merge fixes from PuTTY import.c toint() from misc.c (revids are from hggit conversion) changeset: 4620:60a336a6c85c user: Simon Tatham <[email protected]> date: Thu Feb 25 20:26:33 2016 +0000 files: import.c description: Fix potential segfaults in reading OpenSSH's ASN.1 key format. The length coming back from ber_read_id_len might have overflowed, so treat it as potentially negative. Also, while I'm here, accumulate it inside ber_read_id_len as an unsigned, so as to avoid undefined behaviour on integer overflow, and toint() it before return. Thanks to Hanno Böck for spotting this, with the aid of AFL. (cherry picked from commit 5b7833cd474a24ec098654dcba8cb9509f3bf2c1) Conflicts: import.c (cherry-picker's note: resolving the conflict involved removing an entire section of the original commit which fixed ECDSA code not present on this branch) changeset: 4619:9c6c638d98d8 user: Simon Tatham <[email protected]> date: Sun Jul 14 10:45:54 2013 +0000 files: import.c ssh.c sshdss.c sshpubk.c sshrsa.c description: Tighten up a lot of casts from unsigned to int which are read by one of the GET_32BIT macros and then used as length fields. Missing bounds checks against zero have been added, and also I've introduced a helper function toint() which casts from unsigned to int in such a way as to avoid C undefined behaviour, since I'm not sure I trust compilers any more to do the obviously sensible thing. [originally from svn r9918] changeset: 4618:3957829f24d3 user: Simon Tatham <[email protected]> date: Mon Jul 08 22:36:04 2013 +0000 files: import.c sshdss.c sshrsa.c description: Add an assortment of extra safety checks. [originally from svn r9896] changeset: 4617:2cddee0bce12 user: Jacob Nevins <[email protected]> date: Wed Dec 07 00:24:45 2005 +0000 files: import.c description: Institutional failure to memset() things pointed at rather than pointers. Things should now be zeroed and memory not leaked. Spotted by Brant Thomsen. [originally from svn r6476] changeset: 4616:24ac78a9c71d user: Simon Tatham <[email protected]> date: Wed Feb 11 13:58:27 2004 +0000 files: import.c description: Jacob's last-minute testing found a couple of trivial bugs in import.c, and my attempts to reproduce them in cmdgen found another one there :-) [originally from svn r3847] changeset: 4615:088d39a73db0 user: Simon Tatham <[email protected]> date: Thu Jan 22 18:52:49 2004 +0000 files: import.c description: Placate some gcc warnings. [originally from svn r3761] changeset: 4614:e4288bad4d93 parent: 1758:108b8924593d user: Simon Tatham <[email protected]> date: Fri Oct 03 21:21:23 2003 +0000 files: import.c description: My ASN.1 decoder returned wrong IDs for anything above 0x1E! Good job it's never had to yet. Ahem. [originally from svn r3479]

/* Finds Mersenne primes using the Lucas-Lehmer test 
 *
 * Tom St Denis, [email protected]
 */
#include <time.h>
#include <tommath.h>

int
is_mersenne (long s, int *pp)
{
  mp_int  n, u;
  int     res, k;
  
  *pp = 0;

  if ((res = mp_init (&n)) != MP_OKAY) {
    return res;
  }

  if ((res = mp_init (&u)) != MP_OKAY) {
    goto LBL_N;
  }

  /* n = 2^s - 1 */
  if ((res = mp_2expt(&n, s)) != MP_OKAY) {
     goto LBL_MU;
  }
  if ((res = mp_sub_d (&n, 1, &n)) != MP_OKAY) {
    goto LBL_MU;
  }

  /* set u=4 */
  mp_set (&u, 4);

  /* for k=1 to s-2 do */
  for (k = 1; k <= s - 2; k++) {
    /* u = u^2 - 2 mod n */
    if ((res = mp_sqr (&u, &u)) != MP_OKAY) {
      goto LBL_MU;
    }
    if ((res = mp_sub_d (&u, 2, &u)) != MP_OKAY) {
      goto LBL_MU;
    }

    /* make sure u is positive */
    while (u.sign == MP_NEG) {
      if ((res = mp_add (&u, &n, &u)) != MP_OKAY) {
         goto LBL_MU;
      }
    }

    /* reduce */
    if ((res = mp_reduce_2k (&u, &n, 1)) != MP_OKAY) {
      goto LBL_MU;
    }
  }

  /* if u == 0 then its prime */
  if (mp_iszero (&u) == 1) {
    mp_prime_is_prime(&n, 8, pp);
  if (*pp != 1) printf("FAILURE\n");
  }

  res = MP_OKAY;
LBL_MU:mp_clear (&u);
LBL_N:mp_clear (&n);
  return res;
}

/* square root of a long < 65536 */
long
i_sqrt (long x)
{
  long    x1, x2;

  x2 = 16;
  do {
    x1 = x2;
    x2 = x1 - ((x1 * x1) - x) / (2 * x1);
  } while (x1 != x2);

  if (x1 * x1 > x) {
    --x1;
  }

  return x1;
}

/* is the long prime by brute force */
int
isprime (long k)
{
  long    y, z;

  y = i_sqrt (k);
  for (z = 2; z <= y; z++) {
    if ((k % z) == 0)
      return 0;
  }
  return 1;
}


int
main (void)
{
  int     pp;
  long    k;
  clock_t tt;

  k = 3;

  for (;;) {
    /* start time */
    tt = clock ();

    /* test if 2^k - 1 is prime */
    if (is_mersenne (k, &pp) != MP_OKAY) {
      printf ("Whoa error\n");
      return -1;
    }

    if (pp == 1) {
      /* count time */
      tt = clock () - tt;

      /* display if prime */
      printf ("2^%-5ld - 1 is prime, test took %ld ticks\n", k, tt);
    }

    /* goto next odd exponent */
    k += 2;

    /* but make sure its prime */
    while (isprime (k) == 0) {
      k += 2;
    }
  }
  return 0;
}

/* $Source: /cvs/libtom/libtommath/etc/mersenne.c,v $ */
/* $Revision: 1.3 $ */
/* $Date: 2006/03/31 14:18:47 $ */