/* 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
 * gurantee it works.
 *
 * Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
 */
/* Submited by Dobes Vandermeer  (dobes@smartt.com) */

#include "mycrypt.h"

/*
    (1) append zeros to the end of K to create a B byte string
        (e.g., if K is of length 20 bytes and B=64, then K will be
         appended with 44 zero bytes 0x00)
    (2) XOR (bitwise exclusive-OR) the B byte string computed in step
        (1) with ipad (ipad = the byte 0x36 repeated B times)
    (3) append the stream of data 'text' to the B byte string resulting
        from step (2)
    (4) apply H to the stream generated in step (3)
    (5) XOR (bitwise exclusive-OR) the B byte string computed in
        step (1) with opad (opad = the byte 0x5C repeated B times.)
    (6) append the H result from step (4) to the B byte string
        resulting from step (5)
    (7) apply H to the stream generated in step (6) and output
        the result
*/

#ifdef HMAC

#define HMAC_BLOCKSIZE hash_descriptor[hash].blocksize

int hmac_init(hmac_state *hmac, int hash, const unsigned char *key, unsigned long keylen)
{
    unsigned char buf[MAXBLOCKSIZE];
    unsigned long hashsize;
    unsigned long i, z;
    int err;

    _ARGCHK(hmac != NULL);
    _ARGCHK(key != NULL);

    if ((err = hash_is_valid(hash)) != CRYPT_OK) {
        return err;
    }

    /* valid key length? */
    if (keylen == 0) {
        return CRYPT_INVALID_KEYSIZE;
    }

    hmac->hash = hash;

    // (1) make sure we have a large enough key
    hashsize = hash_descriptor[hash].hashsize;
    if(keylen > HMAC_BLOCKSIZE) {
        z = (unsigned long)sizeof(hmac->key);
        if ((err = hash_memory(hash, key, keylen, hmac->key, &z)) != CRYPT_OK) {
           return err;
        }
        if(hashsize < HMAC_BLOCKSIZE) {
            zeromem((hmac->key) + hashsize, (size_t)(HMAC_BLOCKSIZE - hashsize));
        }
        keylen = hashsize;
    } else {
        memcpy(hmac->key, key, (size_t)keylen);
        if(keylen < HMAC_BLOCKSIZE) {
            zeromem((hmac->key) + keylen, (size_t)(HMAC_BLOCKSIZE - keylen));
        }
    }

    // Create the initial vector for step (3)
    for(i=0; i < HMAC_BLOCKSIZE;   i++) {
       buf[i] = hmac->key[i] ^ 0x36;
    }

    // Pre-pend that to the hash data
    hash_descriptor[hash].init(&hmac->md);
    hash_descriptor[hash].process(&hmac->md, buf, HMAC_BLOCKSIZE);

    return CRYPT_OK;
}

int hmac_process(hmac_state *hmac, const unsigned char *buf, unsigned long len)
{
    int err;
    _ARGCHK(hmac != NULL);
    _ARGCHK(buf != NULL);
    if ((err = hash_is_valid(hmac->hash)) != CRYPT_OK) {
        return err;
    }
    return hash_descriptor[hmac->hash].process(&hmac->md, buf, len);
}

int hmac_done(hmac_state *hmac, unsigned char *hashOut, unsigned long *outlen)
{
    unsigned char buf[MAXBLOCKSIZE];
    unsigned char isha[MAXBLOCKSIZE];
    unsigned long hashsize, i;
    int hash, err;

    _ARGCHK(hmac != NULL);
    _ARGCHK(hashOut != NULL);

    hash = hmac->hash;
    if((err = hash_is_valid(hash)) != CRYPT_OK) {
        return err;
    }

    /* get the hash message digest size */
    hashsize = hash_descriptor[hash].hashsize;

    // Get the hash of the first HMAC vector plus the data
    if ((err = hash_descriptor[hash].done(&hmac->md, isha)) != CRYPT_OK) {
       return err;
    }

    // Create the second HMAC vector vector for step (3)
    for(i=0; i < HMAC_BLOCKSIZE; i++) {
        buf[i] = hmac->key[i] ^ 0x5C;
    }

    // Now calculate the "outer" hash for step (5), (6), and (7)
    hash_descriptor[hash].init(&hmac->md);
    hash_descriptor[hash].process(&hmac->md, buf, HMAC_BLOCKSIZE);
    hash_descriptor[hash].process(&hmac->md, isha, hashsize);
    hash_descriptor[hash].done(&hmac->md, buf);

    // copy to output 
    for (i = 0; i < hashsize && i < *outlen; i++) {
        hashOut[i] = buf[i];
    }
    *outlen = i;

#ifdef CLEAN_STACK
    zeromem(isha, sizeof(buf));
    zeromem(buf,  sizeof(isha));
    zeromem(hmac, sizeof(*hmac));
#endif
    return CRYPT_OK;
}

int hmac_memory(int hash, const unsigned char *key, unsigned long keylen,
                const unsigned char *data, unsigned long len, 
                unsigned char *dst, unsigned long *dstlen)
{
    hmac_state hmac;
    int err;

    _ARGCHK(key    != NULL);
    _ARGCHK(data   != NULL);
    _ARGCHK(dst    != NULL); 
    _ARGCHK(dstlen != NULL);
    
    if((err = hash_is_valid(hash)) != CRYPT_OK) {
        return err;
    }

    if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {
        return err;
    }

    if ((err = hmac_process(&hmac, data, len)) != CRYPT_OK) {
       return err;
    }

    if ((err = hmac_done(&hmac, dst, dstlen)) != CRYPT_OK) {
       return err;
    }
    return CRYPT_OK;
}

/* hmac_file added by Tom St Denis */
int hmac_file(int hash, const char *fname, 
              const unsigned char *key, unsigned long keylen, 
                    unsigned char *dst, unsigned long *dstlen)
{
#ifdef NO_FILE
    return CRYPT_NOP;
#else
   hmac_state hmac;
   FILE *in;
   unsigned char buf[512];
   size_t x;
   int err;

   _ARGCHK(fname  != NULL);
   _ARGCHK(key    != NULL);
   _ARGCHK(dst    != NULL);
   _ARGCHK(dstlen != NULL);
   
   if((err = hash_is_valid(hash)) != CRYPT_OK) {
       return err;
   }

   if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {
       return err;
   }

   in = fopen(fname, "rb");
   if (in == NULL) {
      return CRYPT_FILE_NOTFOUND;
   }

   /* process the file contents */
   do {
      x = fread(buf, 1, sizeof(buf), in);
      if ((err = hmac_process(&hmac, buf, (unsigned long)x)) != CRYPT_OK) {
         /* we don't trap this error since we're already returning an error! */
         fclose(in);
         return err;
      }
   } while (x == sizeof(buf));

   if (fclose(in) != 0) {
      return CRYPT_ERROR;
   }

   /* get final hmac */
   if ((err = hmac_done(&hmac, dst, dstlen)) != CRYPT_OK) {
      return err;
   }

#ifdef CLEAN_STACK
   /* clear memory */
   zeromem(buf, sizeof(buf));
#endif   
   return CRYPT_OK;
#endif
}

/*

    TEST CASES SOURCE:

Network Working Group                                          P. Cheng
Request for Comments: 2202                                          IBM
Category: Informational                                        R. Glenn
                                                                   NIST
                                                         September 1997

                 Test Cases for HMAC-MD5 and HMAC-SHA-1
*/


int hmac_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else    
    unsigned char digest[MAXBLOCKSIZE];
    int i;

    static const struct hmac_test_case {
        int num;
        char *algo;
        unsigned char key[128];
        unsigned long keylen;
        unsigned char data[128];
        unsigned long datalen;
        unsigned char digest[MAXBLOCKSIZE];
    } cases[] = {
        /*
        3. Test Cases for HMAC-SHA-1

        test_case =     1
        key =           0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b
        key_len =       20
        data =          "Hi Ther     20
        digest =        0x4c1a03424b55e07fe7f27be1d58bb9324a9a5a04
        digest-96 =     0x4c1a03424b55e07fe7f27be1
        */
        { 5, "sha1",
            {0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 
             0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 
             0x0c, 0x0c, 0x0c, 0x0c}, 20,
            "Test With Truncation", 20,
            {0x4c, 0x1a, 0x03, 0x42, 0x4b, 0x55, 0xe0, 0x7f, 0xe7, 0xf2,
             0x7b, 0xe1, 0xd5, 0x8b, 0xb9, 0x32, 0x4a, 0x9a, 0x5a, 0x04} },

        /*
        test_case =     6
        key =           0xaa repeated 80 times
        key_len =       80
        data =          "Test Using Larger Than Block-Size Key - Hash Key First"
        data_len =      54
        digest =        0xaa4ae5e15272d00e95705637ce8a3b55ed402112
        */
        { 6, "sha1",
            {0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}, 80,
            "Test Using Larger Than Block-Size Key - Hash Key First", 54,
            {0xaa, 0x4a, 0xe5, 0xe1, 0x52, 0x72, 0xd0, 0x0e,
             0x95, 0x70, 0x56, 0x37, 0xce, 0x8a, 0x3b, 0x55, 
             0xed, 0x40, 0x21, 0x12} },

        /*
        test_case =     7
        key =           0xaa repeated 80 times
        key_len =       80
        data =          "Test Using Larger Than Block-Size Key and Larger
                        Than One Block-Size Data"
        data_len =      73
        digest =        0xe8e99d0f45237d786d6bbaa7965c7808bbff1a91
        */
        { 7, "sha1",
            {0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}, 80,
            "Test Using Larger Than Block-Size Key and Larger Than One Block-Size Data", 73,
            {0xe8, 0xe9, 0x9d, 0x0f, 0x45, 0x23, 0x7d, 0x78, 0x6d,
             0x6b, 0xba, 0xa7, 0x96, 0x5c, 0x78, 0x08, 0xbb, 0xff, 0x1a, 0x91} },

        /*
        2. Test Cases for HMAC-MD5

        test_case =     1
        key =           0x0b 0b 0b 0b 
                          0b 0b 0b 0b
                          0b 0b 0b 0b
                          0b 0b 0b 0b
        key_len =       16
        data =          "Hi There"
        data_len =      8
        digest =        0x92 94 72 7a 
                          36 38 bb 1c 
                          13 f4 8e f8 
                          15 8b fc 9d
        */
        { 1, "md5",
            {0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 
             0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b}, 16,
            "Hi There", 8,
            {0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c, 
             0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d}  },
        /*
        test_case =     2
        key =           "Jefe"
        key_len =       4
        data =          "what do ya want for nothing?"
        data_len =      28
        digest =        0x750c783e6ab0b503eaa86e310a5db738
        */
        { 2, "md5",
            "Jefe", 4,
            "what do ya want for nothing?", 28,
            {0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03, 
             0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38} },

        /*
        test_case =     3
        key =           0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
        key_len         16
        data =          0xdd repeated 50 times
        data_len =      50
        digest =        0x56be34521d144c88dbb8c733f0e8b3f6
        */
        { 3, "md5",
            {0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}, 16,
            {0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd,
             0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd,
             0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd,
             0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd,
             0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd, 0xdd}, 50,
            {0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88,
             0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6} },
        /*

        test_case =     4
        key = 0x0102030405060708090a0b0c0d0e0f10111213141516171819
        key_len         25
        data =          0xcd repeated 50 times
        data_len =      50
        digest =        0x697eaf0aca3a3aea3a75164746ffaa79
        */
        { 4, "md5",
            {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a,
             0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14,
             0x15, 0x16, 0x17, 0x18, 0x19}, 25,
            {0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd,
             0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd,
             0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd,
             0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd,
             0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd, 0xcd}, 50,
            {0x69, 0x7e, 0xaf, 0x0a, 0xca, 0x3a, 0x3a, 0xea, 
             0x3a, 0x75, 0x16, 0x47, 0x46, 0xff, 0xaa, 0x79} },


        /*
 
        test_case =     5
        key =           0x0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c
        key_len =       16
        data =          "Test With Truncation"
        data_len =      20
        digest =        0x56461ef2342edc00f9bab995690efd4c
        digest-96       0x56461ef2342edc00f9bab995
        */
        { 5, "md5",
            {0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 
             0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c}, 16,
            "Test With Truncation", 20,
            {0x56, 0x46, 0x1e, 0xf2, 0x34, 0x2e, 0xdc, 0x00, 
             0xf9, 0xba, 0xb9, 0x95, 0x69, 0x0e, 0xfd, 0x4c} },

        /*

        test_case =     6
        key =           0xaa repeated 80 times
        key_len =       80
        data =          "Test Using Larger Than Block-Size Key - Hash 
Key First"
        data_len =      54
        digest =        0x6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd
        */
        { 6, "md5",
            {0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}, 80,
            "Test Using Larger Than Block-Size Key - Hash Key First", 54,
            {0x6b, 0x1a, 0xb7, 0xfe, 0x4b, 0xd7, 0xbf, 0x8f, 
             0x0b, 0x62, 0xe6, 0xce, 0x61, 0xb9, 0xd0, 0xcd} },

        /*

        test_case =     7
        key =           0xaa repeated 80 times
        key_len =       80
        data =          "Test Using Larger Than Block-Size Key and Larger
                        Than One Block-Size Data"
        data_len =      73
        digest =        0x6f630fad67cda0ee1fb1f562db3aa53e
        */
        { 7, "md5",
            {0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
             0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa}, 80,
            "Test Using Larger Than Block-Size Key and Larger Than One Block-Size Data", 73,
            {0x6f, 0x63, 0x0f, 0xad, 0x67, 0xcd, 0xa0, 0xee,
             0x1f, 0xb1, 0xf5, 0x62, 0xdb, 0x3a, 0xa5, 0x3e} }
    };

    unsigned long outlen;
    int err;
    int tested=0,failed=0;
    for(i=0; i < (int)(sizeof(cases) / sizeof(cases[0])); i++) {
        int hash = find_hash(cases[i].algo);
        if (hash == -1) continue;
        ++tested;
        outlen = sizeof(digest);
        if((err = hmac_memory(hash, cases[i].key, cases[i].keylen, cases[i].data, cases[i].datalen, digest, &outlen)) != CRYPT_OK) {
#if 0
            printf("HMAC-%s test #%d\n", cases[i].algo, cases[i].num);
#endif
            return err;
        }

        if(memcmp(digest, cases[i].digest, (size_t)hash_descriptor[hash].hashsize) != 0)  {
#if 0
            unsigned int j;
            printf("\nHMAC-%s test #%d:\n", cases[i].algo, cases[i].num);
            printf(  "Result:  0x");
            for(j=0; j < hash_descriptor[hash].hashsize; j++) {
                printf("%2x ", digest[j]);
            }
            printf("\nCorrect: 0x");
            for(j=0; j < hash_descriptor[hash].hashsize; j++) {
               printf("%2x ", cases[i].digest[j]);
            }
            printf("\n");
#endif
            failed++;
            //return CRYPT_ERROR;
        } else {
            /* printf("HMAC-%s test #%d: Passed\n", cases[i].algo, cases[i].num); */
        }
    }

    if (failed != 0) {
        return CRYPT_FAIL_TESTVECTOR;
    } else if (tested == 0) {
        return CRYPT_NOP;
    } else {
        return CRYPT_OK;
    }
 #endif
}

#endif