dropbear. Unfortunately, dropbear always sets "/usr/bin:/bin" as default PATH even for the root user which should have /usr/sbin and /sbin too. For a concrete instance of this problem, see the "Remote Unlocking" section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/ It speaks of a bug in the initramfs script because it's written "blkid" instead of "/sbin/blkid"... this is just because the scripts from the initramfs do not expect to have a PATH without the sbin directories and because dropbear is not setting the PATH appropriately for the root user. I'm thus suggesting to use the attached patch to fix this misbehaviour (I did not test it, but it's easy enough). It might seem anecdotic but multiple Kali users have been bitten by this. From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
author Raphael Hertzog <hertzog@debian.org>
date Mon, 09 Jul 2018 16:27:53 +0200
parents 1051e4eea25a
children
line wrap: on
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */

#define DESC_DEF_ONLY
#include "tomcrypt.h"

#ifdef LTM_DESC

#include <tommath.h>

static const struct {
    mp_err mpi_code;
    int ltc_code;
} mpi_to_ltc_codes[] = {
   { MP_OKAY ,  CRYPT_OK},
   { MP_MEM  ,  CRYPT_MEM},
   { MP_VAL  ,  CRYPT_INVALID_ARG},
   { MP_ITER ,  CRYPT_INVALID_PACKET},
   { MP_BUF  ,  CRYPT_BUFFER_OVERFLOW},
};

/**
   Convert a MPI error to a LTC error (Possibly the most powerful function ever!  Oh wait... no)
   @param err    The error to convert
   @return The equivalent LTC error code or CRYPT_ERROR if none found
*/
static int mpi_to_ltc_error(mp_err err)
{
   size_t x;

   for (x = 0; x < sizeof(mpi_to_ltc_codes)/sizeof(mpi_to_ltc_codes[0]); x++) {
       if (err == mpi_to_ltc_codes[x].mpi_code) {
          return mpi_to_ltc_codes[x].ltc_code;
       }
   }
   return CRYPT_ERROR;
}

static int init_mpi(void **a)
{
   LTC_ARGCHK(a != NULL);

   *a = XCALLOC(1, sizeof(mp_int));
   if (*a == NULL) {
      return CRYPT_MEM;
   } else {
      return CRYPT_OK;
   }
}

static int init(void **a)
{
   int err;

   LTC_ARGCHK(a != NULL);

   if ((err = init_mpi(a)) != CRYPT_OK) {
      return err;
   }
   if ((err = mpi_to_ltc_error(mp_init(*a))) != CRYPT_OK) {
      XFREE(*a);
   }
   return err;
}

static void deinit(void *a)
{
   LTC_ARGCHKVD(a != NULL);
   mp_clear(a);
   XFREE(a);
}

static int neg(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_neg(a, b));
}

static int copy(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_copy(a, b));
}

static int init_copy(void **a, void *b)
{
   int err;
   LTC_ARGCHK(a  != NULL);
   LTC_ARGCHK(b  != NULL);
   if ((err = init_mpi(a)) != CRYPT_OK) return err;
   return mpi_to_ltc_error(mp_init_copy(*a, b));
}

/* ---- trivial ---- */
static int set_int(void *a, ltc_mp_digit b)
{
   LTC_ARGCHK(a != NULL);
   mp_set_u32(a, b);
   return CRYPT_OK;
}

static unsigned long get_int(void *a)
{
   LTC_ARGCHK(a != NULL);
   return mp_get_ul(a);
}

static ltc_mp_digit get_digit(void *a, int n)
{
   mp_int *A;
   LTC_ARGCHK(a != NULL);
   A = a;
   return (n >= A->used || n < 0) ? 0 : A->dp[n];
}

static int get_digit_count(void *a)
{
   mp_int *A;
   LTC_ARGCHK(a != NULL);
   A = a;
   return A->used;
}

static int compare(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   switch (mp_cmp(a, b)) {
      case MP_LT: return LTC_MP_LT;
      case MP_EQ: return LTC_MP_EQ;
      case MP_GT: return LTC_MP_GT;
      default:    return 0;
   }
}

static int compare_d(void *a, ltc_mp_digit b)
{
   LTC_ARGCHK(a != NULL);
   switch (mp_cmp_d(a, b)) {
      case MP_LT: return LTC_MP_LT;
      case MP_EQ: return LTC_MP_EQ;
      case MP_GT: return LTC_MP_GT;
      default:    return 0;
   }
}

static int count_bits(void *a)
{
   LTC_ARGCHK(a != NULL);
   return mp_count_bits(a);
}

static int count_lsb_bits(void *a)
{
   LTC_ARGCHK(a != NULL);
   return mp_cnt_lsb(a);
}


static int twoexpt(void *a, int n)
{
   LTC_ARGCHK(a != NULL);
   return mpi_to_ltc_error(mp_2expt(a, n));
}

/* ---- conversions ---- */

/* read ascii string */
static int read_radix(void *a, const char *b, int radix)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_read_radix(a, b, radix));
}

/* write one */
static int write_radix(void *a, char *b, int radix)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_to_radix(a, b, SIZE_MAX, NULL, radix));
}

/* get size as unsigned char string */
static unsigned long unsigned_size(void *a)
{
   LTC_ARGCHK(a != NULL);
   return (unsigned long)mp_ubin_size(a);
}

/* store */
static int unsigned_write(void *a, unsigned char *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_to_ubin(a, b, SIZE_MAX, NULL));
}

/* read */
static int unsigned_read(void *a, unsigned char *b, unsigned long len)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_from_ubin(a, b, (size_t)len));
}

/* add */
static int add(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_add(a, b, c));
}

static int addi(void *a, ltc_mp_digit b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_add_d(a, b, c));
}

/* sub */
static int sub(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_sub(a, b, c));
}

static int subi(void *a, ltc_mp_digit b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_sub_d(a, b, c));
}

/* mul */
static int mul(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_mul(a, b, c));
}

static int muli(void *a, ltc_mp_digit b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_mul_d(a, b, c));
}

/* sqr */
static int sqr(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_sqr(a, b));
}

/* div */
static int divide(void *a, void *b, void *c, void *d)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_div(a, b, c, d));
}

static int div_2(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_div_2(a, b));
}

/* modi */
static int modi(void *a, ltc_mp_digit b, ltc_mp_digit *c)
{
   mp_digit tmp;
   int      err;

   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(c != NULL);

   if ((err = mpi_to_ltc_error(mp_mod_d(a, b, &tmp))) != CRYPT_OK) {
      return err;
   }
   *c = tmp;
   return CRYPT_OK;
}

/* gcd */
static int gcd(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_gcd(a, b, c));
}

/* lcm */
static int lcm(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_lcm(a, b, c));
}

static int addmod(void *a, void *b, void *c, void *d)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   LTC_ARGCHK(d != NULL);
   return mpi_to_ltc_error(mp_addmod(a,b,c,d));
}

static int submod(void *a, void *b, void *c, void *d)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   LTC_ARGCHK(d != NULL);
   return mpi_to_ltc_error(mp_submod(a,b,c,d));
}

static int mulmod(void *a, void *b, void *c, void *d)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   LTC_ARGCHK(d != NULL);
   return mpi_to_ltc_error(mp_mulmod(a,b,c,d));
}

static int sqrmod(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_sqrmod(a,b,c));
}

/* invmod */
static int invmod(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_invmod(a, b, c));
}

/* setup */
static int montgomery_setup(void *a, void **b)
{
   int err;
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   *b = XCALLOC(1, sizeof(mp_digit));
   if (*b == NULL) {
      return CRYPT_MEM;
   }
   if ((err = mpi_to_ltc_error(mp_montgomery_setup(a, (mp_digit *)*b))) != CRYPT_OK) {
      XFREE(*b);
   }
   return err;
}

/* get normalization value */
static int montgomery_normalization(void *a, void *b)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   return mpi_to_ltc_error(mp_montgomery_calc_normalization(a, b));
}

/* reduce */
static int montgomery_reduce(void *a, void *b, void *c)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   return mpi_to_ltc_error(mp_montgomery_reduce(a, b, *((mp_digit *)c)));
}

/* clean up */
static void montgomery_deinit(void *a)
{
   XFREE(a);
}

static int exptmod(void *a, void *b, void *c, void *d)
{
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(b != NULL);
   LTC_ARGCHK(c != NULL);
   LTC_ARGCHK(d != NULL);
   return mpi_to_ltc_error(mp_exptmod(a,b,c,d));
}

static int isprime(void *a, int b, int *c)
{
   int err;
   LTC_ARGCHK(a != NULL);
   LTC_ARGCHK(c != NULL);
   b = mp_prime_rabin_miller_trials(mp_count_bits(a));
   err = mpi_to_ltc_error(mp_prime_is_prime(a, b, c));
   *c = (*c == MP_YES) ? LTC_MP_YES : LTC_MP_NO;
   return err;
}

static int set_rand(void *a, int size)
{
   LTC_ARGCHK(a != NULL);
   return mpi_to_ltc_error(mp_rand(a, size));
}

const ltc_math_descriptor ltm_desc = {

   "LibTomMath",
   (int)MP_DIGIT_BIT,

   &init,
   &init_copy,
   &deinit,

   &neg,
   &copy,

   &set_int,
   &get_int,
   &get_digit,
   &get_digit_count,
   &compare,
   &compare_d,
   &count_bits,
   &count_lsb_bits,
   &twoexpt,

   &read_radix,
   &write_radix,
   &unsigned_size,
   &unsigned_write,
   &unsigned_read,

   &add,
   &addi,
   &sub,
   &subi,
   &mul,
   &muli,
   &sqr,
   &divide,
   &div_2,
   &modi,
   &gcd,
   &lcm,

   &mulmod,
   &sqrmod,
   &invmod,

   &montgomery_setup,
   &montgomery_normalization,
   &montgomery_reduce,
   &montgomery_deinit,

   &exptmod,
   &isprime,

#ifdef LTC_MECC
#ifdef LTC_MECC_FP
   &ltc_ecc_fp_mulmod,
#else
   &ltc_ecc_mulmod,
#endif
   &ltc_ecc_projective_add_point,
   &ltc_ecc_projective_dbl_point,
   &ltc_ecc_map,
#ifdef LTC_ECC_SHAMIR
#ifdef LTC_MECC_FP
   &ltc_ecc_fp_mul2add,
#else
   &ltc_ecc_mul2add,
#endif /* LTC_MECC_FP */
#else
   NULL,
#endif /* LTC_ECC_SHAMIR */
#else
   NULL, NULL, NULL, NULL, NULL,
#endif /* LTC_MECC */

#ifdef LTC_MRSA
   &rsa_make_key,
   &rsa_exptmod,
#else
   NULL, NULL,
#endif
   &addmod,
   &submod,

   &set_rand,

};


#endif

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