view libtomcrypt/src/hashes/md5.c @ 1790:42745af83b7d

Introduce extra delay before closing unauthenticated sessions To make it harder for attackers, introduce a delay to keep an unauthenticated session open a bit longer, thus blocking a connection slot until after the delay. Without this, while there is a limit on the amount of attempts an attacker can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt is still short and thus for each of the allowed parallel attempts many attempts can be chained one after the other. The attempt rate is then: "MAX_UNAUTH_PER_IP / <process time of one attempt>". With the delay, this rate becomes: "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
author Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
date Wed, 15 Feb 2017 13:53:04 +0100
parents 6dba84798cd5
children
line wrap: on
line source

/* 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.
 */
#include "tomcrypt.h"


/**
  @file md5.c
  LTC_MD5 hash function by Tom St Denis
*/

#ifdef LTC_MD5

const struct ltc_hash_descriptor md5_desc =
{
    "md5",
    3,
    16,
    64,

    /* OID */
   { 1, 2, 840, 113549, 2, 5,  },
   6,

    &md5_init,
    &md5_process,
    &md5_done,
    &md5_test,
    NULL
};

#define F(x,y,z)  (z ^ (x & (y ^ z)))
#define G(x,y,z)  (y ^ (z & (y ^ x)))
#define H(x,y,z)  (x^y^z)
#define I(x,y,z)  (y^(x|(~z)))

#ifdef LTC_SMALL_CODE

#define FF(a,b,c,d,M,s,t) \
    a = (a + F(b,c,d) + M + t); a = ROL(a, s) + b;

#define GG(a,b,c,d,M,s,t) \
    a = (a + G(b,c,d) + M + t); a = ROL(a, s) + b;

#define HH(a,b,c,d,M,s,t) \
    a = (a + H(b,c,d) + M + t); a = ROL(a, s) + b;

#define II(a,b,c,d,M,s,t) \
    a = (a + I(b,c,d) + M + t); a = ROL(a, s) + b;

static const unsigned char Worder[64] = {
   0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
   1,6,11,0,5,10,15,4,9,14,3,8,13,2,7,12,
   5,8,11,14,1,4,7,10,13,0,3,6,9,12,15,2,
   0,7,14,5,12,3,10,1,8,15,6,13,4,11,2,9
};

static const unsigned char Rorder[64] = {
   7,12,17,22,7,12,17,22,7,12,17,22,7,12,17,22,
   5,9,14,20,5,9,14,20,5,9,14,20,5,9,14,20,
   4,11,16,23,4,11,16,23,4,11,16,23,4,11,16,23,
   6,10,15,21,6,10,15,21,6,10,15,21,6,10,15,21
};

static const ulong32 Korder[64] = {
0xd76aa478UL, 0xe8c7b756UL, 0x242070dbUL, 0xc1bdceeeUL, 0xf57c0fafUL, 0x4787c62aUL, 0xa8304613UL, 0xfd469501UL,
0x698098d8UL, 0x8b44f7afUL, 0xffff5bb1UL, 0x895cd7beUL, 0x6b901122UL, 0xfd987193UL, 0xa679438eUL, 0x49b40821UL,
0xf61e2562UL, 0xc040b340UL, 0x265e5a51UL, 0xe9b6c7aaUL, 0xd62f105dUL, 0x02441453UL, 0xd8a1e681UL, 0xe7d3fbc8UL,
0x21e1cde6UL, 0xc33707d6UL, 0xf4d50d87UL, 0x455a14edUL, 0xa9e3e905UL, 0xfcefa3f8UL, 0x676f02d9UL, 0x8d2a4c8aUL,
0xfffa3942UL, 0x8771f681UL, 0x6d9d6122UL, 0xfde5380cUL, 0xa4beea44UL, 0x4bdecfa9UL, 0xf6bb4b60UL, 0xbebfbc70UL,
0x289b7ec6UL, 0xeaa127faUL, 0xd4ef3085UL, 0x04881d05UL, 0xd9d4d039UL, 0xe6db99e5UL, 0x1fa27cf8UL, 0xc4ac5665UL,
0xf4292244UL, 0x432aff97UL, 0xab9423a7UL, 0xfc93a039UL, 0x655b59c3UL, 0x8f0ccc92UL, 0xffeff47dUL, 0x85845dd1UL,
0x6fa87e4fUL, 0xfe2ce6e0UL, 0xa3014314UL, 0x4e0811a1UL, 0xf7537e82UL, 0xbd3af235UL, 0x2ad7d2bbUL, 0xeb86d391UL
};

#else

#define FF(a,b,c,d,M,s,t) \
    a = (a + F(b,c,d) + M + t); a = ROLc(a, s) + b;

#define GG(a,b,c,d,M,s,t) \
    a = (a + G(b,c,d) + M + t); a = ROLc(a, s) + b;

#define HH(a,b,c,d,M,s,t) \
    a = (a + H(b,c,d) + M + t); a = ROLc(a, s) + b;

#define II(a,b,c,d,M,s,t) \
    a = (a + I(b,c,d) + M + t); a = ROLc(a, s) + b;


#endif

#ifdef LTC_CLEAN_STACK
static int _md5_compress(hash_state *md, unsigned char *buf)
#else
static int  md5_compress(hash_state *md, unsigned char *buf)
#endif
{
    ulong32 i, W[16], a, b, c, d;
#ifdef LTC_SMALL_CODE
    ulong32 t;
#endif

    /* copy the state into 512-bits into W[0..15] */
    for (i = 0; i < 16; i++) {
        LOAD32L(W[i], buf + (4*i));
    }

    /* copy state */
    a = md->md5.state[0];
    b = md->md5.state[1];
    c = md->md5.state[2];
    d = md->md5.state[3];

#ifdef LTC_SMALL_CODE
    for (i = 0; i < 16; ++i) {
        FF(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
        t = d; d = c; c = b; b = a; a = t;
    }

    for (; i < 32; ++i) {
        GG(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
        t = d; d = c; c = b; b = a; a = t;
    }

    for (; i < 48; ++i) {
        HH(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
        t = d; d = c; c = b; b = a; a = t;
    }

    for (; i < 64; ++i) {
        II(a,b,c,d,W[Worder[i]],Rorder[i],Korder[i]);
        t = d; d = c; c = b; b = a; a = t;
    }

#else
    FF(a,b,c,d,W[0],7,0xd76aa478UL)
    FF(d,a,b,c,W[1],12,0xe8c7b756UL)
    FF(c,d,a,b,W[2],17,0x242070dbUL)
    FF(b,c,d,a,W[3],22,0xc1bdceeeUL)
    FF(a,b,c,d,W[4],7,0xf57c0fafUL)
    FF(d,a,b,c,W[5],12,0x4787c62aUL)
    FF(c,d,a,b,W[6],17,0xa8304613UL)
    FF(b,c,d,a,W[7],22,0xfd469501UL)
    FF(a,b,c,d,W[8],7,0x698098d8UL)
    FF(d,a,b,c,W[9],12,0x8b44f7afUL)
    FF(c,d,a,b,W[10],17,0xffff5bb1UL)
    FF(b,c,d,a,W[11],22,0x895cd7beUL)
    FF(a,b,c,d,W[12],7,0x6b901122UL)
    FF(d,a,b,c,W[13],12,0xfd987193UL)
    FF(c,d,a,b,W[14],17,0xa679438eUL)
    FF(b,c,d,a,W[15],22,0x49b40821UL)
    GG(a,b,c,d,W[1],5,0xf61e2562UL)
    GG(d,a,b,c,W[6],9,0xc040b340UL)
    GG(c,d,a,b,W[11],14,0x265e5a51UL)
    GG(b,c,d,a,W[0],20,0xe9b6c7aaUL)
    GG(a,b,c,d,W[5],5,0xd62f105dUL)
    GG(d,a,b,c,W[10],9,0x02441453UL)
    GG(c,d,a,b,W[15],14,0xd8a1e681UL)
    GG(b,c,d,a,W[4],20,0xe7d3fbc8UL)
    GG(a,b,c,d,W[9],5,0x21e1cde6UL)
    GG(d,a,b,c,W[14],9,0xc33707d6UL)
    GG(c,d,a,b,W[3],14,0xf4d50d87UL)
    GG(b,c,d,a,W[8],20,0x455a14edUL)
    GG(a,b,c,d,W[13],5,0xa9e3e905UL)
    GG(d,a,b,c,W[2],9,0xfcefa3f8UL)
    GG(c,d,a,b,W[7],14,0x676f02d9UL)
    GG(b,c,d,a,W[12],20,0x8d2a4c8aUL)
    HH(a,b,c,d,W[5],4,0xfffa3942UL)
    HH(d,a,b,c,W[8],11,0x8771f681UL)
    HH(c,d,a,b,W[11],16,0x6d9d6122UL)
    HH(b,c,d,a,W[14],23,0xfde5380cUL)
    HH(a,b,c,d,W[1],4,0xa4beea44UL)
    HH(d,a,b,c,W[4],11,0x4bdecfa9UL)
    HH(c,d,a,b,W[7],16,0xf6bb4b60UL)
    HH(b,c,d,a,W[10],23,0xbebfbc70UL)
    HH(a,b,c,d,W[13],4,0x289b7ec6UL)
    HH(d,a,b,c,W[0],11,0xeaa127faUL)
    HH(c,d,a,b,W[3],16,0xd4ef3085UL)
    HH(b,c,d,a,W[6],23,0x04881d05UL)
    HH(a,b,c,d,W[9],4,0xd9d4d039UL)
    HH(d,a,b,c,W[12],11,0xe6db99e5UL)
    HH(c,d,a,b,W[15],16,0x1fa27cf8UL)
    HH(b,c,d,a,W[2],23,0xc4ac5665UL)
    II(a,b,c,d,W[0],6,0xf4292244UL)
    II(d,a,b,c,W[7],10,0x432aff97UL)
    II(c,d,a,b,W[14],15,0xab9423a7UL)
    II(b,c,d,a,W[5],21,0xfc93a039UL)
    II(a,b,c,d,W[12],6,0x655b59c3UL)
    II(d,a,b,c,W[3],10,0x8f0ccc92UL)
    II(c,d,a,b,W[10],15,0xffeff47dUL)
    II(b,c,d,a,W[1],21,0x85845dd1UL)
    II(a,b,c,d,W[8],6,0x6fa87e4fUL)
    II(d,a,b,c,W[15],10,0xfe2ce6e0UL)
    II(c,d,a,b,W[6],15,0xa3014314UL)
    II(b,c,d,a,W[13],21,0x4e0811a1UL)
    II(a,b,c,d,W[4],6,0xf7537e82UL)
    II(d,a,b,c,W[11],10,0xbd3af235UL)
    II(c,d,a,b,W[2],15,0x2ad7d2bbUL)
    II(b,c,d,a,W[9],21,0xeb86d391UL)
#endif

    md->md5.state[0] = md->md5.state[0] + a;
    md->md5.state[1] = md->md5.state[1] + b;
    md->md5.state[2] = md->md5.state[2] + c;
    md->md5.state[3] = md->md5.state[3] + d;

    return CRYPT_OK;
}

#ifdef LTC_CLEAN_STACK
static int md5_compress(hash_state *md, unsigned char *buf)
{
   int err;
   err = _md5_compress(md, buf);
   burn_stack(sizeof(ulong32) * 21);
   return err;
}
#endif

/**
   Initialize the hash state
   @param md   The hash state you wish to initialize
   @return CRYPT_OK if successful
*/
int md5_init(hash_state * md)
{
   LTC_ARGCHK(md != NULL);
   md->md5.state[0] = 0x67452301UL;
   md->md5.state[1] = 0xefcdab89UL;
   md->md5.state[2] = 0x98badcfeUL;
   md->md5.state[3] = 0x10325476UL;
   md->md5.curlen = 0;
   md->md5.length = 0;
   return CRYPT_OK;
}

/**
   Process a block of memory though the hash
   @param md     The hash state
   @param in     The data to hash
   @param inlen  The length of the data (octets)
   @return CRYPT_OK if successful
*/
HASH_PROCESS(md5_process, md5_compress, md5, 64)

/**
   Terminate the hash to get the digest
   @param md  The hash state
   @param out [out] The destination of the hash (16 bytes)
   @return CRYPT_OK if successful
*/
int md5_done(hash_state * md, unsigned char *out)
{
    int i;

    LTC_ARGCHK(md  != NULL);
    LTC_ARGCHK(out != NULL);

    if (md->md5.curlen >= sizeof(md->md5.buf)) {
       return CRYPT_INVALID_ARG;
    }


    /* increase the length of the message */
    md->md5.length += md->md5.curlen * 8;

    /* append the '1' bit */
    md->md5.buf[md->md5.curlen++] = (unsigned char)0x80;

    /* if the length is currently above 56 bytes we append zeros
     * then compress.  Then we can fall back to padding zeros and length
     * encoding like normal.
     */
    if (md->md5.curlen > 56) {
        while (md->md5.curlen < 64) {
            md->md5.buf[md->md5.curlen++] = (unsigned char)0;
        }
        md5_compress(md, md->md5.buf);
        md->md5.curlen = 0;
    }

    /* pad upto 56 bytes of zeroes */
    while (md->md5.curlen < 56) {
        md->md5.buf[md->md5.curlen++] = (unsigned char)0;
    }

    /* store length */
    STORE64L(md->md5.length, md->md5.buf+56);
    md5_compress(md, md->md5.buf);

    /* copy output */
    for (i = 0; i < 4; i++) {
        STORE32L(md->md5.state[i], out+(4*i));
    }
#ifdef LTC_CLEAN_STACK
    zeromem(md, sizeof(hash_state));
#endif
    return CRYPT_OK;
}

/**
  Self-test the hash
  @return CRYPT_OK if successful, CRYPT_NOP if self-tests have been disabled
*/
int  md5_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else
  static const struct {
      const char *msg;
      unsigned char hash[16];
  } tests[] = {
    { "",
      { 0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
        0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e } },
    { "a",
      {0x0c, 0xc1, 0x75, 0xb9, 0xc0, 0xf1, 0xb6, 0xa8,
       0x31, 0xc3, 0x99, 0xe2, 0x69, 0x77, 0x26, 0x61 } },
    { "abc",
      { 0x90, 0x01, 0x50, 0x98, 0x3c, 0xd2, 0x4f, 0xb0,
        0xd6, 0x96, 0x3f, 0x7d, 0x28, 0xe1, 0x7f, 0x72 } },
    { "message digest",
      { 0xf9, 0x6b, 0x69, 0x7d, 0x7c, 0xb7, 0x93, 0x8d,
        0x52, 0x5a, 0x2f, 0x31, 0xaa, 0xf1, 0x61, 0xd0 } },
    { "abcdefghijklmnopqrstuvwxyz",
      { 0xc3, 0xfc, 0xd3, 0xd7, 0x61, 0x92, 0xe4, 0x00,
        0x7d, 0xfb, 0x49, 0x6c, 0xca, 0x67, 0xe1, 0x3b } },
    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
      { 0xd1, 0x74, 0xab, 0x98, 0xd2, 0x77, 0xd9, 0xf5,
        0xa5, 0x61, 0x1c, 0x2c, 0x9f, 0x41, 0x9d, 0x9f } },
    { "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
      { 0x57, 0xed, 0xf4, 0xa2, 0x2b, 0xe3, 0xc9, 0x55,
        0xac, 0x49, 0xda, 0x2e, 0x21, 0x07, 0xb6, 0x7a } },
    { NULL, { 0 } }
  };

  int i;
  unsigned char tmp[16];
  hash_state md;

  for (i = 0; tests[i].msg != NULL; i++) {
      md5_init(&md);
      md5_process(&md, (unsigned char *)tests[i].msg, (unsigned long)strlen(tests[i].msg));
      md5_done(&md, tmp);
      if (compare_testvector(tmp, sizeof(tmp), tests[i].hash, sizeof(tests[i].hash), "MD5", i)) {
         return CRYPT_FAIL_TESTVECTOR;
      }
  }
  return CRYPT_OK;
 #endif
}

#endif



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